Merge branch 'akpm' (patches from Andrew)

Merge updates from Andrew Morton:

 - a few misc bits

 - ocfs2

 - most(?) of MM

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (125 commits)
  thp: fix comments of __pmd_trans_huge_lock()
  cgroup: remove unnecessary 0 check from css_from_id()
  cgroup: fix idr leak for the first cgroup root
  mm: memcontrol: fix documentation for compound parameter
  mm: memcontrol: remove BUG_ON in uncharge_list
  mm: fix build warnings in <linux/compaction.h>
  mm, thp: convert from optimistic swapin collapsing to conservative
  mm, thp: fix comment inconsistency for swapin readahead functions
  thp: update Documentation/{vm/transhuge,filesystems/proc}.txt
  shmem: split huge pages beyond i_size under memory pressure
  thp: introduce CONFIG_TRANSPARENT_HUGE_PAGECACHE
  khugepaged: add support of collapse for tmpfs/shmem pages
  shmem: make shmem_inode_info::lock irq-safe
  khugepaged: move up_read(mmap_sem) out of khugepaged_alloc_page()
  thp: extract khugepaged from mm/huge_memory.c
  shmem, thp: respect MADV_{NO,}HUGEPAGE for file mappings
  shmem: add huge pages support
  shmem: get_unmapped_area align huge page
  shmem: prepare huge= mount option and sysfs knob
  mm, rmap: account shmem thp pages
  ...

42 files changed, 5817 insertions, 3118 deletions

diff --git a/mm/Kconfig b/mm/Kconfig
index 3e2daef3c946..3c81803b00a3 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -440,6 +440,14 @@ choice
 endchoice
 
 #
+# We don't deposit page tables on file THP mapping,
+# but Power makes use of them to address MMU quirk.
+#
+config	TRANSPARENT_HUGE_PAGECACHE
+	def_bool y
+	depends on TRANSPARENT_HUGEPAGE && !PPC
+
+#
 # UP and nommu archs use km based percpu allocator
 #
 config NEED_PER_CPU_KM
diff --git a/mm/Makefile b/mm/Makefile
index 78c6f7dedb83..fc059666c760 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -74,7 +74,7 @@ obj-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o
 obj-$(CONFIG_MEMTEST)		+= memtest.o
 obj-$(CONFIG_MIGRATION) += migrate.o
 obj-$(CONFIG_QUICKLIST) += quicklist.o
-obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o
+obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o khugepaged.o
 obj-$(CONFIG_PAGE_COUNTER) += page_counter.o
 obj-$(CONFIG_MEMCG) += memcontrol.o vmpressure.o
 obj-$(CONFIG_MEMCG_SWAP) += swap_cgroup.o
diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c
index 57b3e9bd6bc5..da91df50ba31 100644
--- a/mm/balloon_compaction.c
+++ b/mm/balloon_compaction.c
@@ -70,7 +70,7 @@ struct page *balloon_page_dequeue(struct balloon_dev_info *b_dev_info)
 		 */
 		if (trylock_page(page)) {
 #ifdef CONFIG_BALLOON_COMPACTION
-			if (!PagePrivate(page)) {
+			if (PageIsolated(page)) {
 				/* raced with isolation */
 				unlock_page(page);
 				continue;
@@ -106,110 +106,50 @@ EXPORT_SYMBOL_GPL(balloon_page_dequeue);
 
 #ifdef CONFIG_BALLOON_COMPACTION
 
-static inline void __isolate_balloon_page(struct page *page)
+bool balloon_page_isolate(struct page *page, isolate_mode_t mode)
+
 {
 	struct balloon_dev_info *b_dev_info = balloon_page_device(page);
 	unsigned long flags;
 
 	spin_lock_irqsave(&b_dev_info->pages_lock, flags);
-	ClearPagePrivate(page);
 	list_del(&page->lru);
 	b_dev_info->isolated_pages++;
 	spin_unlock_irqrestore(&b_dev_info->pages_lock, flags);
+
+	return true;
 }
 
-static inline void __putback_balloon_page(struct page *page)
+void balloon_page_putback(struct page *page)
 {
 	struct balloon_dev_info *b_dev_info = balloon_page_device(page);
 	unsigned long flags;
 
 	spin_lock_irqsave(&b_dev_info->pages_lock, flags);
-	SetPagePrivate(page);
 	list_add(&page->lru, &b_dev_info->pages);
 	b_dev_info->isolated_pages--;
 	spin_unlock_irqrestore(&b_dev_info->pages_lock, flags);
 }
 
-/* __isolate_lru_page() counterpart for a ballooned page */
-bool balloon_page_isolate(struct page *page)
-{
-	/*
-	 * Avoid burning cycles with pages that are yet under __free_pages(),
-	 * or just got freed under us.
-	 *
-	 * In case we 'win' a race for a balloon page being freed under us and
-	 * raise its refcount preventing __free_pages() from doing its job
-	 * the put_page() at the end of this block will take care of
-	 * release this page, thus avoiding a nasty leakage.
-	 */
-	if (likely(get_page_unless_zero(page))) {
-		/*
-		 * As balloon pages are not isolated from LRU lists, concurrent
-		 * compaction threads can race against page migration functions
-		 * as well as race against the balloon driver releasing a page.
-		 *
-		 * In order to avoid having an already isolated balloon page
-		 * being (wrongly) re-isolated while it is under migration,
-		 * or to avoid attempting to isolate pages being released by
-		 * the balloon driver, lets be sure we have the page lock
-		 * before proceeding with the balloon page isolation steps.
-		 */
-		if (likely(trylock_page(page))) {
-			/*
-			 * A ballooned page, by default, has PagePrivate set.
-			 * Prevent concurrent compaction threads from isolating
-			 * an already isolated balloon page by clearing it.
-			 */
-			if (balloon_page_movable(page)) {
-				__isolate_balloon_page(page);
-				unlock_page(page);
-				return true;
-			}
-			unlock_page(page);
-		}
-		put_page(page);
-	}
-	return false;
-}
-
-/* putback_lru_page() counterpart for a ballooned page */
-void balloon_page_putback(struct page *page)
-{
-	/*
-	 * 'lock_page()' stabilizes the page and prevents races against
-	 * concurrent isolation threads attempting to re-isolate it.
-	 */
-	lock_page(page);
-
-	if (__is_movable_balloon_page(page)) {
-		__putback_balloon_page(page);
-		/* drop the extra ref count taken for page isolation */
-		put_page(page);
-	} else {
-		WARN_ON(1);
-		dump_page(page, "not movable balloon page");
-	}
-	unlock_page(page);
-}
 
 /* move_to_new_page() counterpart for a ballooned page */
-int balloon_page_migrate(struct page *newpage,
-			 struct page *page, enum migrate_mode mode)
+int balloon_page_migrate(struct address_space *mapping,
+		struct page *newpage, struct page *page,
+		enum migrate_mode mode)
 {
 	struct balloon_dev_info *balloon = balloon_page_device(page);
-	int rc = -EAGAIN;
 
 	VM_BUG_ON_PAGE(!PageLocked(page), page);
 	VM_BUG_ON_PAGE(!PageLocked(newpage), newpage);
 
-	if (WARN_ON(!__is_movable_balloon_page(page))) {
-		dump_page(page, "not movable balloon page");
-		return rc;
-	}
+	return balloon->migratepage(balloon, newpage, page, mode);
+}
 
-	if (balloon && balloon->migratepage)
-		rc = balloon->migratepage(balloon, newpage, page, mode);
+const struct address_space_operations balloon_aops = {
+	.migratepage = balloon_page_migrate,
+	.isolate_page = balloon_page_isolate,
+	.putback_page = balloon_page_putback,
+};
+EXPORT_SYMBOL_GPL(balloon_aops);
 
-	return rc;
-}
 #endif /* CONFIG_BALLOON_COMPACTION */
diff --git a/mm/compaction.c b/mm/compaction.c
index 7bc04778f84d..64df5fe052db 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -15,11 +15,11 @@
 #include <linux/backing-dev.h>
 #include <linux/sysctl.h>
 #include <linux/sysfs.h>
-#include <linux/balloon_compaction.h>
 #include <linux/page-isolation.h>
 #include <linux/kasan.h>
 #include <linux/kthread.h>
 #include <linux/freezer.h>
+#include <linux/page_owner.h>
 #include "internal.h"
 
 #ifdef CONFIG_COMPACTION
@@ -65,13 +65,27 @@ static unsigned long release_freepages(struct list_head *freelist)
 
 static void map_pages(struct list_head *list)
 {
-	struct page *page;
+	unsigned int i, order, nr_pages;
+	struct page *page, *next;
+	LIST_HEAD(tmp_list);
+
+	list_for_each_entry_safe(page, next, list, lru) {
+		list_del(&page->lru);
 
-	list_for_each_entry(page, list, lru) {
-		arch_alloc_page(page, 0);
-		kernel_map_pages(page, 1, 1);
-		kasan_alloc_pages(page, 0);
+		order = page_private(page);
+		nr_pages = 1 << order;
+
+		post_alloc_hook(page, order, __GFP_MOVABLE);
+		if (order)
+			split_page(page, order);
+
+		for (i = 0; i < nr_pages; i++) {
+			list_add(&page->lru, &tmp_list);
+			page++;
+		}
 	}
+
+	list_splice(&tmp_list, list);
 }
 
 static inline bool migrate_async_suitable(int migratetype)
@@ -81,6 +95,44 @@ static inline bool migrate_async_suitable(int migratetype)
 
 #ifdef CONFIG_COMPACTION
 
+int PageMovable(struct page *page)
+{
+	struct address_space *mapping;
+
+	VM_BUG_ON_PAGE(!PageLocked(page), page);
+	if (!__PageMovable(page))
+		return 0;
+
+	mapping = page_mapping(page);
+	if (mapping && mapping->a_ops && mapping->a_ops->isolate_page)
+		return 1;
+
+	return 0;
+}
+EXPORT_SYMBOL(PageMovable);
+
+void __SetPageMovable(struct page *page, struct address_space *mapping)
+{
+	VM_BUG_ON_PAGE(!PageLocked(page), page);
+	VM_BUG_ON_PAGE((unsigned long)mapping & PAGE_MAPPING_MOVABLE, page);
+	page->mapping = (void *)((unsigned long)mapping | PAGE_MAPPING_MOVABLE);
+}
+EXPORT_SYMBOL(__SetPageMovable);
+
+void __ClearPageMovable(struct page *page)
+{
+	VM_BUG_ON_PAGE(!PageLocked(page), page);
+	VM_BUG_ON_PAGE(!PageMovable(page), page);
+	/*
+	 * Clear registered address_space val with keeping PAGE_MAPPING_MOVABLE
+	 * flag so that VM can catch up released page by driver after isolation.
+	 * With it, VM migration doesn't try to put it back.
+	 */
+	page->mapping = (void *)((unsigned long)page->mapping &
+				PAGE_MAPPING_MOVABLE);
+}
+EXPORT_SYMBOL(__ClearPageMovable);
+
 /* Do not skip compaction more than 64 times */
 #define COMPACT_MAX_DEFER_SHIFT 6
 
@@ -368,12 +420,13 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
 	unsigned long flags = 0;
 	bool locked = false;
 	unsigned long blockpfn = *start_pfn;
+	unsigned int order;
 
 	cursor = pfn_to_page(blockpfn);
 
 	/* Isolate free pages. */
 	for (; blockpfn < end_pfn; blockpfn++, cursor++) {
-		int isolated, i;
+		int isolated;
 		struct page *page = cursor;
 
 		/*
@@ -439,17 +492,17 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
 				goto isolate_fail;
 		}
 
-		/* Found a free page, break it into order-0 pages */
-		isolated = split_free_page(page);
+		/* Found a free page, will break it into order-0 pages */
+		order = page_order(page);
+		isolated = __isolate_free_page(page, order);
 		if (!isolated)
 			break;
+		set_page_private(page, order);
 
 		total_isolated += isolated;
 		cc->nr_freepages += isolated;
-		for (i = 0; i < isolated; i++) {
-			list_add(&page->lru, freelist);
-			page++;
-		}
+		list_add_tail(&page->lru, freelist);
+
 		if (!strict && cc->nr_migratepages <= cc->nr_freepages) {
 			blockpfn += isolated;
 			break;
@@ -568,7 +621,7 @@ isolate_freepages_range(struct compact_control *cc,
 		 */
 	}
 
-	/* split_free_page does not map the pages */
+	/* __isolate_free_page() does not map the pages */
 	map_pages(&freelist);
 
 	if (pfn < end_pfn) {
@@ -670,7 +723,6 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 
 	/* Time to isolate some pages for migration */
 	for (; low_pfn < end_pfn; low_pfn++) {
-		bool is_lru;
 
 		if (skip_on_failure && low_pfn >= next_skip_pfn) {
 			/*
@@ -733,21 +785,6 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 		}
 
 		/*
-		 * Check may be lockless but that's ok as we recheck later.
-		 * It's possible to migrate LRU pages and balloon pages
-		 * Skip any other type of page
-		 */
-		is_lru = PageLRU(page);
-		if (!is_lru) {
-			if (unlikely(balloon_page_movable(page))) {
-				if (balloon_page_isolate(page)) {
-					/* Successfully isolated */
-					goto isolate_success;
-				}
-			}
-		}
-
-		/*
 		 * Regardless of being on LRU, compound pages such as THP and
 		 * hugetlbfs are not to be compacted. We can potentially save
 		 * a lot of iterations if we skip them at once. The check is
@@ -763,8 +800,30 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 			goto isolate_fail;
 		}
 
-		if (!is_lru)
+		/*
+		 * Check may be lockless but that's ok as we recheck later.
+		 * It's possible to migrate LRU and non-lru movable pages.
+		 * Skip any other type of page
+		 */
+		if (!PageLRU(page)) {
+			/*
+			 * __PageMovable can return false positive so we need
+			 * to verify it under page_lock.
+			 */
+			if (unlikely(__PageMovable(page)) &&
+					!PageIsolated(page)) {
+				if (locked) {
+					spin_unlock_irqrestore(&zone->lru_lock,
+									flags);
+					locked = false;
+				}
+
+				if (isolate_movable_page(page, isolate_mode))
+					goto isolate_success;
+			}
+
 			goto isolate_fail;
+		}
 
 		/*
 		 * Migration will fail if an anonymous page is pinned in memory,
@@ -1059,7 +1118,7 @@ static void isolate_freepages(struct compact_control *cc)
 		}
 	}
 
-	/* split_free_page does not map the pages */
+	/* __isolate_free_page() does not map the pages */
 	map_pages(freelist);
 
 	/*
diff --git a/mm/filemap.c b/mm/filemap.c
index 20f3b1f33f0e..e90c1543ec2d 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -114,14 +114,14 @@ static void page_cache_tree_delete(struct address_space *mapping,
 				   struct page *page, void *shadow)
 {
 	struct radix_tree_node *node;
+	int i, nr = PageHuge(page) ? 1 : hpage_nr_pages(page);
 
-	VM_BUG_ON(!PageLocked(page));
-
-	node = radix_tree_replace_clear_tags(&mapping->page_tree, page->index,
-								shadow);
+	VM_BUG_ON_PAGE(!PageLocked(page), page);
+	VM_BUG_ON_PAGE(PageTail(page), page);
+	VM_BUG_ON_PAGE(nr != 1 && shadow, page);
 
 	if (shadow) {
-		mapping->nrexceptional++;
+		mapping->nrexceptional += nr;
 		/*
 		 * Make sure the nrexceptional update is committed before
 		 * the nrpages update so that final truncate racing
@@ -130,31 +130,38 @@ static void page_cache_tree_delete(struct address_space *mapping,
 		 */
 		smp_wmb();
 	}
-	mapping->nrpages--;
+	mapping->nrpages -= nr;
 
-	if (!node)
-		return;
-
-	workingset_node_pages_dec(node);
-	if (shadow)
-		workingset_node_shadows_inc(node);
-	else
-		if (__radix_tree_delete_node(&mapping->page_tree, node))
+	for (i = 0; i < nr; i++) {
+		node = radix_tree_replace_clear_tags(&mapping->page_tree,
+				page->index + i, shadow);
+		if (!node) {
+			VM_BUG_ON_PAGE(nr != 1, page);
 			return;
+		}
 
-	/*
-	 * Track node that only contains shadow entries. DAX mappings contain
-	 * no shadow entries and may contain other exceptional entries so skip
-	 * those.
-	 *
-	 * Avoid acquiring the list_lru lock if already tracked.  The
-	 * list_empty() test is safe as node->private_list is
-	 * protected by mapping->tree_lock.
-	 */
-	if (!dax_mapping(mapping) && !workingset_node_pages(node) &&
-	    list_empty(&node->private_list)) {
-		node->private_data = mapping;
-		list_lru_add(&workingset_shadow_nodes, &node->private_list);
+		workingset_node_pages_dec(node);
+		if (shadow)
+			workingset_node_shadows_inc(node);
+		else
+			if (__radix_tree_delete_node(&mapping->page_tree, node))
+				continue;
+
+		/*
+		 * Track node that only contains shadow entries. DAX mappings
+		 * contain no shadow entries and may contain other exceptional
+		 * entries so skip those.
+		 *
+		 * Avoid acquiring the list_lru lock if already tracked.
+		 * The list_empty() test is safe as node->private_list is
+		 * protected by mapping->tree_lock.
+		 */
+		if (!dax_mapping(mapping) && !workingset_node_pages(node) &&
+				list_empty(&node->private_list)) {
+			node->private_data = mapping;
+			list_lru_add(&workingset_shadow_nodes,
+					&node->private_list);
+		}
 	}
 }
 
@@ -166,6 +173,7 @@ static void page_cache_tree_delete(struct address_space *mapping,
 void __delete_from_page_cache(struct page *page, void *shadow)
 {
 	struct address_space *mapping = page->mapping;
+	int nr = hpage_nr_pages(page);
 
 	trace_mm_filemap_delete_from_page_cache(page);
 	/*
@@ -178,6 +186,7 @@ void __delete_from_page_cache(struct page *page, void *shadow)
 	else
 		cleancache_invalidate_page(mapping, page);
 
+	VM_BUG_ON_PAGE(PageTail(page), page);
 	VM_BUG_ON_PAGE(page_mapped(page), page);
 	if (!IS_ENABLED(CONFIG_DEBUG_VM) && unlikely(page_mapped(page))) {
 		int mapcount;
@@ -209,9 +218,14 @@ void __delete_from_page_cache(struct page *page, void *shadow)
 
 	/* hugetlb pages do not participate in page cache accounting. */
 	if (!PageHuge(page))
-		__dec_zone_page_state(page, NR_FILE_PAGES);
-	if (PageSwapBacked(page))
-		__dec_zone_page_state(page, NR_SHMEM);
+		__mod_zone_page_state(page_zone(page), NR_FILE_PAGES, -nr);
+	if (PageSwapBacked(page)) {
+		__mod_zone_page_state(page_zone(page), NR_SHMEM, -nr);
+		if (PageTransHuge(page))
+			__dec_zone_page_state(page, NR_SHMEM_THPS);
+	} else {
+		VM_BUG_ON_PAGE(PageTransHuge(page) && !PageHuge(page), page);
+	}
 
 	/*
 	 * At this point page must be either written or cleaned by truncate.
@@ -235,9 +249,8 @@ void __delete_from_page_cache(struct page *page, void *shadow)
  */
 void delete_from_page_cache(struct page *page)
 {
-	struct address_space *mapping = page->mapping;
+	struct address_space *mapping = page_mapping(page);
 	unsigned long flags;
-
 	void (*freepage)(struct page *);
 
 	BUG_ON(!PageLocked(page));
@@ -250,7 +263,13 @@ void delete_from_page_cache(struct page *page)
 
 	if (freepage)
 		freepage(page);
-	put_page(page);
+
+	if (PageTransHuge(page) && !PageHuge(page)) {
+		page_ref_sub(page, HPAGE_PMD_NR);
+		VM_BUG_ON_PAGE(page_count(page) <= 0, page);
+	} else {
+		put_page(page);
+	}
 }
 EXPORT_SYMBOL(delete_from_page_cache);
 
@@ -1053,7 +1072,7 @@ EXPORT_SYMBOL(page_cache_prev_hole);
 struct page *find_get_entry(struct address_space *mapping, pgoff_t offset)
 {
 	void **pagep;
-	struct page *page;
+	struct page *head, *page;
 
 	rcu_read_lock();
 repeat:
@@ -1073,16 +1092,24 @@ repeat:
 			 */
 			goto out;
 		}
-		if (!page_cache_get_speculative(page))
+
+		head = compound_head(page);
+		if (!page_cache_get_speculative(head))
 			goto repeat;
 
+		/* The page was split under us? */
+		if (compound_head(page) != head) {
+			put_page(head);
+			goto repeat;
+		}
+
 		/*
 		 * Has the page moved?
 		 * This is part of the lockless pagecache protocol. See
 		 * include/linux/pagemap.h for details.
 		 */
 		if (unlikely(page != *pagep)) {
-			put_page(page);
+			put_page(head);
 			goto repeat;
 		}
 	}
@@ -1118,12 +1145,12 @@ repeat:
 	if (page && !radix_tree_exception(page)) {
 		lock_page(page);
 		/* Has the page been truncated? */
-		if (unlikely(page->mapping != mapping)) {
+		if (unlikely(page_mapping(page) != mapping)) {
 			unlock_page(page);
 			put_page(page);
 			goto repeat;
 		}
-		VM_BUG_ON_PAGE(page->index != offset, page);
+		VM_BUG_ON_PAGE(page_to_pgoff(page) != offset, page);
 	}
 	return page;
 }
@@ -1255,7 +1282,7 @@ unsigned find_get_entries(struct address_space *mapping,
 
 	rcu_read_lock();
 	radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) {
-		struct page *page;
+		struct page *head, *page;
 repeat:
 		page = radix_tree_deref_slot(slot);
 		if (unlikely(!page))
@@ -1272,12 +1299,20 @@ repeat:
 			 */
 			goto export;
 		}
-		if (!page_cache_get_speculative(page))
+
+		head = compound_head(page);
+		if (!page_cache_get_speculative(head))
 			goto repeat;
 
+		/* The page was split under us? */
+		if (compound_head(page) != head) {
+			put_page(head);
+			goto repeat;
+		}
+
 		/* Has the page moved? */
 		if (unlikely(page != *slot)) {
-			put_page(page);
+			put_page(head);
 			goto repeat;
 		}
 export:
@@ -1318,7 +1353,7 @@ unsigned find_get_pages(struct address_space *mapping, pgoff_t start,
 
 	rcu_read_lock();
 	radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) {
-		struct page *page;
+		struct page *head, *page;
 repeat:
 		page = radix_tree_deref_slot(slot);
 		if (unlikely(!page))
@@ -1337,12 +1372,19 @@ repeat:
 			continue;
 		}
 
-		if (!page_cache_get_speculative(page))
+		head = compound_head(page);
+		if (!page_cache_get_speculative(head))
 			goto repeat;
 
+		/* The page was split under us? */
+		if (compound_head(page) != head) {
+			put_page(head);
+			goto repeat;
+		}
+
 		/* Has the page moved? */
 		if (unlikely(page != *slot)) {
-			put_page(page);
+			put_page(head);
 			goto repeat;
 		}
 
@@ -1379,7 +1421,7 @@ unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index,
 
 	rcu_read_lock();
 	radix_tree_for_each_contig(slot, &mapping->page_tree, &iter, index) {
-		struct page *page;
+		struct page *head, *page;
 repeat:
 		page = radix_tree_deref_slot(slot);
 		/* The hole, there no reason to continue */
@@ -1399,12 +1441,19 @@ repeat:
 			break;
 		}
 
-		if (!page_cache_get_speculative(page))
+		head = compound_head(page);
+		if (!page_cache_get_speculative(head))
 			goto repeat;
 
+		/* The page was split under us? */
+		if (compound_head(page) != head) {
+			put_page(head);
+			goto repeat;
+		}
+
 		/* Has the page moved? */
 		if (unlikely(page != *slot)) {
-			put_page(page);
+			put_page(head);
 			goto repeat;
 		}
 
@@ -1413,7 +1462,7 @@ repeat:
 		 * otherwise we can get both false positives and false
 		 * negatives, which is just confusing to the caller.
 		 */
-		if (page->mapping == NULL || page->index != iter.index) {
+		if (page->mapping == NULL || page_to_pgoff(page) != iter.index) {
 			put_page(page);
 			break;
 		}
@@ -1451,7 +1500,7 @@ unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index,
 	rcu_read_lock();
 	radix_tree_for_each_tagged(slot, &mapping->page_tree,
 				   &iter, *index, tag) {
-		struct page *page;
+		struct page *head, *page;
 repeat:
 		page = radix_tree_deref_slot(slot);
 		if (unlikely(!page))
@@ -1476,12 +1525,19 @@ repeat:
 			continue;
 		}
 
-		if (!page_cache_get_speculative(page))
+		head = compound_head(page);
+		if (!page_cache_get_speculative(head))
 			goto repeat;
 
+		/* The page was split under us? */
+		if (compound_head(page) != head) {
+			put_page(head);
+			goto repeat;
+		}
+
 		/* Has the page moved? */
 		if (unlikely(page != *slot)) {
-			put_page(page);
+			put_page(head);
 			goto repeat;
 		}
 
@@ -1525,7 +1581,7 @@ unsigned find_get_entries_tag(struct address_space *mapping, pgoff_t start,
 	rcu_read_lock();
 	radix_tree_for_each_tagged(slot, &mapping->page_tree,
 				   &iter, start, tag) {
-		struct page *page;
+		struct page *head, *page;
 repeat:
 		page = radix_tree_deref_slot(slot);
 		if (unlikely(!page))
@@ -1543,12 +1599,20 @@ repeat:
 			 */
 			goto export;
 		}
-		if (!page_cache_get_speculative(page))
+
+		head = compound_head(page);
+		if (!page_cache_get_speculative(head))
 			goto repeat;
 
+		/* The page was split under us? */
+		if (compound_head(page) != head) {
+			put_page(head);
+			goto repeat;
+		}
+
 		/* Has the page moved? */
 		if (unlikely(page != *slot)) {
-			put_page(page);
+			put_page(head);
 			goto repeat;
 		}
 export:
@@ -2128,21 +2192,21 @@ page_not_uptodate:
 }
 EXPORT_SYMBOL(filemap_fault);
 
-void filemap_map_pages(struct vm_area_struct *vma, struct vm_fault *vmf)
+void filemap_map_pages(struct fault_env *fe,
+		pgoff_t start_pgoff, pgoff_t end_pgoff)
 {
 	struct radix_tree_iter iter;
 	void **slot;
-	struct file *file = vma->vm_file;
+	struct file *file = fe->vma->vm_file;
 	struct address_space *mapping = file->f_mapping;
+	pgoff_t last_pgoff = start_pgoff;
 	loff_t size;
-	struct page *page;
-	unsigned long address = (unsigned long) vmf->virtual_address;
-	unsigned long addr;
-	pte_t *pte;
+	struct page *head, *page;
 
 	rcu_read_lock();
-	radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, vmf->pgoff) {
-		if (iter.index > vmf->max_pgoff)
+	radix_tree_for_each_slot(slot, &mapping->page_tree, &iter,
+			start_pgoff) {
+		if (iter.index > end_pgoff)
 			break;
 repeat:
 		page = radix_tree_deref_slot(slot);
@@ -2156,12 +2220,19 @@ repeat:
 			goto next;
 		}
 
-		if (!page_cache_get_speculative(page))
+		head = compound_head(page);
+		if (!page_cache_get_speculative(head))
 			goto repeat;
 
+		/* The page was split under us? */
+		if (compound_head(page) != head) {
+			put_page(head);
+			goto repeat;
+		}
+
 		/* Has the page moved? */
 		if (unlikely(page != *slot)) {
-			put_page(page);
+			put_page(head);
 			goto repeat;
 		}
 
@@ -2179,14 +2250,15 @@ repeat:
 		if (page->index >= size >> PAGE_SHIFT)
 			goto unlock;
 
-		pte = vmf->pte + page->index - vmf->pgoff;
-		if (!pte_none(*pte))
-			goto unlock;
-
 		if (file->f_ra.mmap_miss > 0)
 			file->f_ra.mmap_miss--;
-		addr = address + (page->index - vmf->pgoff) * PAGE_SIZE;
-		do_set_pte(vma, addr, page, pte, false, false);
+
+		fe->address += (iter.index - last_pgoff) << PAGE_SHIFT;
+		if (fe->pte)
+			fe->pte += iter.index - last_pgoff;
+		last_pgoff = iter.index;
+		if (alloc_set_pte(fe, NULL, page))
+			goto unlock;
 		unlock_page(page);
 		goto next;
 unlock:
@@ -2194,7 +2266,10 @@ unlock:
 skip:
 		put_page(page);
 next:
-		if (iter.index == vmf->max_pgoff)
+		/* Huge page is mapped? No need to proceed. */
+		if (pmd_trans_huge(*fe->pmd))
+			break;
+		if (iter.index == end_pgoff)
 			break;
 	}
 	rcu_read_unlock();
diff --git a/mm/frontswap.c b/mm/frontswap.c
index 27a9924caf61..fec8b5044040 100644
--- a/mm/frontswap.c
+++ b/mm/frontswap.c
@@ -20,6 +20,8 @@
 #include <linux/frontswap.h>
 #include <linux/swapfile.h>
 
+DEFINE_STATIC_KEY_FALSE(frontswap_enabled_key);
+
 /*
  * frontswap_ops are added by frontswap_register_ops, and provide the
  * frontswap "backend" implementation functions.  Multiple implementations
@@ -139,6 +141,8 @@ void frontswap_register_ops(struct frontswap_ops *ops)
 		ops->next = frontswap_ops;
 	} while (cmpxchg(&frontswap_ops, ops->next, ops) != ops->next);
 
+	static_branch_inc(&frontswap_enabled_key);
+
 	spin_lock(&swap_lock);
 	plist_for_each_entry(si, &swap_active_head, list) {
 		if (si->frontswap_map)
@@ -189,7 +193,7 @@ void __frontswap_init(unsigned type, unsigned long *map)
 	struct swap_info_struct *sis = swap_info[type];
 	struct frontswap_ops *ops;
 
-	BUG_ON(sis == NULL);
+	VM_BUG_ON(sis == NULL);
 
 	/*
 	 * p->frontswap is a bitmap that we MUST have to figure out which page
@@ -248,15 +252,9 @@ int __frontswap_store(struct page *page)
 	pgoff_t offset = swp_offset(entry);
 	struct frontswap_ops *ops;
 
-	/*
-	 * Return if no backend registed.
-	 * Don't need to inc frontswap_failed_stores here.
-	 */
-	if (!frontswap_ops)
-		return -1;
-
-	BUG_ON(!PageLocked(page));
-	BUG_ON(sis == NULL);
+	VM_BUG_ON(!frontswap_ops);
+	VM_BUG_ON(!PageLocked(page));
+	VM_BUG_ON(sis == NULL);
 
 	/*
 	 * If a dup, we must remove the old page first; we can't leave the
@@ -303,11 +301,10 @@ int __frontswap_load(struct page *page)
 	pgoff_t offset = swp_offset(entry);
 	struct frontswap_ops *ops;
 
-	if (!frontswap_ops)
-		return -1;
+	VM_BUG_ON(!frontswap_ops);
+	VM_BUG_ON(!PageLocked(page));
+	VM_BUG_ON(sis == NULL);
 
-	BUG_ON(!PageLocked(page));
-	BUG_ON(sis == NULL);
 	if (!__frontswap_test(sis, offset))
 		return -1;
 
@@ -337,10 +334,9 @@ void __frontswap_invalidate_page(unsigned type, pgoff_t offset)
 	struct swap_info_struct *sis = swap_info[type];
 	struct frontswap_ops *ops;
 
-	if (!frontswap_ops)
-		return;
+	VM_BUG_ON(!frontswap_ops);
+	VM_BUG_ON(sis == NULL);
 
-	BUG_ON(sis == NULL);
 	if (!__frontswap_test(sis, offset))
 		return;
 
@@ -360,10 +356,9 @@ void __frontswap_invalidate_area(unsigned type)
 	struct swap_info_struct *sis = swap_info[type];
 	struct frontswap_ops *ops;
 
-	if (!frontswap_ops)
-		return;
+	VM_BUG_ON(!frontswap_ops);
+	VM_BUG_ON(sis == NULL);
 
-	BUG_ON(sis == NULL);
 	if (sis->frontswap_map == NULL)
 		return;
 
diff --git a/mm/gup.c b/mm/gup.c
index c057784c8444..547741f5f7a7 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -279,6 +279,8 @@ struct page *follow_page_mask(struct vm_area_struct *vma,
 			spin_unlock(ptl);
 			ret = 0;
 			split_huge_pmd(vma, pmd, address);
+			if (pmd_trans_unstable(pmd))
+				ret = -EBUSY;
 		} else {
 			get_page(page);
 			spin_unlock(ptl);
@@ -286,6 +288,8 @@ struct page *follow_page_mask(struct vm_area_struct *vma,
 			ret = split_huge_page(page);
 			unlock_page(page);
 			put_page(page);
+			if (pmd_none(*pmd))
+				return no_page_table(vma, flags);
 		}
 
 		return ret ? ERR_PTR(ret) :
@@ -350,7 +354,6 @@ unmap:
 static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma,
 		unsigned long address, unsigned int *flags, int *nonblocking)
 {
-	struct mm_struct *mm = vma->vm_mm;
 	unsigned int fault_flags = 0;
 	int ret;
 
@@ -375,7 +378,7 @@ static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma,
 		fault_flags |= FAULT_FLAG_TRIED;
 	}
 
-	ret = handle_mm_fault(mm, vma, address, fault_flags);
+	ret = handle_mm_fault(vma, address, fault_flags);
 	if (ret & VM_FAULT_ERROR) {
 		if (ret & VM_FAULT_OOM)
 			return -ENOMEM;
@@ -690,7 +693,7 @@ retry:
 	if (!vma_permits_fault(vma, fault_flags))
 		return -EFAULT;
 
-	ret = handle_mm_fault(mm, vma, address, fault_flags);
+	ret = handle_mm_fault(vma, address, fault_flags);
 	major |= ret & VM_FAULT_MAJOR;
 	if (ret & VM_FAULT_ERROR) {
 		if (ret & VM_FAULT_OOM)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 343a2b7e57aa..3647334c2ef9 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -18,7 +18,6 @@
 #include <linux/mm_inline.h>
 #include <linux/swapops.h>
 #include <linux/dax.h>
-#include <linux/kthread.h>
 #include <linux/khugepaged.h>
 #include <linux/freezer.h>
 #include <linux/pfn_t.h>
@@ -30,39 +29,12 @@
 #include <linux/hashtable.h>
 #include <linux/userfaultfd_k.h>
 #include <linux/page_idle.h>
+#include <linux/shmem_fs.h>
 
 #include <asm/tlb.h>
 #include <asm/pgalloc.h>
 #include "internal.h"
 
-enum scan_result {
-	SCAN_FAIL,
-	SCAN_SUCCEED,
-	SCAN_PMD_NULL,
-	SCAN_EXCEED_NONE_PTE,
-	SCAN_PTE_NON_PRESENT,
-	SCAN_PAGE_RO,
-	SCAN_NO_REFERENCED_PAGE,
-	SCAN_PAGE_NULL,
-	SCAN_SCAN_ABORT,
-	SCAN_PAGE_COUNT,
-	SCAN_PAGE_LRU,
-	SCAN_PAGE_LOCK,
-	SCAN_PAGE_ANON,
-	SCAN_PAGE_COMPOUND,
-	SCAN_ANY_PROCESS,
-	SCAN_VMA_NULL,
-	SCAN_VMA_CHECK,
-	SCAN_ADDRESS_RANGE,
-	SCAN_SWAP_CACHE_PAGE,
-	SCAN_DEL_PAGE_LRU,
-	SCAN_ALLOC_HUGE_PAGE_FAIL,
-	SCAN_CGROUP_CHARGE_FAIL
-};
-
-#define CREATE_TRACE_POINTS
-#include <trace/events/huge_memory.h>
-
 /*
  * By default transparent hugepage support is disabled in order that avoid
  * to risk increase the memory footprint of applications without a guaranteed
@@ -82,127 +54,8 @@ unsigned long transparent_hugepage_flags __read_mostly =
 	(1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)|
 	(1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
 
-/* default scan 8*512 pte (or vmas) every 30 second */
-static unsigned int khugepaged_pages_to_scan __read_mostly;
-static unsigned int khugepaged_pages_collapsed;
-static unsigned int khugepaged_full_scans;
-static unsigned int khugepaged_scan_sleep_millisecs __read_mostly = 10000;
-/* during fragmentation poll the hugepage allocator once every minute */
-static unsigned int khugepaged_alloc_sleep_millisecs __read_mostly = 60000;
-static unsigned long khugepaged_sleep_expire;
-static struct task_struct *khugepaged_thread __read_mostly;
-static DEFINE_MUTEX(khugepaged_mutex);
-static DEFINE_SPINLOCK(khugepaged_mm_lock);
-static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait);
-/*
- * default collapse hugepages if there is at least one pte mapped like
- * it would have happened if the vma was large enough during page
- * fault.
- */
-static unsigned int khugepaged_max_ptes_none __read_mostly;
-
-static int khugepaged(void *none);
-static int khugepaged_slab_init(void);
-static void khugepaged_slab_exit(void);
-
-#define MM_SLOTS_HASH_BITS 10
-static __read_mostly DEFINE_HASHTABLE(mm_slots_hash, MM_SLOTS_HASH_BITS);
-
-static struct kmem_cache *mm_slot_cache __read_mostly;
-
-/**
- * struct mm_slot - hash lookup from mm to mm_slot
- * @hash: hash collision list
- * @mm_node: khugepaged scan list headed in khugepaged_scan.mm_head
- * @mm: the mm that this information is valid for
- */
-struct mm_slot {
-	struct hlist_node hash;
-	struct list_head mm_node;
-	struct mm_struct *mm;
-};
-
-/**
- * struct khugepaged_scan - cursor for scanning
- * @mm_head: the head of the mm list to scan
- * @mm_slot: the current mm_slot we are scanning
- * @address: the next address inside that to be scanned
- *
- * There is only the one khugepaged_scan instance of this cursor structure.
- */
-struct khugepaged_scan {
-	struct list_head mm_head;
-	struct mm_slot *mm_slot;
-	unsigned long address;
-};
-static struct khugepaged_scan khugepaged_scan = {
-	.mm_head = LIST_HEAD_INIT(khugepaged_scan.mm_head),
-};
-
 static struct shrinker deferred_split_shrinker;
 
-static void set_recommended_min_free_kbytes(void)
-{
-	struct zone *zone;
-	int nr_zones = 0;
-	unsigned long recommended_min;
-
-	for_each_populated_zone(zone)
-		nr_zones++;
-
-	/* Ensure 2 pageblocks are free to assist fragmentation avoidance */
-	recommended_min = pageblock_nr_pages * nr_zones * 2;
-
-	/*
-	 * Make sure that on average at least two pageblocks are almost free
-	 * of another type, one for a migratetype to fall back to and a
-	 * second to avoid subsequent fallbacks of other types There are 3
-	 * MIGRATE_TYPES we care about.
-	 */
-	recommended_min += pageblock_nr_pages * nr_zones *
-			   MIGRATE_PCPTYPES * MIGRATE_PCPTYPES;
-
-	/* don't ever allow to reserve more than 5% of the lowmem */
-	recommended_min = min(recommended_min,
-			      (unsigned long) nr_free_buffer_pages() / 20);
-	recommended_min <<= (PAGE_SHIFT-10);
-
-	if (recommended_min > min_free_kbytes) {
-		if (user_min_free_kbytes >= 0)
-			pr_info("raising min_free_kbytes from %d to %lu to help transparent hugepage allocations\n",
-				min_free_kbytes, recommended_min);
-
-		min_free_kbytes = recommended_min;
-	}
-	setup_per_zone_wmarks();
-}
-
-static int start_stop_khugepaged(void)
-{
-	int err = 0;
-	if (khugepaged_enabled()) {
-		if (!khugepaged_thread)
-			khugepaged_thread = kthread_run(khugepaged, NULL,
-							"khugepaged");
-		if (IS_ERR(khugepaged_thread)) {
-			pr_err("khugepaged: kthread_run(khugepaged) failed\n");
-			err = PTR_ERR(khugepaged_thread);
-			khugepaged_thread = NULL;
-			goto fail;
-		}
-
-		if (!list_empty(&khugepaged_scan.mm_head))
-			wake_up_interruptible(&khugepaged_wait);
-
-		set_recommended_min_free_kbytes();
-	} else if (khugepaged_thread) {
-		kthread_stop(khugepaged_thread);
-		khugepaged_thread = NULL;
-	}
-fail:
-	return err;
-}
-
 static atomic_t huge_zero_refcount;
 struct page *huge_zero_page __read_mostly;
 
@@ -328,12 +181,7 @@ static ssize_t enabled_store(struct kobject *kobj,
 				TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG);
 
 	if (ret > 0) {
-		int err;
-
-		mutex_lock(&khugepaged_mutex);
-		err = start_stop_khugepaged();
-		mutex_unlock(&khugepaged_mutex);
-
+		int err = start_stop_khugepaged();
 		if (err)
 			ret = err;
 	}
@@ -343,7 +191,7 @@ static ssize_t enabled_store(struct kobject *kobj,
 static struct kobj_attribute enabled_attr =
 	__ATTR(enabled, 0644, enabled_show, enabled_store);
 
-static ssize_t single_flag_show(struct kobject *kobj,
+ssize_t single_hugepage_flag_show(struct kobject *kobj,
 				struct kobj_attribute *attr, char *buf,
 				enum transparent_hugepage_flag flag)
 {
@@ -351,7 +199,7 @@ static ssize_t single_flag_show(struct kobject *kobj,
 		       !!test_bit(flag, &transparent_hugepage_flags));
 }
 
-static ssize_t single_flag_store(struct kobject *kobj,
+ssize_t single_hugepage_flag_store(struct kobject *kobj,
 				 struct kobj_attribute *attr,
 				 const char *buf, size_t count,
 				 enum transparent_hugepage_flag flag)
@@ -406,13 +254,13 @@ static struct kobj_attribute defrag_attr =
 static ssize_t use_zero_page_show(struct kobject *kobj,
 		struct kobj_attribute *attr, char *buf)
 {
-	return single_flag_show(kobj, attr, buf,
+	return single_hugepage_flag_show(kobj, attr, buf,
 				TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
 }
 static ssize_t use_zero_page_store(struct kobject *kobj,
 		struct kobj_attribute *attr, const char *buf, size_t count)
 {
-	return single_flag_store(kobj, attr, buf, count,
+	return single_hugepage_flag_store(kobj, attr, buf, count,
 				 TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
 }
 static struct kobj_attribute use_zero_page_attr =
@@ -421,14 +269,14 @@ static struct kobj_attribute use_zero_page_attr =
 static ssize_t debug_cow_show(struct kobject *kobj,
 				struct kobj_attribute *attr, char *buf)
 {
-	return single_flag_show(kobj, attr, buf,
+	return single_hugepage_flag_show(kobj, attr, buf,
 				TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG);
 }
 static ssize_t debug_cow_store(struct kobject *kobj,
 			       struct kobj_attribute *attr,
 			       const char *buf, size_t count)
 {
-	return single_flag_store(kobj, attr, buf, count,
+	return single_hugepage_flag_store(kobj, attr, buf, count,
 				 TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG);
 }
 static struct kobj_attribute debug_cow_attr =
@@ -439,6 +287,9 @@ static struct attribute *hugepage_attr[] = {
 	&enabled_attr.attr,
 	&defrag_attr.attr,
 	&use_zero_page_attr.attr,
+#if defined(CONFIG_SHMEM) && defined(CONFIG_TRANSPARENT_HUGE_PAGECACHE)
+	&shmem_enabled_attr.attr,
+#endif
 #ifdef CONFIG_DEBUG_VM
 	&debug_cow_attr.attr,
 #endif
@@ -449,171 +300,6 @@ static struct attribute_group hugepage_attr_group = {
 	.attrs = hugepage_attr,
 };
 
-static ssize_t scan_sleep_millisecs_show(struct kobject *kobj,
-					 struct kobj_attribute *attr,
-					 char *buf)
-{
-	return sprintf(buf, "%u\n", khugepaged_scan_sleep_millisecs);
-}
-
-static ssize_t scan_sleep_millisecs_store(struct kobject *kobj,
-					  struct kobj_attribute *attr,
-					  const char *buf, size_t count)
-{
-	unsigned long msecs;
-	int err;
-
-	err = kstrtoul(buf, 10, &msecs);
-	if (err || msecs > UINT_MAX)
-		return -EINVAL;
-
-	khugepaged_scan_sleep_millisecs = msecs;
-	khugepaged_sleep_expire = 0;
-	wake_up_interruptible(&khugepaged_wait);
-
-	return count;
-}
-static struct kobj_attribute scan_sleep_millisecs_attr =
-	__ATTR(scan_sleep_millisecs, 0644, scan_sleep_millisecs_show,
-	       scan_sleep_millisecs_store);
-
-static ssize_t alloc_sleep_millisecs_show(struct kobject *kobj,
-					  struct kobj_attribute *attr,
-					  char *buf)
-{
-	return sprintf(buf, "%u\n", khugepaged_alloc_sleep_millisecs);
-}
-
-static ssize_t alloc_sleep_millisecs_store(struct kobject *kobj,
-					   struct kobj_attribute *attr,
-					   const char *buf, size_t count)
-{
-	unsigned long msecs;
-	int err;
-
-	err = kstrtoul(buf, 10, &msecs);
-	if (err || msecs > UINT_MAX)
-		return -EINVAL;
-
-	khugepaged_alloc_sleep_millisecs = msecs;
-	khugepaged_sleep_expire = 0;
-	wake_up_interruptible(&khugepaged_wait);
-
-	return count;
-}
-static struct kobj_attribute alloc_sleep_millisecs_attr =
-	__ATTR(alloc_sleep_millisecs, 0644, alloc_sleep_millisecs_show,
-	       alloc_sleep_millisecs_store);
-
-static ssize_t pages_to_scan_show(struct kobject *kobj,
-				  struct kobj_attribute *attr,
-				  char *buf)
-{
-	return sprintf(buf, "%u\n", khugepaged_pages_to_scan);
-}
-static ssize_t pages_to_scan_store(struct kobject *kobj,
-				   struct kobj_attribute *attr,
-				   const char *buf, size_t count)
-{
-	int err;
-	unsigned long pages;
-
-	err = kstrtoul(buf, 10, &pages);
-	if (err || !pages || pages > UINT_MAX)
-		return -EINVAL;
-
-	khugepaged_pages_to_scan = pages;
-
-	return count;
-}
-static struct kobj_attribute pages_to_scan_attr =
-	__ATTR(pages_to_scan, 0644, pages_to_scan_show,
-	       pages_to_scan_store);
-
-static ssize_t pages_collapsed_show(struct kobject *kobj,
-				    struct kobj_attribute *attr,
-				    char *buf)
-{
-	return sprintf(buf, "%u\n", khugepaged_pages_collapsed);
-}
-static struct kobj_attribute pages_collapsed_attr =
-	__ATTR_RO(pages_collapsed);
-
-static ssize_t full_scans_show(struct kobject *kobj,
-			       struct kobj_attribute *attr,
-			       char *buf)
-{
-	return sprintf(buf, "%u\n", khugepaged_full_scans);
-}
-static struct kobj_attribute full_scans_attr =
-	__ATTR_RO(full_scans);
-
-static ssize_t khugepaged_defrag_show(struct kobject *kobj,
-				      struct kobj_attribute *attr, char *buf)
-{
-	return single_flag_show(kobj, attr, buf,
-				TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG);
-}
-static ssize_t khugepaged_defrag_store(struct kobject *kobj,
-				       struct kobj_attribute *attr,
-				       const char *buf, size_t count)
-{
-	return single_flag_store(kobj, attr, buf, count,
-				 TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG);
-}
-static struct kobj_attribute khugepaged_defrag_attr =
-	__ATTR(defrag, 0644, khugepaged_defrag_show,
-	       khugepaged_defrag_store);
-
-/*
- * max_ptes_none controls if khugepaged should collapse hugepages over
- * any unmapped ptes in turn potentially increasing the memory
- * footprint of the vmas. When max_ptes_none is 0 khugepaged will not
- * reduce the available free memory in the system as it
- * runs. Increasing max_ptes_none will instead potentially reduce the
- * free memory in the system during the khugepaged scan.
- */
-static ssize_t khugepaged_max_ptes_none_show(struct kobject *kobj,
-					     struct kobj_attribute *attr,
-					     char *buf)
-{
-	return sprintf(buf, "%u\n", khugepaged_max_ptes_none);
-}
-static ssize_t khugepaged_max_ptes_none_store(struct kobject *kobj,
-					      struct kobj_attribute *attr,
-					      const char *buf, size_t count)
-{
-	int err;
-	unsigned long max_ptes_none;
-
-	err = kstrtoul(buf, 10, &max_ptes_none);
-	if (err || max_ptes_none > HPAGE_PMD_NR-1)
-		return -EINVAL;
-
-	khugepaged_max_ptes_none = max_ptes_none;
-
-	return count;
-}
-static struct kobj_attribute khugepaged_max_ptes_none_attr =
-	__ATTR(max_ptes_none, 0644, khugepaged_max_ptes_none_show,
-	       khugepaged_max_ptes_none_store);
-
-static struct attribute *khugepaged_attr[] = {
-	&khugepaged_defrag_attr.attr,
-	&khugepaged_max_ptes_none_attr.attr,
-	&pages_to_scan_attr.attr,
-	&pages_collapsed_attr.attr,
-	&full_scans_attr.attr,
-	&scan_sleep_millisecs_attr.attr,
-	&alloc_sleep_millisecs_attr.attr,
-	NULL,
-};
-
-static struct attribute_group khugepaged_attr_group = {
-	.attrs = khugepaged_attr,
-	.name = "khugepaged",
-};
-
 static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj)
 {
 	int err;
@@ -672,8 +358,6 @@ static int __init hugepage_init(void)
 		return -EINVAL;
 	}
 
-	khugepaged_pages_to_scan = HPAGE_PMD_NR * 8;
-	khugepaged_max_ptes_none = HPAGE_PMD_NR - 1;
 	/*
 	 * hugepages can't be allocated by the buddy allocator
 	 */
@@ -688,7 +372,7 @@ static int __init hugepage_init(void)
 	if (err)
 		goto err_sysfs;
 
-	err = khugepaged_slab_init();
+	err = khugepaged_init();
 	if (err)
 		goto err_slab;
 
@@ -719,7 +403,7 @@ err_khugepaged:
 err_split_shrinker:
 	unregister_shrinker(&huge_zero_page_shrinker);
 err_hzp_shrinker:
-	khugepaged_slab_exit();
+	khugepaged_destroy();
 err_slab:
 	hugepage_exit_sysfs(hugepage_kobj);
 err_sysfs:
@@ -765,11 +449,6 @@ pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma)
 	return pmd;
 }
 
-static inline pmd_t mk_huge_pmd(struct page *page, pgprot_t prot)
-{
-	return pmd_mkhuge(mk_pmd(page, prot));
-}
-
 static inline struct list_head *page_deferred_list(struct page *page)
 {
 	/*
@@ -790,26 +469,23 @@ void prep_transhuge_page(struct page *page)
 	set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR);
 }
 
-static int __do_huge_pmd_anonymous_page(struct mm_struct *mm,
-					struct vm_area_struct *vma,
-					unsigned long address, pmd_t *pmd,
-					struct page *page, gfp_t gfp,
-					unsigned int flags)
+static int __do_huge_pmd_anonymous_page(struct fault_env *fe, struct page *page,
+		gfp_t gfp)
 {
+	struct vm_area_struct *vma = fe->vma;
 	struct mem_cgroup *memcg;
 	pgtable_t pgtable;
-	spinlock_t *ptl;
-	unsigned long haddr = address & HPAGE_PMD_MASK;
+	unsigned long haddr = fe->address & HPAGE_PMD_MASK;
 
 	VM_BUG_ON_PAGE(!PageCompound(page), page);
 
-	if (mem_cgroup_try_charge(page, mm, gfp, &memcg, true)) {
+	if (mem_cgroup_try_charge(page, vma->vm_mm, gfp, &memcg, true)) {
 		put_page(page);
 		count_vm_event(THP_FAULT_FALLBACK);
 		return VM_FAULT_FALLBACK;
 	}
 
-	pgtable = pte_alloc_one(mm, haddr);
+	pgtable = pte_alloc_one(vma->vm_mm, haddr);
 	if (unlikely(!pgtable)) {
 		mem_cgroup_cancel_charge(page, memcg, true);
 		put_page(page);
@@ -824,12 +500,12 @@ static int __do_huge_pmd_anonymous_page(struct mm_struct *mm,
 	 */
 	__SetPageUptodate(page);
 
-	ptl = pmd_lock(mm, pmd);
-	if (unlikely(!pmd_none(*pmd))) {
-		spin_unlock(ptl);
+	fe->ptl = pmd_lock(vma->vm_mm, fe->pmd);
+	if (unlikely(!pmd_none(*fe->pmd))) {
+		spin_unlock(fe->ptl);
 		mem_cgroup_cancel_charge(page, memcg, true);
 		put_page(page);
-		pte_free(mm, pgtable);
+		pte_free(vma->vm_mm, pgtable);
 	} else {
 		pmd_t entry;
 
@@ -837,12 +513,11 @@ static int __do_huge_pmd_anonymous_page(struct mm_struct *mm,
 		if (userfaultfd_missing(vma)) {
 			int ret;
 
-			spin_unlock(ptl);
+			spin_unlock(fe->ptl);
 			mem_cgroup_cancel_charge(page, memcg, true);
 			put_page(page);
-			pte_free(mm, pgtable);
-			ret = handle_userfault(vma, address, flags,
-					       VM_UFFD_MISSING);
+			pte_free(vma->vm_mm, pgtable);
+			ret = handle_userfault(fe, VM_UFFD_MISSING);
 			VM_BUG_ON(ret & VM_FAULT_FALLBACK);
 			return ret;
 		}
@@ -852,11 +527,11 @@ static int __do_huge_pmd_anonymous_page(struct mm_struct *mm,
 		page_add_new_anon_rmap(page, vma, haddr, true);
 		mem_cgroup_commit_charge(page, memcg, false, true);
 		lru_cache_add_active_or_unevictable(page, vma);
-		pgtable_trans_huge_deposit(mm, pmd, pgtable);
-		set_pmd_at(mm, haddr, pmd, entry);
-		add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR);
-		atomic_long_inc(&mm->nr_ptes);
-		spin_unlock(ptl);
+		pgtable_trans_huge_deposit(vma->vm_mm, fe->pmd, pgtable);
+		set_pmd_at(vma->vm_mm, haddr, fe->pmd, entry);
+		add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR);
+		atomic_long_inc(&vma->vm_mm->nr_ptes);
+		spin_unlock(fe->ptl);
 		count_vm_event(THP_FAULT_ALLOC);
 	}
 
@@ -883,12 +558,6 @@ static inline gfp_t alloc_hugepage_direct_gfpmask(struct vm_area_struct *vma)
 	return GFP_TRANSHUGE | reclaim_flags;
 }
 
-/* Defrag for khugepaged will enter direct reclaim/compaction if necessary */
-static inline gfp_t alloc_hugepage_khugepaged_gfpmask(void)
-{
-	return GFP_TRANSHUGE | (khugepaged_defrag() ? __GFP_DIRECT_RECLAIM : 0);
-}
-
 /* Caller must hold page table lock. */
 static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm,
 		struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd,
@@ -906,13 +575,12 @@ static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm,
 	return true;
 }
 
-int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
-			       unsigned long address, pmd_t *pmd,
-			       unsigned int flags)
+int do_huge_pmd_anonymous_page(struct fault_env *fe)
 {
+	struct vm_area_struct *vma = fe->vma;
 	gfp_t gfp;
 	struct page *page;
-	unsigned long haddr = address & HPAGE_PMD_MASK;
+	unsigned long haddr = fe->address & HPAGE_PMD_MASK;
 
 	if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end)
 		return VM_FAULT_FALLBACK;
@@ -920,42 +588,40 @@ int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
 		return VM_FAULT_OOM;
 	if (unlikely(khugepaged_enter(vma, vma->vm_flags)))
 		return VM_FAULT_OOM;
-	if (!(flags & FAULT_FLAG_WRITE) && !mm_forbids_zeropage(mm) &&
+	if (!(fe->flags & FAULT_FLAG_WRITE) &&
+			!mm_forbids_zeropage(vma->vm_mm) &&
 			transparent_hugepage_use_zero_page()) {
-		spinlock_t *ptl;
 		pgtable_t pgtable;
 		struct page *zero_page;
 		bool set;
 		int ret;
-		pgtable = pte_alloc_one(mm, haddr);
+		pgtable = pte_alloc_one(vma->vm_mm, haddr);
 		if (unlikely(!pgtable))
 			return VM_FAULT_OOM;
 		zero_page = get_huge_zero_page();
 		if (unlikely(!zero_page)) {
-			pte_free(mm, pgtable);
+			pte_free(vma->vm_mm, pgtable);
 			count_vm_event(THP_FAULT_FALLBACK);
 			return VM_FAULT_FALLBACK;
 		}
-		ptl = pmd_lock(mm, pmd);
+		fe->ptl = pmd_lock(vma->vm_mm, fe->pmd);
 		ret = 0;
 		set = false;
-		if (pmd_none(*pmd)) {
+		if (pmd_none(*fe->pmd)) {
 			if (userfaultfd_missing(vma)) {
-				spin_unlock(ptl);
-				ret = handle_userfault(vma, address, flags,
-						       VM_UFFD_MISSING);
+				spin_unlock(fe->ptl);
+				ret = handle_userfault(fe, VM_UFFD_MISSING);
 				VM_BUG_ON(ret & VM_FAULT_FALLBACK);
 			} else {
-				set_huge_zero_page(pgtable, mm, vma,
-						   haddr, pmd,
-						   zero_page);
-				spin_unlock(ptl);
+				set_huge_zero_page(pgtable, vma->vm_mm, vma,
+						   haddr, fe->pmd, zero_page);
+				spin_unlock(fe->ptl);
 				set = true;
 			}
 		} else
-			spin_unlock(ptl);
+			spin_unlock(fe->ptl);
 		if (!set) {
-			pte_free(mm, pgtable);
+			pte_free(vma->vm_mm, pgtable);
 			put_huge_zero_page();
 		}
 		return ret;
@@ -967,8 +633,7 @@ int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
 		return VM_FAULT_FALLBACK;
 	}
 	prep_transhuge_page(page);
-	return __do_huge_pmd_anonymous_page(mm, vma, address, pmd, page, gfp,
-					    flags);
+	return __do_huge_pmd_anonymous_page(fe, page, gfp);
 }
 
 static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
@@ -1080,14 +745,15 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 	struct page *src_page;
 	pmd_t pmd;
 	pgtable_t pgtable = NULL;
-	int ret;
+	int ret = -ENOMEM;
 
-	if (!vma_is_dax(vma)) {
-		ret = -ENOMEM;
-		pgtable = pte_alloc_one(dst_mm, addr);
-		if (unlikely(!pgtable))
-			goto out;
-	}
+	/* Skip if can be re-fill on fault */
+	if (!vma_is_anonymous(vma))
+		return 0;
+
+	pgtable = pte_alloc_one(dst_mm, addr);
+	if (unlikely(!pgtable))
+		goto out;
 
 	dst_ptl = pmd_lock(dst_mm, dst_pmd);
 	src_ptl = pmd_lockptr(src_mm, src_pmd);
@@ -1095,7 +761,7 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 
 	ret = -EAGAIN;
 	pmd = *src_pmd;
-	if (unlikely(!pmd_trans_huge(pmd) && !pmd_devmap(pmd))) {
+	if (unlikely(!pmd_trans_huge(pmd))) {
 		pte_free(dst_mm, pgtable);
 		goto out_unlock;
 	}
@@ -1118,16 +784,13 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 		goto out_unlock;
 	}
 
-	if (!vma_is_dax(vma)) {
-		/* thp accounting separate from pmd_devmap accounting */
-		src_page = pmd_page(pmd);
-		VM_BUG_ON_PAGE(!PageHead(src_page), src_page);
-		get_page(src_page);
-		page_dup_rmap(src_page, true);
-		add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR);
-		atomic_long_inc(&dst_mm->nr_ptes);
-		pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable);
-	}
+	src_page = pmd_page(pmd);
+	VM_BUG_ON_PAGE(!PageHead(src_page), src_page);
+	get_page(src_page);
+	page_dup_rmap(src_page, true);
+	add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR);
+	atomic_long_inc(&dst_mm->nr_ptes);
+	pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable);
 
 	pmdp_set_wrprotect(src_mm, addr, src_pmd);
 	pmd = pmd_mkold(pmd_wrprotect(pmd));
@@ -1141,38 +804,31 @@ out:
 	return ret;
 }
 
-void huge_pmd_set_accessed(struct mm_struct *mm,
-			   struct vm_area_struct *vma,
-			   unsigned long address,
-			   pmd_t *pmd, pmd_t orig_pmd,
-			   int dirty)
+void huge_pmd_set_accessed(struct fault_env *fe, pmd_t orig_pmd)
 {
-	spinlock_t *ptl;
 	pmd_t entry;
 	unsigned long haddr;
 
-	ptl = pmd_lock(mm, pmd);
-	if (unlikely(!pmd_same(*pmd, orig_pmd)))
+	fe->ptl = pmd_lock(fe->vma->vm_mm, fe->pmd);
+	if (unlikely(!pmd_same(*fe->pmd, orig_pmd)))
 		goto unlock;
 
 	entry = pmd_mkyoung(orig_pmd);
-	haddr = address & HPAGE_PMD_MASK;
-	if (pmdp_set_access_flags(vma, haddr, pmd, entry, dirty))
-		update_mmu_cache_pmd(vma, address, pmd);
+	haddr = fe->address & HPAGE_PMD_MASK;
+	if (pmdp_set_access_flags(fe->vma, haddr, fe->pmd, entry,
+				fe->flags & FAULT_FLAG_WRITE))
+		update_mmu_cache_pmd(fe->vma, fe->address, fe->pmd);
 
 unlock:
-	spin_unlock(ptl);
+	spin_unlock(fe->ptl);
 }
 
-static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm,
-					struct vm_area_struct *vma,
-					unsigned long address,
-					pmd_t *pmd, pmd_t orig_pmd,
-					struct page *page,
-					unsigned long haddr)
+static int do_huge_pmd_wp_page_fallback(struct fault_env *fe, pmd_t orig_pmd,
+		struct page *page)
 {
+	struct vm_area_struct *vma = fe->vma;
+	unsigned long haddr = fe->address & HPAGE_PMD_MASK;
 	struct mem_cgroup *memcg;
-	spinlock_t *ptl;
 	pgtable_t pgtable;
 	pmd_t _pmd;
 	int ret = 0, i;
@@ -1189,11 +845,11 @@ static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm,
 
 	for (i = 0; i < HPAGE_PMD_NR; i++) {
 		pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE |
-					       __GFP_OTHER_NODE,
-					       vma, address, page_to_nid(page));
+					       __GFP_OTHER_NODE, vma,
+					       fe->address, page_to_nid(page));
 		if (unlikely(!pages[i] ||
-			     mem_cgroup_try_charge(pages[i], mm, GFP_KERNEL,
-						   &memcg, false))) {
+			     mem_cgroup_try_charge(pages[i], vma->vm_mm,
+				     GFP_KERNEL, &memcg, false))) {
 			if (pages[i])
 				put_page(pages[i]);
 			while (--i >= 0) {
@@ -1219,41 +875,41 @@ static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm,
 
 	mmun_start = haddr;
 	mmun_end   = haddr + HPAGE_PMD_SIZE;
-	mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
+	mmu_notifier_invalidate_range_start(vma->vm_mm, mmun_start, mmun_end);
 
-	ptl = pmd_lock(mm, pmd);
-	if (unlikely(!pmd_same(*pmd, orig_pmd)))
+	fe->ptl = pmd_lock(vma->vm_mm, fe->pmd);
+	if (unlikely(!pmd_same(*fe->pmd, orig_pmd)))
 		goto out_free_pages;
 	VM_BUG_ON_PAGE(!PageHead(page), page);
 
-	pmdp_huge_clear_flush_notify(vma, haddr, pmd);
+	pmdp_huge_clear_flush_notify(vma, haddr, fe->pmd);
 	/* leave pmd empty until pte is filled */
 
-	pgtable = pgtable_trans_huge_withdraw(mm, pmd);
-	pmd_populate(mm, &_pmd, pgtable);
+	pgtable = pgtable_trans_huge_withdraw(vma->vm_mm, fe->pmd);
+	pmd_populate(vma->vm_mm, &_pmd, pgtable);
 
 	for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) {
-		pte_t *pte, entry;
+		pte_t entry;
 		entry = mk_pte(pages[i], vma->vm_page_prot);
 		entry = maybe_mkwrite(pte_mkdirty(entry), vma);
 		memcg = (void *)page_private(pages[i]);
 		set_page_private(pages[i], 0);
-		page_add_new_anon_rmap(pages[i], vma, haddr, false);
+		page_add_new_anon_rmap(pages[i], fe->vma, haddr, false);
 		mem_cgroup_commit_charge(pages[i], memcg, false, false);
 		lru_cache_add_active_or_unevictable(pages[i], vma);
-		pte = pte_offset_map(&_pmd, haddr);
-		VM_BUG_ON(!pte_none(*pte));
-		set_pte_at(mm, haddr, pte, entry);
-		pte_unmap(pte);
+		fe->pte = pte_offset_map(&_pmd, haddr);
+		VM_BUG_ON(!pte_none(*fe->pte));
+		set_pte_at(vma->vm_mm, haddr, fe->pte, entry);
+		pte_unmap(fe->pte);
 	}
 	kfree(pages);
 
 	smp_wmb(); /* make pte visible before pmd */
-	pmd_populate(mm, pmd, pgtable);
+	pmd_populate(vma->vm_mm, fe->pmd, pgtable);
 	page_remove_rmap(page, true);
-	spin_unlock(ptl);
+	spin_unlock(fe->ptl);
 
-	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
+	mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start, mmun_end);
 
 	ret |= VM_FAULT_WRITE;
 	put_page(page);
@@ -1262,8 +918,8 @@ out:
 	return ret;
 
 out_free_pages:
-	spin_unlock(ptl);
-	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
+	spin_unlock(fe->ptl);
+	mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start, mmun_end);
 	for (i = 0; i < HPAGE_PMD_NR; i++) {
 		memcg = (void *)page_private(pages[i]);
 		set_page_private(pages[i], 0);
@@ -1274,25 +930,23 @@ out_free_pages:
 	goto out;
 }
 
-int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
-			unsigned long address, pmd_t *pmd, pmd_t orig_pmd)
+int do_huge_pmd_wp_page(struct fault_env *fe, pmd_t orig_pmd)
 {
-	spinlock_t *ptl;
-	int ret = 0;
+	struct vm_area_struct *vma = fe->vma;
 	struct page *page = NULL, *new_page;
 	struct mem_cgroup *memcg;
-	unsigned long haddr;
+	unsigned long haddr = fe->address & HPAGE_PMD_MASK;
 	unsigned long mmun_start;	/* For mmu_notifiers */
 	unsigned long mmun_end;		/* For mmu_notifiers */
 	gfp_t huge_gfp;			/* for allocation and charge */
+	int ret = 0;
 
-	ptl = pmd_lockptr(mm, pmd);
+	fe->ptl = pmd_lockptr(vma->vm_mm, fe->pmd);
 	VM_BUG_ON_VMA(!vma->anon_vma, vma);
-	haddr = address & HPAGE_PMD_MASK;
 	if (is_huge_zero_pmd(orig_pmd))
 		goto alloc;
-	spin_lock(ptl);
-	if (unlikely(!pmd_same(*pmd, orig_pmd)))
+	spin_lock(fe->ptl);
+	if (unlikely(!pmd_same(*fe->pmd, orig_pmd)))
 		goto out_unlock;
 
 	page = pmd_page(orig_pmd);
@@ -1305,13 +959,13 @@ int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
 		pmd_t entry;
 		entry = pmd_mkyoung(orig_pmd);
 		entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
-		if (pmdp_set_access_flags(vma, haddr, pmd, entry,  1))
-			update_mmu_cache_pmd(vma, address, pmd);
+		if (pmdp_set_access_flags(vma, haddr, fe->pmd, entry,  1))
+			update_mmu_cache_pmd(vma, fe->address, fe->pmd);
 		ret |= VM_FAULT_WRITE;
 		goto out_unlock;
 	}
 	get_page(page);
-	spin_unlock(ptl);
+	spin_unlock(fe->ptl);
 alloc:
 	if (transparent_hugepage_enabled(vma) &&
 	    !transparent_hugepage_debug_cow()) {
@@ -1324,13 +978,12 @@ alloc:
 		prep_transhuge_page(new_page);
 	} else {
 		if (!page) {
-			split_huge_pmd(vma, pmd, address);
+			split_huge_pmd(vma, fe->pmd, fe->address);
 			ret |= VM_FAULT_FALLBACK;
 		} else {
-			ret = do_huge_pmd_wp_page_fallback(mm, vma, address,
-					pmd, orig_pmd, page, haddr);
+			ret = do_huge_pmd_wp_page_fallback(fe, orig_pmd, page);
 			if (ret & VM_FAULT_OOM) {
-				split_huge_pmd(vma, pmd, address);
+				split_huge_pmd(vma, fe->pmd, fe->address);
 				ret |= VM_FAULT_FALLBACK;
 			}
 			put_page(page);
@@ -1339,14 +992,12 @@ alloc:
 		goto out;
 	}
 
-	if (unlikely(mem_cgroup_try_charge(new_page, mm, huge_gfp, &memcg,
-					   true))) {
+	if (unlikely(mem_cgroup_try_charge(new_page, vma->vm_mm,
+					huge_gfp, &memcg, true))) {
 		put_page(new_page);
-		if (page) {
-			split_huge_pmd(vma, pmd, address);
+		split_huge_pmd(vma, fe->pmd, fe->address);
+		if (page)
 			put_page(page);
-		} else
-			split_huge_pmd(vma, pmd, address);
 		ret |= VM_FAULT_FALLBACK;
 		count_vm_event(THP_FAULT_FALLBACK);
 		goto out;
@@ -1362,13 +1013,13 @@ alloc:
 
 	mmun_start = haddr;
 	mmun_end   = haddr + HPAGE_PMD_SIZE;
-	mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
+	mmu_notifier_invalidate_range_start(vma->vm_mm, mmun_start, mmun_end);
 
-	spin_lock(ptl);
+	spin_lock(fe->ptl);
 	if (page)
 		put_page(page);
-	if (unlikely(!pmd_same(*pmd, orig_pmd))) {
-		spin_unlock(ptl);
+	if (unlikely(!pmd_same(*fe->pmd, orig_pmd))) {
+		spin_unlock(fe->ptl);
 		mem_cgroup_cancel_charge(new_page, memcg, true);
 		put_page(new_page);
 		goto out_mn;
@@ -1376,14 +1027,14 @@ alloc:
 		pmd_t entry;
 		entry = mk_huge_pmd(new_page, vma->vm_page_prot);
 		entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
-		pmdp_huge_clear_flush_notify(vma, haddr, pmd);
+		pmdp_huge_clear_flush_notify(vma, haddr, fe->pmd);
 		page_add_new_anon_rmap(new_page, vma, haddr, true);
 		mem_cgroup_commit_charge(new_page, memcg, false, true);
 		lru_cache_add_active_or_unevictable(new_page, vma);
-		set_pmd_at(mm, haddr, pmd, entry);
-		update_mmu_cache_pmd(vma, address, pmd);
+		set_pmd_at(vma->vm_mm, haddr, fe->pmd, entry);
+		update_mmu_cache_pmd(vma, fe->address, fe->pmd);
 		if (!page) {
-			add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR);
+			add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR);
 			put_huge_zero_page();
 		} else {
 			VM_BUG_ON_PAGE(!PageHead(page), page);
@@ -1392,13 +1043,13 @@ alloc:
 		}
 		ret |= VM_FAULT_WRITE;
 	}
-	spin_unlock(ptl);
+	spin_unlock(fe->ptl);
 out_mn:
-	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
+	mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start, mmun_end);
 out:
 	return ret;
 out_unlock:
-	spin_unlock(ptl);
+	spin_unlock(fe->ptl);
 	return ret;
 }
 
@@ -1432,6 +1083,8 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
 		 * We don't mlock() pte-mapped THPs. This way we can avoid
 		 * leaking mlocked pages into non-VM_LOCKED VMAs.
 		 *
+		 * For anon THP:
+		 *
 		 * In most cases the pmd is the only mapping of the page as we
 		 * break COW for the mlock() -- see gup_flags |= FOLL_WRITE for
 		 * writable private mappings in populate_vma_page_range().
@@ -1439,15 +1092,26 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
 		 * The only scenario when we have the page shared here is if we
 		 * mlocking read-only mapping shared over fork(). We skip
 		 * mlocking such pages.
+		 *
+		 * For file THP:
+		 *
+		 * We can expect PageDoubleMap() to be stable under page lock:
+		 * for file pages we set it in page_add_file_rmap(), which
+		 * requires page to be locked.
 		 */
-		if (compound_mapcount(page) == 1 && !PageDoubleMap(page) &&
-				page->mapping && trylock_page(page)) {
-			lru_add_drain();
-			if (page->mapping)
-				mlock_vma_page(page);
-			unlock_page(page);
-		}
+
+		if (PageAnon(page) && compound_mapcount(page) != 1)
+			goto skip_mlock;
+		if (PageDoubleMap(page) || !page->mapping)
+			goto skip_mlock;
+		if (!trylock_page(page))
+			goto skip_mlock;
+		lru_add_drain();
+		if (page->mapping && !PageDoubleMap(page))
+			mlock_vma_page(page);
+		unlock_page(page);
 	}
+skip_mlock:
 	page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT;
 	VM_BUG_ON_PAGE(!PageCompound(page), page);
 	if (flags & FOLL_GET)
@@ -1458,13 +1122,12 @@ out:
 }
 
 /* NUMA hinting page fault entry point for trans huge pmds */
-int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
-				unsigned long addr, pmd_t pmd, pmd_t *pmdp)
+int do_huge_pmd_numa_page(struct fault_env *fe, pmd_t pmd)
 {
-	spinlock_t *ptl;
+	struct vm_area_struct *vma = fe->vma;
 	struct anon_vma *anon_vma = NULL;
 	struct page *page;
-	unsigned long haddr = addr & HPAGE_PMD_MASK;
+	unsigned long haddr = fe->address & HPAGE_PMD_MASK;
 	int page_nid = -1, this_nid = numa_node_id();
 	int target_nid, last_cpupid = -1;
 	bool page_locked;
@@ -1475,8 +1138,8 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	/* A PROT_NONE fault should not end up here */
 	BUG_ON(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)));
 
-	ptl = pmd_lock(mm, pmdp);
-	if (unlikely(!pmd_same(pmd, *pmdp)))
+	fe->ptl = pmd_lock(vma->vm_mm, fe->pmd);
+	if (unlikely(!pmd_same(pmd, *fe->pmd)))
 		goto out_unlock;
 
 	/*
@@ -1484,9 +1147,9 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	 * without disrupting NUMA hinting information. Do not relock and
 	 * check_same as the page may no longer be mapped.
 	 */
-	if (unlikely(pmd_trans_migrating(*pmdp))) {
-		page = pmd_page(*pmdp);
-		spin_unlock(ptl);
+	if (unlikely(pmd_trans_migrating(*fe->pmd))) {
+		page = pmd_page(*fe->pmd);
+		spin_unlock(fe->ptl);
 		wait_on_page_locked(page);
 		goto out;
 	}
@@ -1519,7 +1182,7 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 
 	/* Migration could have started since the pmd_trans_migrating check */
 	if (!page_locked) {
-		spin_unlock(ptl);
+		spin_unlock(fe->ptl);
 		wait_on_page_locked(page);
 		page_nid = -1;
 		goto out;
@@ -1530,12 +1193,12 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	 * to serialises splits
 	 */
 	get_page(page);
-	spin_unlock(ptl);
+	spin_unlock(fe->ptl);
 	anon_vma = page_lock_anon_vma_read(page);
 
 	/* Confirm the PMD did not change while page_table_lock was released */
-	spin_lock(ptl);
-	if (unlikely(!pmd_same(pmd, *pmdp))) {
+	spin_lock(fe->ptl);
+	if (unlikely(!pmd_same(pmd, *fe->pmd))) {
 		unlock_page(page);
 		put_page(page);
 		page_nid = -1;
@@ -1553,9 +1216,9 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	 * Migrate the THP to the requested node, returns with page unlocked
 	 * and access rights restored.
 	 */
-	spin_unlock(ptl);
-	migrated = migrate_misplaced_transhuge_page(mm, vma,
-				pmdp, pmd, addr, page, target_nid);
+	spin_unlock(fe->ptl);
+	migrated = migrate_misplaced_transhuge_page(vma->vm_mm, vma,
+				fe->pmd, pmd, fe->address, page, target_nid);
 	if (migrated) {
 		flags |= TNF_MIGRATED;
 		page_nid = target_nid;
@@ -1570,18 +1233,18 @@ clear_pmdnuma:
 	pmd = pmd_mkyoung(pmd);
 	if (was_writable)
 		pmd = pmd_mkwrite(pmd);
-	set_pmd_at(mm, haddr, pmdp, pmd);
-	update_mmu_cache_pmd(vma, addr, pmdp);
+	set_pmd_at(vma->vm_mm, haddr, fe->pmd, pmd);
+	update_mmu_cache_pmd(vma, fe->address, fe->pmd);
 	unlock_page(page);
 out_unlock:
-	spin_unlock(ptl);
+	spin_unlock(fe->ptl);
 
 out:
 	if (anon_vma)
 		page_unlock_anon_vma_read(anon_vma);
 
 	if (page_nid != -1)
-		task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, flags);
+		task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR, fe->flags);
 
 	return 0;
 }
@@ -1684,12 +1347,18 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 		struct page *page = pmd_page(orig_pmd);
 		page_remove_rmap(page, true);
 		VM_BUG_ON_PAGE(page_mapcount(page) < 0, page);
-		add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
 		VM_BUG_ON_PAGE(!PageHead(page), page);
-		pte_free(tlb->mm, pgtable_trans_huge_withdraw(tlb->mm, pmd));
-		atomic_long_dec(&tlb->mm->nr_ptes);
+		if (PageAnon(page)) {
+			pgtable_t pgtable;
+			pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd);
+			pte_free(tlb->mm, pgtable);
+			atomic_long_dec(&tlb->mm->nr_ptes);
+			add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
+		} else {
+			add_mm_counter(tlb->mm, MM_FILEPAGES, -HPAGE_PMD_NR);
+		}
 		spin_unlock(ptl);
-		tlb_remove_page(tlb, page);
+		tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE);
 	}
 	return 1;
 }
@@ -1779,7 +1448,8 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
 				entry = pmd_mkwrite(entry);
 			ret = HPAGE_PMD_NR;
 			set_pmd_at(mm, addr, pmd, entry);
-			BUG_ON(!preserve_write && pmd_write(entry));
+			BUG_ON(vma_is_anonymous(vma) && !preserve_write &&
+					pmd_write(entry));
 		}
 		spin_unlock(ptl);
 	}
@@ -1788,10 +1458,10 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
 }
 
 /*
- * Returns true if a given pmd maps a thp, false otherwise.
+ * Returns page table lock pointer if a given pmd maps a thp, NULL otherwise.
  *
- * Note that if it returns true, this routine returns without unlocking page
- * table lock. So callers must unlock it.
+ * Note that if it returns page table lock pointer, this routine returns without
+ * unlocking page table lock. So callers must unlock it.
  */
 spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma)
 {
@@ -1803,1040 +1473,6 @@ spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma)
 	return NULL;
 }
 
-#define VM_NO_THP (VM_SPECIAL | VM_HUGETLB | VM_SHARED | VM_MAYSHARE)
-
-int hugepage_madvise(struct vm_area_struct *vma,
-		     unsigned long *vm_flags, int advice)
-{
-	switch (advice) {
-	case MADV_HUGEPAGE:
-#ifdef CONFIG_S390
-		/*
-		 * qemu blindly sets MADV_HUGEPAGE on all allocations, but s390
-		 * can't handle this properly after s390_enable_sie, so we simply
-		 * ignore the madvise to prevent qemu from causing a SIGSEGV.
-		 */
-		if (mm_has_pgste(vma->vm_mm))
-			return 0;
-#endif
-		/*
-		 * Be somewhat over-protective like KSM for now!
-		 */
-		if (*vm_flags & VM_NO_THP)
-			return -EINVAL;
-		*vm_flags &= ~VM_NOHUGEPAGE;
-		*vm_flags |= VM_HUGEPAGE;
-		/*
-		 * If the vma become good for khugepaged to scan,
-		 * register it here without waiting a page fault that
-		 * may not happen any time soon.
-		 */
-		if (unlikely(khugepaged_enter_vma_merge(vma, *vm_flags)))
-			return -ENOMEM;
-		break;
-	case MADV_NOHUGEPAGE:
-		/*
-		 * Be somewhat over-protective like KSM for now!
-		 */
-		if (*vm_flags & VM_NO_THP)
-			return -EINVAL;
-		*vm_flags &= ~VM_HUGEPAGE;
-		*vm_flags |= VM_NOHUGEPAGE;
-		/*
-		 * Setting VM_NOHUGEPAGE will prevent khugepaged from scanning
-		 * this vma even if we leave the mm registered in khugepaged if
-		 * it got registered before VM_NOHUGEPAGE was set.
-		 */
-		break;
-	}
-
-	return 0;
-}
-
-static int __init khugepaged_slab_init(void)
-{
-	mm_slot_cache = kmem_cache_create("khugepaged_mm_slot",
-					  sizeof(struct mm_slot),
-					  __alignof__(struct mm_slot), 0, NULL);
-	if (!mm_slot_cache)
-		return -ENOMEM;
-
-	return 0;
-}
-
-static void __init khugepaged_slab_exit(void)
-{
-	kmem_cache_destroy(mm_slot_cache);
-}
-
-static inline struct mm_slot *alloc_mm_slot(void)
-{
-	if (!mm_slot_cache)	/* initialization failed */
-		return NULL;
-	return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL);
-}
-
-static inline void free_mm_slot(struct mm_slot *mm_slot)
-{
-	kmem_cache_free(mm_slot_cache, mm_slot);
-}
-
-static struct mm_slot *get_mm_slot(struct mm_struct *mm)
-{
-	struct mm_slot *mm_slot;
-
-	hash_for_each_possible(mm_slots_hash, mm_slot, hash, (unsigned long)mm)
-		if (mm == mm_slot->mm)
-			return mm_slot;
-
-	return NULL;
-}
-
-static void insert_to_mm_slots_hash(struct mm_struct *mm,
-				    struct mm_slot *mm_slot)
-{
-	mm_slot->mm = mm;
-	hash_add(mm_slots_hash, &mm_slot->hash, (long)mm);
-}
-
-static inline int khugepaged_test_exit(struct mm_struct *mm)
-{
-	return atomic_read(&mm->mm_users) == 0;
-}
-
-int __khugepaged_enter(struct mm_struct *mm)
-{
-	struct mm_slot *mm_slot;
-	int wakeup;
-
-	mm_slot = alloc_mm_slot();
-	if (!mm_slot)
-		return -ENOMEM;
-
-	/* __khugepaged_exit() must not run from under us */
-	VM_BUG_ON_MM(khugepaged_test_exit(mm), mm);
-	if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) {
-		free_mm_slot(mm_slot);
-		return 0;
-	}
-
-	spin_lock(&khugepaged_mm_lock);
-	insert_to_mm_slots_hash(mm, mm_slot);
-	/*
-	 * Insert just behind the scanning cursor, to let the area settle
-	 * down a little.
-	 */
-	wakeup = list_empty(&khugepaged_scan.mm_head);
-	list_add_tail(&mm_slot->mm_node, &khugepaged_scan.mm_head);
-	spin_unlock(&khugepaged_mm_lock);
-
-	atomic_inc(&mm->mm_count);
-	if (wakeup)
-		wake_up_interruptible(&khugepaged_wait);
-
-	return 0;
-}
-
-int khugepaged_enter_vma_merge(struct vm_area_struct *vma,
-			       unsigned long vm_flags)
-{
-	unsigned long hstart, hend;
-	if (!vma->anon_vma)
-		/*
-		 * Not yet faulted in so we will register later in the
-		 * page fault if needed.
-		 */
-		return 0;
-	if (vma->vm_ops || (vm_flags & VM_NO_THP))
-		/* khugepaged not yet working on file or special mappings */
-		return 0;
-	hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
-	hend = vma->vm_end & HPAGE_PMD_MASK;
-	if (hstart < hend)
-		return khugepaged_enter(vma, vm_flags);
-	return 0;
-}
-
-void __khugepaged_exit(struct mm_struct *mm)
-{
-	struct mm_slot *mm_slot;
-	int free = 0;
-
-	spin_lock(&khugepaged_mm_lock);
-	mm_slot = get_mm_slot(mm);
-	if (mm_slot && khugepaged_scan.mm_slot != mm_slot) {
-		hash_del(&mm_slot->hash);
-		list_del(&mm_slot->mm_node);
-		free = 1;
-	}
-	spin_unlock(&khugepaged_mm_lock);
-
-	if (free) {
-		clear_bit(MMF_VM_HUGEPAGE, &mm->flags);
-		free_mm_slot(mm_slot);
-		mmdrop(mm);
-	} else if (mm_slot) {
-		/*
-		 * This is required to serialize against
-		 * khugepaged_test_exit() (which is guaranteed to run
-		 * under mmap sem read mode). Stop here (after we
-		 * return all pagetables will be destroyed) until
-		 * khugepaged has finished working on the pagetables
-		 * under the mmap_sem.
-		 */
-		down_write(&mm->mmap_sem);
-		up_write(&mm->mmap_sem);
-	}
-}
-
-static void release_pte_page(struct page *page)
-{
-	/* 0 stands for page_is_file_cache(page) == false */
-	dec_zone_page_state(page, NR_ISOLATED_ANON + 0);
-	unlock_page(page);
-	putback_lru_page(page);
-}
-
-static void release_pte_pages(pte_t *pte, pte_t *_pte)
-{
-	while (--_pte >= pte) {
-		pte_t pteval = *_pte;
-		if (!pte_none(pteval) && !is_zero_pfn(pte_pfn(pteval)))
-			release_pte_page(pte_page(pteval));
-	}
-}
-
-static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
-					unsigned long address,
-					pte_t *pte)
-{
-	struct page *page = NULL;
-	pte_t *_pte;
-	int none_or_zero = 0, result = 0;
-	bool referenced = false, writable = false;
-
-	for (_pte = pte; _pte < pte+HPAGE_PMD_NR;
-	     _pte++, address += PAGE_SIZE) {
-		pte_t pteval = *_pte;
-		if (pte_none(pteval) || (pte_present(pteval) &&
-				is_zero_pfn(pte_pfn(pteval)))) {
-			if (!userfaultfd_armed(vma) &&
-			    ++none_or_zero <= khugepaged_max_ptes_none) {
-				continue;
-			} else {
-				result = SCAN_EXCEED_NONE_PTE;
-				goto out;
-			}
-		}
-		if (!pte_present(pteval)) {
-			result = SCAN_PTE_NON_PRESENT;
-			goto out;
-		}
-		page = vm_normal_page(vma, address, pteval);
-		if (unlikely(!page)) {
-			result = SCAN_PAGE_NULL;
-			goto out;
-		}
-
-		VM_BUG_ON_PAGE(PageCompound(page), page);
-		VM_BUG_ON_PAGE(!PageAnon(page), page);
-		VM_BUG_ON_PAGE(!PageSwapBacked(page), page);
-
-		/*
-		 * We can do it before isolate_lru_page because the
-		 * page can't be freed from under us. NOTE: PG_lock
-		 * is needed to serialize against split_huge_page
-		 * when invoked from the VM.
-		 */
-		if (!trylock_page(page)) {
-			result = SCAN_PAGE_LOCK;
-			goto out;
-		}
-
-		/*
-		 * cannot use mapcount: can't collapse if there's a gup pin.
-		 * The page must only be referenced by the scanned process
-		 * and page swap cache.
-		 */
-		if (page_count(page) != 1 + !!PageSwapCache(page)) {
-			unlock_page(page);
-			result = SCAN_PAGE_COUNT;
-			goto out;
-		}
-		if (pte_write(pteval)) {
-			writable = true;
-		} else {
-			if (PageSwapCache(page) &&
-			    !reuse_swap_page(page, NULL)) {
-				unlock_page(page);
-				result = SCAN_SWAP_CACHE_PAGE;
-				goto out;
-			}
-			/*
-			 * Page is not in the swap cache. It can be collapsed
-			 * into a THP.
-			 */
-		}
-
-		/*
-		 * Isolate the page to avoid collapsing an hugepage
-		 * currently in use by the VM.
-		 */
-		if (isolate_lru_page(page)) {
-			unlock_page(page);
-			result = SCAN_DEL_PAGE_LRU;
-			goto out;
-		}
-		/* 0 stands for page_is_file_cache(page) == false */
-		inc_zone_page_state(page, NR_ISOLATED_ANON + 0);
-		VM_BUG_ON_PAGE(!PageLocked(page), page);
-		VM_BUG_ON_PAGE(PageLRU(page), page);
-
-		/* If there is no mapped pte young don't collapse the page */
-		if (pte_young(pteval) ||
-		    page_is_young(page) || PageReferenced(page) ||
-		    mmu_notifier_test_young(vma->vm_mm, address))
-			referenced = true;
-	}
-	if (likely(writable)) {
-		if (likely(referenced)) {
-			result = SCAN_SUCCEED;
-			trace_mm_collapse_huge_page_isolate(page, none_or_zero,
-							    referenced, writable, result);
-			return 1;
-		}
-	} else {
-		result = SCAN_PAGE_RO;
-	}
-
-out:
-	release_pte_pages(pte, _pte);
-	trace_mm_collapse_huge_page_isolate(page, none_or_zero,
-					    referenced, writable, result);
-	return 0;
-}
-
-static void __collapse_huge_page_copy(pte_t *pte, struct page *page,
-				      struct vm_area_struct *vma,
-				      unsigned long address,
-				      spinlock_t *ptl)
-{
-	pte_t *_pte;
-	for (_pte = pte; _pte < pte+HPAGE_PMD_NR; _pte++) {
-		pte_t pteval = *_pte;
-		struct page *src_page;
-
-		if (pte_none(pteval) || is_zero_pfn(pte_pfn(pteval))) {
-			clear_user_highpage(page, address);
-			add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1);
-			if (is_zero_pfn(pte_pfn(pteval))) {
-				/*
-				 * ptl mostly unnecessary.
-				 */
-				spin_lock(ptl);
-				/*
-				 * paravirt calls inside pte_clear here are
-				 * superfluous.
-				 */
-				pte_clear(vma->vm_mm, address, _pte);
-				spin_unlock(ptl);
-			}
-		} else {
-			src_page = pte_page(pteval);
-			copy_user_highpage(page, src_page, address, vma);
-			VM_BUG_ON_PAGE(page_mapcount(src_page) != 1, src_page);
-			release_pte_page(src_page);
-			/*
-			 * ptl mostly unnecessary, but preempt has to
-			 * be disabled to update the per-cpu stats
-			 * inside page_remove_rmap().
-			 */
-			spin_lock(ptl);
-			/*
-			 * paravirt calls inside pte_clear here are
-			 * superfluous.
-			 */
-			pte_clear(vma->vm_mm, address, _pte);
-			page_remove_rmap(src_page, false);
-			spin_unlock(ptl);
-			free_page_and_swap_cache(src_page);
-		}
-
-		address += PAGE_SIZE;
-		page++;
-	}
-}
-
-static void khugepaged_alloc_sleep(void)
-{
-	DEFINE_WAIT(wait);
-
-	add_wait_queue(&khugepaged_wait, &wait);
-	freezable_schedule_timeout_interruptible(
-		msecs_to_jiffies(khugepaged_alloc_sleep_millisecs));
-	remove_wait_queue(&khugepaged_wait, &wait);
-}
-
-static int khugepaged_node_load[MAX_NUMNODES];
-
-static bool khugepaged_scan_abort(int nid)
-{
-	int i;
-
-	/*
-	 * If zone_reclaim_mode is disabled, then no extra effort is made to
-	 * allocate memory locally.
-	 */
-	if (!zone_reclaim_mode)
-		return false;
-
-	/* If there is a count for this node already, it must be acceptable */
-	if (khugepaged_node_load[nid])
-		return false;
-
-	for (i = 0; i < MAX_NUMNODES; i++) {
-		if (!khugepaged_node_load[i])
-			continue;
-		if (node_distance(nid, i) > RECLAIM_DISTANCE)
-			return true;
-	}
-	return false;
-}
-
-#ifdef CONFIG_NUMA
-static int khugepaged_find_target_node(void)
-{
-	static int last_khugepaged_target_node = NUMA_NO_NODE;
-	int nid, target_node = 0, max_value = 0;
-
-	/* find first node with max normal pages hit */
-	for (nid = 0; nid < MAX_NUMNODES; nid++)
-		if (khugepaged_node_load[nid] > max_value) {
-			max_value = khugepaged_node_load[nid];
-			target_node = nid;
-		}
-
-	/* do some balance if several nodes have the same hit record */
-	if (target_node <= last_khugepaged_target_node)
-		for (nid = last_khugepaged_target_node + 1; nid < MAX_NUMNODES;
-				nid++)
-			if (max_value == khugepaged_node_load[nid]) {
-				target_node = nid;
-				break;
-			}
-
-	last_khugepaged_target_node = target_node;
-	return target_node;
-}
-
-static bool khugepaged_prealloc_page(struct page **hpage, bool *wait)
-{
-	if (IS_ERR(*hpage)) {
-		if (!*wait)
-			return false;
-
-		*wait = false;
-		*hpage = NULL;
-		khugepaged_alloc_sleep();
-	} else if (*hpage) {
-		put_page(*hpage);
-		*hpage = NULL;
-	}
-
-	return true;
-}
-
-static struct page *
-khugepaged_alloc_page(struct page **hpage, gfp_t gfp, struct mm_struct *mm,
-		       unsigned long address, int node)
-{
-	VM_BUG_ON_PAGE(*hpage, *hpage);
-
-	/*
-	 * Before allocating the hugepage, release the mmap_sem read lock.
-	 * The allocation can take potentially a long time if it involves
-	 * sync compaction, and we do not need to hold the mmap_sem during
-	 * that. We will recheck the vma after taking it again in write mode.
-	 */
-	up_read(&mm->mmap_sem);
-
-	*hpage = __alloc_pages_node(node, gfp, HPAGE_PMD_ORDER);
-	if (unlikely(!*hpage)) {
-		count_vm_event(THP_COLLAPSE_ALLOC_FAILED);
-		*hpage = ERR_PTR(-ENOMEM);
-		return NULL;
-	}
-
-	prep_transhuge_page(*hpage);
-	count_vm_event(THP_COLLAPSE_ALLOC);
-	return *hpage;
-}
-#else
-static int khugepaged_find_target_node(void)
-{
-	return 0;
-}
-
-static inline struct page *alloc_khugepaged_hugepage(void)
-{
-	struct page *page;
-
-	page = alloc_pages(alloc_hugepage_khugepaged_gfpmask(),
-			   HPAGE_PMD_ORDER);
-	if (page)
-		prep_transhuge_page(page);
-	return page;
-}
-
-static struct page *khugepaged_alloc_hugepage(bool *wait)
-{
-	struct page *hpage;
-
-	do {
-		hpage = alloc_khugepaged_hugepage();
-		if (!hpage) {
-			count_vm_event(THP_COLLAPSE_ALLOC_FAILED);
-			if (!*wait)
-				return NULL;
-
-			*wait = false;
-			khugepaged_alloc_sleep();
-		} else
-			count_vm_event(THP_COLLAPSE_ALLOC);
-	} while (unlikely(!hpage) && likely(khugepaged_enabled()));
-
-	return hpage;
-}
-
-static bool khugepaged_prealloc_page(struct page **hpage, bool *wait)
-{
-	if (!*hpage)
-		*hpage = khugepaged_alloc_hugepage(wait);
-
-	if (unlikely(!*hpage))
-		return false;
-
-	return true;
-}
-
-static struct page *
-khugepaged_alloc_page(struct page **hpage, gfp_t gfp, struct mm_struct *mm,
-		       unsigned long address, int node)
-{
-	up_read(&mm->mmap_sem);
-	VM_BUG_ON(!*hpage);
-
-	return  *hpage;
-}
-#endif
-
-static bool hugepage_vma_check(struct vm_area_struct *vma)
-{
-	if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) ||
-	    (vma->vm_flags & VM_NOHUGEPAGE))
-		return false;
-	if (!vma->anon_vma || vma->vm_ops)
-		return false;
-	if (is_vma_temporary_stack(vma))
-		return false;
-	return !(vma->vm_flags & VM_NO_THP);
-}
-
-static void collapse_huge_page(struct mm_struct *mm,
-				   unsigned long address,
-				   struct page **hpage,
-				   struct vm_area_struct *vma,
-				   int node)
-{
-	pmd_t *pmd, _pmd;
-	pte_t *pte;
-	pgtable_t pgtable;
-	struct page *new_page;
-	spinlock_t *pmd_ptl, *pte_ptl;
-	int isolated = 0, result = 0;
-	unsigned long hstart, hend;
-	struct mem_cgroup *memcg;
-	unsigned long mmun_start;	/* For mmu_notifiers */
-	unsigned long mmun_end;		/* For mmu_notifiers */
-	gfp_t gfp;
-
-	VM_BUG_ON(address & ~HPAGE_PMD_MASK);
-
-	/* Only allocate from the target node */
-	gfp = alloc_hugepage_khugepaged_gfpmask() | __GFP_OTHER_NODE | __GFP_THISNODE;
-
-	/* release the mmap_sem read lock. */
-	new_page = khugepaged_alloc_page(hpage, gfp, mm, address, node);
-	if (!new_page) {
-		result = SCAN_ALLOC_HUGE_PAGE_FAIL;
-		goto out_nolock;
-	}
-
-	if (unlikely(mem_cgroup_try_charge(new_page, mm, gfp, &memcg, true))) {
-		result = SCAN_CGROUP_CHARGE_FAIL;
-		goto out_nolock;
-	}
-
-	/*
-	 * Prevent all access to pagetables with the exception of
-	 * gup_fast later hanlded by the ptep_clear_flush and the VM
-	 * handled by the anon_vma lock + PG_lock.
-	 */
-	down_write(&mm->mmap_sem);
-	if (unlikely(khugepaged_test_exit(mm))) {
-		result = SCAN_ANY_PROCESS;
-		goto out;
-	}
-
-	vma = find_vma(mm, address);
-	if (!vma) {
-		result = SCAN_VMA_NULL;
-		goto out;
-	}
-	hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
-	hend = vma->vm_end & HPAGE_PMD_MASK;
-	if (address < hstart || address + HPAGE_PMD_SIZE > hend) {
-		result = SCAN_ADDRESS_RANGE;
-		goto out;
-	}
-	if (!hugepage_vma_check(vma)) {
-		result = SCAN_VMA_CHECK;
-		goto out;
-	}
-	pmd = mm_find_pmd(mm, address);
-	if (!pmd) {
-		result = SCAN_PMD_NULL;
-		goto out;
-	}
-
-	anon_vma_lock_write(vma->anon_vma);
-
-	pte = pte_offset_map(pmd, address);
-	pte_ptl = pte_lockptr(mm, pmd);
-
-	mmun_start = address;
-	mmun_end   = address + HPAGE_PMD_SIZE;
-	mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
-	pmd_ptl = pmd_lock(mm, pmd); /* probably unnecessary */
-	/*
-	 * After this gup_fast can't run anymore. This also removes
-	 * any huge TLB entry from the CPU so we won't allow
-	 * huge and small TLB entries for the same virtual address
-	 * to avoid the risk of CPU bugs in that area.
-	 */
-	_pmd = pmdp_collapse_flush(vma, address, pmd);
-	spin_unlock(pmd_ptl);
-	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
-
-	spin_lock(pte_ptl);
-	isolated = __collapse_huge_page_isolate(vma, address, pte);
-	spin_unlock(pte_ptl);
-
-	if (unlikely(!isolated)) {
-		pte_unmap(pte);
-		spin_lock(pmd_ptl);
-		BUG_ON(!pmd_none(*pmd));
-		/*
-		 * We can only use set_pmd_at when establishing
-		 * hugepmds and never for establishing regular pmds that
-		 * points to regular pagetables. Use pmd_populate for that
-		 */
-		pmd_populate(mm, pmd, pmd_pgtable(_pmd));
-		spin_unlock(pmd_ptl);
-		anon_vma_unlock_write(vma->anon_vma);
-		result = SCAN_FAIL;
-		goto out;
-	}
-
-	/*
-	 * All pages are isolated and locked so anon_vma rmap
-	 * can't run anymore.
-	 */
-	anon_vma_unlock_write(vma->anon_vma);
-
-	__collapse_huge_page_copy(pte, new_page, vma, address, pte_ptl);
-	pte_unmap(pte);
-	__SetPageUptodate(new_page);
-	pgtable = pmd_pgtable(_pmd);
-
-	_pmd = mk_huge_pmd(new_page, vma->vm_page_prot);
-	_pmd = maybe_pmd_mkwrite(pmd_mkdirty(_pmd), vma);
-
-	/*
-	 * spin_lock() below is not the equivalent of smp_wmb(), so
-	 * this is needed to avoid the copy_huge_page writes to become
-	 * visible after the set_pmd_at() write.
-	 */
-	smp_wmb();
-
-	spin_lock(pmd_ptl);
-	BUG_ON(!pmd_none(*pmd));
-	page_add_new_anon_rmap(new_page, vma, address, true);
-	mem_cgroup_commit_charge(new_page, memcg, false, true);
-	lru_cache_add_active_or_unevictable(new_page, vma);
-	pgtable_trans_huge_deposit(mm, pmd, pgtable);
-	set_pmd_at(mm, address, pmd, _pmd);
-	update_mmu_cache_pmd(vma, address, pmd);
-	spin_unlock(pmd_ptl);
-
-	*hpage = NULL;
-
-	khugepaged_pages_collapsed++;
-	result = SCAN_SUCCEED;
-out_up_write:
-	up_write(&mm->mmap_sem);
-	trace_mm_collapse_huge_page(mm, isolated, result);
-	return;
-
-out_nolock:
-	trace_mm_collapse_huge_page(mm, isolated, result);
-	return;
-out:
-	mem_cgroup_cancel_charge(new_page, memcg, true);
-	goto out_up_write;
-}
-
-static int khugepaged_scan_pmd(struct mm_struct *mm,
-			       struct vm_area_struct *vma,
-			       unsigned long address,
-			       struct page **hpage)
-{
-	pmd_t *pmd;
-	pte_t *pte, *_pte;
-	int ret = 0, none_or_zero = 0, result = 0;
-	struct page *page = NULL;
-	unsigned long _address;
-	spinlock_t *ptl;
-	int node = NUMA_NO_NODE;
-	bool writable = false, referenced = false;
-
-	VM_BUG_ON(address & ~HPAGE_PMD_MASK);
-
-	pmd = mm_find_pmd(mm, address);
-	if (!pmd) {
-		result = SCAN_PMD_NULL;
-		goto out;
-	}
-
-	memset(khugepaged_node_load, 0, sizeof(khugepaged_node_load));
-	pte = pte_offset_map_lock(mm, pmd, address, &ptl);
-	for (_address = address, _pte = pte; _pte < pte+HPAGE_PMD_NR;
-	     _pte++, _address += PAGE_SIZE) {
-		pte_t pteval = *_pte;
-		if (pte_none(pteval) || is_zero_pfn(pte_pfn(pteval))) {
-			if (!userfaultfd_armed(vma) &&
-			    ++none_or_zero <= khugepaged_max_ptes_none) {
-				continue;
-			} else {
-				result = SCAN_EXCEED_NONE_PTE;
-				goto out_unmap;
-			}
-		}
-		if (!pte_present(pteval)) {
-			result = SCAN_PTE_NON_PRESENT;
-			goto out_unmap;
-		}
-		if (pte_write(pteval))
-			writable = true;
-
-		page = vm_normal_page(vma, _address, pteval);
-		if (unlikely(!page)) {
-			result = SCAN_PAGE_NULL;
-			goto out_unmap;
-		}
-
-		/* TODO: teach khugepaged to collapse THP mapped with pte */
-		if (PageCompound(page)) {
-			result = SCAN_PAGE_COMPOUND;
-			goto out_unmap;
-		}
-
-		/*
-		 * Record which node the original page is from and save this
-		 * information to khugepaged_node_load[].
-		 * Khupaged will allocate hugepage from the node has the max
-		 * hit record.
-		 */
-		node = page_to_nid(page);
-		if (khugepaged_scan_abort(node)) {
-			result = SCAN_SCAN_ABORT;
-			goto out_unmap;
-		}
-		khugepaged_node_load[node]++;
-		if (!PageLRU(page)) {
-			result = SCAN_PAGE_LRU;
-			goto out_unmap;
-		}
-		if (PageLocked(page)) {
-			result = SCAN_PAGE_LOCK;
-			goto out_unmap;
-		}
-		if (!PageAnon(page)) {
-			result = SCAN_PAGE_ANON;
-			goto out_unmap;
-		}
-
-		/*
-		 * cannot use mapcount: can't collapse if there's a gup pin.
-		 * The page must only be referenced by the scanned process
-		 * and page swap cache.
-		 */
-		if (page_count(page) != 1 + !!PageSwapCache(page)) {
-			result = SCAN_PAGE_COUNT;
-			goto out_unmap;
-		}
-		if (pte_young(pteval) ||
-		    page_is_young(page) || PageReferenced(page) ||
-		    mmu_notifier_test_young(vma->vm_mm, address))
-			referenced = true;
-	}
-	if (writable) {
-		if (referenced) {
-			result = SCAN_SUCCEED;
-			ret = 1;
-		} else {
-			result = SCAN_NO_REFERENCED_PAGE;
-		}
-	} else {
-		result = SCAN_PAGE_RO;
-	}
-out_unmap:
-	pte_unmap_unlock(pte, ptl);
-	if (ret) {
-		node = khugepaged_find_target_node();
-		/* collapse_huge_page will return with the mmap_sem released */
-		collapse_huge_page(mm, address, hpage, vma, node);
-	}
-out:
-	trace_mm_khugepaged_scan_pmd(mm, page, writable, referenced,
-				     none_or_zero, result);
-	return ret;
-}
-
-static void collect_mm_slot(struct mm_slot *mm_slot)
-{
-	struct mm_struct *mm = mm_slot->mm;
-
-	VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock));
-
-	if (khugepaged_test_exit(mm)) {
-		/* free mm_slot */
-		hash_del(&mm_slot->hash);
-		list_del(&mm_slot->mm_node);
-
-		/*
-		 * Not strictly needed because the mm exited already.
-		 *
-		 * clear_bit(MMF_VM_HUGEPAGE, &mm->flags);
-		 */
-
-		/* khugepaged_mm_lock actually not necessary for the below */
-		free_mm_slot(mm_slot);
-		mmdrop(mm);
-	}
-}
-
-static unsigned int khugepaged_scan_mm_slot(unsigned int pages,
-					    struct page **hpage)
-	__releases(&khugepaged_mm_lock)
-	__acquires(&khugepaged_mm_lock)
-{
-	struct mm_slot *mm_slot;
-	struct mm_struct *mm;
-	struct vm_area_struct *vma;
-	int progress = 0;
-
-	VM_BUG_ON(!pages);
-	VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock));
-
-	if (khugepaged_scan.mm_slot)
-		mm_slot = khugepaged_scan.mm_slot;
-	else {
-		mm_slot = list_entry(khugepaged_scan.mm_head.next,
-				     struct mm_slot, mm_node);
-		khugepaged_scan.address = 0;
-		khugepaged_scan.mm_slot = mm_slot;
-	}
-	spin_unlock(&khugepaged_mm_lock);
-
-	mm = mm_slot->mm;
-	down_read(&mm->mmap_sem);
-	if (unlikely(khugepaged_test_exit(mm)))
-		vma = NULL;
-	else
-		vma = find_vma(mm, khugepaged_scan.address);
-
-	progress++;
-	for (; vma; vma = vma->vm_next) {
-		unsigned long hstart, hend;
-
-		cond_resched();
-		if (unlikely(khugepaged_test_exit(mm))) {
-			progress++;
-			break;
-		}
-		if (!hugepage_vma_check(vma)) {
-skip:
-			progress++;
-			continue;
-		}
-		hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
-		hend = vma->vm_end & HPAGE_PMD_MASK;
-		if (hstart >= hend)
-			goto skip;
-		if (khugepaged_scan.address > hend)
-			goto skip;
-		if (khugepaged_scan.address < hstart)
-			khugepaged_scan.address = hstart;
-		VM_BUG_ON(khugepaged_scan.address & ~HPAGE_PMD_MASK);
-
-		while (khugepaged_scan.address < hend) {
-			int ret;
-			cond_resched();
-			if (unlikely(khugepaged_test_exit(mm)))
-				goto breakouterloop;
-
-			VM_BUG_ON(khugepaged_scan.address < hstart ||
-				  khugepaged_scan.address + HPAGE_PMD_SIZE >
-				  hend);
-			ret = khugepaged_scan_pmd(mm, vma,
-						  khugepaged_scan.address,
-						  hpage);
-			/* move to next address */
-			khugepaged_scan.address += HPAGE_PMD_SIZE;
-			progress += HPAGE_PMD_NR;
-			if (ret)
-				/* we released mmap_sem so break loop */
-				goto breakouterloop_mmap_sem;
-			if (progress >= pages)
-				goto breakouterloop;
-		}
-	}
-breakouterloop:
-	up_read(&mm->mmap_sem); /* exit_mmap will destroy ptes after this */
-breakouterloop_mmap_sem:
-
-	spin_lock(&khugepaged_mm_lock);
-	VM_BUG_ON(khugepaged_scan.mm_slot != mm_slot);
-	/*
-	 * Release the current mm_slot if this mm is about to die, or
-	 * if we scanned all vmas of this mm.
-	 */
-	if (khugepaged_test_exit(mm) || !vma) {
-		/*
-		 * Make sure that if mm_users is reaching zero while
-		 * khugepaged runs here, khugepaged_exit will find
-		 * mm_slot not pointing to the exiting mm.
-		 */
-		if (mm_slot->mm_node.next != &khugepaged_scan.mm_head) {
-			khugepaged_scan.mm_slot = list_entry(
-				mm_slot->mm_node.next,
-				struct mm_slot, mm_node);
-			khugepaged_scan.address = 0;
-		} else {
-			khugepaged_scan.mm_slot = NULL;
-			khugepaged_full_scans++;
-		}
-
-		collect_mm_slot(mm_slot);
-	}
-
-	return progress;
-}
-
-static int khugepaged_has_work(void)
-{
-	return !list_empty(&khugepaged_scan.mm_head) &&
-		khugepaged_enabled();
-}
-
-static int khugepaged_wait_event(void)
-{
-	return !list_empty(&khugepaged_scan.mm_head) ||
-		kthread_should_stop();
-}
-
-static void khugepaged_do_scan(void)
-{
-	struct page *hpage = NULL;
-	unsigned int progress = 0, pass_through_head = 0;
-	unsigned int pages = khugepaged_pages_to_scan;
-	bool wait = true;
-
-	barrier(); /* write khugepaged_pages_to_scan to local stack */
-
-	while (progress < pages) {
-		if (!khugepaged_prealloc_page(&hpage, &wait))
-			break;
-
-		cond_resched();
-
-		if (unlikely(kthread_should_stop() || try_to_freeze()))
-			break;
-
-		spin_lock(&khugepaged_mm_lock);
-		if (!khugepaged_scan.mm_slot)
-			pass_through_head++;
-		if (khugepaged_has_work() &&
-		    pass_through_head < 2)
-			progress += khugepaged_scan_mm_slot(pages - progress,
-							    &hpage);
-		else
-			progress = pages;
-		spin_unlock(&khugepaged_mm_lock);
-	}
-
-	if (!IS_ERR_OR_NULL(hpage))
-		put_page(hpage);
-}
-
-static bool khugepaged_should_wakeup(void)
-{
-	return kthread_should_stop() ||
-	       time_after_eq(jiffies, khugepaged_sleep_expire);
-}
-
-static void khugepaged_wait_work(void)
-{
-	if (khugepaged_has_work()) {
-		const unsigned long scan_sleep_jiffies =
-			msecs_to_jiffies(khugepaged_scan_sleep_millisecs);
-
-		if (!scan_sleep_jiffies)
-			return;
-
-		khugepaged_sleep_expire = jiffies + scan_sleep_jiffies;
-		wait_event_freezable_timeout(khugepaged_wait,
-					     khugepaged_should_wakeup(),
-					     scan_sleep_jiffies);
-		return;
-	}
-
-	if (khugepaged_enabled())
-		wait_event_freezable(khugepaged_wait, khugepaged_wait_event());
-}
-
-static int khugepaged(void *none)
-{
-	struct mm_slot *mm_slot;
-
-	set_freezable();
-	set_user_nice(current, MAX_NICE);
-
-	while (!kthread_should_stop()) {
-		khugepaged_do_scan();
-		khugepaged_wait_work();
-	}
-
-	spin_lock(&khugepaged_mm_lock);
-	mm_slot = khugepaged_scan.mm_slot;
-	khugepaged_scan.mm_slot = NULL;
-	if (mm_slot)
-		collect_mm_slot(mm_slot);
-	spin_unlock(&khugepaged_mm_lock);
-	return 0;
-}
-
 static void __split_huge_zero_page_pmd(struct vm_area_struct *vma,
 		unsigned long haddr, pmd_t *pmd)
 {
@@ -2883,10 +1519,18 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
 
 	count_vm_event(THP_SPLIT_PMD);
 
-	if (vma_is_dax(vma)) {
-		pmd_t _pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd);
+	if (!vma_is_anonymous(vma)) {
+		_pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd);
 		if (is_huge_zero_pmd(_pmd))
 			put_huge_zero_page();
+		if (vma_is_dax(vma))
+			return;
+		page = pmd_page(_pmd);
+		if (!PageReferenced(page) && pmd_young(_pmd))
+			SetPageReferenced(page);
+		page_remove_rmap(page, true);
+		put_page(page);
+		add_mm_counter(mm, MM_FILEPAGES, -HPAGE_PMD_NR);
 		return;
 	} else if (is_huge_zero_pmd(*pmd)) {
 		return __split_huge_zero_page_pmd(vma, haddr, pmd);
@@ -2942,7 +1586,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
 
 	if (atomic_add_negative(-1, compound_mapcount_ptr(page))) {
 		/* Last compound_mapcount is gone. */
-		__dec_zone_page_state(page, NR_ANON_TRANSPARENT_HUGEPAGES);
+		__dec_zone_page_state(page, NR_ANON_THPS);
 		if (TestClearPageDoubleMap(page)) {
 			/* No need in mapcount reference anymore */
 			for (i = 0; i < HPAGE_PMD_NR; i++)
@@ -3076,12 +1720,15 @@ void vma_adjust_trans_huge(struct vm_area_struct *vma,
 
 static void freeze_page(struct page *page)
 {
-	enum ttu_flags ttu_flags = TTU_MIGRATION | TTU_IGNORE_MLOCK |
-		TTU_IGNORE_ACCESS | TTU_RMAP_LOCKED;
+	enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS |
+		TTU_RMAP_LOCKED;
 	int i, ret;
 
 	VM_BUG_ON_PAGE(!PageHead(page), page);
 
+	if (PageAnon(page))
+		ttu_flags |= TTU_MIGRATION;
+
 	/* We only need TTU_SPLIT_HUGE_PMD once */
 	ret = try_to_unmap(page, ttu_flags | TTU_SPLIT_HUGE_PMD);
 	for (i = 1; !ret && i < HPAGE_PMD_NR; i++) {
@@ -3091,7 +1738,7 @@ static void freeze_page(struct page *page)
 
 		ret = try_to_unmap(page + i, ttu_flags);
 	}
-	VM_BUG_ON(ret);
+	VM_BUG_ON_PAGE(ret, page + i - 1);
 }
 
 static void unfreeze_page(struct page *page)
@@ -3113,15 +1760,20 @@ static void __split_huge_page_tail(struct page *head, int tail,
 	/*
 	 * tail_page->_refcount is zero and not changing from under us. But
 	 * get_page_unless_zero() may be running from under us on the
-	 * tail_page. If we used atomic_set() below instead of atomic_inc(), we
-	 * would then run atomic_set() concurrently with
+	 * tail_page. If we used atomic_set() below instead of atomic_inc() or
+	 * atomic_add(), we would then run atomic_set() concurrently with
 	 * get_page_unless_zero(), and atomic_set() is implemented in C not
 	 * using locked ops. spin_unlock on x86 sometime uses locked ops
 	 * because of PPro errata 66, 92, so unless somebody can guarantee
 	 * atomic_set() here would be safe on all archs (and not only on x86),
-	 * it's safer to use atomic_inc().
+	 * it's safer to use atomic_inc()/atomic_add().
 	 */
-	page_ref_inc(page_tail);
+	if (PageAnon(head)) {
+		page_ref_inc(page_tail);
+	} else {
+		/* Additional pin to radix tree */
+		page_ref_add(page_tail, 2);
+	}
 
 	page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
 	page_tail->flags |= (head->flags &
@@ -3157,25 +1809,46 @@ static void __split_huge_page_tail(struct page *head, int tail,
 	lru_add_page_tail(head, page_tail, lruvec, list);
 }
 
-static void __split_huge_page(struct page *page, struct list_head *list)
+static void __split_huge_page(struct page *page, struct list_head *list,
+		unsigned long flags)
 {
 	struct page *head = compound_head(page);
 	struct zone *zone = page_zone(head);
 	struct lruvec *lruvec;
+	pgoff_t end = -1;
 	int i;
 
-	/* prevent PageLRU to go away from under us, and freeze lru stats */
-	spin_lock_irq(&zone->lru_lock);
 	lruvec = mem_cgroup_page_lruvec(head, zone);
 
 	/* complete memcg works before add pages to LRU */
 	mem_cgroup_split_huge_fixup(head);
 
-	for (i = HPAGE_PMD_NR - 1; i >= 1; i--)
+	if (!PageAnon(page))
+		end = DIV_ROUND_UP(i_size_read(head->mapping->host), PAGE_SIZE);
+
+	for (i = HPAGE_PMD_NR - 1; i >= 1; i--) {
 		__split_huge_page_tail(head, i, lruvec, list);
+		/* Some pages can be beyond i_size: drop them from page cache */
+		if (head[i].index >= end) {
+			__ClearPageDirty(head + i);
+			__delete_from_page_cache(head + i, NULL);
+			if (IS_ENABLED(CONFIG_SHMEM) && PageSwapBacked(head))
+				shmem_uncharge(head->mapping->host, 1);
+			put_page(head + i);
+		}
+	}
 
 	ClearPageCompound(head);
-	spin_unlock_irq(&zone->lru_lock);
+	/* See comment in __split_huge_page_tail() */
+	if (PageAnon(head)) {
+		page_ref_inc(head);
+	} else {
+		/* Additional pin to radix tree */
+		page_ref_add(head, 2);
+		spin_unlock(&head->mapping->tree_lock);
+	}
+
+	spin_unlock_irqrestore(&page_zone(head)->lru_lock, flags);
 
 	unfreeze_page(head);
 
@@ -3198,18 +1871,22 @@ static void __split_huge_page(struct page *page, struct list_head *list)
 
 int total_mapcount(struct page *page)
 {
-	int i, ret;
+	int i, compound, ret;
 
 	VM_BUG_ON_PAGE(PageTail(page), page);
 
 	if (likely(!PageCompound(page)))
 		return atomic_read(&page->_mapcount) + 1;
 
-	ret = compound_mapcount(page);
+	compound = compound_mapcount(page);
 	if (PageHuge(page))
-		return ret;
+		return compound;
+	ret = compound;
 	for (i = 0; i < HPAGE_PMD_NR; i++)
 		ret += atomic_read(&page[i]._mapcount) + 1;
+	/* File pages has compound_mapcount included in _mapcount */
+	if (!PageAnon(page))
+		return ret - compound * HPAGE_PMD_NR;
 	if (PageDoubleMap(page))
 		ret -= HPAGE_PMD_NR;
 	return ret;
@@ -3296,36 +1973,54 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
 {
 	struct page *head = compound_head(page);
 	struct pglist_data *pgdata = NODE_DATA(page_to_nid(head));
-	struct anon_vma *anon_vma;
-	int count, mapcount, ret;
+	struct anon_vma *anon_vma = NULL;
+	struct address_space *mapping = NULL;
+	int count, mapcount, extra_pins, ret;
 	bool mlocked;
 	unsigned long flags;
 
 	VM_BUG_ON_PAGE(is_huge_zero_page(page), page);
-	VM_BUG_ON_PAGE(!PageAnon(page), page);
 	VM_BUG_ON_PAGE(!PageLocked(page), page);
 	VM_BUG_ON_PAGE(!PageSwapBacked(page), page);
 	VM_BUG_ON_PAGE(!PageCompound(page), page);
 
-	/*
-	 * The caller does not necessarily hold an mmap_sem that would prevent
-	 * the anon_vma disappearing so we first we take a reference to it
-	 * and then lock the anon_vma for write. This is similar to
-	 * page_lock_anon_vma_read except the write lock is taken to serialise
-	 * against parallel split or collapse operations.
-	 */
-	anon_vma = page_get_anon_vma(head);
-	if (!anon_vma) {
-		ret = -EBUSY;
-		goto out;
+	if (PageAnon(head)) {
+		/*
+		 * The caller does not necessarily hold an mmap_sem that would
+		 * prevent the anon_vma disappearing so we first we take a
+		 * reference to it and then lock the anon_vma for write. This
+		 * is similar to page_lock_anon_vma_read except the write lock
+		 * is taken to serialise against parallel split or collapse
+		 * operations.
+		 */
+		anon_vma = page_get_anon_vma(head);
+		if (!anon_vma) {
+			ret = -EBUSY;
+			goto out;
+		}
+		extra_pins = 0;
+		mapping = NULL;
+		anon_vma_lock_write(anon_vma);
+	} else {
+		mapping = head->mapping;
+
+		/* Truncated ? */
+		if (!mapping) {
+			ret = -EBUSY;
+			goto out;
+		}
+
+		/* Addidional pins from radix tree */
+		extra_pins = HPAGE_PMD_NR;
+		anon_vma = NULL;
+		i_mmap_lock_read(mapping);
 	}
-	anon_vma_lock_write(anon_vma);
 
 	/*
 	 * Racy check if we can split the page, before freeze_page() will
 	 * split PMDs
 	 */
-	if (total_mapcount(head) != page_count(head) - 1) {
+	if (total_mapcount(head) != page_count(head) - extra_pins - 1) {
 		ret = -EBUSY;
 		goto out_unlock;
 	}
@@ -3338,35 +2033,62 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
 	if (mlocked)
 		lru_add_drain();
 
+	/* prevent PageLRU to go away from under us, and freeze lru stats */
+	spin_lock_irqsave(&page_zone(head)->lru_lock, flags);
+
+	if (mapping) {
+		void **pslot;
+
+		spin_lock(&mapping->tree_lock);
+		pslot = radix_tree_lookup_slot(&mapping->page_tree,
+				page_index(head));
+		/*
+		 * Check if the head page is present in radix tree.
+		 * We assume all tail are present too, if head is there.
+		 */
+		if (radix_tree_deref_slot_protected(pslot,
+					&mapping->tree_lock) != head)
+			goto fail;
+	}
+
 	/* Prevent deferred_split_scan() touching ->_refcount */
-	spin_lock_irqsave(&pgdata->split_queue_lock, flags);
+	spin_lock(&pgdata->split_queue_lock);
 	count = page_count(head);
 	mapcount = total_mapcount(head);
-	if (!mapcount && count == 1) {
+	if (!mapcount && page_ref_freeze(head, 1 + extra_pins)) {
 		if (!list_empty(page_deferred_list(head))) {
 			pgdata->split_queue_len--;
 			list_del(page_deferred_list(head));
 		}
-		spin_unlock_irqrestore(&pgdata->split_queue_lock, flags);
-		__split_huge_page(page, list);
+		if (mapping)
+			__dec_zone_page_state(page, NR_SHMEM_THPS);
+		spin_unlock(&pgdata->split_queue_lock);
+		__split_huge_page(page, list, flags);
 		ret = 0;
-	} else if (IS_ENABLED(CONFIG_DEBUG_VM) && mapcount) {
-		spin_unlock_irqrestore(&pgdata->split_queue_lock, flags);
-		pr_alert("total_mapcount: %u, page_count(): %u\n",
-				mapcount, count);
-		if (PageTail(page))
-			dump_page(head, NULL);
-		dump_page(page, "total_mapcount(head) > 0");
-		BUG();
 	} else {
-		spin_unlock_irqrestore(&pgdata->split_queue_lock, flags);
+		if (IS_ENABLED(CONFIG_DEBUG_VM) && mapcount) {
+			pr_alert("total_mapcount: %u, page_count(): %u\n",
+					mapcount, count);
+			if (PageTail(page))
+				dump_page(head, NULL);
+			dump_page(page, "total_mapcount(head) > 0");
+			BUG();
+		}
+		spin_unlock(&pgdata->split_queue_lock);
+fail:		if (mapping)
+			spin_unlock(&mapping->tree_lock);
+		spin_unlock_irqrestore(&page_zone(head)->lru_lock, flags);
 		unfreeze_page(head);
 		ret = -EBUSY;
 	}
 
 out_unlock:
-	anon_vma_unlock_write(anon_vma);
-	put_anon_vma(anon_vma);
+	if (anon_vma) {
+		anon_vma_unlock_write(anon_vma);
+		put_anon_vma(anon_vma);
+	}
+	if (mapping)
+		i_mmap_unlock_read(mapping);
 out:
 	count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED);
 	return ret;
@@ -3489,8 +2211,7 @@ static int split_huge_pages_set(void *data, u64 val)
 			if (zone != page_zone(page))
 				goto next;
 
-			if (!PageHead(page) || !PageAnon(page) ||
-					PageHuge(page))
+			if (!PageHead(page) || PageHuge(page) || !PageLRU(page))
 				goto next;
 
 			total++;
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index cc2a99e9cbc8..abc1c5fb7222 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3179,7 +3179,6 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
 			    unsigned long start, unsigned long end,
 			    struct page *ref_page)
 {
-	int force_flush = 0;
 	struct mm_struct *mm = vma->vm_mm;
 	unsigned long address;
 	pte_t *ptep;
@@ -3198,19 +3197,22 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
 	tlb_start_vma(tlb, vma);
 	mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
 	address = start;
-again:
 	for (; address < end; address += sz) {
 		ptep = huge_pte_offset(mm, address);
 		if (!ptep)
 			continue;
 
 		ptl = huge_pte_lock(h, mm, ptep);
-		if (huge_pmd_unshare(mm, &address, ptep))
-			goto unlock;
+		if (huge_pmd_unshare(mm, &address, ptep)) {
+			spin_unlock(ptl);
+			continue;
+		}
 
 		pte = huge_ptep_get(ptep);
-		if (huge_pte_none(pte))
-			goto unlock;
+		if (huge_pte_none(pte)) {
+			spin_unlock(ptl);
+			continue;
+		}
 
 		/*
 		 * Migrating hugepage or HWPoisoned hugepage is already
@@ -3218,7 +3220,8 @@ again:
 		 */
 		if (unlikely(!pte_present(pte))) {
 			huge_pte_clear(mm, address, ptep);
-			goto unlock;
+			spin_unlock(ptl);
+			continue;
 		}
 
 		page = pte_page(pte);
@@ -3228,9 +3231,10 @@ again:
 		 * are about to unmap is the actual page of interest.
 		 */
 		if (ref_page) {
-			if (page != ref_page)
-				goto unlock;
-
+			if (page != ref_page) {
+				spin_unlock(ptl);
+				continue;
+			}
 			/*
 			 * Mark the VMA as having unmapped its page so that
 			 * future faults in this VMA will fail rather than
@@ -3246,30 +3250,14 @@ again:
 
 		hugetlb_count_sub(pages_per_huge_page(h), mm);
 		page_remove_rmap(page, true);
-		force_flush = !__tlb_remove_page(tlb, page);
-		if (force_flush) {
-			address += sz;
-			spin_unlock(ptl);
-			break;
-		}
-		/* Bail out after unmapping reference page if supplied */
-		if (ref_page) {
-			spin_unlock(ptl);
-			break;
-		}
-unlock:
+
 		spin_unlock(ptl);
-	}
-	/*
-	 * mmu_gather ran out of room to batch pages, we break out of
-	 * the PTE lock to avoid doing the potential expensive TLB invalidate
-	 * and page-free while holding it.
-	 */
-	if (force_flush) {
-		force_flush = 0;
-		tlb_flush_mmu(tlb);
-		if (address < end && !ref_page)
-			goto again;
+		tlb_remove_page_size(tlb, page, huge_page_size(h));
+		/*
+		 * Bail out after unmapping reference page if supplied
+		 */
+		if (ref_page)
+			break;
 	}
 	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
 	tlb_end_vma(tlb, vma);
diff --git a/mm/internal.h b/mm/internal.h
index 2524ec880e24..9b6a6c43ac39 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -36,6 +36,8 @@
 /* Do not use these with a slab allocator */
 #define GFP_SLAB_BUG_MASK (__GFP_DMA32|__GFP_HIGHMEM|~__GFP_BITS_MASK)
 
+int do_swap_page(struct fault_env *fe, pte_t orig_pte);
+
 void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
 		unsigned long floor, unsigned long ceiling);
 
@@ -150,6 +152,8 @@ extern int __isolate_free_page(struct page *page, unsigned int order);
 extern void __free_pages_bootmem(struct page *page, unsigned long pfn,
 					unsigned int order);
 extern void prep_compound_page(struct page *page, unsigned int order);
+extern void post_alloc_hook(struct page *page, unsigned int order,
+					gfp_t gfp_flags);
 extern int user_min_free_kbytes;
 
 #if defined CONFIG_COMPACTION || defined CONFIG_CMA
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
new file mode 100644
index 000000000000..7dbee698d6aa
--- /dev/null
+++ b/mm/khugepaged.c
@@ -0,0 +1,1922 @@
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/mmu_notifier.h>
+#include <linux/rmap.h>
+#include <linux/swap.h>
+#include <linux/mm_inline.h>
+#include <linux/kthread.h>
+#include <linux/khugepaged.h>
+#include <linux/freezer.h>
+#include <linux/mman.h>
+#include <linux/hashtable.h>
+#include <linux/userfaultfd_k.h>
+#include <linux/page_idle.h>
+#include <linux/swapops.h>
+#include <linux/shmem_fs.h>
+
+#include <asm/tlb.h>
+#include <asm/pgalloc.h>
+#include "internal.h"
+
+enum scan_result {
+	SCAN_FAIL,
+	SCAN_SUCCEED,
+	SCAN_PMD_NULL,
+	SCAN_EXCEED_NONE_PTE,
+	SCAN_PTE_NON_PRESENT,
+	SCAN_PAGE_RO,
+	SCAN_LACK_REFERENCED_PAGE,
+	SCAN_PAGE_NULL,
+	SCAN_SCAN_ABORT,
+	SCAN_PAGE_COUNT,
+	SCAN_PAGE_LRU,
+	SCAN_PAGE_LOCK,
+	SCAN_PAGE_ANON,
+	SCAN_PAGE_COMPOUND,
+	SCAN_ANY_PROCESS,
+	SCAN_VMA_NULL,
+	SCAN_VMA_CHECK,
+	SCAN_ADDRESS_RANGE,
+	SCAN_SWAP_CACHE_PAGE,
+	SCAN_DEL_PAGE_LRU,
+	SCAN_ALLOC_HUGE_PAGE_FAIL,
+	SCAN_CGROUP_CHARGE_FAIL,
+	SCAN_EXCEED_SWAP_PTE,
+	SCAN_TRUNCATED,
+};
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/huge_memory.h>
+
+/* default scan 8*512 pte (or vmas) every 30 second */
+static unsigned int khugepaged_pages_to_scan __read_mostly;
+static unsigned int khugepaged_pages_collapsed;
+static unsigned int khugepaged_full_scans;
+static unsigned int khugepaged_scan_sleep_millisecs __read_mostly = 10000;
+/* during fragmentation poll the hugepage allocator once every minute */
+static unsigned int khugepaged_alloc_sleep_millisecs __read_mostly = 60000;
+static unsigned long khugepaged_sleep_expire;
+static DEFINE_SPINLOCK(khugepaged_mm_lock);
+static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait);
+/*
+ * default collapse hugepages if there is at least one pte mapped like
+ * it would have happened if the vma was large enough during page
+ * fault.
+ */
+static unsigned int khugepaged_max_ptes_none __read_mostly;
+static unsigned int khugepaged_max_ptes_swap __read_mostly;
+
+#define MM_SLOTS_HASH_BITS 10
+static __read_mostly DEFINE_HASHTABLE(mm_slots_hash, MM_SLOTS_HASH_BITS);
+
+static struct kmem_cache *mm_slot_cache __read_mostly;
+
+/**
+ * struct mm_slot - hash lookup from mm to mm_slot
+ * @hash: hash collision list
+ * @mm_node: khugepaged scan list headed in khugepaged_scan.mm_head
+ * @mm: the mm that this information is valid for
+ */
+struct mm_slot {
+	struct hlist_node hash;
+	struct list_head mm_node;
+	struct mm_struct *mm;
+};
+
+/**
+ * struct khugepaged_scan - cursor for scanning
+ * @mm_head: the head of the mm list to scan
+ * @mm_slot: the current mm_slot we are scanning
+ * @address: the next address inside that to be scanned
+ *
+ * There is only the one khugepaged_scan instance of this cursor structure.
+ */
+struct khugepaged_scan {
+	struct list_head mm_head;
+	struct mm_slot *mm_slot;
+	unsigned long address;
+};
+
+static struct khugepaged_scan khugepaged_scan = {
+	.mm_head = LIST_HEAD_INIT(khugepaged_scan.mm_head),
+};
+
+static ssize_t scan_sleep_millisecs_show(struct kobject *kobj,
+					 struct kobj_attribute *attr,
+					 char *buf)
+{
+	return sprintf(buf, "%u\n", khugepaged_scan_sleep_millisecs);
+}
+
+static ssize_t scan_sleep_millisecs_store(struct kobject *kobj,
+					  struct kobj_attribute *attr,
+					  const char *buf, size_t count)
+{
+	unsigned long msecs;
+	int err;
+
+	err = kstrtoul(buf, 10, &msecs);
+	if (err || msecs > UINT_MAX)
+		return -EINVAL;
+
+	khugepaged_scan_sleep_millisecs = msecs;
+	khugepaged_sleep_expire = 0;
+	wake_up_interruptible(&khugepaged_wait);
+
+	return count;
+}
+static struct kobj_attribute scan_sleep_millisecs_attr =
+	__ATTR(scan_sleep_millisecs, 0644, scan_sleep_millisecs_show,
+	       scan_sleep_millisecs_store);
+
+static ssize_t alloc_sleep_millisecs_show(struct kobject *kobj,
+					  struct kobj_attribute *attr,
+					  char *buf)
+{
+	return sprintf(buf, "%u\n", khugepaged_alloc_sleep_millisecs);
+}
+
+static ssize_t alloc_sleep_millisecs_store(struct kobject *kobj,
+					   struct kobj_attribute *attr,
+					   const char *buf, size_t count)
+{
+	unsigned long msecs;
+	int err;
+
+	err = kstrtoul(buf, 10, &msecs);
+	if (err || msecs > UINT_MAX)
+		return -EINVAL;
+
+	khugepaged_alloc_sleep_millisecs = msecs;
+	khugepaged_sleep_expire = 0;
+	wake_up_interruptible(&khugepaged_wait);
+
+	return count;
+}
+static struct kobj_attribute alloc_sleep_millisecs_attr =
+	__ATTR(alloc_sleep_millisecs, 0644, alloc_sleep_millisecs_show,
+	       alloc_sleep_millisecs_store);
+
+static ssize_t pages_to_scan_show(struct kobject *kobj,
+				  struct kobj_attribute *attr,
+				  char *buf)
+{
+	return sprintf(buf, "%u\n", khugepaged_pages_to_scan);
+}
+static ssize_t pages_to_scan_store(struct kobject *kobj,
+				   struct kobj_attribute *attr,
+				   const char *buf, size_t count)
+{
+	int err;
+	unsigned long pages;
+
+	err = kstrtoul(buf, 10, &pages);
+	if (err || !pages || pages > UINT_MAX)
+		return -EINVAL;
+
+	khugepaged_pages_to_scan = pages;
+
+	return count;
+}
+static struct kobj_attribute pages_to_scan_attr =
+	__ATTR(pages_to_scan, 0644, pages_to_scan_show,
+	       pages_to_scan_store);
+
+static ssize_t pages_collapsed_show(struct kobject *kobj,
+				    struct kobj_attribute *attr,
+				    char *buf)
+{
+	return sprintf(buf, "%u\n", khugepaged_pages_collapsed);
+}
+static struct kobj_attribute pages_collapsed_attr =
+	__ATTR_RO(pages_collapsed);
+
+static ssize_t full_scans_show(struct kobject *kobj,
+			       struct kobj_attribute *attr,
+			       char *buf)
+{
+	return sprintf(buf, "%u\n", khugepaged_full_scans);
+}
+static struct kobj_attribute full_scans_attr =
+	__ATTR_RO(full_scans);
+
+static ssize_t khugepaged_defrag_show(struct kobject *kobj,
+				      struct kobj_attribute *attr, char *buf)
+{
+	return single_hugepage_flag_show(kobj, attr, buf,
+				TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG);
+}
+static ssize_t khugepaged_defrag_store(struct kobject *kobj,
+				       struct kobj_attribute *attr,
+				       const char *buf, size_t count)
+{
+	return single_hugepage_flag_store(kobj, attr, buf, count,
+				 TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG);
+}
+static struct kobj_attribute khugepaged_defrag_attr =
+	__ATTR(defrag, 0644, khugepaged_defrag_show,
+	       khugepaged_defrag_store);
+
+/*
+ * max_ptes_none controls if khugepaged should collapse hugepages over
+ * any unmapped ptes in turn potentially increasing the memory
+ * footprint of the vmas. When max_ptes_none is 0 khugepaged will not
+ * reduce the available free memory in the system as it
+ * runs. Increasing max_ptes_none will instead potentially reduce the
+ * free memory in the system during the khugepaged scan.
+ */
+static ssize_t khugepaged_max_ptes_none_show(struct kobject *kobj,
+					     struct kobj_attribute *attr,
+					     char *buf)
+{
+	return sprintf(buf, "%u\n", khugepaged_max_ptes_none);
+}
+static ssize_t khugepaged_max_ptes_none_store(struct kobject *kobj,
+					      struct kobj_attribute *attr,
+					      const char *buf, size_t count)
+{
+	int err;
+	unsigned long max_ptes_none;
+
+	err = kstrtoul(buf, 10, &max_ptes_none);
+	if (err || max_ptes_none > HPAGE_PMD_NR-1)
+		return -EINVAL;
+
+	khugepaged_max_ptes_none = max_ptes_none;
+
+	return count;
+}
+static struct kobj_attribute khugepaged_max_ptes_none_attr =
+	__ATTR(max_ptes_none, 0644, khugepaged_max_ptes_none_show,
+	       khugepaged_max_ptes_none_store);
+
+static ssize_t khugepaged_max_ptes_swap_show(struct kobject *kobj,
+					     struct kobj_attribute *attr,
+					     char *buf)
+{
+	return sprintf(buf, "%u\n", khugepaged_max_ptes_swap);
+}
+
+static ssize_t khugepaged_max_ptes_swap_store(struct kobject *kobj,
+					      struct kobj_attribute *attr,
+					      const char *buf, size_t count)
+{
+	int err;
+	unsigned long max_ptes_swap;
+
+	err  = kstrtoul(buf, 10, &max_ptes_swap);
+	if (err || max_ptes_swap > HPAGE_PMD_NR-1)
+		return -EINVAL;
+
+	khugepaged_max_ptes_swap = max_ptes_swap;
+
+	return count;
+}
+
+static struct kobj_attribute khugepaged_max_ptes_swap_attr =
+	__ATTR(max_ptes_swap, 0644, khugepaged_max_ptes_swap_show,
+	       khugepaged_max_ptes_swap_store);
+
+static struct attribute *khugepaged_attr[] = {
+	&khugepaged_defrag_attr.attr,
+	&khugepaged_max_ptes_none_attr.attr,
+	&pages_to_scan_attr.attr,
+	&pages_collapsed_attr.attr,
+	&full_scans_attr.attr,
+	&scan_sleep_millisecs_attr.attr,
+	&alloc_sleep_millisecs_attr.attr,
+	&khugepaged_max_ptes_swap_attr.attr,
+	NULL,
+};
+
+struct attribute_group khugepaged_attr_group = {
+	.attrs = khugepaged_attr,
+	.name = "khugepaged",
+};
+
+#define VM_NO_KHUGEPAGED (VM_SPECIAL | VM_HUGETLB)
+
+int hugepage_madvise(struct vm_area_struct *vma,
+		     unsigned long *vm_flags, int advice)
+{
+	switch (advice) {
+	case MADV_HUGEPAGE:
+#ifdef CONFIG_S390
+		/*
+		 * qemu blindly sets MADV_HUGEPAGE on all allocations, but s390
+		 * can't handle this properly after s390_enable_sie, so we simply
+		 * ignore the madvise to prevent qemu from causing a SIGSEGV.
+		 */
+		if (mm_has_pgste(vma->vm_mm))
+			return 0;
+#endif
+		*vm_flags &= ~VM_NOHUGEPAGE;
+		*vm_flags |= VM_HUGEPAGE;
+		/*
+		 * If the vma become good for khugepaged to scan,
+		 * register it here without waiting a page fault that
+		 * may not happen any time soon.
+		 */
+		if (!(*vm_flags & VM_NO_KHUGEPAGED) &&
+				khugepaged_enter_vma_merge(vma, *vm_flags))
+			return -ENOMEM;
+		break;
+	case MADV_NOHUGEPAGE:
+		*vm_flags &= ~VM_HUGEPAGE;
+		*vm_flags |= VM_NOHUGEPAGE;
+		/*
+		 * Setting VM_NOHUGEPAGE will prevent khugepaged from scanning
+		 * this vma even if we leave the mm registered in khugepaged if
+		 * it got registered before VM_NOHUGEPAGE was set.
+		 */
+		break;
+	}
+
+	return 0;
+}
+
+int __init khugepaged_init(void)
+{
+	mm_slot_cache = kmem_cache_create("khugepaged_mm_slot",
+					  sizeof(struct mm_slot),
+					  __alignof__(struct mm_slot), 0, NULL);
+	if (!mm_slot_cache)
+		return -ENOMEM;
+
+	khugepaged_pages_to_scan = HPAGE_PMD_NR * 8;
+	khugepaged_max_ptes_none = HPAGE_PMD_NR - 1;
+	khugepaged_max_ptes_swap = HPAGE_PMD_NR / 8;
+
+	return 0;
+}
+
+void __init khugepaged_destroy(void)
+{
+	kmem_cache_destroy(mm_slot_cache);
+}
+
+static inline struct mm_slot *alloc_mm_slot(void)
+{
+	if (!mm_slot_cache)	/* initialization failed */
+		return NULL;
+	return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL);
+}
+
+static inline void free_mm_slot(struct mm_slot *mm_slot)
+{
+	kmem_cache_free(mm_slot_cache, mm_slot);
+}
+
+static struct mm_slot *get_mm_slot(struct mm_struct *mm)
+{
+	struct mm_slot *mm_slot;
+
+	hash_for_each_possible(mm_slots_hash, mm_slot, hash, (unsigned long)mm)
+		if (mm == mm_slot->mm)
+			return mm_slot;
+
+	return NULL;
+}
+
+static void insert_to_mm_slots_hash(struct mm_struct *mm,
+				    struct mm_slot *mm_slot)
+{
+	mm_slot->mm = mm;
+	hash_add(mm_slots_hash, &mm_slot->hash, (long)mm);
+}
+
+static inline int khugepaged_test_exit(struct mm_struct *mm)
+{
+	return atomic_read(&mm->mm_users) == 0;
+}
+
+int __khugepaged_enter(struct mm_struct *mm)
+{
+	struct mm_slot *mm_slot;
+	int wakeup;
+
+	mm_slot = alloc_mm_slot();
+	if (!mm_slot)
+		return -ENOMEM;
+
+	/* __khugepaged_exit() must not run from under us */
+	VM_BUG_ON_MM(khugepaged_test_exit(mm), mm);
+	if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) {
+		free_mm_slot(mm_slot);
+		return 0;
+	}
+
+	spin_lock(&khugepaged_mm_lock);
+	insert_to_mm_slots_hash(mm, mm_slot);
+	/*
+	 * Insert just behind the scanning cursor, to let the area settle
+	 * down a little.
+	 */
+	wakeup = list_empty(&khugepaged_scan.mm_head);
+	list_add_tail(&mm_slot->mm_node, &khugepaged_scan.mm_head);
+	spin_unlock(&khugepaged_mm_lock);
+
+	atomic_inc(&mm->mm_count);
+	if (wakeup)
+		wake_up_interruptible(&khugepaged_wait);
+
+	return 0;
+}
+
+int khugepaged_enter_vma_merge(struct vm_area_struct *vma,
+			       unsigned long vm_flags)
+{
+	unsigned long hstart, hend;
+	if (!vma->anon_vma)
+		/*
+		 * Not yet faulted in so we will register later in the
+		 * page fault if needed.
+		 */
+		return 0;
+	if (vma->vm_ops || (vm_flags & VM_NO_KHUGEPAGED))
+		/* khugepaged not yet working on file or special mappings */
+		return 0;
+	hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
+	hend = vma->vm_end & HPAGE_PMD_MASK;
+	if (hstart < hend)
+		return khugepaged_enter(vma, vm_flags);
+	return 0;
+}
+
+void __khugepaged_exit(struct mm_struct *mm)
+{
+	struct mm_slot *mm_slot;
+	int free = 0;
+
+	spin_lock(&khugepaged_mm_lock);
+	mm_slot = get_mm_slot(mm);
+	if (mm_slot && khugepaged_scan.mm_slot != mm_slot) {
+		hash_del(&mm_slot->hash);
+		list_del(&mm_slot->mm_node);
+		free = 1;
+	}
+	spin_unlock(&khugepaged_mm_lock);
+
+	if (free) {
+		clear_bit(MMF_VM_HUGEPAGE, &mm->flags);
+		free_mm_slot(mm_slot);
+		mmdrop(mm);
+	} else if (mm_slot) {
+		/*
+		 * This is required to serialize against
+		 * khugepaged_test_exit() (which is guaranteed to run
+		 * under mmap sem read mode). Stop here (after we
+		 * return all pagetables will be destroyed) until
+		 * khugepaged has finished working on the pagetables
+		 * under the mmap_sem.
+		 */
+		down_write(&mm->mmap_sem);
+		up_write(&mm->mmap_sem);
+	}
+}
+
+static void release_pte_page(struct page *page)
+{
+	/* 0 stands for page_is_file_cache(page) == false */
+	dec_zone_page_state(page, NR_ISOLATED_ANON + 0);
+	unlock_page(page);
+	putback_lru_page(page);
+}
+
+static void release_pte_pages(pte_t *pte, pte_t *_pte)
+{
+	while (--_pte >= pte) {
+		pte_t pteval = *_pte;
+		if (!pte_none(pteval) && !is_zero_pfn(pte_pfn(pteval)))
+			release_pte_page(pte_page(pteval));
+	}
+}
+
+static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
+					unsigned long address,
+					pte_t *pte)
+{
+	struct page *page = NULL;
+	pte_t *_pte;
+	int none_or_zero = 0, result = 0, referenced = 0;
+	bool writable = false;
+
+	for (_pte = pte; _pte < pte+HPAGE_PMD_NR;
+	     _pte++, address += PAGE_SIZE) {
+		pte_t pteval = *_pte;
+		if (pte_none(pteval) || (pte_present(pteval) &&
+				is_zero_pfn(pte_pfn(pteval)))) {
+			if (!userfaultfd_armed(vma) &&
+			    ++none_or_zero <= khugepaged_max_ptes_none) {
+				continue;
+			} else {
+				result = SCAN_EXCEED_NONE_PTE;
+				goto out;
+			}
+		}
+		if (!pte_present(pteval)) {
+			result = SCAN_PTE_NON_PRESENT;
+			goto out;
+		}
+		page = vm_normal_page(vma, address, pteval);
+		if (unlikely(!page)) {
+			result = SCAN_PAGE_NULL;
+			goto out;
+		}
+
+		VM_BUG_ON_PAGE(PageCompound(page), page);
+		VM_BUG_ON_PAGE(!PageAnon(page), page);
+		VM_BUG_ON_PAGE(!PageSwapBacked(page), page);
+
+		/*
+		 * We can do it before isolate_lru_page because the
+		 * page can't be freed from under us. NOTE: PG_lock
+		 * is needed to serialize against split_huge_page
+		 * when invoked from the VM.
+		 */
+		if (!trylock_page(page)) {
+			result = SCAN_PAGE_LOCK;
+			goto out;
+		}
+
+		/*
+		 * cannot use mapcount: can't collapse if there's a gup pin.
+		 * The page must only be referenced by the scanned process
+		 * and page swap cache.
+		 */
+		if (page_count(page) != 1 + !!PageSwapCache(page)) {
+			unlock_page(page);
+			result = SCAN_PAGE_COUNT;
+			goto out;
+		}
+		if (pte_write(pteval)) {
+			writable = true;
+		} else {
+			if (PageSwapCache(page) &&
+			    !reuse_swap_page(page, NULL)) {
+				unlock_page(page);
+				result = SCAN_SWAP_CACHE_PAGE;
+				goto out;
+			}
+			/*
+			 * Page is not in the swap cache. It can be collapsed
+			 * into a THP.
+			 */
+		}
+
+		/*
+		 * Isolate the page to avoid collapsing an hugepage
+		 * currently in use by the VM.
+		 */
+		if (isolate_lru_page(page)) {
+			unlock_page(page);
+			result = SCAN_DEL_PAGE_LRU;
+			goto out;
+		}
+		/* 0 stands for page_is_file_cache(page) == false */
+		inc_zone_page_state(page, NR_ISOLATED_ANON + 0);
+		VM_BUG_ON_PAGE(!PageLocked(page), page);
+		VM_BUG_ON_PAGE(PageLRU(page), page);
+
+		/* There should be enough young pte to collapse the page */
+		if (pte_young(pteval) ||
+		    page_is_young(page) || PageReferenced(page) ||
+		    mmu_notifier_test_young(vma->vm_mm, address))
+			referenced++;
+	}
+	if (likely(writable)) {
+		if (likely(referenced)) {
+			result = SCAN_SUCCEED;
+			trace_mm_collapse_huge_page_isolate(page, none_or_zero,
+							    referenced, writable, result);
+			return 1;
+		}
+	} else {
+		result = SCAN_PAGE_RO;
+	}
+
+out:
+	release_pte_pages(pte, _pte);
+	trace_mm_collapse_huge_page_isolate(page, none_or_zero,
+					    referenced, writable, result);
+	return 0;
+}
+
+static void __collapse_huge_page_copy(pte_t *pte, struct page *page,
+				      struct vm_area_struct *vma,
+				      unsigned long address,
+				      spinlock_t *ptl)
+{
+	pte_t *_pte;
+	for (_pte = pte; _pte < pte+HPAGE_PMD_NR; _pte++) {
+		pte_t pteval = *_pte;
+		struct page *src_page;
+
+		if (pte_none(pteval) || is_zero_pfn(pte_pfn(pteval))) {
+			clear_user_highpage(page, address);
+			add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1);
+			if (is_zero_pfn(pte_pfn(pteval))) {
+				/*
+				 * ptl mostly unnecessary.
+				 */
+				spin_lock(ptl);
+				/*
+				 * paravirt calls inside pte_clear here are
+				 * superfluous.
+				 */
+				pte_clear(vma->vm_mm, address, _pte);
+				spin_unlock(ptl);
+			}
+		} else {
+			src_page = pte_page(pteval);
+			copy_user_highpage(page, src_page, address, vma);
+			VM_BUG_ON_PAGE(page_mapcount(src_page) != 1, src_page);
+			release_pte_page(src_page);
+			/*
+			 * ptl mostly unnecessary, but preempt has to
+			 * be disabled to update the per-cpu stats
+			 * inside page_remove_rmap().
+			 */
+			spin_lock(ptl);
+			/*
+			 * paravirt calls inside pte_clear here are
+			 * superfluous.
+			 */
+			pte_clear(vma->vm_mm, address, _pte);
+			page_remove_rmap(src_page, false);
+			spin_unlock(ptl);
+			free_page_and_swap_cache(src_page);
+		}
+
+		address += PAGE_SIZE;
+		page++;
+	}
+}
+
+static void khugepaged_alloc_sleep(void)
+{
+	DEFINE_WAIT(wait);
+
+	add_wait_queue(&khugepaged_wait, &wait);
+	freezable_schedule_timeout_interruptible(
+		msecs_to_jiffies(khugepaged_alloc_sleep_millisecs));
+	remove_wait_queue(&khugepaged_wait, &wait);
+}
+
+static int khugepaged_node_load[MAX_NUMNODES];
+
+static bool khugepaged_scan_abort(int nid)
+{
+	int i;
+
+	/*
+	 * If zone_reclaim_mode is disabled, then no extra effort is made to
+	 * allocate memory locally.
+	 */
+	if (!zone_reclaim_mode)
+		return false;
+
+	/* If there is a count for this node already, it must be acceptable */
+	if (khugepaged_node_load[nid])
+		return false;
+
+	for (i = 0; i < MAX_NUMNODES; i++) {
+		if (!khugepaged_node_load[i])
+			continue;
+		if (node_distance(nid, i) > RECLAIM_DISTANCE)
+			return true;
+	}
+	return false;
+}
+
+/* Defrag for khugepaged will enter direct reclaim/compaction if necessary */
+static inline gfp_t alloc_hugepage_khugepaged_gfpmask(void)
+{
+	return GFP_TRANSHUGE | (khugepaged_defrag() ? __GFP_DIRECT_RECLAIM : 0);
+}
+
+#ifdef CONFIG_NUMA
+static int khugepaged_find_target_node(void)
+{
+	static int last_khugepaged_target_node = NUMA_NO_NODE;
+	int nid, target_node = 0, max_value = 0;
+
+	/* find first node with max normal pages hit */
+	for (nid = 0; nid < MAX_NUMNODES; nid++)
+		if (khugepaged_node_load[nid] > max_value) {
+			max_value = khugepaged_node_load[nid];
+			target_node = nid;
+		}
+
+	/* do some balance if several nodes have the same hit record */
+	if (target_node <= last_khugepaged_target_node)
+		for (nid = last_khugepaged_target_node + 1; nid < MAX_NUMNODES;
+				nid++)
+			if (max_value == khugepaged_node_load[nid]) {
+				target_node = nid;
+				break;
+			}
+
+	last_khugepaged_target_node = target_node;
+	return target_node;
+}
+
+static bool khugepaged_prealloc_page(struct page **hpage, bool *wait)
+{
+	if (IS_ERR(*hpage)) {
+		if (!*wait)
+			return false;
+
+		*wait = false;
+		*hpage = NULL;
+		khugepaged_alloc_sleep();
+	} else if (*hpage) {
+		put_page(*hpage);
+		*hpage = NULL;
+	}
+
+	return true;
+}
+
+static struct page *
+khugepaged_alloc_page(struct page **hpage, gfp_t gfp, int node)
+{
+	VM_BUG_ON_PAGE(*hpage, *hpage);
+
+	*hpage = __alloc_pages_node(node, gfp, HPAGE_PMD_ORDER);
+	if (unlikely(!*hpage)) {
+		count_vm_event(THP_COLLAPSE_ALLOC_FAILED);
+		*hpage = ERR_PTR(-ENOMEM);
+		return NULL;
+	}
+
+	prep_transhuge_page(*hpage);
+	count_vm_event(THP_COLLAPSE_ALLOC);
+	return *hpage;
+}
+#else
+static int khugepaged_find_target_node(void)
+{
+	return 0;
+}
+
+static inline struct page *alloc_khugepaged_hugepage(void)
+{
+	struct page *page;
+
+	page = alloc_pages(alloc_hugepage_khugepaged_gfpmask(),
+			   HPAGE_PMD_ORDER);
+	if (page)
+		prep_transhuge_page(page);
+	return page;
+}
+
+static struct page *khugepaged_alloc_hugepage(bool *wait)
+{
+	struct page *hpage;
+
+	do {
+		hpage = alloc_khugepaged_hugepage();
+		if (!hpage) {
+			count_vm_event(THP_COLLAPSE_ALLOC_FAILED);
+			if (!*wait)
+				return NULL;
+
+			*wait = false;
+			khugepaged_alloc_sleep();
+		} else
+			count_vm_event(THP_COLLAPSE_ALLOC);
+	} while (unlikely(!hpage) && likely(khugepaged_enabled()));
+
+	return hpage;
+}
+
+static bool khugepaged_prealloc_page(struct page **hpage, bool *wait)
+{
+	if (!*hpage)
+		*hpage = khugepaged_alloc_hugepage(wait);
+
+	if (unlikely(!*hpage))
+		return false;
+
+	return true;
+}
+
+static struct page *
+khugepaged_alloc_page(struct page **hpage, gfp_t gfp, int node)
+{
+	VM_BUG_ON(!*hpage);
+
+	return  *hpage;
+}
+#endif
+
+static bool hugepage_vma_check(struct vm_area_struct *vma)
+{
+	if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) ||
+	    (vma->vm_flags & VM_NOHUGEPAGE))
+		return false;
+	if (shmem_file(vma->vm_file)) {
+		if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE))
+			return false;
+		return IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) - vma->vm_pgoff,
+				HPAGE_PMD_NR);
+	}
+	if (!vma->anon_vma || vma->vm_ops)
+		return false;
+	if (is_vma_temporary_stack(vma))
+		return false;
+	return !(vma->vm_flags & VM_NO_KHUGEPAGED);
+}
+
+/*
+ * If mmap_sem temporarily dropped, revalidate vma
+ * before taking mmap_sem.
+ * Return 0 if succeeds, otherwise return none-zero
+ * value (scan code).
+ */
+
+static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address)
+{
+	struct vm_area_struct *vma;
+	unsigned long hstart, hend;
+
+	if (unlikely(khugepaged_test_exit(mm)))
+		return SCAN_ANY_PROCESS;
+
+	vma = find_vma(mm, address);
+	if (!vma)
+		return SCAN_VMA_NULL;
+
+	hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
+	hend = vma->vm_end & HPAGE_PMD_MASK;
+	if (address < hstart || address + HPAGE_PMD_SIZE > hend)
+		return SCAN_ADDRESS_RANGE;
+	if (!hugepage_vma_check(vma))
+		return SCAN_VMA_CHECK;
+	return 0;
+}
+
+/*
+ * Bring missing pages in from swap, to complete THP collapse.
+ * Only done if khugepaged_scan_pmd believes it is worthwhile.
+ *
+ * Called and returns without pte mapped or spinlocks held,
+ * but with mmap_sem held to protect against vma changes.
+ */
+
+static bool __collapse_huge_page_swapin(struct mm_struct *mm,
+					struct vm_area_struct *vma,
+					unsigned long address, pmd_t *pmd,
+					int referenced)
+{
+	pte_t pteval;
+	int swapped_in = 0, ret = 0;
+	struct fault_env fe = {
+		.vma = vma,
+		.address = address,
+		.flags = FAULT_FLAG_ALLOW_RETRY,
+		.pmd = pmd,
+	};
+
+	fe.pte = pte_offset_map(pmd, address);
+	for (; fe.address < address + HPAGE_PMD_NR*PAGE_SIZE;
+			fe.pte++, fe.address += PAGE_SIZE) {
+		pteval = *fe.pte;
+		if (!is_swap_pte(pteval))
+			continue;
+		swapped_in++;
+		/* we only decide to swapin, if there is enough young ptes */
+		if (referenced < HPAGE_PMD_NR/2) {
+			trace_mm_collapse_huge_page_swapin(mm, swapped_in, referenced, 0);
+			return false;
+		}
+		ret = do_swap_page(&fe, pteval);
+
+		/* do_swap_page returns VM_FAULT_RETRY with released mmap_sem */
+		if (ret & VM_FAULT_RETRY) {
+			down_read(&mm->mmap_sem);
+			if (hugepage_vma_revalidate(mm, address)) {
+				/* vma is no longer available, don't continue to swapin */
+				trace_mm_collapse_huge_page_swapin(mm, swapped_in, referenced, 0);
+				return false;
+			}
+			/* check if the pmd is still valid */
+			if (mm_find_pmd(mm, address) != pmd)
+				return false;
+		}
+		if (ret & VM_FAULT_ERROR) {
+			trace_mm_collapse_huge_page_swapin(mm, swapped_in, referenced, 0);
+			return false;
+		}
+		/* pte is unmapped now, we need to map it */
+		fe.pte = pte_offset_map(pmd, fe.address);
+	}
+	fe.pte--;
+	pte_unmap(fe.pte);
+	trace_mm_collapse_huge_page_swapin(mm, swapped_in, referenced, 1);
+	return true;
+}
+
+static void collapse_huge_page(struct mm_struct *mm,
+				   unsigned long address,
+				   struct page **hpage,
+				   struct vm_area_struct *vma,
+				   int node, int referenced)
+{
+	pmd_t *pmd, _pmd;
+	pte_t *pte;
+	pgtable_t pgtable;
+	struct page *new_page;
+	spinlock_t *pmd_ptl, *pte_ptl;
+	int isolated = 0, result = 0;
+	struct mem_cgroup *memcg;
+	unsigned long mmun_start;	/* For mmu_notifiers */
+	unsigned long mmun_end;		/* For mmu_notifiers */
+	gfp_t gfp;
+
+	VM_BUG_ON(address & ~HPAGE_PMD_MASK);
+
+	/* Only allocate from the target node */
+	gfp = alloc_hugepage_khugepaged_gfpmask() | __GFP_OTHER_NODE | __GFP_THISNODE;
+
+	/*
+	 * Before allocating the hugepage, release the mmap_sem read lock.
+	 * The allocation can take potentially a long time if it involves
+	 * sync compaction, and we do not need to hold the mmap_sem during
+	 * that. We will recheck the vma after taking it again in write mode.
+	 */
+	up_read(&mm->mmap_sem);
+	new_page = khugepaged_alloc_page(hpage, gfp, node);
+	if (!new_page) {
+		result = SCAN_ALLOC_HUGE_PAGE_FAIL;
+		goto out_nolock;
+	}
+
+	if (unlikely(mem_cgroup_try_charge(new_page, mm, gfp, &memcg, true))) {
+		result = SCAN_CGROUP_CHARGE_FAIL;
+		goto out_nolock;
+	}
+
+	down_read(&mm->mmap_sem);
+	result = hugepage_vma_revalidate(mm, address);
+	if (result) {
+		mem_cgroup_cancel_charge(new_page, memcg, true);
+		up_read(&mm->mmap_sem);
+		goto out_nolock;
+	}
+
+	pmd = mm_find_pmd(mm, address);
+	if (!pmd) {
+		result = SCAN_PMD_NULL;
+		mem_cgroup_cancel_charge(new_page, memcg, true);
+		up_read(&mm->mmap_sem);
+		goto out_nolock;
+	}
+
+	/*
+	 * __collapse_huge_page_swapin always returns with mmap_sem locked.
+	 * If it fails, we release mmap_sem and jump out_nolock.
+	 * Continuing to collapse causes inconsistency.
+	 */
+	if (!__collapse_huge_page_swapin(mm, vma, address, pmd, referenced)) {
+		mem_cgroup_cancel_charge(new_page, memcg, true);
+		up_read(&mm->mmap_sem);
+		goto out_nolock;
+	}
+
+	up_read(&mm->mmap_sem);
+	/*
+	 * Prevent all access to pagetables with the exception of
+	 * gup_fast later handled by the ptep_clear_flush and the VM
+	 * handled by the anon_vma lock + PG_lock.
+	 */
+	down_write(&mm->mmap_sem);
+	result = hugepage_vma_revalidate(mm, address);
+	if (result)
+		goto out;
+	/* check if the pmd is still valid */
+	if (mm_find_pmd(mm, address) != pmd)
+		goto out;
+
+	anon_vma_lock_write(vma->anon_vma);
+
+	pte = pte_offset_map(pmd, address);
+	pte_ptl = pte_lockptr(mm, pmd);
+
+	mmun_start = address;
+	mmun_end   = address + HPAGE_PMD_SIZE;
+	mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
+	pmd_ptl = pmd_lock(mm, pmd); /* probably unnecessary */
+	/*
+	 * After this gup_fast can't run anymore. This also removes
+	 * any huge TLB entry from the CPU so we won't allow
+	 * huge and small TLB entries for the same virtual address
+	 * to avoid the risk of CPU bugs in that area.
+	 */
+	_pmd = pmdp_collapse_flush(vma, address, pmd);
+	spin_unlock(pmd_ptl);
+	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
+
+	spin_lock(pte_ptl);
+	isolated = __collapse_huge_page_isolate(vma, address, pte);
+	spin_unlock(pte_ptl);
+
+	if (unlikely(!isolated)) {
+		pte_unmap(pte);
+		spin_lock(pmd_ptl);
+		BUG_ON(!pmd_none(*pmd));
+		/*
+		 * We can only use set_pmd_at when establishing
+		 * hugepmds and never for establishing regular pmds that
+		 * points to regular pagetables. Use pmd_populate for that
+		 */
+		pmd_populate(mm, pmd, pmd_pgtable(_pmd));
+		spin_unlock(pmd_ptl);
+		anon_vma_unlock_write(vma->anon_vma);
+		result = SCAN_FAIL;
+		goto out;
+	}
+
+	/*
+	 * All pages are isolated and locked so anon_vma rmap
+	 * can't run anymore.
+	 */
+	anon_vma_unlock_write(vma->anon_vma);
+
+	__collapse_huge_page_copy(pte, new_page, vma, address, pte_ptl);
+	pte_unmap(pte);
+	__SetPageUptodate(new_page);
+	pgtable = pmd_pgtable(_pmd);
+
+	_pmd = mk_huge_pmd(new_page, vma->vm_page_prot);
+	_pmd = maybe_pmd_mkwrite(pmd_mkdirty(_pmd), vma);
+
+	/*
+	 * spin_lock() below is not the equivalent of smp_wmb(), so
+	 * this is needed to avoid the copy_huge_page writes to become
+	 * visible after the set_pmd_at() write.
+	 */
+	smp_wmb();
+
+	spin_lock(pmd_ptl);
+	BUG_ON(!pmd_none(*pmd));
+	page_add_new_anon_rmap(new_page, vma, address, true);
+	mem_cgroup_commit_charge(new_page, memcg, false, true);
+	lru_cache_add_active_or_unevictable(new_page, vma);
+	pgtable_trans_huge_deposit(mm, pmd, pgtable);
+	set_pmd_at(mm, address, pmd, _pmd);
+	update_mmu_cache_pmd(vma, address, pmd);
+	spin_unlock(pmd_ptl);
+
+	*hpage = NULL;
+
+	khugepaged_pages_collapsed++;
+	result = SCAN_SUCCEED;
+out_up_write:
+	up_write(&mm->mmap_sem);
+out_nolock:
+	trace_mm_collapse_huge_page(mm, isolated, result);
+	return;
+out:
+	mem_cgroup_cancel_charge(new_page, memcg, true);
+	goto out_up_write;
+}
+
+static int khugepaged_scan_pmd(struct mm_struct *mm,
+			       struct vm_area_struct *vma,
+			       unsigned long address,
+			       struct page **hpage)
+{
+	pmd_t *pmd;
+	pte_t *pte, *_pte;
+	int ret = 0, none_or_zero = 0, result = 0, referenced = 0;
+	struct page *page = NULL;
+	unsigned long _address;
+	spinlock_t *ptl;
+	int node = NUMA_NO_NODE, unmapped = 0;
+	bool writable = false;
+
+	VM_BUG_ON(address & ~HPAGE_PMD_MASK);
+
+	pmd = mm_find_pmd(mm, address);
+	if (!pmd) {
+		result = SCAN_PMD_NULL;
+		goto out;
+	}
+
+	memset(khugepaged_node_load, 0, sizeof(khugepaged_node_load));
+	pte = pte_offset_map_lock(mm, pmd, address, &ptl);
+	for (_address = address, _pte = pte; _pte < pte+HPAGE_PMD_NR;
+	     _pte++, _address += PAGE_SIZE) {
+		pte_t pteval = *_pte;
+		if (is_swap_pte(pteval)) {
+			if (++unmapped <= khugepaged_max_ptes_swap) {
+				continue;
+			} else {
+				result = SCAN_EXCEED_SWAP_PTE;
+				goto out_unmap;
+			}
+		}
+		if (pte_none(pteval) || is_zero_pfn(pte_pfn(pteval))) {
+			if (!userfaultfd_armed(vma) &&
+			    ++none_or_zero <= khugepaged_max_ptes_none) {
+				continue;
+			} else {
+				result = SCAN_EXCEED_NONE_PTE;
+				goto out_unmap;
+			}
+		}
+		if (!pte_present(pteval)) {
+			result = SCAN_PTE_NON_PRESENT;
+			goto out_unmap;
+		}
+		if (pte_write(pteval))
+			writable = true;
+
+		page = vm_normal_page(vma, _address, pteval);
+		if (unlikely(!page)) {
+			result = SCAN_PAGE_NULL;
+			goto out_unmap;
+		}
+
+		/* TODO: teach khugepaged to collapse THP mapped with pte */
+		if (PageCompound(page)) {
+			result = SCAN_PAGE_COMPOUND;
+			goto out_unmap;
+		}
+
+		/*
+		 * Record which node the original page is from and save this
+		 * information to khugepaged_node_load[].
+		 * Khupaged will allocate hugepage from the node has the max
+		 * hit record.
+		 */
+		node = page_to_nid(page);
+		if (khugepaged_scan_abort(node)) {
+			result = SCAN_SCAN_ABORT;
+			goto out_unmap;
+		}
+		khugepaged_node_load[node]++;
+		if (!PageLRU(page)) {
+			result = SCAN_PAGE_LRU;
+			goto out_unmap;
+		}
+		if (PageLocked(page)) {
+			result = SCAN_PAGE_LOCK;
+			goto out_unmap;
+		}
+		if (!PageAnon(page)) {
+			result = SCAN_PAGE_ANON;
+			goto out_unmap;
+		}
+
+		/*
+		 * cannot use mapcount: can't collapse if there's a gup pin.
+		 * The page must only be referenced by the scanned process
+		 * and page swap cache.
+		 */
+		if (page_count(page) != 1 + !!PageSwapCache(page)) {
+			result = SCAN_PAGE_COUNT;
+			goto out_unmap;
+		}
+		if (pte_young(pteval) ||
+		    page_is_young(page) || PageReferenced(page) ||
+		    mmu_notifier_test_young(vma->vm_mm, address))
+			referenced++;
+	}
+	if (writable) {
+		if (referenced) {
+			result = SCAN_SUCCEED;
+			ret = 1;
+		} else {
+			result = SCAN_LACK_REFERENCED_PAGE;
+		}
+	} else {
+		result = SCAN_PAGE_RO;
+	}
+out_unmap:
+	pte_unmap_unlock(pte, ptl);
+	if (ret) {
+		node = khugepaged_find_target_node();
+		/* collapse_huge_page will return with the mmap_sem released */
+		collapse_huge_page(mm, address, hpage, vma, node, referenced);
+	}
+out:
+	trace_mm_khugepaged_scan_pmd(mm, page, writable, referenced,
+				     none_or_zero, result, unmapped);
+	return ret;
+}
+
+static void collect_mm_slot(struct mm_slot *mm_slot)
+{
+	struct mm_struct *mm = mm_slot->mm;
+
+	VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock));
+
+	if (khugepaged_test_exit(mm)) {
+		/* free mm_slot */
+		hash_del(&mm_slot->hash);
+		list_del(&mm_slot->mm_node);
+
+		/*
+		 * Not strictly needed because the mm exited already.
+		 *
+		 * clear_bit(MMF_VM_HUGEPAGE, &mm->flags);
+		 */
+
+		/* khugepaged_mm_lock actually not necessary for the below */
+		free_mm_slot(mm_slot);
+		mmdrop(mm);
+	}
+}
+
+#if defined(CONFIG_SHMEM) && defined(CONFIG_TRANSPARENT_HUGE_PAGECACHE)
+static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff)
+{
+	struct vm_area_struct *vma;
+	unsigned long addr;
+	pmd_t *pmd, _pmd;
+
+	i_mmap_lock_write(mapping);
+	vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
+		/* probably overkill */
+		if (vma->anon_vma)
+			continue;
+		addr = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
+		if (addr & ~HPAGE_PMD_MASK)
+			continue;
+		if (vma->vm_end < addr + HPAGE_PMD_SIZE)
+			continue;
+		pmd = mm_find_pmd(vma->vm_mm, addr);
+		if (!pmd)
+			continue;
+		/*
+		 * We need exclusive mmap_sem to retract page table.
+		 * If trylock fails we would end up with pte-mapped THP after
+		 * re-fault. Not ideal, but it's more important to not disturb
+		 * the system too much.
+		 */
+		if (down_write_trylock(&vma->vm_mm->mmap_sem)) {
+			spinlock_t *ptl = pmd_lock(vma->vm_mm, pmd);
+			/* assume page table is clear */
+			_pmd = pmdp_collapse_flush(vma, addr, pmd);
+			spin_unlock(ptl);
+			up_write(&vma->vm_mm->mmap_sem);
+			atomic_long_dec(&vma->vm_mm->nr_ptes);
+			pte_free(vma->vm_mm, pmd_pgtable(_pmd));
+		}
+	}
+	i_mmap_unlock_write(mapping);
+}
+
+/**
+ * collapse_shmem - collapse small tmpfs/shmem pages into huge one.
+ *
+ * Basic scheme is simple, details are more complex:
+ *  - allocate and freeze a new huge page;
+ *  - scan over radix tree replacing old pages the new one
+ *    + swap in pages if necessary;
+ *    + fill in gaps;
+ *    + keep old pages around in case if rollback is required;
+ *  - if replacing succeed:
+ *    + copy data over;
+ *    + free old pages;
+ *    + unfreeze huge page;
+ *  - if replacing failed;
+ *    + put all pages back and unfreeze them;
+ *    + restore gaps in the radix-tree;
+ *    + free huge page;
+ */
+static void collapse_shmem(struct mm_struct *mm,
+		struct address_space *mapping, pgoff_t start,
+		struct page **hpage, int node)
+{
+	gfp_t gfp;
+	struct page *page, *new_page, *tmp;
+	struct mem_cgroup *memcg;
+	pgoff_t index, end = start + HPAGE_PMD_NR;
+	LIST_HEAD(pagelist);
+	struct radix_tree_iter iter;
+	void **slot;
+	int nr_none = 0, result = SCAN_SUCCEED;
+
+	VM_BUG_ON(start & (HPAGE_PMD_NR - 1));
+
+	/* Only allocate from the target node */
+	gfp = alloc_hugepage_khugepaged_gfpmask() |
+		__GFP_OTHER_NODE | __GFP_THISNODE;
+
+	new_page = khugepaged_alloc_page(hpage, gfp, node);
+	if (!new_page) {
+		result = SCAN_ALLOC_HUGE_PAGE_FAIL;
+		goto out;
+	}
+
+	if (unlikely(mem_cgroup_try_charge(new_page, mm, gfp, &memcg, true))) {
+		result = SCAN_CGROUP_CHARGE_FAIL;
+		goto out;
+	}
+
+	new_page->index = start;
+	new_page->mapping = mapping;
+	__SetPageSwapBacked(new_page);
+	__SetPageLocked(new_page);
+	BUG_ON(!page_ref_freeze(new_page, 1));
+
+
+	/*
+	 * At this point the new_page is 'frozen' (page_count() is zero), locked
+	 * and not up-to-date. It's safe to insert it into radix tree, because
+	 * nobody would be able to map it or use it in other way until we
+	 * unfreeze it.
+	 */
+
+	index = start;
+	spin_lock_irq(&mapping->tree_lock);
+	radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) {
+		int n = min(iter.index, end) - index;
+
+		/*
+		 * Handle holes in the radix tree: charge it from shmem and
+		 * insert relevant subpage of new_page into the radix-tree.
+		 */
+		if (n && !shmem_charge(mapping->host, n)) {
+			result = SCAN_FAIL;
+			break;
+		}
+		nr_none += n;
+		for (; index < min(iter.index, end); index++) {
+			radix_tree_insert(&mapping->page_tree, index,
+					new_page + (index % HPAGE_PMD_NR));
+		}
+
+		/* We are done. */
+		if (index >= end)
+			break;
+
+		page = radix_tree_deref_slot_protected(slot,
+				&mapping->tree_lock);
+		if (radix_tree_exceptional_entry(page) || !PageUptodate(page)) {
+			spin_unlock_irq(&mapping->tree_lock);
+			/* swap in or instantiate fallocated page */
+			if (shmem_getpage(mapping->host, index, &page,
+						SGP_NOHUGE)) {
+				result = SCAN_FAIL;
+				goto tree_unlocked;
+			}
+			spin_lock_irq(&mapping->tree_lock);
+		} else if (trylock_page(page)) {
+			get_page(page);
+		} else {
+			result = SCAN_PAGE_LOCK;
+			break;
+		}
+
+		/*
+		 * The page must be locked, so we can drop the tree_lock
+		 * without racing with truncate.
+		 */
+		VM_BUG_ON_PAGE(!PageLocked(page), page);
+		VM_BUG_ON_PAGE(!PageUptodate(page), page);
+		VM_BUG_ON_PAGE(PageTransCompound(page), page);
+
+		if (page_mapping(page) != mapping) {
+			result = SCAN_TRUNCATED;
+			goto out_unlock;
+		}
+		spin_unlock_irq(&mapping->tree_lock);
+
+		if (isolate_lru_page(page)) {
+			result = SCAN_DEL_PAGE_LRU;
+			goto out_isolate_failed;
+		}
+
+		if (page_mapped(page))
+			unmap_mapping_range(mapping, index << PAGE_SHIFT,
+					PAGE_SIZE, 0);
+
+		spin_lock_irq(&mapping->tree_lock);
+
+		VM_BUG_ON_PAGE(page_mapped(page), page);
+
+		/*
+		 * The page is expected to have page_count() == 3:
+		 *  - we hold a pin on it;
+		 *  - one reference from radix tree;
+		 *  - one from isolate_lru_page;
+		 */
+		if (!page_ref_freeze(page, 3)) {
+			result = SCAN_PAGE_COUNT;
+			goto out_lru;
+		}
+
+		/*
+		 * Add the page to the list to be able to undo the collapse if
+		 * something go wrong.
+		 */
+		list_add_tail(&page->lru, &pagelist);
+
+		/* Finally, replace with the new page. */
+		radix_tree_replace_slot(slot,
+				new_page + (index % HPAGE_PMD_NR));
+
+		index++;
+		continue;
+out_lru:
+		spin_unlock_irq(&mapping->tree_lock);
+		putback_lru_page(page);
+out_isolate_failed:
+		unlock_page(page);
+		put_page(page);
+		goto tree_unlocked;
+out_unlock:
+		unlock_page(page);
+		put_page(page);
+		break;
+	}
+
+	/*
+	 * Handle hole in radix tree at the end of the range.
+	 * This code only triggers if there's nothing in radix tree
+	 * beyond 'end'.
+	 */
+	if (result == SCAN_SUCCEED && index < end) {
+		int n = end - index;
+
+		if (!shmem_charge(mapping->host, n)) {
+			result = SCAN_FAIL;
+			goto tree_locked;
+		}
+
+		for (; index < end; index++) {
+			radix_tree_insert(&mapping->page_tree, index,
+					new_page + (index % HPAGE_PMD_NR));
+		}
+		nr_none += n;
+	}
+
+tree_locked:
+	spin_unlock_irq(&mapping->tree_lock);
+tree_unlocked:
+
+	if (result == SCAN_SUCCEED) {
+		unsigned long flags;
+		struct zone *zone = page_zone(new_page);
+
+		/*
+		 * Replacing old pages with new one has succeed, now we need to
+		 * copy the content and free old pages.
+		 */
+		list_for_each_entry_safe(page, tmp, &pagelist, lru) {
+			copy_highpage(new_page + (page->index % HPAGE_PMD_NR),
+					page);
+			list_del(&page->lru);
+			unlock_page(page);
+			page_ref_unfreeze(page, 1);
+			page->mapping = NULL;
+			ClearPageActive(page);
+			ClearPageUnevictable(page);
+			put_page(page);
+		}
+
+		local_irq_save(flags);
+		__inc_zone_page_state(new_page, NR_SHMEM_THPS);
+		if (nr_none) {
+			__mod_zone_page_state(zone, NR_FILE_PAGES, nr_none);
+			__mod_zone_page_state(zone, NR_SHMEM, nr_none);
+		}
+		local_irq_restore(flags);
+
+		/*
+		 * Remove pte page tables, so we can re-faulti
+		 * the page as huge.
+		 */
+		retract_page_tables(mapping, start);
+
+		/* Everything is ready, let's unfreeze the new_page */
+		set_page_dirty(new_page);
+		SetPageUptodate(new_page);
+		page_ref_unfreeze(new_page, HPAGE_PMD_NR);
+		mem_cgroup_commit_charge(new_page, memcg, false, true);
+		lru_cache_add_anon(new_page);
+		unlock_page(new_page);
+
+		*hpage = NULL;
+	} else {
+		/* Something went wrong: rollback changes to the radix-tree */
+		shmem_uncharge(mapping->host, nr_none);
+		spin_lock_irq(&mapping->tree_lock);
+		radix_tree_for_each_slot(slot, &mapping->page_tree, &iter,
+				start) {
+			if (iter.index >= end)
+				break;
+			page = list_first_entry_or_null(&pagelist,
+					struct page, lru);
+			if (!page || iter.index < page->index) {
+				if (!nr_none)
+					break;
+				/* Put holes back where they were */
+				radix_tree_replace_slot(slot, NULL);
+				nr_none--;
+				continue;
+			}
+
+			VM_BUG_ON_PAGE(page->index != iter.index, page);
+
+			/* Unfreeze the page. */
+			list_del(&page->lru);
+			page_ref_unfreeze(page, 2);
+			radix_tree_replace_slot(slot, page);
+			spin_unlock_irq(&mapping->tree_lock);
+			putback_lru_page(page);
+			unlock_page(page);
+			spin_lock_irq(&mapping->tree_lock);
+		}
+		VM_BUG_ON(nr_none);
+		spin_unlock_irq(&mapping->tree_lock);
+
+		/* Unfreeze new_page, caller would take care about freeing it */
+		page_ref_unfreeze(new_page, 1);
+		mem_cgroup_cancel_charge(new_page, memcg, true);
+		unlock_page(new_page);
+		new_page->mapping = NULL;
+	}
+out:
+	VM_BUG_ON(!list_empty(&pagelist));
+	/* TODO: tracepoints */
+}
+
+static void khugepaged_scan_shmem(struct mm_struct *mm,
+		struct address_space *mapping,
+		pgoff_t start, struct page **hpage)
+{
+	struct page *page = NULL;
+	struct radix_tree_iter iter;
+	void **slot;
+	int present, swap;
+	int node = NUMA_NO_NODE;
+	int result = SCAN_SUCCEED;
+
+	present = 0;
+	swap = 0;
+	memset(khugepaged_node_load, 0, sizeof(khugepaged_node_load));
+	rcu_read_lock();
+	radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) {
+		if (iter.index >= start + HPAGE_PMD_NR)
+			break;
+
+		page = radix_tree_deref_slot(slot);
+		if (radix_tree_deref_retry(page)) {
+			slot = radix_tree_iter_retry(&iter);
+			continue;
+		}
+
+		if (radix_tree_exception(page)) {
+			if (++swap > khugepaged_max_ptes_swap) {
+				result = SCAN_EXCEED_SWAP_PTE;
+				break;
+			}
+			continue;
+		}
+
+		if (PageTransCompound(page)) {
+			result = SCAN_PAGE_COMPOUND;
+			break;
+		}
+
+		node = page_to_nid(page);
+		if (khugepaged_scan_abort(node)) {
+			result = SCAN_SCAN_ABORT;
+			break;
+		}
+		khugepaged_node_load[node]++;
+
+		if (!PageLRU(page)) {
+			result = SCAN_PAGE_LRU;
+			break;
+		}
+
+		if (page_count(page) != 1 + page_mapcount(page)) {
+			result = SCAN_PAGE_COUNT;
+			break;
+		}
+
+		/*
+		 * We probably should check if the page is referenced here, but
+		 * nobody would transfer pte_young() to PageReferenced() for us.
+		 * And rmap walk here is just too costly...
+		 */
+
+		present++;
+
+		if (need_resched()) {
+			cond_resched_rcu();
+			slot = radix_tree_iter_next(&iter);
+		}
+	}
+	rcu_read_unlock();
+
+	if (result == SCAN_SUCCEED) {
+		if (present < HPAGE_PMD_NR - khugepaged_max_ptes_none) {
+			result = SCAN_EXCEED_NONE_PTE;
+		} else {
+			node = khugepaged_find_target_node();
+			collapse_shmem(mm, mapping, start, hpage, node);
+		}
+	}
+
+	/* TODO: tracepoints */
+}
+#else
+static void khugepaged_scan_shmem(struct mm_struct *mm,
+		struct address_space *mapping,
+		pgoff_t start, struct page **hpage)
+{
+	BUILD_BUG();
+}
+#endif
+
+static unsigned int khugepaged_scan_mm_slot(unsigned int pages,
+					    struct page **hpage)
+	__releases(&khugepaged_mm_lock)
+	__acquires(&khugepaged_mm_lock)
+{
+	struct mm_slot *mm_slot;
+	struct mm_struct *mm;
+	struct vm_area_struct *vma;
+	int progress = 0;
+
+	VM_BUG_ON(!pages);
+	VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock));
+
+	if (khugepaged_scan.mm_slot)
+		mm_slot = khugepaged_scan.mm_slot;
+	else {
+		mm_slot = list_entry(khugepaged_scan.mm_head.next,
+				     struct mm_slot, mm_node);
+		khugepaged_scan.address = 0;
+		khugepaged_scan.mm_slot = mm_slot;
+	}
+	spin_unlock(&khugepaged_mm_lock);
+
+	mm = mm_slot->mm;
+	down_read(&mm->mmap_sem);
+	if (unlikely(khugepaged_test_exit(mm)))
+		vma = NULL;
+	else
+		vma = find_vma(mm, khugepaged_scan.address);
+
+	progress++;
+	for (; vma; vma = vma->vm_next) {
+		unsigned long hstart, hend;
+
+		cond_resched();
+		if (unlikely(khugepaged_test_exit(mm))) {
+			progress++;
+			break;
+		}
+		if (!hugepage_vma_check(vma)) {
+skip:
+			progress++;
+			continue;
+		}
+		hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
+		hend = vma->vm_end & HPAGE_PMD_MASK;
+		if (hstart >= hend)
+			goto skip;
+		if (khugepaged_scan.address > hend)
+			goto skip;
+		if (khugepaged_scan.address < hstart)
+			khugepaged_scan.address = hstart;
+		VM_BUG_ON(khugepaged_scan.address & ~HPAGE_PMD_MASK);
+
+		while (khugepaged_scan.address < hend) {
+			int ret;
+			cond_resched();
+			if (unlikely(khugepaged_test_exit(mm)))
+				goto breakouterloop;
+
+			VM_BUG_ON(khugepaged_scan.address < hstart ||
+				  khugepaged_scan.address + HPAGE_PMD_SIZE >
+				  hend);
+			if (shmem_file(vma->vm_file)) {
+				struct file *file;
+				pgoff_t pgoff = linear_page_index(vma,
+						khugepaged_scan.address);
+				if (!shmem_huge_enabled(vma))
+					goto skip;
+				file = get_file(vma->vm_file);
+				up_read(&mm->mmap_sem);
+				ret = 1;
+				khugepaged_scan_shmem(mm, file->f_mapping,
+						pgoff, hpage);
+				fput(file);
+			} else {
+				ret = khugepaged_scan_pmd(mm, vma,
+						khugepaged_scan.address,
+						hpage);
+			}
+			/* move to next address */
+			khugepaged_scan.address += HPAGE_PMD_SIZE;
+			progress += HPAGE_PMD_NR;
+			if (ret)
+				/* we released mmap_sem so break loop */
+				goto breakouterloop_mmap_sem;
+			if (progress >= pages)
+				goto breakouterloop;
+		}
+	}
+breakouterloop:
+	up_read(&mm->mmap_sem); /* exit_mmap will destroy ptes after this */
+breakouterloop_mmap_sem:
+
+	spin_lock(&khugepaged_mm_lock);
+	VM_BUG_ON(khugepaged_scan.mm_slot != mm_slot);
+	/*
+	 * Release the current mm_slot if this mm is about to die, or
+	 * if we scanned all vmas of this mm.
+	 */
+	if (khugepaged_test_exit(mm) || !vma) {
+		/*
+		 * Make sure that if mm_users is reaching zero while
+		 * khugepaged runs here, khugepaged_exit will find
+		 * mm_slot not pointing to the exiting mm.
+		 */
+		if (mm_slot->mm_node.next != &khugepaged_scan.mm_head) {
+			khugepaged_scan.mm_slot = list_entry(
+				mm_slot->mm_node.next,
+				struct mm_slot, mm_node);
+			khugepaged_scan.address = 0;
+		} else {
+			khugepaged_scan.mm_slot = NULL;
+			khugepaged_full_scans++;
+		}
+
+		collect_mm_slot(mm_slot);
+	}
+
+	return progress;
+}
+
+static int khugepaged_has_work(void)
+{
+	return !list_empty(&khugepaged_scan.mm_head) &&
+		khugepaged_enabled();
+}
+
+static int khugepaged_wait_event(void)
+{
+	return !list_empty(&khugepaged_scan.mm_head) ||
+		kthread_should_stop();
+}
+
+static void khugepaged_do_scan(void)
+{
+	struct page *hpage = NULL;
+	unsigned int progress = 0, pass_through_head = 0;
+	unsigned int pages = khugepaged_pages_to_scan;
+	bool wait = true;
+
+	barrier(); /* write khugepaged_pages_to_scan to local stack */
+
+	while (progress < pages) {
+		if (!khugepaged_prealloc_page(&hpage, &wait))
+			break;
+
+		cond_resched();
+
+		if (unlikely(kthread_should_stop() || try_to_freeze()))
+			break;
+
+		spin_lock(&khugepaged_mm_lock);
+		if (!khugepaged_scan.mm_slot)
+			pass_through_head++;
+		if (khugepaged_has_work() &&
+		    pass_through_head < 2)
+			progress += khugepaged_scan_mm_slot(pages - progress,
+							    &hpage);
+		else
+			progress = pages;
+		spin_unlock(&khugepaged_mm_lock);
+	}
+
+	if (!IS_ERR_OR_NULL(hpage))
+		put_page(hpage);
+}
+
+static bool khugepaged_should_wakeup(void)
+{
+	return kthread_should_stop() ||
+	       time_after_eq(jiffies, khugepaged_sleep_expire);
+}
+
+static void khugepaged_wait_work(void)
+{
+	if (khugepaged_has_work()) {
+		const unsigned long scan_sleep_jiffies =
+			msecs_to_jiffies(khugepaged_scan_sleep_millisecs);
+
+		if (!scan_sleep_jiffies)
+			return;
+
+		khugepaged_sleep_expire = jiffies + scan_sleep_jiffies;
+		wait_event_freezable_timeout(khugepaged_wait,
+					     khugepaged_should_wakeup(),
+					     scan_sleep_jiffies);
+		return;
+	}
+
+	if (khugepaged_enabled())
+		wait_event_freezable(khugepaged_wait, khugepaged_wait_event());
+}
+
+static int khugepaged(void *none)
+{
+	struct mm_slot *mm_slot;
+
+	set_freezable();
+	set_user_nice(current, MAX_NICE);
+
+	while (!kthread_should_stop()) {
+		khugepaged_do_scan();
+		khugepaged_wait_work();
+	}
+
+	spin_lock(&khugepaged_mm_lock);
+	mm_slot = khugepaged_scan.mm_slot;
+	khugepaged_scan.mm_slot = NULL;
+	if (mm_slot)
+		collect_mm_slot(mm_slot);
+	spin_unlock(&khugepaged_mm_lock);
+	return 0;
+}
+
+static void set_recommended_min_free_kbytes(void)
+{
+	struct zone *zone;
+	int nr_zones = 0;
+	unsigned long recommended_min;
+
+	for_each_populated_zone(zone)
+		nr_zones++;
+
+	/* Ensure 2 pageblocks are free to assist fragmentation avoidance */
+	recommended_min = pageblock_nr_pages * nr_zones * 2;
+
+	/*
+	 * Make sure that on average at least two pageblocks are almost free
+	 * of another type, one for a migratetype to fall back to and a
+	 * second to avoid subsequent fallbacks of other types There are 3
+	 * MIGRATE_TYPES we care about.
+	 */
+	recommended_min += pageblock_nr_pages * nr_zones *
+			   MIGRATE_PCPTYPES * MIGRATE_PCPTYPES;
+
+	/* don't ever allow to reserve more than 5% of the lowmem */
+	recommended_min = min(recommended_min,
+			      (unsigned long) nr_free_buffer_pages() / 20);
+	recommended_min <<= (PAGE_SHIFT-10);
+
+	if (recommended_min > min_free_kbytes) {
+		if (user_min_free_kbytes >= 0)
+			pr_info("raising min_free_kbytes from %d to %lu to help transparent hugepage allocations\n",
+				min_free_kbytes, recommended_min);
+
+		min_free_kbytes = recommended_min;
+	}
+	setup_per_zone_wmarks();
+}
+
+int start_stop_khugepaged(void)
+{
+	static struct task_struct *khugepaged_thread __read_mostly;
+	static DEFINE_MUTEX(khugepaged_mutex);
+	int err = 0;
+
+	mutex_lock(&khugepaged_mutex);
+	if (khugepaged_enabled()) {
+		if (!khugepaged_thread)
+			khugepaged_thread = kthread_run(khugepaged, NULL,
+							"khugepaged");
+		if (IS_ERR(khugepaged_thread)) {
+			pr_err("khugepaged: kthread_run(khugepaged) failed\n");
+			err = PTR_ERR(khugepaged_thread);
+			khugepaged_thread = NULL;
+			goto fail;
+		}
+
+		if (!list_empty(&khugepaged_scan.mm_head))
+			wake_up_interruptible(&khugepaged_wait);
+
+		set_recommended_min_free_kbytes();
+	} else if (khugepaged_thread) {
+		kthread_stop(khugepaged_thread);
+		khugepaged_thread = NULL;
+	}
+fail:
+	mutex_unlock(&khugepaged_mutex);
+	return err;
+}
diff --git a/mm/ksm.c b/mm/ksm.c
index 4786b4150f62..73d43bafd9fb 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -376,9 +376,8 @@ static int break_ksm(struct vm_area_struct *vma, unsigned long addr)
 		if (IS_ERR_OR_NULL(page))
 			break;
 		if (PageKsm(page))
-			ret = handle_mm_fault(vma->vm_mm, vma, addr,
-							FAULT_FLAG_WRITE |
-							FAULT_FLAG_REMOTE);
+			ret = handle_mm_fault(vma, addr,
+					FAULT_FLAG_WRITE | FAULT_FLAG_REMOTE);
 		else
 			ret = VM_FAULT_WRITE;
 		put_page(page);
@@ -532,8 +531,8 @@ static struct page *get_ksm_page(struct stable_node *stable_node, bool lock_it)
 	void *expected_mapping;
 	unsigned long kpfn;
 
-	expected_mapping = (void *)stable_node +
-				(PAGE_MAPPING_ANON | PAGE_MAPPING_KSM);
+	expected_mapping = (void *)((unsigned long)stable_node |
+					PAGE_MAPPING_KSM);
 again:
 	kpfn = READ_ONCE(stable_node->kpfn);
 	page = pfn_to_page(kpfn);
diff --git a/mm/memblock.c b/mm/memblock.c
index ac1248933b31..ca099159b45a 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -584,6 +584,9 @@ repeat:
 					       nid, flags);
 	}
 
+	if (!nr_new)
+		return 0;
+
 	/*
 	 * If this was the first round, resize array and repeat for actual
 	 * insertions; otherwise, merge and return.
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 5339c89dff63..f3a84c64f35c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1259,6 +1259,7 @@ static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
 	struct oom_control oc = {
 		.zonelist = NULL,
 		.nodemask = NULL,
+		.memcg = memcg,
 		.gfp_mask = gfp_mask,
 		.order = order,
 	};
@@ -1281,7 +1282,7 @@ static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
 		goto unlock;
 	}
 
-	check_panic_on_oom(&oc, CONSTRAINT_MEMCG, memcg);
+	check_panic_on_oom(&oc, CONSTRAINT_MEMCG);
 	totalpages = mem_cgroup_get_limit(memcg) ? : 1;
 	for_each_mem_cgroup_tree(iter, memcg) {
 		struct css_task_iter it;
@@ -1289,7 +1290,7 @@ static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
 
 		css_task_iter_start(&iter->css, &it);
 		while ((task = css_task_iter_next(&it))) {
-			switch (oom_scan_process_thread(&oc, task, totalpages)) {
+			switch (oom_scan_process_thread(&oc, task)) {
 			case OOM_SCAN_SELECT:
 				if (chosen)
 					put_task_struct(chosen);
@@ -1329,7 +1330,7 @@ static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
 
 	if (chosen) {
 		points = chosen_points * 1000 / totalpages;
-		oom_kill_process(&oc, chosen, points, totalpages, memcg,
+		oom_kill_process(&oc, chosen, points, totalpages,
 				 "Memory cgroup out of memory");
 	}
 unlock:
@@ -2272,20 +2273,30 @@ static void memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg,
 	current->memcg_kmem_skip_account = 0;
 }
 
-/*
+static inline bool memcg_kmem_bypass(void)
+{
+	if (in_interrupt() || !current->mm || (current->flags & PF_KTHREAD))
+		return true;
+	return false;
+}
+
+/**
+ * memcg_kmem_get_cache: select the correct per-memcg cache for allocation
+ * @cachep: the original global kmem cache
+ *
  * Return the kmem_cache we're supposed to use for a slab allocation.
  * We try to use the current memcg's version of the cache.
  *
- * If the cache does not exist yet, if we are the first user of it,
- * we either create it immediately, if possible, or create it asynchronously
- * in a workqueue.
- * In the latter case, we will let the current allocation go through with
- * the original cache.
+ * If the cache does not exist yet, if we are the first user of it, we
+ * create it asynchronously in a workqueue and let the current allocation
+ * go through with the original cache.
  *
- * Can't be called in interrupt context or from kernel threads.
- * This function needs to be called with rcu_read_lock() held.
+ * This function takes a reference to the cache it returns to assure it
+ * won't get destroyed while we are working with it. Once the caller is
+ * done with it, memcg_kmem_put_cache() must be called to release the
+ * reference.
  */
-struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp)
+struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep)
 {
 	struct mem_cgroup *memcg;
 	struct kmem_cache *memcg_cachep;
@@ -2293,10 +2304,7 @@ struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp)
 
 	VM_BUG_ON(!is_root_cache(cachep));
 
-	if (cachep->flags & SLAB_ACCOUNT)
-		gfp |= __GFP_ACCOUNT;
-
-	if (!(gfp & __GFP_ACCOUNT))
+	if (memcg_kmem_bypass())
 		return cachep;
 
 	if (current->memcg_kmem_skip_account)
@@ -2329,14 +2337,27 @@ out:
 	return cachep;
 }
 
-void __memcg_kmem_put_cache(struct kmem_cache *cachep)
+/**
+ * memcg_kmem_put_cache: drop reference taken by memcg_kmem_get_cache
+ * @cachep: the cache returned by memcg_kmem_get_cache
+ */
+void memcg_kmem_put_cache(struct kmem_cache *cachep)
 {
 	if (!is_root_cache(cachep))
 		css_put(&cachep->memcg_params.memcg->css);
 }
 
-int __memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
-			      struct mem_cgroup *memcg)
+/**
+ * memcg_kmem_charge: charge a kmem page
+ * @page: page to charge
+ * @gfp: reclaim mode
+ * @order: allocation order
+ * @memcg: memory cgroup to charge
+ *
+ * Returns 0 on success, an error code on failure.
+ */
+int memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
+			    struct mem_cgroup *memcg)
 {
 	unsigned int nr_pages = 1 << order;
 	struct page_counter *counter;
@@ -2357,19 +2378,34 @@ int __memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
 	return 0;
 }
 
-int __memcg_kmem_charge(struct page *page, gfp_t gfp, int order)
+/**
+ * memcg_kmem_charge: charge a kmem page to the current memory cgroup
+ * @page: page to charge
+ * @gfp: reclaim mode
+ * @order: allocation order
+ *
+ * Returns 0 on success, an error code on failure.
+ */
+int memcg_kmem_charge(struct page *page, gfp_t gfp, int order)
 {
 	struct mem_cgroup *memcg;
 	int ret = 0;
 
+	if (memcg_kmem_bypass())
+		return 0;
+
 	memcg = get_mem_cgroup_from_mm(current->mm);
 	if (!mem_cgroup_is_root(memcg))
-		ret = __memcg_kmem_charge_memcg(page, gfp, order, memcg);
+		ret = memcg_kmem_charge_memcg(page, gfp, order, memcg);
 	css_put(&memcg->css);
 	return ret;
 }
-
-void __memcg_kmem_uncharge(struct page *page, int order)
+/**
+ * memcg_kmem_uncharge: uncharge a kmem page
+ * @page: page to uncharge
+ * @order: allocation order
+ */
+void memcg_kmem_uncharge(struct page *page, int order)
 {
 	struct mem_cgroup *memcg = page->mem_cgroup;
 	unsigned int nr_pages = 1 << order;
@@ -4409,7 +4445,7 @@ static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
 
 #ifdef CONFIG_SWAP
 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
-			unsigned long addr, pte_t ptent, swp_entry_t *entry)
+			pte_t ptent, swp_entry_t *entry)
 {
 	struct page *page = NULL;
 	swp_entry_t ent = pte_to_swp_entry(ptent);
@@ -4428,7 +4464,7 @@ static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
 }
 #else
 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
-			unsigned long addr, pte_t ptent, swp_entry_t *entry)
+			pte_t ptent, swp_entry_t *entry)
 {
 	return NULL;
 }
@@ -4471,7 +4507,7 @@ static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
 /**
  * mem_cgroup_move_account - move account of the page
  * @page: the page
- * @nr_pages: number of regular pages (>1 for huge pages)
+ * @compound: charge the page as compound or small page
  * @from: mem_cgroup which the page is moved from.
  * @to:	mem_cgroup which the page is moved to. @from != @to.
  *
@@ -4593,7 +4629,7 @@ static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
 	if (pte_present(ptent))
 		page = mc_handle_present_pte(vma, addr, ptent);
 	else if (is_swap_pte(ptent))
-		page = mc_handle_swap_pte(vma, addr, ptent, &ent);
+		page = mc_handle_swap_pte(vma, ptent, &ent);
 	else if (pte_none(ptent))
 		page = mc_handle_file_pte(vma, addr, ptent, &ent);
 
@@ -5333,6 +5369,7 @@ bool mem_cgroup_low(struct mem_cgroup *root, struct mem_cgroup *memcg)
  * @mm: mm context of the victim
  * @gfp_mask: reclaim mode
  * @memcgp: charged memcg return
+ * @compound: charge the page as compound or small page
  *
  * Try to charge @page to the memcg that @mm belongs to, reclaiming
  * pages according to @gfp_mask if necessary.
@@ -5395,6 +5432,7 @@ out:
  * @page: page to charge
  * @memcg: memcg to charge the page to
  * @lrucare: page might be on LRU already
+ * @compound: charge the page as compound or small page
  *
  * Finalize a charge transaction started by mem_cgroup_try_charge(),
  * after page->mapping has been set up.  This must happen atomically
@@ -5446,6 +5484,7 @@ void mem_cgroup_commit_charge(struct page *page, struct mem_cgroup *memcg,
  * mem_cgroup_cancel_charge - cancel a page charge
  * @page: page to charge
  * @memcg: memcg to charge the page to
+ * @compound: charge the page as compound or small page
  *
  * Cancel a charge transaction started by mem_cgroup_try_charge().
  */
@@ -5469,15 +5508,18 @@ void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg,
 
 static void uncharge_batch(struct mem_cgroup *memcg, unsigned long pgpgout,
 			   unsigned long nr_anon, unsigned long nr_file,
-			   unsigned long nr_huge, struct page *dummy_page)
+			   unsigned long nr_huge, unsigned long nr_kmem,
+			   struct page *dummy_page)
 {
-	unsigned long nr_pages = nr_anon + nr_file;
+	unsigned long nr_pages = nr_anon + nr_file + nr_kmem;
 	unsigned long flags;
 
 	if (!mem_cgroup_is_root(memcg)) {
 		page_counter_uncharge(&memcg->memory, nr_pages);
 		if (do_memsw_account())
 			page_counter_uncharge(&memcg->memsw, nr_pages);
+		if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && nr_kmem)
+			page_counter_uncharge(&memcg->kmem, nr_kmem);
 		memcg_oom_recover(memcg);
 	}
 
@@ -5500,6 +5542,7 @@ static void uncharge_list(struct list_head *page_list)
 	unsigned long nr_anon = 0;
 	unsigned long nr_file = 0;
 	unsigned long nr_huge = 0;
+	unsigned long nr_kmem = 0;
 	unsigned long pgpgout = 0;
 	struct list_head *next;
 	struct page *page;
@@ -5510,8 +5553,6 @@ static void uncharge_list(struct list_head *page_list)
 	 */
 	next = page_list->next;
 	do {
-		unsigned int nr_pages = 1;
-
 		page = list_entry(next, struct page, lru);
 		next = page->lru.next;
 
@@ -5530,31 +5571,34 @@ static void uncharge_list(struct list_head *page_list)
 		if (memcg != page->mem_cgroup) {
 			if (memcg) {
 				uncharge_batch(memcg, pgpgout, nr_anon, nr_file,
-					       nr_huge, page);
-				pgpgout = nr_anon = nr_file = nr_huge = 0;
+					       nr_huge, nr_kmem, page);
+				pgpgout = nr_anon = nr_file =
+					nr_huge = nr_kmem = 0;
 			}
 			memcg = page->mem_cgroup;
 		}
 
-		if (PageTransHuge(page)) {
-			nr_pages <<= compound_order(page);
-			VM_BUG_ON_PAGE(!PageTransHuge(page), page);
-			nr_huge += nr_pages;
-		}
+		if (!PageKmemcg(page)) {
+			unsigned int nr_pages = 1;
 
-		if (PageAnon(page))
-			nr_anon += nr_pages;
-		else
-			nr_file += nr_pages;
+			if (PageTransHuge(page)) {
+				nr_pages <<= compound_order(page);
+				nr_huge += nr_pages;
+			}
+			if (PageAnon(page))
+				nr_anon += nr_pages;
+			else
+				nr_file += nr_pages;
+			pgpgout++;
+		} else
+			nr_kmem += 1 << compound_order(page);
 
 		page->mem_cgroup = NULL;
-
-		pgpgout++;
 	} while (next != page_list);
 
 	if (memcg)
 		uncharge_batch(memcg, pgpgout, nr_anon, nr_file,
-			       nr_huge, page);
+			       nr_huge, nr_kmem, page);
 }
 
 /**
diff --git a/mm/memory.c b/mm/memory.c
index 9e046819e619..4425b6059339 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -233,6 +233,7 @@ void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long
 #ifdef CONFIG_HAVE_RCU_TABLE_FREE
 	tlb->batch = NULL;
 #endif
+	tlb->page_size = 0;
 
 	__tlb_reset_range(tlb);
 }
@@ -292,23 +293,31 @@ void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long e
  *	handling the additional races in SMP caused by other CPUs caching valid
  *	mappings in their TLBs. Returns the number of free page slots left.
  *	When out of page slots we must call tlb_flush_mmu().
+ *returns true if the caller should flush.
  */
-int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
+bool __tlb_remove_page_size(struct mmu_gather *tlb, struct page *page, int page_size)
 {
 	struct mmu_gather_batch *batch;
 
 	VM_BUG_ON(!tlb->end);
 
+	if (!tlb->page_size)
+		tlb->page_size = page_size;
+	else {
+		if (page_size != tlb->page_size)
+			return true;
+	}
+
 	batch = tlb->active;
-	batch->pages[batch->nr++] = page;
 	if (batch->nr == batch->max) {
 		if (!tlb_next_batch(tlb))
-			return 0;
+			return true;
 		batch = tlb->active;
 	}
 	VM_BUG_ON_PAGE(batch->nr > batch->max, page);
 
-	return batch->max - batch->nr;
+	batch->pages[batch->nr++] = page;
+	return false;
 }
 
 #endif /* HAVE_GENERIC_MMU_GATHER */
@@ -1109,6 +1118,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
 	pte_t *start_pte;
 	pte_t *pte;
 	swp_entry_t entry;
+	struct page *pending_page = NULL;
 
 again:
 	init_rss_vec(rss);
@@ -1132,7 +1142,7 @@ again:
 				 * unmap shared but keep private pages.
 				 */
 				if (details->check_mapping &&
-				    details->check_mapping != page->mapping)
+				    details->check_mapping != page_rmapping(page))
 					continue;
 			}
 			ptent = ptep_get_and_clear_full(mm, addr, pte,
@@ -1160,8 +1170,9 @@ again:
 			page_remove_rmap(page, false);
 			if (unlikely(page_mapcount(page) < 0))
 				print_bad_pte(vma, addr, ptent, page);
-			if (unlikely(!__tlb_remove_page(tlb, page))) {
+			if (unlikely(__tlb_remove_page(tlb, page))) {
 				force_flush = 1;
+				pending_page = page;
 				addr += PAGE_SIZE;
 				break;
 			}
@@ -1202,7 +1213,11 @@ again:
 	if (force_flush) {
 		force_flush = 0;
 		tlb_flush_mmu_free(tlb);
-
+		if (pending_page) {
+			/* remove the page with new size */
+			__tlb_remove_pte_page(tlb, pending_page);
+			pending_page = NULL;
+		}
 		if (addr != end)
 			goto again;
 	}
@@ -1479,7 +1494,7 @@ static int insert_page(struct vm_area_struct *vma, unsigned long addr,
 	/* Ok, finally just insert the thing.. */
 	get_page(page);
 	inc_mm_counter_fast(mm, mm_counter_file(page));
-	page_add_file_rmap(page);
+	page_add_file_rmap(page, false);
 	set_pte_at(mm, addr, pte, mk_pte(page, prot));
 
 	retval = 0;
@@ -2055,13 +2070,11 @@ static int do_page_mkwrite(struct vm_area_struct *vma, struct page *page,
  * case, all we need to do here is to mark the page as writable and update
  * any related book-keeping.
  */
-static inline int wp_page_reuse(struct mm_struct *mm,
-			struct vm_area_struct *vma, unsigned long address,
-			pte_t *page_table, spinlock_t *ptl, pte_t orig_pte,
-			struct page *page, int page_mkwrite,
-			int dirty_shared)
-	__releases(ptl)
+static inline int wp_page_reuse(struct fault_env *fe, pte_t orig_pte,
+			struct page *page, int page_mkwrite, int dirty_shared)
+	__releases(fe->ptl)
 {
+	struct vm_area_struct *vma = fe->vma;
 	pte_t entry;
 	/*
 	 * Clear the pages cpupid information as the existing
@@ -2071,12 +2084,12 @@ static inline int wp_page_reuse(struct mm_struct *mm,
 	if (page)
 		page_cpupid_xchg_last(page, (1 << LAST_CPUPID_SHIFT) - 1);
 
-	flush_cache_page(vma, address, pte_pfn(orig_pte));
+	flush_cache_page(vma, fe->address, pte_pfn(orig_pte));
 	entry = pte_mkyoung(orig_pte);
 	entry = maybe_mkwrite(pte_mkdirty(entry), vma);
-	if (ptep_set_access_flags(vma, address, page_table, entry, 1))
-		update_mmu_cache(vma, address, page_table);
-	pte_unmap_unlock(page_table, ptl);
+	if (ptep_set_access_flags(vma, fe->address, fe->pte, entry, 1))
+		update_mmu_cache(vma, fe->address, fe->pte);
+	pte_unmap_unlock(fe->pte, fe->ptl);
 
 	if (dirty_shared) {
 		struct address_space *mapping;
@@ -2122,30 +2135,31 @@ static inline int wp_page_reuse(struct mm_struct *mm,
  *   held to the old page, as well as updating the rmap.
  * - In any case, unlock the PTL and drop the reference we took to the old page.
  */
-static int wp_page_copy(struct mm_struct *mm, struct vm_area_struct *vma,
-			unsigned long address, pte_t *page_table, pmd_t *pmd,
-			pte_t orig_pte, struct page *old_page)
+static int wp_page_copy(struct fault_env *fe, pte_t orig_pte,
+		struct page *old_page)
 {
+	struct vm_area_struct *vma = fe->vma;
+	struct mm_struct *mm = vma->vm_mm;
 	struct page *new_page = NULL;
-	spinlock_t *ptl = NULL;
 	pte_t entry;
 	int page_copied = 0;
-	const unsigned long mmun_start = address & PAGE_MASK;	/* For mmu_notifiers */
-	const unsigned long mmun_end = mmun_start + PAGE_SIZE;	/* For mmu_notifiers */
+	const unsigned long mmun_start = fe->address & PAGE_MASK;
+	const unsigned long mmun_end = mmun_start + PAGE_SIZE;
 	struct mem_cgroup *memcg;
 
 	if (unlikely(anon_vma_prepare(vma)))
 		goto oom;
 
 	if (is_zero_pfn(pte_pfn(orig_pte))) {
-		new_page = alloc_zeroed_user_highpage_movable(vma, address);
+		new_page = alloc_zeroed_user_highpage_movable(vma, fe->address);
 		if (!new_page)
 			goto oom;
 	} else {
-		new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
+		new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma,
+				fe->address);
 		if (!new_page)
 			goto oom;
-		cow_user_page(new_page, old_page, address, vma);
+		cow_user_page(new_page, old_page, fe->address, vma);
 	}
 
 	if (mem_cgroup_try_charge(new_page, mm, GFP_KERNEL, &memcg, false))
@@ -2158,8 +2172,8 @@ static int wp_page_copy(struct mm_struct *mm, struct vm_area_struct *vma,
 	/*
 	 * Re-check the pte - we dropped the lock
 	 */
-	page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
-	if (likely(pte_same(*page_table, orig_pte))) {
+	fe->pte = pte_offset_map_lock(mm, fe->pmd, fe->address, &fe->ptl);
+	if (likely(pte_same(*fe->pte, orig_pte))) {
 		if (old_page) {
 			if (!PageAnon(old_page)) {
 				dec_mm_counter_fast(mm,
@@ -2169,7 +2183,7 @@ static int wp_page_copy(struct mm_struct *mm, struct vm_area_struct *vma,
 		} else {
 			inc_mm_counter_fast(mm, MM_ANONPAGES);
 		}
-		flush_cache_page(vma, address, pte_pfn(orig_pte));
+		flush_cache_page(vma, fe->address, pte_pfn(orig_pte));
 		entry = mk_pte(new_page, vma->vm_page_prot);
 		entry = maybe_mkwrite(pte_mkdirty(entry), vma);
 		/*
@@ -2178,8 +2192,8 @@ static int wp_page_copy(struct mm_struct *mm, struct vm_area_struct *vma,
 		 * seen in the presence of one thread doing SMC and another
 		 * thread doing COW.
 		 */
-		ptep_clear_flush_notify(vma, address, page_table);
-		page_add_new_anon_rmap(new_page, vma, address, false);
+		ptep_clear_flush_notify(vma, fe->address, fe->pte);
+		page_add_new_anon_rmap(new_page, vma, fe->address, false);
 		mem_cgroup_commit_charge(new_page, memcg, false, false);
 		lru_cache_add_active_or_unevictable(new_page, vma);
 		/*
@@ -2187,8 +2201,8 @@ static int wp_page_copy(struct mm_struct *mm, struct vm_area_struct *vma,
 		 * mmu page tables (such as kvm shadow page tables), we want the
 		 * new page to be mapped directly into the secondary page table.
 		 */
-		set_pte_at_notify(mm, address, page_table, entry);
-		update_mmu_cache(vma, address, page_table);
+		set_pte_at_notify(mm, fe->address, fe->pte, entry);
+		update_mmu_cache(vma, fe->address, fe->pte);
 		if (old_page) {
 			/*
 			 * Only after switching the pte to the new page may
@@ -2225,7 +2239,7 @@ static int wp_page_copy(struct mm_struct *mm, struct vm_area_struct *vma,
 	if (new_page)
 		put_page(new_page);
 
-	pte_unmap_unlock(page_table, ptl);
+	pte_unmap_unlock(fe->pte, fe->ptl);
 	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
 	if (old_page) {
 		/*
@@ -2253,44 +2267,43 @@ oom:
  * Handle write page faults for VM_MIXEDMAP or VM_PFNMAP for a VM_SHARED
  * mapping
  */
-static int wp_pfn_shared(struct mm_struct *mm,
-			struct vm_area_struct *vma, unsigned long address,
-			pte_t *page_table, spinlock_t *ptl, pte_t orig_pte,
-			pmd_t *pmd)
+static int wp_pfn_shared(struct fault_env *fe,  pte_t orig_pte)
 {
+	struct vm_area_struct *vma = fe->vma;
+
 	if (vma->vm_ops && vma->vm_ops->pfn_mkwrite) {
 		struct vm_fault vmf = {
 			.page = NULL,
-			.pgoff = linear_page_index(vma, address),
-			.virtual_address = (void __user *)(address & PAGE_MASK),
+			.pgoff = linear_page_index(vma, fe->address),
+			.virtual_address =
+				(void __user *)(fe->address & PAGE_MASK),
 			.flags = FAULT_FLAG_WRITE | FAULT_FLAG_MKWRITE,
 		};
 		int ret;
 
-		pte_unmap_unlock(page_table, ptl);
+		pte_unmap_unlock(fe->pte, fe->ptl);
 		ret = vma->vm_ops->pfn_mkwrite(vma, &vmf);
 		if (ret & VM_FAULT_ERROR)
 			return ret;
-		page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
+		fe->pte = pte_offset_map_lock(vma->vm_mm, fe->pmd, fe->address,
+				&fe->ptl);
 		/*
 		 * We might have raced with another page fault while we
 		 * released the pte_offset_map_lock.
 		 */
-		if (!pte_same(*page_table, orig_pte)) {
-			pte_unmap_unlock(page_table, ptl);
+		if (!pte_same(*fe->pte, orig_pte)) {
+			pte_unmap_unlock(fe->pte, fe->ptl);
 			return 0;
 		}
 	}
-	return wp_page_reuse(mm, vma, address, page_table, ptl, orig_pte,
-			     NULL, 0, 0);
+	return wp_page_reuse(fe, orig_pte, NULL, 0, 0);
 }
 
-static int wp_page_shared(struct mm_struct *mm, struct vm_area_struct *vma,
-			  unsigned long address, pte_t *page_table,
-			  pmd_t *pmd, spinlock_t *ptl, pte_t orig_pte,
-			  struct page *old_page)
-	__releases(ptl)
+static int wp_page_shared(struct fault_env *fe, pte_t orig_pte,
+		struct page *old_page)
+	__releases(fe->ptl)
 {
+	struct vm_area_struct *vma = fe->vma;
 	int page_mkwrite = 0;
 
 	get_page(old_page);
@@ -2298,8 +2311,8 @@ static int wp_page_shared(struct mm_struct *mm, struct vm_area_struct *vma,
 	if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
 		int tmp;
 
-		pte_unmap_unlock(page_table, ptl);
-		tmp = do_page_mkwrite(vma, old_page, address);
+		pte_unmap_unlock(fe->pte, fe->ptl);
+		tmp = do_page_mkwrite(vma, old_page, fe->address);
 		if (unlikely(!tmp || (tmp &
 				      (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) {
 			put_page(old_page);
@@ -2311,19 +2324,18 @@ static int wp_page_shared(struct mm_struct *mm, struct vm_area_struct *vma,
 		 * they did, we just return, as we can count on the
 		 * MMU to tell us if they didn't also make it writable.
 		 */
-		page_table = pte_offset_map_lock(mm, pmd, address,
-						 &ptl);
-		if (!pte_same(*page_table, orig_pte)) {
+		fe->pte = pte_offset_map_lock(vma->vm_mm, fe->pmd, fe->address,
+						 &fe->ptl);
+		if (!pte_same(*fe->pte, orig_pte)) {
 			unlock_page(old_page);
-			pte_unmap_unlock(page_table, ptl);
+			pte_unmap_unlock(fe->pte, fe->ptl);
 			put_page(old_page);
 			return 0;
 		}
 		page_mkwrite = 1;
 	}
 
-	return wp_page_reuse(mm, vma, address, page_table, ptl,
-			     orig_pte, old_page, page_mkwrite, 1);
+	return wp_page_reuse(fe, orig_pte, old_page, page_mkwrite, 1);
 }
 
 /*
@@ -2344,14 +2356,13 @@ static int wp_page_shared(struct mm_struct *mm, struct vm_area_struct *vma,
  * but allow concurrent faults), with pte both mapped and locked.
  * We return with mmap_sem still held, but pte unmapped and unlocked.
  */
-static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
-		unsigned long address, pte_t *page_table, pmd_t *pmd,
-		spinlock_t *ptl, pte_t orig_pte)
-	__releases(ptl)
+static int do_wp_page(struct fault_env *fe, pte_t orig_pte)
+	__releases(fe->ptl)
 {
+	struct vm_area_struct *vma = fe->vma;
 	struct page *old_page;
 
-	old_page = vm_normal_page(vma, address, orig_pte);
+	old_page = vm_normal_page(vma, fe->address, orig_pte);
 	if (!old_page) {
 		/*
 		 * VM_MIXEDMAP !pfn_valid() case, or VM_SOFTDIRTY clear on a
@@ -2362,12 +2373,10 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
 		 */
 		if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
 				     (VM_WRITE|VM_SHARED))
-			return wp_pfn_shared(mm, vma, address, page_table, ptl,
-					     orig_pte, pmd);
+			return wp_pfn_shared(fe, orig_pte);
 
-		pte_unmap_unlock(page_table, ptl);
-		return wp_page_copy(mm, vma, address, page_table, pmd,
-				    orig_pte, old_page);
+		pte_unmap_unlock(fe->pte, fe->ptl);
+		return wp_page_copy(fe, orig_pte, old_page);
 	}
 
 	/*
@@ -2378,13 +2387,13 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
 		int total_mapcount;
 		if (!trylock_page(old_page)) {
 			get_page(old_page);
-			pte_unmap_unlock(page_table, ptl);
+			pte_unmap_unlock(fe->pte, fe->ptl);
 			lock_page(old_page);
-			page_table = pte_offset_map_lock(mm, pmd, address,
-							 &ptl);
-			if (!pte_same(*page_table, orig_pte)) {
+			fe->pte = pte_offset_map_lock(vma->vm_mm, fe->pmd,
+					fe->address, &fe->ptl);
+			if (!pte_same(*fe->pte, orig_pte)) {
 				unlock_page(old_page);
-				pte_unmap_unlock(page_table, ptl);
+				pte_unmap_unlock(fe->pte, fe->ptl);
 				put_page(old_page);
 				return 0;
 			}
@@ -2402,14 +2411,12 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
 				page_move_anon_rmap(old_page, vma);
 			}
 			unlock_page(old_page);
-			return wp_page_reuse(mm, vma, address, page_table, ptl,
-					     orig_pte, old_page, 0, 0);
+			return wp_page_reuse(fe, orig_pte, old_page, 0, 0);
 		}
 		unlock_page(old_page);
 	} else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
 					(VM_WRITE|VM_SHARED))) {
-		return wp_page_shared(mm, vma, address, page_table, pmd,
-				      ptl, orig_pte, old_page);
+		return wp_page_shared(fe, orig_pte, old_page);
 	}
 
 	/*
@@ -2417,9 +2424,8 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	 */
 	get_page(old_page);
 
-	pte_unmap_unlock(page_table, ptl);
-	return wp_page_copy(mm, vma, address, page_table, pmd,
-			    orig_pte, old_page);
+	pte_unmap_unlock(fe->pte, fe->ptl);
+	return wp_page_copy(fe, orig_pte, old_page);
 }
 
 static void unmap_mapping_range_vma(struct vm_area_struct *vma,
@@ -2507,11 +2513,9 @@ EXPORT_SYMBOL(unmap_mapping_range);
  * We return with the mmap_sem locked or unlocked in the same cases
  * as does filemap_fault().
  */
-static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
-		unsigned long address, pte_t *page_table, pmd_t *pmd,
-		unsigned int flags, pte_t orig_pte)
+int do_swap_page(struct fault_env *fe, pte_t orig_pte)
 {
-	spinlock_t *ptl;
+	struct vm_area_struct *vma = fe->vma;
 	struct page *page, *swapcache;
 	struct mem_cgroup *memcg;
 	swp_entry_t entry;
@@ -2520,17 +2524,17 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	int exclusive = 0;
 	int ret = 0;
 
-	if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
+	if (!pte_unmap_same(vma->vm_mm, fe->pmd, fe->pte, orig_pte))
 		goto out;
 
 	entry = pte_to_swp_entry(orig_pte);
 	if (unlikely(non_swap_entry(entry))) {
 		if (is_migration_entry(entry)) {
-			migration_entry_wait(mm, pmd, address);
+			migration_entry_wait(vma->vm_mm, fe->pmd, fe->address);
 		} else if (is_hwpoison_entry(entry)) {
 			ret = VM_FAULT_HWPOISON;
 		} else {
-			print_bad_pte(vma, address, orig_pte, NULL);
+			print_bad_pte(vma, fe->address, orig_pte, NULL);
 			ret = VM_FAULT_SIGBUS;
 		}
 		goto out;
@@ -2539,14 +2543,15 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	page = lookup_swap_cache(entry);
 	if (!page) {
 		page = swapin_readahead(entry,
-					GFP_HIGHUSER_MOVABLE, vma, address);
+					GFP_HIGHUSER_MOVABLE, vma, fe->address);
 		if (!page) {
 			/*
 			 * Back out if somebody else faulted in this pte
 			 * while we released the pte lock.
 			 */
-			page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
-			if (likely(pte_same(*page_table, orig_pte)))
+			fe->pte = pte_offset_map_lock(vma->vm_mm, fe->pmd,
+					fe->address, &fe->ptl);
+			if (likely(pte_same(*fe->pte, orig_pte)))
 				ret = VM_FAULT_OOM;
 			delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
 			goto unlock;
@@ -2555,7 +2560,7 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
 		/* Had to read the page from swap area: Major fault */
 		ret = VM_FAULT_MAJOR;
 		count_vm_event(PGMAJFAULT);
-		mem_cgroup_count_vm_event(mm, PGMAJFAULT);
+		mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT);
 	} else if (PageHWPoison(page)) {
 		/*
 		 * hwpoisoned dirty swapcache pages are kept for killing
@@ -2568,7 +2573,7 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	}
 
 	swapcache = page;
-	locked = lock_page_or_retry(page, mm, flags);
+	locked = lock_page_or_retry(page, vma->vm_mm, fe->flags);
 
 	delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
 	if (!locked) {
@@ -2585,14 +2590,15 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	if (unlikely(!PageSwapCache(page) || page_private(page) != entry.val))
 		goto out_page;
 
-	page = ksm_might_need_to_copy(page, vma, address);
+	page = ksm_might_need_to_copy(page, vma, fe->address);
 	if (unlikely(!page)) {
 		ret = VM_FAULT_OOM;
 		page = swapcache;
 		goto out_page;
 	}
 
-	if (mem_cgroup_try_charge(page, mm, GFP_KERNEL, &memcg, false)) {
+	if (mem_cgroup_try_charge(page, vma->vm_mm, GFP_KERNEL,
+				&memcg, false)) {
 		ret = VM_FAULT_OOM;
 		goto out_page;
 	}
@@ -2600,8 +2606,9 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	/*
 	 * Back out if somebody else already faulted in this pte.
 	 */
-	page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
-	if (unlikely(!pte_same(*page_table, orig_pte)))
+	fe->pte = pte_offset_map_lock(vma->vm_mm, fe->pmd, fe->address,
+			&fe->ptl);
+	if (unlikely(!pte_same(*fe->pte, orig_pte)))
 		goto out_nomap;
 
 	if (unlikely(!PageUptodate(page))) {
@@ -2619,24 +2626,24 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	 * must be called after the swap_free(), or it will never succeed.
 	 */
 
-	inc_mm_counter_fast(mm, MM_ANONPAGES);
-	dec_mm_counter_fast(mm, MM_SWAPENTS);
+	inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES);
+	dec_mm_counter_fast(vma->vm_mm, MM_SWAPENTS);
 	pte = mk_pte(page, vma->vm_page_prot);
-	if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page, NULL)) {
+	if ((fe->flags & FAULT_FLAG_WRITE) && reuse_swap_page(page, NULL)) {
 		pte = maybe_mkwrite(pte_mkdirty(pte), vma);
-		flags &= ~FAULT_FLAG_WRITE;
+		fe->flags &= ~FAULT_FLAG_WRITE;
 		ret |= VM_FAULT_WRITE;
 		exclusive = RMAP_EXCLUSIVE;
 	}
 	flush_icache_page(vma, page);
 	if (pte_swp_soft_dirty(orig_pte))
 		pte = pte_mksoft_dirty(pte);
-	set_pte_at(mm, address, page_table, pte);
+	set_pte_at(vma->vm_mm, fe->address, fe->pte, pte);
 	if (page == swapcache) {
-		do_page_add_anon_rmap(page, vma, address, exclusive);
+		do_page_add_anon_rmap(page, vma, fe->address, exclusive);
 		mem_cgroup_commit_charge(page, memcg, true, false);
 	} else { /* ksm created a completely new copy */
-		page_add_new_anon_rmap(page, vma, address, false);
+		page_add_new_anon_rmap(page, vma, fe->address, false);
 		mem_cgroup_commit_charge(page, memcg, false, false);
 		lru_cache_add_active_or_unevictable(page, vma);
 	}
@@ -2659,22 +2666,22 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
 		put_page(swapcache);
 	}
 
-	if (flags & FAULT_FLAG_WRITE) {
-		ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte);
+	if (fe->flags & FAULT_FLAG_WRITE) {
+		ret |= do_wp_page(fe, pte);
 		if (ret & VM_FAULT_ERROR)
 			ret &= VM_FAULT_ERROR;
 		goto out;
 	}
 
 	/* No need to invalidate - it was non-present before */
-	update_mmu_cache(vma, address, page_table);
+	update_mmu_cache(vma, fe->address, fe->pte);
 unlock:
-	pte_unmap_unlock(page_table, ptl);
+	pte_unmap_unlock(fe->pte, fe->ptl);
 out:
 	return ret;
 out_nomap:
 	mem_cgroup_cancel_charge(page, memcg, false);
-	pte_unmap_unlock(page_table, ptl);
+	pte_unmap_unlock(fe->pte, fe->ptl);
 out_page:
 	unlock_page(page);
 out_release:
@@ -2725,37 +2732,51 @@ static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned lo
  * but allow concurrent faults), and pte mapped but not yet locked.
  * We return with mmap_sem still held, but pte unmapped and unlocked.
  */
-static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
-		unsigned long address, pte_t *page_table, pmd_t *pmd,
-		unsigned int flags)
+static int do_anonymous_page(struct fault_env *fe)
 {
+	struct vm_area_struct *vma = fe->vma;
 	struct mem_cgroup *memcg;
 	struct page *page;
-	spinlock_t *ptl;
 	pte_t entry;
 
-	pte_unmap(page_table);
-
 	/* File mapping without ->vm_ops ? */
 	if (vma->vm_flags & VM_SHARED)
 		return VM_FAULT_SIGBUS;
 
 	/* Check if we need to add a guard page to the stack */
-	if (check_stack_guard_page(vma, address) < 0)
+	if (check_stack_guard_page(vma, fe->address) < 0)
 		return VM_FAULT_SIGSEGV;
 
+	/*
+	 * Use pte_alloc() instead of pte_alloc_map().  We can't run
+	 * pte_offset_map() on pmds where a huge pmd might be created
+	 * from a different thread.
+	 *
+	 * pte_alloc_map() is safe to use under down_write(mmap_sem) or when
+	 * parallel threads are excluded by other means.
+	 *
+	 * Here we only have down_read(mmap_sem).
+	 */
+	if (pte_alloc(vma->vm_mm, fe->pmd, fe->address))
+		return VM_FAULT_OOM;
+
+	/* See the comment in pte_alloc_one_map() */
+	if (unlikely(pmd_trans_unstable(fe->pmd)))
+		return 0;
+
 	/* Use the zero-page for reads */
-	if (!(flags & FAULT_FLAG_WRITE) && !mm_forbids_zeropage(mm)) {
-		entry = pte_mkspecial(pfn_pte(my_zero_pfn(address),
+	if (!(fe->flags & FAULT_FLAG_WRITE) &&
+			!mm_forbids_zeropage(vma->vm_mm)) {
+		entry = pte_mkspecial(pfn_pte(my_zero_pfn(fe->address),
 						vma->vm_page_prot));
-		page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
-		if (!pte_none(*page_table))
+		fe->pte = pte_offset_map_lock(vma->vm_mm, fe->pmd, fe->address,
+				&fe->ptl);
+		if (!pte_none(*fe->pte))
 			goto unlock;
 		/* Deliver the page fault to userland, check inside PT lock */
 		if (userfaultfd_missing(vma)) {
-			pte_unmap_unlock(page_table, ptl);
-			return handle_userfault(vma, address, flags,
-						VM_UFFD_MISSING);
+			pte_unmap_unlock(fe->pte, fe->ptl);
+			return handle_userfault(fe, VM_UFFD_MISSING);
 		}
 		goto setpte;
 	}
@@ -2763,11 +2784,11 @@ static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	/* Allocate our own private page. */
 	if (unlikely(anon_vma_prepare(vma)))
 		goto oom;
-	page = alloc_zeroed_user_highpage_movable(vma, address);
+	page = alloc_zeroed_user_highpage_movable(vma, fe->address);
 	if (!page)
 		goto oom;
 
-	if (mem_cgroup_try_charge(page, mm, GFP_KERNEL, &memcg, false))
+	if (mem_cgroup_try_charge(page, vma->vm_mm, GFP_KERNEL, &memcg, false))
 		goto oom_free_page;
 
 	/*
@@ -2781,30 +2802,30 @@ static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	if (vma->vm_flags & VM_WRITE)
 		entry = pte_mkwrite(pte_mkdirty(entry));
 
-	page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
-	if (!pte_none(*page_table))
+	fe->pte = pte_offset_map_lock(vma->vm_mm, fe->pmd, fe->address,
+			&fe->ptl);
+	if (!pte_none(*fe->pte))
 		goto release;
 
 	/* Deliver the page fault to userland, check inside PT lock */
 	if (userfaultfd_missing(vma)) {
-		pte_unmap_unlock(page_table, ptl);
+		pte_unmap_unlock(fe->pte, fe->ptl);
 		mem_cgroup_cancel_charge(page, memcg, false);
 		put_page(page);
-		return handle_userfault(vma, address, flags,
-					VM_UFFD_MISSING);
+		return handle_userfault(fe, VM_UFFD_MISSING);
 	}
 
-	inc_mm_counter_fast(mm, MM_ANONPAGES);
-	page_add_new_anon_rmap(page, vma, address, false);
+	inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES);
+	page_add_new_anon_rmap(page, vma, fe->address, false);
 	mem_cgroup_commit_charge(page, memcg, false, false);
 	lru_cache_add_active_or_unevictable(page, vma);
 setpte:
-	set_pte_at(mm, address, page_table, entry);
+	set_pte_at(vma->vm_mm, fe->address, fe->pte, entry);
 
 	/* No need to invalidate - it was non-present before */
-	update_mmu_cache(vma, address, page_table);
+	update_mmu_cache(vma, fe->address, fe->pte);
 unlock:
-	pte_unmap_unlock(page_table, ptl);
+	pte_unmap_unlock(fe->pte, fe->ptl);
 	return 0;
 release:
 	mem_cgroup_cancel_charge(page, memcg, false);
@@ -2821,17 +2842,16 @@ oom:
  * released depending on flags and vma->vm_ops->fault() return value.
  * See filemap_fault() and __lock_page_retry().
  */
-static int __do_fault(struct vm_area_struct *vma, unsigned long address,
-			pgoff_t pgoff, unsigned int flags,
-			struct page *cow_page, struct page **page,
-			void **entry)
+static int __do_fault(struct fault_env *fe, pgoff_t pgoff,
+		struct page *cow_page, struct page **page, void **entry)
 {
+	struct vm_area_struct *vma = fe->vma;
 	struct vm_fault vmf;
 	int ret;
 
-	vmf.virtual_address = (void __user *)(address & PAGE_MASK);
+	vmf.virtual_address = (void __user *)(fe->address & PAGE_MASK);
 	vmf.pgoff = pgoff;
-	vmf.flags = flags;
+	vmf.flags = fe->flags;
 	vmf.page = NULL;
 	vmf.gfp_mask = __get_fault_gfp_mask(vma);
 	vmf.cow_page = cow_page;
@@ -2860,41 +2880,168 @@ static int __do_fault(struct vm_area_struct *vma, unsigned long address,
 	return ret;
 }
 
+static int pte_alloc_one_map(struct fault_env *fe)
+{
+	struct vm_area_struct *vma = fe->vma;
+
+	if (!pmd_none(*fe->pmd))
+		goto map_pte;
+	if (fe->prealloc_pte) {
+		fe->ptl = pmd_lock(vma->vm_mm, fe->pmd);
+		if (unlikely(!pmd_none(*fe->pmd))) {
+			spin_unlock(fe->ptl);
+			goto map_pte;
+		}
+
+		atomic_long_inc(&vma->vm_mm->nr_ptes);
+		pmd_populate(vma->vm_mm, fe->pmd, fe->prealloc_pte);
+		spin_unlock(fe->ptl);
+		fe->prealloc_pte = 0;
+	} else if (unlikely(pte_alloc(vma->vm_mm, fe->pmd, fe->address))) {
+		return VM_FAULT_OOM;
+	}
+map_pte:
+	/*
+	 * If a huge pmd materialized under us just retry later.  Use
+	 * pmd_trans_unstable() instead of pmd_trans_huge() to ensure the pmd
+	 * didn't become pmd_trans_huge under us and then back to pmd_none, as
+	 * a result of MADV_DONTNEED running immediately after a huge pmd fault
+	 * in a different thread of this mm, in turn leading to a misleading
+	 * pmd_trans_huge() retval.  All we have to ensure is that it is a
+	 * regular pmd that we can walk with pte_offset_map() and we can do that
+	 * through an atomic read in C, which is what pmd_trans_unstable()
+	 * provides.
+	 */
+	if (pmd_trans_unstable(fe->pmd) || pmd_devmap(*fe->pmd))
+		return VM_FAULT_NOPAGE;
+
+	fe->pte = pte_offset_map_lock(vma->vm_mm, fe->pmd, fe->address,
+			&fe->ptl);
+	return 0;
+}
+
+#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
+
+#define HPAGE_CACHE_INDEX_MASK (HPAGE_PMD_NR - 1)
+static inline bool transhuge_vma_suitable(struct vm_area_struct *vma,
+		unsigned long haddr)
+{
+	if (((vma->vm_start >> PAGE_SHIFT) & HPAGE_CACHE_INDEX_MASK) !=
+			(vma->vm_pgoff & HPAGE_CACHE_INDEX_MASK))
+		return false;
+	if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end)
+		return false;
+	return true;
+}
+
+static int do_set_pmd(struct fault_env *fe, struct page *page)
+{
+	struct vm_area_struct *vma = fe->vma;
+	bool write = fe->flags & FAULT_FLAG_WRITE;
+	unsigned long haddr = fe->address & HPAGE_PMD_MASK;
+	pmd_t entry;
+	int i, ret;
+
+	if (!transhuge_vma_suitable(vma, haddr))
+		return VM_FAULT_FALLBACK;
+
+	ret = VM_FAULT_FALLBACK;
+	page = compound_head(page);
+
+	fe->ptl = pmd_lock(vma->vm_mm, fe->pmd);
+	if (unlikely(!pmd_none(*fe->pmd)))
+		goto out;
+
+	for (i = 0; i < HPAGE_PMD_NR; i++)
+		flush_icache_page(vma, page + i);
+
+	entry = mk_huge_pmd(page, vma->vm_page_prot);
+	if (write)
+		entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
+
+	add_mm_counter(vma->vm_mm, MM_FILEPAGES, HPAGE_PMD_NR);
+	page_add_file_rmap(page, true);
+
+	set_pmd_at(vma->vm_mm, haddr, fe->pmd, entry);
+
+	update_mmu_cache_pmd(vma, haddr, fe->pmd);
+
+	/* fault is handled */
+	ret = 0;
+	count_vm_event(THP_FILE_MAPPED);
+out:
+	spin_unlock(fe->ptl);
+	return ret;
+}
+#else
+static int do_set_pmd(struct fault_env *fe, struct page *page)
+{
+	BUILD_BUG();
+	return 0;
+}
+#endif
+
 /**
- * do_set_pte - setup new PTE entry for given page and add reverse page mapping.
+ * alloc_set_pte - setup new PTE entry for given page and add reverse page
+ * mapping. If needed, the fucntion allocates page table or use pre-allocated.
  *
- * @vma: virtual memory area
- * @address: user virtual address
+ * @fe: fault environment
+ * @memcg: memcg to charge page (only for private mappings)
  * @page: page to map
- * @pte: pointer to target page table entry
- * @write: true, if new entry is writable
- * @anon: true, if it's anonymous page
  *
- * Caller must hold page table lock relevant for @pte.
+ * Caller must take care of unlocking fe->ptl, if fe->pte is non-NULL on return.
  *
  * Target users are page handler itself and implementations of
  * vm_ops->map_pages.
  */
-void do_set_pte(struct vm_area_struct *vma, unsigned long address,
-		struct page *page, pte_t *pte, bool write, bool anon)
+int alloc_set_pte(struct fault_env *fe, struct mem_cgroup *memcg,
+		struct page *page)
 {
+	struct vm_area_struct *vma = fe->vma;
+	bool write = fe->flags & FAULT_FLAG_WRITE;
 	pte_t entry;
+	int ret;
+
+	if (pmd_none(*fe->pmd) && PageTransCompound(page) &&
+			IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE)) {
+		/* THP on COW? */
+		VM_BUG_ON_PAGE(memcg, page);
+
+		ret = do_set_pmd(fe, page);
+		if (ret != VM_FAULT_FALLBACK)
+			return ret;
+	}
+
+	if (!fe->pte) {
+		ret = pte_alloc_one_map(fe);
+		if (ret)
+			return ret;
+	}
+
+	/* Re-check under ptl */
+	if (unlikely(!pte_none(*fe->pte)))
+		return VM_FAULT_NOPAGE;
 
 	flush_icache_page(vma, page);
 	entry = mk_pte(page, vma->vm_page_prot);
 	if (write)
 		entry = maybe_mkwrite(pte_mkdirty(entry), vma);
-	if (anon) {
+	/* copy-on-write page */
+	if (write && !(vma->vm_flags & VM_SHARED)) {
 		inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES);
-		page_add_new_anon_rmap(page, vma, address, false);
+		page_add_new_anon_rmap(page, vma, fe->address, false);
+		mem_cgroup_commit_charge(page, memcg, false, false);
+		lru_cache_add_active_or_unevictable(page, vma);
 	} else {
 		inc_mm_counter_fast(vma->vm_mm, mm_counter_file(page));
-		page_add_file_rmap(page);
+		page_add_file_rmap(page, false);
 	}
-	set_pte_at(vma->vm_mm, address, pte, entry);
+	set_pte_at(vma->vm_mm, fe->address, fe->pte, entry);
 
 	/* no need to invalidate: a not-present page won't be cached */
-	update_mmu_cache(vma, address, pte);
+	update_mmu_cache(vma, fe->address, fe->pte);
+
+	return 0;
 }
 
 static unsigned long fault_around_bytes __read_mostly =
@@ -2961,57 +3108,66 @@ late_initcall(fault_around_debugfs);
  * fault_around_pages() value (and therefore to page order).  This way it's
  * easier to guarantee that we don't cross page table boundaries.
  */
-static void do_fault_around(struct vm_area_struct *vma, unsigned long address,
-		pte_t *pte, pgoff_t pgoff, unsigned int flags)
+static int do_fault_around(struct fault_env *fe, pgoff_t start_pgoff)
 {
-	unsigned long start_addr, nr_pages, mask;
-	pgoff_t max_pgoff;
-	struct vm_fault vmf;
-	int off;
+	unsigned long address = fe->address, nr_pages, mask;
+	pgoff_t end_pgoff;
+	int off, ret = 0;
 
 	nr_pages = READ_ONCE(fault_around_bytes) >> PAGE_SHIFT;
 	mask = ~(nr_pages * PAGE_SIZE - 1) & PAGE_MASK;
 
-	start_addr = max(address & mask, vma->vm_start);
-	off = ((address - start_addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);
-	pte -= off;
-	pgoff -= off;
+	fe->address = max(address & mask, fe->vma->vm_start);
+	off = ((address - fe->address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);
+	start_pgoff -= off;
 
 	/*
-	 *  max_pgoff is either end of page table or end of vma
-	 *  or fault_around_pages() from pgoff, depending what is nearest.
+	 *  end_pgoff is either end of page table or end of vma
+	 *  or fault_around_pages() from start_pgoff, depending what is nearest.
 	 */
-	max_pgoff = pgoff - ((start_addr >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) +
+	end_pgoff = start_pgoff -
+		((fe->address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) +
 		PTRS_PER_PTE - 1;
-	max_pgoff = min3(max_pgoff, vma_pages(vma) + vma->vm_pgoff - 1,
-			pgoff + nr_pages - 1);
+	end_pgoff = min3(end_pgoff, vma_pages(fe->vma) + fe->vma->vm_pgoff - 1,
+			start_pgoff + nr_pages - 1);
 
-	/* Check if it makes any sense to call ->map_pages */
-	while (!pte_none(*pte)) {
-		if (++pgoff > max_pgoff)
-			return;
-		start_addr += PAGE_SIZE;
-		if (start_addr >= vma->vm_end)
-			return;
-		pte++;
+	if (pmd_none(*fe->pmd)) {
+		fe->prealloc_pte = pte_alloc_one(fe->vma->vm_mm, fe->address);
+		smp_wmb(); /* See comment in __pte_alloc() */
 	}
 
-	vmf.virtual_address = (void __user *) start_addr;
-	vmf.pte = pte;
-	vmf.pgoff = pgoff;
-	vmf.max_pgoff = max_pgoff;
-	vmf.flags = flags;
-	vmf.gfp_mask = __get_fault_gfp_mask(vma);
-	vma->vm_ops->map_pages(vma, &vmf);
+	fe->vma->vm_ops->map_pages(fe, start_pgoff, end_pgoff);
+
+	/* preallocated pagetable is unused: free it */
+	if (fe->prealloc_pte) {
+		pte_free(fe->vma->vm_mm, fe->prealloc_pte);
+		fe->prealloc_pte = 0;
+	}
+	/* Huge page is mapped? Page fault is solved */
+	if (pmd_trans_huge(*fe->pmd)) {
+		ret = VM_FAULT_NOPAGE;
+		goto out;
+	}
+
+	/* ->map_pages() haven't done anything useful. Cold page cache? */
+	if (!fe->pte)
+		goto out;
+
+	/* check if the page fault is solved */
+	fe->pte -= (fe->address >> PAGE_SHIFT) - (address >> PAGE_SHIFT);
+	if (!pte_none(*fe->pte))
+		ret = VM_FAULT_NOPAGE;
+	pte_unmap_unlock(fe->pte, fe->ptl);
+out:
+	fe->address = address;
+	fe->pte = NULL;
+	return ret;
 }
 
-static int do_read_fault(struct mm_struct *mm, struct vm_area_struct *vma,
-		unsigned long address, pmd_t *pmd,
-		pgoff_t pgoff, unsigned int flags, pte_t orig_pte)
+static int do_read_fault(struct fault_env *fe, pgoff_t pgoff)
 {
+	struct vm_area_struct *vma = fe->vma;
 	struct page *fault_page;
-	spinlock_t *ptl;
-	pte_t *pte;
 	int ret = 0;
 
 	/*
@@ -3020,85 +3176,64 @@ static int do_read_fault(struct mm_struct *mm, struct vm_area_struct *vma,
 	 * something).
 	 */
 	if (vma->vm_ops->map_pages && fault_around_bytes >> PAGE_SHIFT > 1) {
-		pte = pte_offset_map_lock(mm, pmd, address, &ptl);
-		do_fault_around(vma, address, pte, pgoff, flags);
-		if (!pte_same(*pte, orig_pte))
-			goto unlock_out;
-		pte_unmap_unlock(pte, ptl);
+		ret = do_fault_around(fe, pgoff);
+		if (ret)
+			return ret;
 	}
 
-	ret = __do_fault(vma, address, pgoff, flags, NULL, &fault_page, NULL);
+	ret = __do_fault(fe, pgoff, NULL, &fault_page, NULL);
 	if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
 		return ret;
 
-	pte = pte_offset_map_lock(mm, pmd, address, &ptl);
-	if (unlikely(!pte_same(*pte, orig_pte))) {
-		pte_unmap_unlock(pte, ptl);
-		unlock_page(fault_page);
-		put_page(fault_page);
-		return ret;
-	}
-	do_set_pte(vma, address, fault_page, pte, false, false);
+	ret |= alloc_set_pte(fe, NULL, fault_page);
+	if (fe->pte)
+		pte_unmap_unlock(fe->pte, fe->ptl);
 	unlock_page(fault_page);
-unlock_out:
-	pte_unmap_unlock(pte, ptl);
+	if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
+		put_page(fault_page);
 	return ret;
 }
 
-static int do_cow_fault(struct mm_struct *mm, struct vm_area_struct *vma,
-		unsigned long address, pmd_t *pmd,
-		pgoff_t pgoff, unsigned int flags, pte_t orig_pte)
+static int do_cow_fault(struct fault_env *fe, pgoff_t pgoff)
 {
+	struct vm_area_struct *vma = fe->vma;
 	struct page *fault_page, *new_page;
 	void *fault_entry;
 	struct mem_cgroup *memcg;
-	spinlock_t *ptl;
-	pte_t *pte;
 	int ret;
 
 	if (unlikely(anon_vma_prepare(vma)))
 		return VM_FAULT_OOM;
 
-	new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
+	new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, fe->address);
 	if (!new_page)
 		return VM_FAULT_OOM;
 
-	if (mem_cgroup_try_charge(new_page, mm, GFP_KERNEL, &memcg, false)) {
+	if (mem_cgroup_try_charge(new_page, vma->vm_mm, GFP_KERNEL,
+				&memcg, false)) {
 		put_page(new_page);
 		return VM_FAULT_OOM;
 	}
 
-	ret = __do_fault(vma, address, pgoff, flags, new_page, &fault_page,
-			 &fault_entry);
+	ret = __do_fault(fe, pgoff, new_page, &fault_page, &fault_entry);
 	if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
 		goto uncharge_out;
 
 	if (!(ret & VM_FAULT_DAX_LOCKED))
-		copy_user_highpage(new_page, fault_page, address, vma);
+		copy_user_highpage(new_page, fault_page, fe->address, vma);
 	__SetPageUptodate(new_page);
 
-	pte = pte_offset_map_lock(mm, pmd, address, &ptl);
-	if (unlikely(!pte_same(*pte, orig_pte))) {
-		pte_unmap_unlock(pte, ptl);
-		if (!(ret & VM_FAULT_DAX_LOCKED)) {
-			unlock_page(fault_page);
-			put_page(fault_page);
-		} else {
-			dax_unlock_mapping_entry(vma->vm_file->f_mapping,
-						 pgoff);
-		}
-		goto uncharge_out;
-	}
-	do_set_pte(vma, address, new_page, pte, true, true);
-	mem_cgroup_commit_charge(new_page, memcg, false, false);
-	lru_cache_add_active_or_unevictable(new_page, vma);
-	pte_unmap_unlock(pte, ptl);
+	ret |= alloc_set_pte(fe, memcg, new_page);
+	if (fe->pte)
+		pte_unmap_unlock(fe->pte, fe->ptl);
 	if (!(ret & VM_FAULT_DAX_LOCKED)) {
 		unlock_page(fault_page);
 		put_page(fault_page);
 	} else {
 		dax_unlock_mapping_entry(vma->vm_file->f_mapping, pgoff);
 	}
+	if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
+		goto uncharge_out;
 	return ret;
 uncharge_out:
 	mem_cgroup_cancel_charge(new_page, memcg, false);
@@ -3106,18 +3241,15 @@ uncharge_out:
 	return ret;
 }
 
-static int do_shared_fault(struct mm_struct *mm, struct vm_area_struct *vma,
-		unsigned long address, pmd_t *pmd,
-		pgoff_t pgoff, unsigned int flags, pte_t orig_pte)
+static int do_shared_fault(struct fault_env *fe, pgoff_t pgoff)
 {
+	struct vm_area_struct *vma = fe->vma;
 	struct page *fault_page;
 	struct address_space *mapping;
-	spinlock_t *ptl;
-	pte_t *pte;
 	int dirtied = 0;
 	int ret, tmp;
 
-	ret = __do_fault(vma, address, pgoff, flags, NULL, &fault_page, NULL);
+	ret = __do_fault(fe, pgoff, NULL, &fault_page, NULL);
 	if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
 		return ret;
 
@@ -3127,7 +3259,7 @@ static int do_shared_fault(struct mm_struct *mm, struct vm_area_struct *vma,
 	 */
 	if (vma->vm_ops->page_mkwrite) {
 		unlock_page(fault_page);
-		tmp = do_page_mkwrite(vma, fault_page, address);
+		tmp = do_page_mkwrite(vma, fault_page, fe->address);
 		if (unlikely(!tmp ||
 				(tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) {
 			put_page(fault_page);
@@ -3135,15 +3267,15 @@ static int do_shared_fault(struct mm_struct *mm, struct vm_area_struct *vma,
 		}
 	}
 
-	pte = pte_offset_map_lock(mm, pmd, address, &ptl);
-	if (unlikely(!pte_same(*pte, orig_pte))) {
-		pte_unmap_unlock(pte, ptl);
+	ret |= alloc_set_pte(fe, NULL, fault_page);
+	if (fe->pte)
+		pte_unmap_unlock(fe->pte, fe->ptl);
+	if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE |
+					VM_FAULT_RETRY))) {
 		unlock_page(fault_page);
 		put_page(fault_page);
 		return ret;
 	}
-	do_set_pte(vma, address, fault_page, pte, true, false);
-	pte_unmap_unlock(pte, ptl);
 
 	if (set_page_dirty(fault_page))
 		dirtied = 1;
@@ -3175,23 +3307,19 @@ static int do_shared_fault(struct mm_struct *mm, struct vm_area_struct *vma,
  * The mmap_sem may have been released depending on flags and our
  * return value.  See filemap_fault() and __lock_page_or_retry().
  */
-static int do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
-		unsigned long address, pte_t *page_table, pmd_t *pmd,
-		unsigned int flags, pte_t orig_pte)
+static int do_fault(struct fault_env *fe)
 {
-	pgoff_t pgoff = linear_page_index(vma, address);
+	struct vm_area_struct *vma = fe->vma;
+	pgoff_t pgoff = linear_page_index(vma, fe->address);
 
-	pte_unmap(page_table);
 	/* The VMA was not fully populated on mmap() or missing VM_DONTEXPAND */
 	if (!vma->vm_ops->fault)
 		return VM_FAULT_SIGBUS;
-	if (!(flags & FAULT_FLAG_WRITE))
-		return do_read_fault(mm, vma, address, pmd, pgoff, flags,
-				orig_pte);
+	if (!(fe->flags & FAULT_FLAG_WRITE))
+		return do_read_fault(fe, pgoff);
 	if (!(vma->vm_flags & VM_SHARED))
-		return do_cow_fault(mm, vma, address, pmd, pgoff, flags,
-				orig_pte);
-	return do_shared_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
+		return do_cow_fault(fe, pgoff);
+	return do_shared_fault(fe, pgoff);
 }
 
 static int numa_migrate_prep(struct page *page, struct vm_area_struct *vma,
@@ -3209,11 +3337,10 @@ static int numa_migrate_prep(struct page *page, struct vm_area_struct *vma,
 	return mpol_misplaced(page, vma, addr);
 }
 
-static int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
-		   unsigned long addr, pte_t pte, pte_t *ptep, pmd_t *pmd)
+static int do_numa_page(struct fault_env *fe, pte_t pte)
 {
+	struct vm_area_struct *vma = fe->vma;
 	struct page *page = NULL;
-	spinlock_t *ptl;
 	int page_nid = -1;
 	int last_cpupid;
 	int target_nid;
@@ -3233,10 +3360,10 @@ static int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	* page table entry is not accessible, so there would be no
 	* concurrent hardware modifications to the PTE.
 	*/
-	ptl = pte_lockptr(mm, pmd);
-	spin_lock(ptl);
-	if (unlikely(!pte_same(*ptep, pte))) {
-		pte_unmap_unlock(ptep, ptl);
+	fe->ptl = pte_lockptr(vma->vm_mm, fe->pmd);
+	spin_lock(fe->ptl);
+	if (unlikely(!pte_same(*fe->pte, pte))) {
+		pte_unmap_unlock(fe->pte, fe->ptl);
 		goto out;
 	}
 
@@ -3245,18 +3372,18 @@ static int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	pte = pte_mkyoung(pte);
 	if (was_writable)
 		pte = pte_mkwrite(pte);
-	set_pte_at(mm, addr, ptep, pte);
-	update_mmu_cache(vma, addr, ptep);
+	set_pte_at(vma->vm_mm, fe->address, fe->pte, pte);
+	update_mmu_cache(vma, fe->address, fe->pte);
 
-	page = vm_normal_page(vma, addr, pte);
+	page = vm_normal_page(vma, fe->address, pte);
 	if (!page) {
-		pte_unmap_unlock(ptep, ptl);
+		pte_unmap_unlock(fe->pte, fe->ptl);
 		return 0;
 	}
 
 	/* TODO: handle PTE-mapped THP */
 	if (PageCompound(page)) {
-		pte_unmap_unlock(ptep, ptl);
+		pte_unmap_unlock(fe->pte, fe->ptl);
 		return 0;
 	}
 
@@ -3280,8 +3407,9 @@ static int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 
 	last_cpupid = page_cpupid_last(page);
 	page_nid = page_to_nid(page);
-	target_nid = numa_migrate_prep(page, vma, addr, page_nid, &flags);
-	pte_unmap_unlock(ptep, ptl);
+	target_nid = numa_migrate_prep(page, vma, fe->address, page_nid,
+			&flags);
+	pte_unmap_unlock(fe->pte, fe->ptl);
 	if (target_nid == -1) {
 		put_page(page);
 		goto out;
@@ -3301,24 +3429,29 @@ out:
 	return 0;
 }
 
-static int create_huge_pmd(struct mm_struct *mm, struct vm_area_struct *vma,
-			unsigned long address, pmd_t *pmd, unsigned int flags)
+static int create_huge_pmd(struct fault_env *fe)
 {
+	struct vm_area_struct *vma = fe->vma;
 	if (vma_is_anonymous(vma))
-		return do_huge_pmd_anonymous_page(mm, vma, address, pmd, flags);
+		return do_huge_pmd_anonymous_page(fe);
 	if (vma->vm_ops->pmd_fault)
-		return vma->vm_ops->pmd_fault(vma, address, pmd, flags);
+		return vma->vm_ops->pmd_fault(vma, fe->address, fe->pmd,
+				fe->flags);
 	return VM_FAULT_FALLBACK;
 }
 
-static int wp_huge_pmd(struct mm_struct *mm, struct vm_area_struct *vma,
-			unsigned long address, pmd_t *pmd, pmd_t orig_pmd,
-			unsigned int flags)
+static int wp_huge_pmd(struct fault_env *fe, pmd_t orig_pmd)
 {
-	if (vma_is_anonymous(vma))
-		return do_huge_pmd_wp_page(mm, vma, address, pmd, orig_pmd);
-	if (vma->vm_ops->pmd_fault)
-		return vma->vm_ops->pmd_fault(vma, address, pmd, flags);
+	if (vma_is_anonymous(fe->vma))
+		return do_huge_pmd_wp_page(fe, orig_pmd);
+	if (fe->vma->vm_ops->pmd_fault)
+		return fe->vma->vm_ops->pmd_fault(fe->vma, fe->address, fe->pmd,
+				fe->flags);
+
+	/* COW handled on pte level: split pmd */
+	VM_BUG_ON_VMA(fe->vma->vm_flags & VM_SHARED, fe->vma);
+	split_huge_pmd(fe->vma, fe->pmd, fe->address);
+
 	return VM_FAULT_FALLBACK;
 }
 
@@ -3331,59 +3464,79 @@ static int wp_huge_pmd(struct mm_struct *mm, struct vm_area_struct *vma,
  * with external mmu caches can use to update those (ie the Sparc or
  * PowerPC hashed page tables that act as extended TLBs).
  *
- * We enter with non-exclusive mmap_sem (to exclude vma changes,
- * but allow concurrent faults), and pte mapped but not yet locked.
- * We return with pte unmapped and unlocked.
+ * We enter with non-exclusive mmap_sem (to exclude vma changes, but allow
+ * concurrent faults).
  *
- * The mmap_sem may have been released depending on flags and our
- * return value.  See filemap_fault() and __lock_page_or_retry().
+ * The mmap_sem may have been released depending on flags and our return value.
+ * See filemap_fault() and __lock_page_or_retry().
  */
-static int handle_pte_fault(struct mm_struct *mm,
-		     struct vm_area_struct *vma, unsigned long address,
-		     pte_t *pte, pmd_t *pmd, unsigned int flags)
+static int handle_pte_fault(struct fault_env *fe)
 {
 	pte_t entry;
-	spinlock_t *ptl;
 
-	/*
-	 * some architectures can have larger ptes than wordsize,
-	 * e.g.ppc44x-defconfig has CONFIG_PTE_64BIT=y and CONFIG_32BIT=y,
-	 * so READ_ONCE or ACCESS_ONCE cannot guarantee atomic accesses.
-	 * The code below just needs a consistent view for the ifs and
-	 * we later double check anyway with the ptl lock held. So here
-	 * a barrier will do.
-	 */
-	entry = *pte;
-	barrier();
-	if (!pte_present(entry)) {
+	if (unlikely(pmd_none(*fe->pmd))) {
+		/*
+		 * Leave __pte_alloc() until later: because vm_ops->fault may
+		 * want to allocate huge page, and if we expose page table
+		 * for an instant, it will be difficult to retract from
+		 * concurrent faults and from rmap lookups.
+		 */
+		fe->pte = NULL;
+	} else {
+		/* See comment in pte_alloc_one_map() */
+		if (pmd_trans_unstable(fe->pmd) || pmd_devmap(*fe->pmd))
+			return 0;
+		/*
+		 * A regular pmd is established and it can't morph into a huge
+		 * pmd from under us anymore at this point because we hold the
+		 * mmap_sem read mode and khugepaged takes it in write mode.
+		 * So now it's safe to run pte_offset_map().
+		 */
+		fe->pte = pte_offset_map(fe->pmd, fe->address);
+
+		entry = *fe->pte;
+
+		/*
+		 * some architectures can have larger ptes than wordsize,
+		 * e.g.ppc44x-defconfig has CONFIG_PTE_64BIT=y and
+		 * CONFIG_32BIT=y, so READ_ONCE or ACCESS_ONCE cannot guarantee
+		 * atomic accesses.  The code below just needs a consistent
+		 * view for the ifs and we later double check anyway with the
+		 * ptl lock held. So here a barrier will do.
+		 */
+		barrier();
 		if (pte_none(entry)) {
-			if (vma_is_anonymous(vma))
-				return do_anonymous_page(mm, vma, address,
-							 pte, pmd, flags);
-			else
-				return do_fault(mm, vma, address, pte, pmd,
-						flags, entry);
+			pte_unmap(fe->pte);
+			fe->pte = NULL;
 		}
-		return do_swap_page(mm, vma, address,
-					pte, pmd, flags, entry);
 	}
 
+	if (!fe->pte) {
+		if (vma_is_anonymous(fe->vma))
+			return do_anonymous_page(fe);
+		else
+			return do_fault(fe);
+	}
+
+	if (!pte_present(entry))
+		return do_swap_page(fe, entry);
+
 	if (pte_protnone(entry))
-		return do_numa_page(mm, vma, address, entry, pte, pmd);
+		return do_numa_page(fe, entry);
 
-	ptl = pte_lockptr(mm, pmd);
-	spin_lock(ptl);
-	if (unlikely(!pte_same(*pte, entry)))
+	fe->ptl = pte_lockptr(fe->vma->vm_mm, fe->pmd);
+	spin_lock(fe->ptl);
+	if (unlikely(!pte_same(*fe->pte, entry)))
 		goto unlock;
-	if (flags & FAULT_FLAG_WRITE) {
+	if (fe->flags & FAULT_FLAG_WRITE) {
 		if (!pte_write(entry))
-			return do_wp_page(mm, vma, address,
-					pte, pmd, ptl, entry);
+			return do_wp_page(fe, entry);
 		entry = pte_mkdirty(entry);
 	}
 	entry = pte_mkyoung(entry);
-	if (ptep_set_access_flags(vma, address, pte, entry, flags & FAULT_FLAG_WRITE)) {
-		update_mmu_cache(vma, address, pte);
+	if (ptep_set_access_flags(fe->vma, fe->address, fe->pte, entry,
+				fe->flags & FAULT_FLAG_WRITE)) {
+		update_mmu_cache(fe->vma, fe->address, fe->pte);
 	} else {
 		/*
 		 * This is needed only for protection faults but the arch code
@@ -3391,11 +3544,11 @@ static int handle_pte_fault(struct mm_struct *mm,
 		 * This still avoids useless tlb flushes for .text page faults
 		 * with threads.
 		 */
-		if (flags & FAULT_FLAG_WRITE)
-			flush_tlb_fix_spurious_fault(vma, address);
+		if (fe->flags & FAULT_FLAG_WRITE)
+			flush_tlb_fix_spurious_fault(fe->vma, fe->address);
 	}
 unlock:
-	pte_unmap_unlock(pte, ptl);
+	pte_unmap_unlock(fe->pte, fe->ptl);
 	return 0;
 }
 
@@ -3405,87 +3558,51 @@ unlock:
  * The mmap_sem may have been released depending on flags and our
  * return value.  See filemap_fault() and __lock_page_or_retry().
  */
-static int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
-			     unsigned long address, unsigned int flags)
+static int __handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
+		unsigned int flags)
 {
+	struct fault_env fe = {
+		.vma = vma,
+		.address = address,
+		.flags = flags,
+	};
+	struct mm_struct *mm = vma->vm_mm;
 	pgd_t *pgd;
 	pud_t *pud;
-	pmd_t *pmd;
-	pte_t *pte;
-
-	if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE,
-					    flags & FAULT_FLAG_INSTRUCTION,
-					    flags & FAULT_FLAG_REMOTE))
-		return VM_FAULT_SIGSEGV;
-
-	if (unlikely(is_vm_hugetlb_page(vma)))
-		return hugetlb_fault(mm, vma, address, flags);
 
 	pgd = pgd_offset(mm, address);
 	pud = pud_alloc(mm, pgd, address);
 	if (!pud)
 		return VM_FAULT_OOM;
-	pmd = pmd_alloc(mm, pud, address);
-	if (!pmd)
+	fe.pmd = pmd_alloc(mm, pud, address);
+	if (!fe.pmd)
 		return VM_FAULT_OOM;
-	if (pmd_none(*pmd) && transparent_hugepage_enabled(vma)) {
-		int ret = create_huge_pmd(mm, vma, address, pmd, flags);
+	if (pmd_none(*fe.pmd) && transparent_hugepage_enabled(vma)) {
+		int ret = create_huge_pmd(&fe);
 		if (!(ret & VM_FAULT_FALLBACK))
 			return ret;
 	} else {
-		pmd_t orig_pmd = *pmd;
+		pmd_t orig_pmd = *fe.pmd;
 		int ret;
 
 		barrier();
 		if (pmd_trans_huge(orig_pmd) || pmd_devmap(orig_pmd)) {
-			unsigned int dirty = flags & FAULT_FLAG_WRITE;
-
 			if (pmd_protnone(orig_pmd))
-				return do_huge_pmd_numa_page(mm, vma, address,
-							     orig_pmd, pmd);
+				return do_huge_pmd_numa_page(&fe, orig_pmd);
 
-			if (dirty && !pmd_write(orig_pmd)) {
-				ret = wp_huge_pmd(mm, vma, address, pmd,
-							orig_pmd, flags);
+			if ((fe.flags & FAULT_FLAG_WRITE) &&
+					!pmd_write(orig_pmd)) {
+				ret = wp_huge_pmd(&fe, orig_pmd);
 				if (!(ret & VM_FAULT_FALLBACK))
 					return ret;
 			} else {
-				huge_pmd_set_accessed(mm, vma, address, pmd,
-						      orig_pmd, dirty);
+				huge_pmd_set_accessed(&fe, orig_pmd);
 				return 0;
 			}
 		}
 	}
 
-	/*
-	 * Use pte_alloc() instead of pte_alloc_map, because we can't
-	 * run pte_offset_map on the pmd, if an huge pmd could
-	 * materialize from under us from a different thread.
-	 */
-	if (unlikely(pte_alloc(mm, pmd, address)))
-		return VM_FAULT_OOM;
-	/*
-	 * If a huge pmd materialized under us just retry later.  Use
-	 * pmd_trans_unstable() instead of pmd_trans_huge() to ensure the pmd
-	 * didn't become pmd_trans_huge under us and then back to pmd_none, as
-	 * a result of MADV_DONTNEED running immediately after a huge pmd fault
-	 * in a different thread of this mm, in turn leading to a misleading
-	 * pmd_trans_huge() retval.  All we have to ensure is that it is a
-	 * regular pmd that we can walk with pte_offset_map() and we can do that
-	 * through an atomic read in C, which is what pmd_trans_unstable()
-	 * provides.
-	 */
-	if (unlikely(pmd_trans_unstable(pmd) || pmd_devmap(*pmd)))
-		return 0;
-	/*
-	 * A regular pmd is established and it can't morph into a huge pmd
-	 * from under us anymore at this point because we hold the mmap_sem
-	 * read mode and khugepaged takes it in write mode. So now it's
-	 * safe to run pte_offset_map().
-	 */
-	pte = pte_offset_map(pmd, address);
-
-	return handle_pte_fault(mm, vma, address, pte, pmd, flags);
+	return handle_pte_fault(&fe);
 }
 
 /*
@@ -3494,15 +3611,15 @@ static int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
  * The mmap_sem may have been released depending on flags and our
  * return value.  See filemap_fault() and __lock_page_or_retry().
  */
-int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
-		    unsigned long address, unsigned int flags)
+int handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
+		unsigned int flags)
 {
 	int ret;
 
 	__set_current_state(TASK_RUNNING);
 
 	count_vm_event(PGFAULT);
-	mem_cgroup_count_vm_event(mm, PGFAULT);
+	mem_cgroup_count_vm_event(vma->vm_mm, PGFAULT);
 
 	/* do counter updates before entering really critical section. */
 	check_sync_rss_stat(current);
@@ -3514,7 +3631,15 @@ int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
 	if (flags & FAULT_FLAG_USER)
 		mem_cgroup_oom_enable();
 
-	ret = __handle_mm_fault(mm, vma, address, flags);
+	if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE,
+					    flags & FAULT_FLAG_INSTRUCTION,
+					    flags & FAULT_FLAG_REMOTE))
+		return VM_FAULT_SIGSEGV;
+
+	if (unlikely(is_vm_hugetlb_page(vma)))
+		ret = hugetlb_fault(vma->vm_mm, vma, address, flags);
+	else
+		ret = __handle_mm_fault(vma, address, flags);
 
 	if (flags & FAULT_FLAG_USER) {
 		mem_cgroup_oom_disable();
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index e3cbdcaff2a5..82d0b98d27f8 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -449,6 +449,25 @@ out_fail:
 	return -1;
 }
 
+static struct zone * __meminit move_pfn_range(int zone_shift,
+		unsigned long start_pfn, unsigned long end_pfn)
+{
+	struct zone *zone = page_zone(pfn_to_page(start_pfn));
+	int ret = 0;
+
+	if (zone_shift < 0)
+		ret = move_pfn_range_left(zone + zone_shift, zone,
+					  start_pfn, end_pfn);
+	else if (zone_shift)
+		ret = move_pfn_range_right(zone, zone + zone_shift,
+					   start_pfn, end_pfn);
+
+	if (ret)
+		return NULL;
+
+	return zone + zone_shift;
+}
+
 static void __meminit grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn,
 				      unsigned long end_pfn)
 {
@@ -1028,6 +1047,37 @@ static void node_states_set_node(int node, struct memory_notify *arg)
 	node_set_state(node, N_MEMORY);
 }
 
+int zone_can_shift(unsigned long pfn, unsigned long nr_pages,
+		   enum zone_type target)
+{
+	struct zone *zone = page_zone(pfn_to_page(pfn));
+	enum zone_type idx = zone_idx(zone);
+	int i;
+
+	if (idx < target) {
+		/* pages must be at end of current zone */
+		if (pfn + nr_pages != zone_end_pfn(zone))
+			return 0;
+
+		/* no zones in use between current zone and target */
+		for (i = idx + 1; i < target; i++)
+			if (zone_is_initialized(zone - idx + i))
+				return 0;
+	}
+
+	if (target < idx) {
+		/* pages must be at beginning of current zone */
+		if (pfn != zone->zone_start_pfn)
+			return 0;
+
+		/* no zones in use between current zone and target */
+		for (i = target + 1; i < idx; i++)
+			if (zone_is_initialized(zone - idx + i))
+				return 0;
+	}
+
+	return target - idx;
+}
 
 /* Must be protected by mem_hotplug_begin() */
 int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type)
@@ -1039,6 +1089,7 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
 	int nid;
 	int ret;
 	struct memory_notify arg;
+	int zone_shift = 0;
 
 	/*
 	 * This doesn't need a lock to do pfn_to_page().
@@ -1052,19 +1103,14 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
 	    !can_online_high_movable(zone))
 		return -EINVAL;
 
-	if (online_type == MMOP_ONLINE_KERNEL &&
-	    zone_idx(zone) == ZONE_MOVABLE) {
-		if (move_pfn_range_left(zone - 1, zone, pfn, pfn + nr_pages))
-			return -EINVAL;
-	}
-	if (online_type == MMOP_ONLINE_MOVABLE &&
-	    zone_idx(zone) == ZONE_MOVABLE - 1) {
-		if (move_pfn_range_right(zone, zone + 1, pfn, pfn + nr_pages))
-			return -EINVAL;
-	}
+	if (online_type == MMOP_ONLINE_KERNEL)
+		zone_shift = zone_can_shift(pfn, nr_pages, ZONE_NORMAL);
+	else if (online_type == MMOP_ONLINE_MOVABLE)
+		zone_shift = zone_can_shift(pfn, nr_pages, ZONE_MOVABLE);
 
-	/* Previous code may changed the zone of the pfn range */
-	zone = page_zone(pfn_to_page(pfn));
+	zone = move_pfn_range(zone_shift, pfn, pfn + nr_pages);
+	if (!zone)
+		return -EINVAL;
 
 	arg.start_pfn = pfn;
 	arg.nr_pages = nr_pages;
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 297d6854f849..53e40d3f3933 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -512,6 +512,8 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
 		}
 	}
 
+	if (pmd_trans_unstable(pmd))
+		return 0;
 retry:
 	pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
 	for (; addr != end; pte++, addr += PAGE_SIZE) {
@@ -529,7 +531,7 @@ retry:
 		nid = page_to_nid(page);
 		if (node_isset(nid, *qp->nmask) == !!(flags & MPOL_MF_INVERT))
 			continue;
-		if (PageTransCompound(page) && PageAnon(page)) {
+		if (PageTransCompound(page)) {
 			get_page(page);
 			pte_unmap_unlock(pte, ptl);
 			lock_page(page);
diff --git a/mm/migrate.c b/mm/migrate.c
index bd3fdc202e8b..2232f6923cc7 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -31,6 +31,7 @@
 #include <linux/vmalloc.h>
 #include <linux/security.h>
 #include <linux/backing-dev.h>
+#include <linux/compaction.h>
 #include <linux/syscalls.h>
 #include <linux/hugetlb.h>
 #include <linux/hugetlb_cgroup.h>
@@ -73,6 +74,81 @@ int migrate_prep_local(void)
 	return 0;
 }
 
+bool isolate_movable_page(struct page *page, isolate_mode_t mode)
+{
+	struct address_space *mapping;
+
+	/*
+	 * Avoid burning cycles with pages that are yet under __free_pages(),
+	 * or just got freed under us.
+	 *
+	 * In case we 'win' a race for a movable page being freed under us and
+	 * raise its refcount preventing __free_pages() from doing its job
+	 * the put_page() at the end of this block will take care of
+	 * release this page, thus avoiding a nasty leakage.
+	 */
+	if (unlikely(!get_page_unless_zero(page)))
+		goto out;
+
+	/*
+	 * Check PageMovable before holding a PG_lock because page's owner
+	 * assumes anybody doesn't touch PG_lock of newly allocated page
+	 * so unconditionally grapping the lock ruins page's owner side.
+	 */
+	if (unlikely(!__PageMovable(page)))
+		goto out_putpage;
+	/*
+	 * As movable pages are not isolated from LRU lists, concurrent
+	 * compaction threads can race against page migration functions
+	 * as well as race against the releasing a page.
+	 *
+	 * In order to avoid having an already isolated movable page
+	 * being (wrongly) re-isolated while it is under migration,
+	 * or to avoid attempting to isolate pages being released,
+	 * lets be sure we have the page lock
+	 * before proceeding with the movable page isolation steps.
+	 */
+	if (unlikely(!trylock_page(page)))
+		goto out_putpage;
+
+	if (!PageMovable(page) || PageIsolated(page))
+		goto out_no_isolated;
+
+	mapping = page_mapping(page);
+	VM_BUG_ON_PAGE(!mapping, page);
+
+	if (!mapping->a_ops->isolate_page(page, mode))
+		goto out_no_isolated;
+
+	/* Driver shouldn't use PG_isolated bit of page->flags */
+	WARN_ON_ONCE(PageIsolated(page));
+	__SetPageIsolated(page);
+	unlock_page(page);
+
+	return true;
+
+out_no_isolated:
+	unlock_page(page);
+out_putpage:
+	put_page(page);
+out:
+	return false;
+}
+
+/* It should be called on page which is PG_movable */
+void putback_movable_page(struct page *page)
+{
+	struct address_space *mapping;
+
+	VM_BUG_ON_PAGE(!PageLocked(page), page);
+	VM_BUG_ON_PAGE(!PageMovable(page), page);
+	VM_BUG_ON_PAGE(!PageIsolated(page), page);
+
+	mapping = page_mapping(page);
+	mapping->a_ops->putback_page(page);
+	__ClearPageIsolated(page);
+}
+
 /*
  * Put previously isolated pages back onto the appropriate lists
  * from where they were once taken off for compaction/migration.
@@ -94,10 +170,23 @@ void putback_movable_pages(struct list_head *l)
 		list_del(&page->lru);
 		dec_zone_page_state(page, NR_ISOLATED_ANON +
 				page_is_file_cache(page));
-		if (unlikely(isolated_balloon_page(page)))
-			balloon_page_putback(page);
-		else
+		/*
+		 * We isolated non-lru movable page so here we can use
+		 * __PageMovable because LRU page's mapping cannot have
+		 * PAGE_MAPPING_MOVABLE.
+		 */
+		if (unlikely(__PageMovable(page))) {
+			VM_BUG_ON_PAGE(!PageIsolated(page), page);
+			lock_page(page);
+			if (PageMovable(page))
+				putback_movable_page(page);
+			else
+				__ClearPageIsolated(page);
+			unlock_page(page);
+			put_page(page);
+		} else {
 			putback_lru_page(page);
+		}
 	}
 }
 
@@ -170,7 +259,7 @@ static int remove_migration_pte(struct page *new, struct vm_area_struct *vma,
 	} else if (PageAnon(new))
 		page_add_anon_rmap(new, vma, addr, false);
 	else
-		page_add_file_rmap(new);
+		page_add_file_rmap(new, false);
 
 	if (vma->vm_flags & VM_LOCKED && !PageTransCompound(new))
 		mlock_vma_page(new);
@@ -594,7 +683,7 @@ EXPORT_SYMBOL(migrate_page_copy);
  ***********************************************************/
 
 /*
- * Common logic to directly migrate a single page suitable for
+ * Common logic to directly migrate a single LRU page suitable for
  * pages that do not use PagePrivate/PagePrivate2.
  *
  * Pages are locked upon entry and exit.
@@ -757,33 +846,72 @@ static int move_to_new_page(struct page *newpage, struct page *page,
 				enum migrate_mode mode)
 {
 	struct address_space *mapping;
-	int rc;
+	int rc = -EAGAIN;
+	bool is_lru = !__PageMovable(page);
 
 	VM_BUG_ON_PAGE(!PageLocked(page), page);
 	VM_BUG_ON_PAGE(!PageLocked(newpage), newpage);
 
 	mapping = page_mapping(page);
-	if (!mapping)
-		rc = migrate_page(mapping, newpage, page, mode);
-	else if (mapping->a_ops->migratepage)
+
+	if (likely(is_lru)) {
+		if (!mapping)
+			rc = migrate_page(mapping, newpage, page, mode);
+		else if (mapping->a_ops->migratepage)
+			/*
+			 * Most pages have a mapping and most filesystems
+			 * provide a migratepage callback. Anonymous pages
+			 * are part of swap space which also has its own
+			 * migratepage callback. This is the most common path
+			 * for page migration.
+			 */
+			rc = mapping->a_ops->migratepage(mapping, newpage,
+							page, mode);
+		else
+			rc = fallback_migrate_page(mapping, newpage,
+							page, mode);
+	} else {
 		/*
-		 * Most pages have a mapping and most filesystems provide a
-		 * migratepage callback. Anonymous pages are part of swap
-		 * space which also has its own migratepage callback. This
-		 * is the most common path for page migration.
+		 * In case of non-lru page, it could be released after
+		 * isolation step. In that case, we shouldn't try migration.
 		 */
-		rc = mapping->a_ops->migratepage(mapping, newpage, page, mode);
-	else
-		rc = fallback_migrate_page(mapping, newpage, page, mode);
+		VM_BUG_ON_PAGE(!PageIsolated(page), page);
+		if (!PageMovable(page)) {
+			rc = MIGRATEPAGE_SUCCESS;
+			__ClearPageIsolated(page);
+			goto out;
+		}
+
+		rc = mapping->a_ops->migratepage(mapping, newpage,
+						page, mode);
+		WARN_ON_ONCE(rc == MIGRATEPAGE_SUCCESS &&
+			!PageIsolated(page));
+	}
 
 	/*
 	 * When successful, old pagecache page->mapping must be cleared before
 	 * page is freed; but stats require that PageAnon be left as PageAnon.
 	 */
 	if (rc == MIGRATEPAGE_SUCCESS) {
-		if (!PageAnon(page))
+		if (__PageMovable(page)) {
+			VM_BUG_ON_PAGE(!PageIsolated(page), page);
+
+			/*
+			 * We clear PG_movable under page_lock so any compactor
+			 * cannot try to migrate this page.
+			 */
+			__ClearPageIsolated(page);
+		}
+
+		/*
+		 * Anonymous and movable page->mapping will be cleard by
+		 * free_pages_prepare so don't reset it here for keeping
+		 * the type to work PageAnon, for example.
+		 */
+		if (!PageMappingFlags(page))
 			page->mapping = NULL;
 	}
+out:
 	return rc;
 }
 
@@ -793,6 +921,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage,
 	int rc = -EAGAIN;
 	int page_was_mapped = 0;
 	struct anon_vma *anon_vma = NULL;
+	bool is_lru = !__PageMovable(page);
 
 	if (!trylock_page(page)) {
 		if (!force || mode == MIGRATE_ASYNC)
@@ -861,15 +990,8 @@ static int __unmap_and_move(struct page *page, struct page *newpage,
 	if (unlikely(!trylock_page(newpage)))
 		goto out_unlock;
 
-	if (unlikely(isolated_balloon_page(page))) {
-		/*
-		 * A ballooned page does not need any special attention from
-		 * physical to virtual reverse mapping procedures.
-		 * Skip any attempt to unmap PTEs or to remap swap cache,
-		 * in order to avoid burning cycles at rmap level, and perform
-		 * the page migration right away (proteced by page lock).
-		 */
-		rc = balloon_page_migrate(newpage, page, mode);
+	if (unlikely(!is_lru)) {
+		rc = move_to_new_page(newpage, page, mode);
 		goto out_unlock_both;
 	}
 
@@ -915,6 +1037,19 @@ out_unlock:
 		put_anon_vma(anon_vma);
 	unlock_page(page);
 out:
+	/*
+	 * If migration is successful, decrease refcount of the newpage
+	 * which will not free the page because new page owner increased
+	 * refcounter. As well, if it is LRU page, add the page to LRU
+	 * list in here.
+	 */
+	if (rc == MIGRATEPAGE_SUCCESS) {
+		if (unlikely(__PageMovable(newpage)))
+			put_page(newpage);
+		else
+			putback_lru_page(newpage);
+	}
+
 	return rc;
 }
 
@@ -948,6 +1083,18 @@ static ICE_noinline int unmap_and_move(new_page_t get_new_page,
 
 	if (page_count(page) == 1) {
 		/* page was freed from under us. So we are done. */
+		ClearPageActive(page);
+		ClearPageUnevictable(page);
+		if (unlikely(__PageMovable(page))) {
+			lock_page(page);
+			if (!PageMovable(page))
+				__ClearPageIsolated(page);
+			unlock_page(page);
+		}
+		if (put_new_page)
+			put_new_page(newpage, private);
+		else
+			put_page(newpage);
 		goto out;
 	}
 
@@ -960,10 +1107,8 @@ static ICE_noinline int unmap_and_move(new_page_t get_new_page,
 	}
 
 	rc = __unmap_and_move(page, newpage, force, mode);
-	if (rc == MIGRATEPAGE_SUCCESS) {
-		put_new_page = NULL;
+	if (rc == MIGRATEPAGE_SUCCESS)
 		set_page_owner_migrate_reason(newpage, reason);
-	}
 
 out:
 	if (rc != -EAGAIN) {
@@ -976,33 +1121,45 @@ out:
 		list_del(&page->lru);
 		dec_zone_page_state(page, NR_ISOLATED_ANON +
 				page_is_file_cache(page));
-		/* Soft-offlined page shouldn't go through lru cache list */
-		if (reason == MR_MEMORY_FAILURE && rc == MIGRATEPAGE_SUCCESS) {
+	}
+
+	/*
+	 * If migration is successful, releases reference grabbed during
+	 * isolation. Otherwise, restore the page to right list unless
+	 * we want to retry.
+	 */
+	if (rc == MIGRATEPAGE_SUCCESS) {
+		put_page(page);
+		if (reason == MR_MEMORY_FAILURE) {
 			/*
-			 * With this release, we free successfully migrated
-			 * page and set PG_HWPoison on just freed page
-			 * intentionally. Although it's rather weird, it's how
-			 * HWPoison flag works at the moment.
+			 * Set PG_HWPoison on just freed page
+			 * intentionally. Although it's rather weird,
+			 * it's how HWPoison flag works at the moment.
 			 */
-			put_page(page);
 			if (!test_set_page_hwpoison(page))
 				num_poisoned_pages_inc();
-		} else
-			putback_lru_page(page);
-	}
+		}
+	} else {
+		if (rc != -EAGAIN) {
+			if (likely(!__PageMovable(page))) {
+				putback_lru_page(page);
+				goto put_new;
+			}
 
-	/*
-	 * If migration was not successful and there's a freeing callback, use
-	 * it.  Otherwise, putback_lru_page() will drop the reference grabbed
-	 * during isolation.
-	 */
-	if (put_new_page)
-		put_new_page(newpage, private);
-	else if (unlikely(__is_movable_balloon_page(newpage))) {
-		/* drop our reference, page already in the balloon */
-		put_page(newpage);
-	} else
-		putback_lru_page(newpage);
+			lock_page(page);
+			if (PageMovable(page))
+				putback_movable_page(page);
+			else
+				__ClearPageIsolated(page);
+			unlock_page(page);
+			put_page(page);
+		}
+put_new:
+		if (put_new_page)
+			put_new_page(newpage, private);
+		else
+			put_page(newpage);
+	}
 
 	if (result) {
 		if (rc)
@@ -1829,8 +1986,7 @@ fail_putback:
 	}
 
 	orig_entry = *pmd;
-	entry = mk_pmd(new_page, vma->vm_page_prot);
-	entry = pmd_mkhuge(entry);
+	entry = mk_huge_pmd(new_page, vma->vm_page_prot);
 	entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
 
 	/*
diff --git a/mm/mmap.c b/mm/mmap.c
index 234edffec1d0..86b18f334f4f 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -25,6 +25,7 @@
 #include <linux/personality.h>
 #include <linux/security.h>
 #include <linux/hugetlb.h>
+#include <linux/shmem_fs.h>
 #include <linux/profile.h>
 #include <linux/export.h>
 #include <linux/mount.h>
@@ -675,6 +676,8 @@ again:			remove_next = 1 + (end > next->vm_end);
 		}
 	}
 
+	vma_adjust_trans_huge(vma, start, end, adjust_next);
+
 	if (file) {
 		mapping = file->f_mapping;
 		root = &mapping->i_mmap;
@@ -695,8 +698,6 @@ again:			remove_next = 1 + (end > next->vm_end);
 		}
 	}
 
-	vma_adjust_trans_huge(vma, start, end, adjust_next);
-
 	anon_vma = vma->anon_vma;
 	if (!anon_vma && adjust_next)
 		anon_vma = next->anon_vma;
@@ -1897,8 +1898,19 @@ get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
 		return -ENOMEM;
 
 	get_area = current->mm->get_unmapped_area;
-	if (file && file->f_op->get_unmapped_area)
-		get_area = file->f_op->get_unmapped_area;
+	if (file) {
+		if (file->f_op->get_unmapped_area)
+			get_area = file->f_op->get_unmapped_area;
+	} else if (flags & MAP_SHARED) {
+		/*
+		 * mmap_region() will call shmem_zero_setup() to create a file,
+		 * so use shmem's get_unmapped_area in case it can be huge.
+		 * do_mmap_pgoff() will clear pgoff, so match alignment.
+		 */
+		pgoff = 0;
+		get_area = shmem_get_unmapped_area;
+	}
+
 	addr = get_area(file, addr, len, pgoff, flags);
 	if (IS_ERR_VALUE(addr))
 		return addr;
@@ -2591,6 +2603,12 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
 		/* drop PG_Mlocked flag for over-mapped range */
 		for (tmp = vma; tmp->vm_start >= start + size;
 				tmp = tmp->vm_next) {
+			/*
+			 * Split pmd and munlock page on the border
+			 * of the range.
+			 */
+			vma_adjust_trans_huge(tmp, start, start + size, 0);
+
 			munlock_vma_pages_range(tmp,
 					max(tmp->vm_start, start),
 					min(tmp->vm_end, start + size));
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 5019a1ef2848..a4830f0325fe 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -163,7 +163,7 @@ static inline unsigned long change_pmd_range(struct vm_area_struct *vma,
 		if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) {
 			if (next - addr != HPAGE_PMD_SIZE) {
 				split_huge_pmd(vma, pmd, addr);
-				if (pmd_none(*pmd))
+				if (pmd_trans_unstable(pmd))
 					continue;
 			} else {
 				int nr_ptes = change_huge_pmd(vma, pmd, addr,
diff --git a/mm/mremap.c b/mm/mremap.c
index 1f157adfdaf9..da22ad2a5678 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -210,9 +210,8 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
 				}
 			}
 			split_huge_pmd(vma, old_pmd, old_addr);
-			if (pmd_none(*old_pmd))
+			if (pmd_trans_unstable(old_pmd))
 				continue;
-			VM_BUG_ON(pmd_trans_huge(*old_pmd));
 		}
 		if (pte_alloc(new_vma->vm_mm, new_pmd, new_addr))
 			break;
diff --git a/mm/nommu.c b/mm/nommu.c
index c2e58880207f..95daf81a4855 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1809,7 +1809,8 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 }
 EXPORT_SYMBOL(filemap_fault);
 
-void filemap_map_pages(struct vm_area_struct *vma, struct vm_fault *vmf)
+void filemap_map_pages(struct fault_env *fe,
+		pgoff_t start_pgoff, pgoff_t end_pgoff)
 {
 	BUG();
 }
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index ddf74487f848..d4a929d79470 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -274,7 +274,7 @@ static enum oom_constraint constrained_alloc(struct oom_control *oc,
 #endif
 
 enum oom_scan_t oom_scan_process_thread(struct oom_control *oc,
-			struct task_struct *task, unsigned long totalpages)
+					struct task_struct *task)
 {
 	if (oom_unkillable_task(task, NULL, oc->nodemask))
 		return OOM_SCAN_CONTINUE;
@@ -311,7 +311,7 @@ static struct task_struct *select_bad_process(struct oom_control *oc,
 	for_each_process(p) {
 		unsigned int points;
 
-		switch (oom_scan_process_thread(oc, p, totalpages)) {
+		switch (oom_scan_process_thread(oc, p)) {
 		case OOM_SCAN_SELECT:
 			chosen = p;
 			chosen_points = ULONG_MAX;
@@ -383,8 +383,7 @@ static void dump_tasks(struct mem_cgroup *memcg, const nodemask_t *nodemask)
 	rcu_read_unlock();
 }
 
-static void dump_header(struct oom_control *oc, struct task_struct *p,
-			struct mem_cgroup *memcg)
+static void dump_header(struct oom_control *oc, struct task_struct *p)
 {
 	pr_warn("%s invoked oom-killer: gfp_mask=%#x(%pGg), order=%d, oom_score_adj=%hd\n",
 		current->comm, oc->gfp_mask, &oc->gfp_mask, oc->order,
@@ -392,12 +391,12 @@ static void dump_header(struct oom_control *oc, struct task_struct *p,
 
 	cpuset_print_current_mems_allowed();
 	dump_stack();
-	if (memcg)
-		mem_cgroup_print_oom_info(memcg, p);
+	if (oc->memcg)
+		mem_cgroup_print_oom_info(oc->memcg, p);
 	else
 		show_mem(SHOW_MEM_FILTER_NODES);
 	if (sysctl_oom_dump_tasks)
-		dump_tasks(memcg, oc->nodemask);
+		dump_tasks(oc->memcg, oc->nodemask);
 }
 
 /*
@@ -453,7 +452,7 @@ static bool __oom_reap_task(struct task_struct *tsk)
 	 * We have to make sure to not race with the victim exit path
 	 * and cause premature new oom victim selection:
 	 * __oom_reap_task		exit_mm
-	 *   atomic_inc_not_zero
+	 *   mmget_not_zero
 	 *				  mmput
 	 *				    atomic_dec_and_test
 	 *				  exit_oom_victim
@@ -475,12 +474,22 @@ static bool __oom_reap_task(struct task_struct *tsk)
 	if (!p)
 		goto unlock_oom;
 	mm = p->mm;
-	atomic_inc(&mm->mm_users);
+	atomic_inc(&mm->mm_count);
 	task_unlock(p);
 
 	if (!down_read_trylock(&mm->mmap_sem)) {
 		ret = false;
-		goto unlock_oom;
+		goto mm_drop;
+	}
+
+	/*
+	 * increase mm_users only after we know we will reap something so
+	 * that the mmput_async is called only when we have reaped something
+	 * and delayed __mmput doesn't matter that much
+	 */
+	if (!mmget_not_zero(mm)) {
+		up_read(&mm->mmap_sem);
+		goto mm_drop;
 	}
 
 	tlb_gather_mmu(&tlb, mm, 0, -1);
@@ -522,15 +531,16 @@ static bool __oom_reap_task(struct task_struct *tsk)
 	 * to release its memory.
 	 */
 	set_bit(MMF_OOM_REAPED, &mm->flags);
-unlock_oom:
-	mutex_unlock(&oom_lock);
 	/*
 	 * Drop our reference but make sure the mmput slow path is called from a
 	 * different context because we shouldn't risk we get stuck there and
 	 * put the oom_reaper out of the way.
 	 */
-	if (mm)
-		mmput_async(mm);
+	mmput_async(mm);
+mm_drop:
+	mmdrop(mm);
+unlock_oom:
+	mutex_unlock(&oom_lock);
 	return ret;
 }
 
@@ -739,7 +749,7 @@ void oom_killer_enable(void)
  */
 void oom_kill_process(struct oom_control *oc, struct task_struct *p,
 		      unsigned int points, unsigned long totalpages,
-		      struct mem_cgroup *memcg, const char *message)
+		      const char *message)
 {
 	struct task_struct *victim = p;
 	struct task_struct *child;
@@ -765,7 +775,7 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p,
 	task_unlock(p);
 
 	if (__ratelimit(&oom_rs))
-		dump_header(oc, p, memcg);
+		dump_header(oc, p);
 
 	pr_err("%s: Kill process %d (%s) score %u or sacrifice child\n",
 		message, task_pid_nr(p), p->comm, points);
@@ -786,8 +796,8 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p,
 			/*
 			 * oom_badness() returns 0 if the thread is unkillable
 			 */
-			child_points = oom_badness(child, memcg, oc->nodemask,
-								totalpages);
+			child_points = oom_badness(child,
+					oc->memcg, oc->nodemask, totalpages);
 			if (child_points > victim_points) {
 				put_task_struct(victim);
 				victim = child;
@@ -865,8 +875,7 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p,
 /*
  * Determines whether the kernel must panic because of the panic_on_oom sysctl.
  */
-void check_panic_on_oom(struct oom_control *oc, enum oom_constraint constraint,
-			struct mem_cgroup *memcg)
+void check_panic_on_oom(struct oom_control *oc, enum oom_constraint constraint)
 {
 	if (likely(!sysctl_panic_on_oom))
 		return;
@@ -882,7 +891,7 @@ void check_panic_on_oom(struct oom_control *oc, enum oom_constraint constraint,
 	/* Do not panic for oom kills triggered by sysrq */
 	if (is_sysrq_oom(oc))
 		return;
-	dump_header(oc, NULL, memcg);
+	dump_header(oc, NULL);
 	panic("Out of memory: %s panic_on_oom is enabled\n",
 		sysctl_panic_on_oom == 2 ? "compulsory" : "system-wide");
 }
@@ -957,13 +966,13 @@ bool out_of_memory(struct oom_control *oc)
 	constraint = constrained_alloc(oc, &totalpages);
 	if (constraint != CONSTRAINT_MEMORY_POLICY)
 		oc->nodemask = NULL;
-	check_panic_on_oom(oc, constraint, NULL);
+	check_panic_on_oom(oc, constraint);
 
 	if (sysctl_oom_kill_allocating_task && current->mm &&
 	    !oom_unkillable_task(current, NULL, oc->nodemask) &&
 	    current->signal->oom_score_adj != OOM_SCORE_ADJ_MIN) {
 		get_task_struct(current);
-		oom_kill_process(oc, current, 0, totalpages, NULL,
+		oom_kill_process(oc, current, 0, totalpages,
 				 "Out of memory (oom_kill_allocating_task)");
 		return true;
 	}
@@ -971,12 +980,11 @@ bool out_of_memory(struct oom_control *oc)
 	p = select_bad_process(oc, &points, totalpages);
 	/* Found nothing?!?! Either we hang forever, or we panic. */
 	if (!p && !is_sysrq_oom(oc)) {
-		dump_header(oc, NULL, NULL);
+		dump_header(oc, NULL);
 		panic("Out of memory and no killable processes...\n");
 	}
 	if (p && p != (void *)-1UL) {
-		oom_kill_process(oc, p, points, totalpages, NULL,
-				 "Out of memory");
+		oom_kill_process(oc, p, points, totalpages, "Out of memory");
 		/*
 		 * Give the killed process a good chance to exit before trying
 		 * to allocate memory again.
@@ -988,14 +996,15 @@ bool out_of_memory(struct oom_control *oc)
 
 /*
  * The pagefault handler calls here because it is out of memory, so kill a
- * memory-hogging task.  If any populated zone has ZONE_OOM_LOCKED set, a
- * parallel oom killing is already in progress so do nothing.
+ * memory-hogging task. If oom_lock is held by somebody else, a parallel oom
+ * killing is already in progress so do nothing.
  */
 void pagefault_out_of_memory(void)
 {
 	struct oom_control oc = {
 		.zonelist = NULL,
 		.nodemask = NULL,
+		.memcg = NULL,
 		.gfp_mask = 0,
 		.order = 0,
 	};
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index e2481949494c..d578d2a56b19 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2563,6 +2563,7 @@ int set_page_dirty(struct page *page)
 {
 	struct address_space *mapping = page_mapping(page);
 
+	page = compound_head(page);
 	if (likely(mapping)) {
 		int (*spd)(struct page *) = mapping->a_ops->set_page_dirty;
 		/*
@@ -2747,6 +2748,11 @@ int test_clear_page_writeback(struct page *page)
 				__wb_writeout_inc(wb);
 			}
 		}
+
+		if (mapping->host && !mapping_tagged(mapping,
+						     PAGECACHE_TAG_WRITEBACK))
+			sb_clear_inode_writeback(mapping->host);
+
 		spin_unlock_irqrestore(&mapping->tree_lock, flags);
 	} else {
 		ret = TestClearPageWriteback(page);
@@ -2774,11 +2780,24 @@ int __test_set_page_writeback(struct page *page, bool keep_write)
 		spin_lock_irqsave(&mapping->tree_lock, flags);
 		ret = TestSetPageWriteback(page);
 		if (!ret) {
+			bool on_wblist;
+
+			on_wblist = mapping_tagged(mapping,
+						   PAGECACHE_TAG_WRITEBACK);
+
 			radix_tree_tag_set(&mapping->page_tree,
 						page_index(page),
 						PAGECACHE_TAG_WRITEBACK);
 			if (bdi_cap_account_writeback(bdi))
 				__inc_wb_stat(inode_to_wb(inode), WB_WRITEBACK);
+
+			/*
+			 * We can come through here when swapping anonymous
+			 * pages, so we don't necessarily have an inode to track
+			 * for sync.
+			 */
+			if (mapping->host && !on_wblist)
+				sb_mark_inode_writeback(mapping->host);
 		}
 		if (!PageDirty(page))
 			radix_tree_tag_clear(&mapping->page_tree,
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8b3e1341b754..452513bf02ce 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -63,6 +63,7 @@
 #include <linux/sched/rt.h>
 #include <linux/page_owner.h>
 #include <linux/kthread.h>
+#include <linux/memcontrol.h>
 
 #include <asm/sections.h>
 #include <asm/tlbflush.h>
@@ -1006,6 +1007,8 @@ static __always_inline bool free_pages_prepare(struct page *page,
 
 		VM_BUG_ON_PAGE(compound && compound_order(page) != order, page);
 
+		if (compound)
+			ClearPageDoubleMap(page);
 		for (i = 1; i < (1 << order); i++) {
 			if (compound)
 				bad += free_tail_pages_check(page, page + i);
@@ -1016,8 +1019,12 @@ static __always_inline bool free_pages_prepare(struct page *page,
 			(page + i)->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
 		}
 	}
-	if (PageAnonHead(page))
+	if (PageMappingFlags(page))
 		page->mapping = NULL;
+	if (memcg_kmem_enabled() && PageKmemcg(page)) {
+		memcg_kmem_uncharge(page, order);
+		__ClearPageKmemcg(page);
+	}
 	if (check_free)
 		bad += free_pages_check(page);
 	if (bad)
@@ -1724,6 +1731,19 @@ static bool check_new_pages(struct page *page, unsigned int order)
 	return false;
 }
 
+inline void post_alloc_hook(struct page *page, unsigned int order,
+				gfp_t gfp_flags)
+{
+	set_page_private(page, 0);
+	set_page_refcounted(page);
+
+	arch_alloc_page(page, order);
+	kernel_map_pages(page, 1 << order, 1);
+	kernel_poison_pages(page, 1 << order, 1);
+	kasan_alloc_pages(page, order);
+	set_page_owner(page, order, gfp_flags);
+}
+
 static void prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags,
 							unsigned int alloc_flags)
 {
@@ -1736,13 +1756,7 @@ static void prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags
 			poisoned &= page_is_poisoned(p);
 	}
 
-	set_page_private(page, 0);
-	set_page_refcounted(page);
-
-	arch_alloc_page(page, order);
-	kernel_map_pages(page, 1 << order, 1);
-	kernel_poison_pages(page, 1 << order, 1);
-	kasan_alloc_pages(page, order);
+	post_alloc_hook(page, order, gfp_flags);
 
 	if (!free_pages_prezeroed(poisoned) && (gfp_flags & __GFP_ZERO))
 		for (i = 0; i < (1 << order); i++)
@@ -1751,8 +1765,6 @@ static void prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags
 	if (order && (gfp_flags & __GFP_COMP))
 		prep_compound_page(page, order);
 
-	set_page_owner(page, order, gfp_flags);
-
 	/*
 	 * page is set pfmemalloc when ALLOC_NO_WATERMARKS was necessary to
 	 * allocate the page. The expectation is that the caller is taking
@@ -2461,7 +2473,6 @@ void free_hot_cold_page_list(struct list_head *list, bool cold)
 void split_page(struct page *page, unsigned int order)
 {
 	int i;
-	gfp_t gfp_mask;
 
 	VM_BUG_ON_PAGE(PageCompound(page), page);
 	VM_BUG_ON_PAGE(!page_count(page), page);
@@ -2475,12 +2486,9 @@ void split_page(struct page *page, unsigned int order)
 		split_page(virt_to_page(page[0].shadow), order);
 #endif
 
-	gfp_mask = get_page_owner_gfp(page);
-	set_page_owner(page, 0, gfp_mask);
-	for (i = 1; i < (1 << order); i++) {
+	for (i = 1; i < (1 << order); i++)
 		set_page_refcounted(page + i);
-		set_page_owner(page + i, 0, gfp_mask);
-	}
+	split_page_owner(page, order);
 }
 EXPORT_SYMBOL_GPL(split_page);
 
@@ -2509,8 +2517,6 @@ int __isolate_free_page(struct page *page, unsigned int order)
 	zone->free_area[order].nr_free--;
 	rmv_page_order(page);
 
-	set_page_owner(page, order, __GFP_MOVABLE);
-
 	/* Set the pageblock if the isolated page is at least a pageblock */
 	if (order >= pageblock_order - 1) {
 		struct page *endpage = page + (1 << order) - 1;
@@ -2527,33 +2533,6 @@ int __isolate_free_page(struct page *page, unsigned int order)
 }
 
 /*
- * Similar to split_page except the page is already free. As this is only
- * being used for migration, the migratetype of the block also changes.
- * As this is called with interrupts disabled, the caller is responsible
- * for calling arch_alloc_page() and kernel_map_page() after interrupts
- * are enabled.
- *
- * Note: this is probably too low level an operation for use in drivers.
- * Please consult with lkml before using this in your driver.
- */
-int split_free_page(struct page *page)
-{
-	unsigned int order;
-	int nr_pages;
-
-	order = page_order(page);
-
-	nr_pages = __isolate_free_page(page, order);
-	if (!nr_pages)
-		return 0;
-
-	/* Split into individual pages */
-	set_page_refcounted(page);
-	split_page(page, order);
-	return nr_pages;
-}
-
-/*
  * Update NUMA hit/miss statistics
  *
  * Must be called with interrupts disabled.
@@ -3105,6 +3084,7 @@ __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
 	struct oom_control oc = {
 		.zonelist = ac->zonelist,
 		.nodemask = ac->nodemask,
+		.memcg = NULL,
 		.gfp_mask = gfp_mask,
 		.order = order,
 	};
@@ -3868,6 +3848,14 @@ no_zone:
 	}
 
 out:
+	if (memcg_kmem_enabled() && (gfp_mask & __GFP_ACCOUNT) && page) {
+		if (unlikely(memcg_kmem_charge(page, gfp_mask, order))) {
+			__free_pages(page, order);
+			page = NULL;
+		} else
+			__SetPageKmemcg(page);
+	}
+
 	if (kmemcheck_enabled && page)
 		kmemcheck_pagealloc_alloc(page, order, gfp_mask);
 
@@ -4023,56 +4011,6 @@ void __free_page_frag(void *addr)
 }
 EXPORT_SYMBOL(__free_page_frag);
 
-/*
- * alloc_kmem_pages charges newly allocated pages to the kmem resource counter
- * of the current memory cgroup if __GFP_ACCOUNT is set, other than that it is
- * equivalent to alloc_pages.
- *
- * It should be used when the caller would like to use kmalloc, but since the
- * allocation is large, it has to fall back to the page allocator.
- */
-struct page *alloc_kmem_pages(gfp_t gfp_mask, unsigned int order)
-{
-	struct page *page;
-
-	page = alloc_pages(gfp_mask, order);
-	if (page && memcg_kmem_charge(page, gfp_mask, order) != 0) {
-		__free_pages(page, order);
-		page = NULL;
-	}
-	return page;
-}
-
-struct page *alloc_kmem_pages_node(int nid, gfp_t gfp_mask, unsigned int order)
-{
-	struct page *page;
-
-	page = alloc_pages_node(nid, gfp_mask, order);
-	if (page && memcg_kmem_charge(page, gfp_mask, order) != 0) {
-		__free_pages(page, order);
-		page = NULL;
-	}
-	return page;
-}
-
-/*
- * __free_kmem_pages and free_kmem_pages will free pages allocated with
- * alloc_kmem_pages.
- */
-void __free_kmem_pages(struct page *page, unsigned int order)
-{
-	memcg_kmem_uncharge(page, order);
-	__free_pages(page, order);
-}
-
-void free_kmem_pages(unsigned long addr, unsigned int order)
-{
-	if (addr != 0) {
-		VM_BUG_ON(!virt_addr_valid((void *)addr));
-		__free_kmem_pages(virt_to_page((void *)addr), order);
-	}
-}
-
 static void *make_alloc_exact(unsigned long addr, unsigned int order,
 		size_t size)
 {
@@ -4374,6 +4312,9 @@ void show_free_areas(unsigned int filter)
 		" unevictable:%lu dirty:%lu writeback:%lu unstable:%lu\n"
 		" slab_reclaimable:%lu slab_unreclaimable:%lu\n"
 		" mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n"
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+		" anon_thp: %lu shmem_thp: %lu shmem_pmdmapped: %lu\n"
+#endif
 		" free:%lu free_pcp:%lu free_cma:%lu\n",
 		global_page_state(NR_ACTIVE_ANON),
 		global_page_state(NR_INACTIVE_ANON),
@@ -4391,6 +4332,11 @@ void show_free_areas(unsigned int filter)
 		global_page_state(NR_SHMEM),
 		global_page_state(NR_PAGETABLE),
 		global_page_state(NR_BOUNCE),
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+		global_page_state(NR_ANON_THPS) * HPAGE_PMD_NR,
+		global_page_state(NR_SHMEM_THPS) * HPAGE_PMD_NR,
+		global_page_state(NR_SHMEM_PMDMAPPED) * HPAGE_PMD_NR,
+#endif
 		global_page_state(NR_FREE_PAGES),
 		free_pcp,
 		global_page_state(NR_FREE_CMA_PAGES));
@@ -4425,6 +4371,11 @@ void show_free_areas(unsigned int filter)
 			" writeback:%lukB"
 			" mapped:%lukB"
 			" shmem:%lukB"
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+			" shmem_thp: %lukB"
+			" shmem_pmdmapped: %lukB"
+			" anon_thp: %lukB"
+#endif
 			" slab_reclaimable:%lukB"
 			" slab_unreclaimable:%lukB"
 			" kernel_stack:%lukB"
@@ -4457,6 +4408,12 @@ void show_free_areas(unsigned int filter)
 			K(zone_page_state(zone, NR_WRITEBACK)),
 			K(zone_page_state(zone, NR_FILE_MAPPED)),
 			K(zone_page_state(zone, NR_SHMEM)),
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+			K(zone_page_state(zone, NR_SHMEM_THPS) * HPAGE_PMD_NR),
+			K(zone_page_state(zone, NR_SHMEM_PMDMAPPED)
+					* HPAGE_PMD_NR),
+			K(zone_page_state(zone, NR_ANON_THPS) * HPAGE_PMD_NR),
+#endif
 			K(zone_page_state(zone, NR_SLAB_RECLAIMABLE)),
 			K(zone_page_state(zone, NR_SLAB_UNRECLAIMABLE)),
 			zone_page_state(zone, NR_KERNEL_STACK) *
@@ -6467,15 +6424,18 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn)
 				sizeof(arch_zone_lowest_possible_pfn));
 	memset(arch_zone_highest_possible_pfn, 0,
 				sizeof(arch_zone_highest_possible_pfn));
-	arch_zone_lowest_possible_pfn[0] = find_min_pfn_with_active_regions();
-	arch_zone_highest_possible_pfn[0] = max_zone_pfn[0];
-	for (i = 1; i < MAX_NR_ZONES; i++) {
+
+	start_pfn = find_min_pfn_with_active_regions();
+
+	for (i = 0; i < MAX_NR_ZONES; i++) {
 		if (i == ZONE_MOVABLE)
 			continue;
-		arch_zone_lowest_possible_pfn[i] =
-			arch_zone_highest_possible_pfn[i-1];
-		arch_zone_highest_possible_pfn[i] =
-			max(max_zone_pfn[i], arch_zone_lowest_possible_pfn[i]);
+
+		end_pfn = max(max_zone_pfn[i], start_pfn);
+		arch_zone_lowest_possible_pfn[i] = start_pfn;
+		arch_zone_highest_possible_pfn[i] = end_pfn;
+
+		start_pfn = end_pfn;
 	}
 	arch_zone_lowest_possible_pfn[ZONE_MOVABLE] = 0;
 	arch_zone_highest_possible_pfn[ZONE_MOVABLE] = 0;
diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 612122bf6a42..064b7fb6e0b5 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -7,6 +7,7 @@
 #include <linux/pageblock-flags.h>
 #include <linux/memory.h>
 #include <linux/hugetlb.h>
+#include <linux/page_owner.h>
 #include "internal.h"
 
 #define CREATE_TRACE_POINTS
@@ -80,7 +81,7 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype)
 {
 	struct zone *zone;
 	unsigned long flags, nr_pages;
-	struct page *isolated_page = NULL;
+	bool isolated_page = false;
 	unsigned int order;
 	unsigned long page_idx, buddy_idx;
 	struct page *buddy;
@@ -108,9 +109,7 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype)
 			if (pfn_valid_within(page_to_pfn(buddy)) &&
 			    !is_migrate_isolate_page(buddy)) {
 				__isolate_free_page(page, order);
-				kernel_map_pages(page, (1 << order), 1);
-				set_page_refcounted(page);
-				isolated_page = page;
+				isolated_page = true;
 			}
 		}
 	}
@@ -128,8 +127,10 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype)
 	zone->nr_isolate_pageblock--;
 out:
 	spin_unlock_irqrestore(&zone->lock, flags);
-	if (isolated_page)
-		__free_pages(isolated_page, order);
+	if (isolated_page) {
+		post_alloc_hook(page, order, __GFP_MOVABLE);
+		__free_pages(page, order);
+	}
 }
 
 static inline struct page *
diff --git a/mm/page_owner.c b/mm/page_owner.c
index fedeba88c9cb..ec6dc1886f71 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -7,11 +7,22 @@
 #include <linux/page_owner.h>
 #include <linux/jump_label.h>
 #include <linux/migrate.h>
+#include <linux/stackdepot.h>
+
 #include "internal.h"
 
+/*
+ * TODO: teach PAGE_OWNER_STACK_DEPTH (__dump_page_owner and save_stack)
+ * to use off stack temporal storage
+ */
+#define PAGE_OWNER_STACK_DEPTH (16)
+
 static bool page_owner_disabled = true;
 DEFINE_STATIC_KEY_FALSE(page_owner_inited);
 
+static depot_stack_handle_t dummy_handle;
+static depot_stack_handle_t failure_handle;
+
 static void init_early_allocated_pages(void);
 
 static int early_page_owner_param(char *buf)
@@ -34,11 +45,41 @@ static bool need_page_owner(void)
 	return true;
 }
 
+static noinline void register_dummy_stack(void)
+{
+	unsigned long entries[4];
+	struct stack_trace dummy;
+
+	dummy.nr_entries = 0;
+	dummy.max_entries = ARRAY_SIZE(entries);
+	dummy.entries = &entries[0];
+	dummy.skip = 0;
+
+	save_stack_trace(&dummy);
+	dummy_handle = depot_save_stack(&dummy, GFP_KERNEL);
+}
+
+static noinline void register_failure_stack(void)
+{
+	unsigned long entries[4];
+	struct stack_trace failure;
+
+	failure.nr_entries = 0;
+	failure.max_entries = ARRAY_SIZE(entries);
+	failure.entries = &entries[0];
+	failure.skip = 0;
+
+	save_stack_trace(&failure);
+	failure_handle = depot_save_stack(&failure, GFP_KERNEL);
+}
+
 static void init_page_owner(void)
 {
 	if (page_owner_disabled)
 		return;
 
+	register_dummy_stack();
+	register_failure_stack();
 	static_branch_enable(&page_owner_inited);
 	init_early_allocated_pages();
 }
@@ -61,25 +102,66 @@ void __reset_page_owner(struct page *page, unsigned int order)
 	}
 }
 
-void __set_page_owner(struct page *page, unsigned int order, gfp_t gfp_mask)
+static inline bool check_recursive_alloc(struct stack_trace *trace,
+					unsigned long ip)
 {
-	struct page_ext *page_ext = lookup_page_ext(page);
+	int i, count;
+
+	if (!trace->nr_entries)
+		return false;
+
+	for (i = 0, count = 0; i < trace->nr_entries; i++) {
+		if (trace->entries[i] == ip && ++count == 2)
+			return true;
+	}
+
+	return false;
+}
 
+static noinline depot_stack_handle_t save_stack(gfp_t flags)
+{
+	unsigned long entries[PAGE_OWNER_STACK_DEPTH];
 	struct stack_trace trace = {
 		.nr_entries = 0,
-		.max_entries = ARRAY_SIZE(page_ext->trace_entries),
-		.entries = &page_ext->trace_entries[0],
-		.skip = 3,
+		.entries = entries,
+		.max_entries = PAGE_OWNER_STACK_DEPTH,
+		.skip = 0
 	};
+	depot_stack_handle_t handle;
+
+	save_stack_trace(&trace);
+	if (trace.nr_entries != 0 &&
+	    trace.entries[trace.nr_entries-1] == ULONG_MAX)
+		trace.nr_entries--;
+
+	/*
+	 * We need to check recursion here because our request to stackdepot
+	 * could trigger memory allocation to save new entry. New memory
+	 * allocation would reach here and call depot_save_stack() again
+	 * if we don't catch it. There is still not enough memory in stackdepot
+	 * so it would try to allocate memory again and loop forever.
+	 */
+	if (check_recursive_alloc(&trace, _RET_IP_))
+		return dummy_handle;
+
+	handle = depot_save_stack(&trace, flags);
+	if (!handle)
+		handle = failure_handle;
+
+	return handle;
+}
+
+noinline void __set_page_owner(struct page *page, unsigned int order,
+					gfp_t gfp_mask)
+{
+	struct page_ext *page_ext = lookup_page_ext(page);
 
 	if (unlikely(!page_ext))
 		return;
 
-	save_stack_trace(&trace);
-
+	page_ext->handle = save_stack(gfp_mask);
 	page_ext->order = order;
 	page_ext->gfp_mask = gfp_mask;
-	page_ext->nr_entries = trace.nr_entries;
 	page_ext->last_migrate_reason = -1;
 
 	__set_bit(PAGE_EXT_OWNER, &page_ext->flags);
@@ -94,34 +176,31 @@ void __set_page_owner_migrate_reason(struct page *page, int reason)
 	page_ext->last_migrate_reason = reason;
 }
 
-gfp_t __get_page_owner_gfp(struct page *page)
+void __split_page_owner(struct page *page, unsigned int order)
 {
+	int i;
 	struct page_ext *page_ext = lookup_page_ext(page);
+
 	if (unlikely(!page_ext))
-		/*
-		 * The caller just returns 0 if no valid gfp
-		 * So return 0 here too.
-		 */
-		return 0;
+		return;
 
-	return page_ext->gfp_mask;
+	page_ext->order = 0;
+	for (i = 1; i < (1 << order); i++)
+		__copy_page_owner(page, page + i);
 }
 
 void __copy_page_owner(struct page *oldpage, struct page *newpage)
 {
 	struct page_ext *old_ext = lookup_page_ext(oldpage);
 	struct page_ext *new_ext = lookup_page_ext(newpage);
-	int i;
 
 	if (unlikely(!old_ext || !new_ext))
 		return;
 
 	new_ext->order = old_ext->order;
 	new_ext->gfp_mask = old_ext->gfp_mask;
-	new_ext->nr_entries = old_ext->nr_entries;
-
-	for (i = 0; i < ARRAY_SIZE(new_ext->trace_entries); i++)
-		new_ext->trace_entries[i] = old_ext->trace_entries[i];
+	new_ext->last_migrate_reason = old_ext->last_migrate_reason;
+	new_ext->handle = old_ext->handle;
 
 	/*
 	 * We don't clear the bit on the oldpage as it's going to be freed
@@ -137,14 +216,18 @@ void __copy_page_owner(struct page *oldpage, struct page *newpage)
 
 static ssize_t
 print_page_owner(char __user *buf, size_t count, unsigned long pfn,
-		struct page *page, struct page_ext *page_ext)
+		struct page *page, struct page_ext *page_ext,
+		depot_stack_handle_t handle)
 {
 	int ret;
 	int pageblock_mt, page_mt;
 	char *kbuf;
+	unsigned long entries[PAGE_OWNER_STACK_DEPTH];
 	struct stack_trace trace = {
-		.nr_entries = page_ext->nr_entries,
-		.entries = &page_ext->trace_entries[0],
+		.nr_entries = 0,
+		.entries = entries,
+		.max_entries = PAGE_OWNER_STACK_DEPTH,
+		.skip = 0
 	};
 
 	kbuf = kmalloc(count, GFP_KERNEL);
@@ -173,6 +256,7 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn,
 	if (ret >= count)
 		goto err;
 
+	depot_fetch_stack(handle, &trace);
 	ret += snprint_stack_trace(kbuf + ret, count - ret, &trace, 0);
 	if (ret >= count)
 		goto err;
@@ -203,10 +287,14 @@ err:
 void __dump_page_owner(struct page *page)
 {
 	struct page_ext *page_ext = lookup_page_ext(page);
+	unsigned long entries[PAGE_OWNER_STACK_DEPTH];
 	struct stack_trace trace = {
-		.nr_entries = page_ext->nr_entries,
-		.entries = &page_ext->trace_entries[0],
+		.nr_entries = 0,
+		.entries = entries,
+		.max_entries = PAGE_OWNER_STACK_DEPTH,
+		.skip = 0
 	};
+	depot_stack_handle_t handle;
 	gfp_t gfp_mask;
 	int mt;
 
@@ -222,6 +310,13 @@ void __dump_page_owner(struct page *page)
 		return;
 	}
 
+	handle = READ_ONCE(page_ext->handle);
+	if (!handle) {
+		pr_alert("page_owner info is not active (free page?)\n");
+		return;
+	}
+
+	depot_fetch_stack(handle, &trace);
 	pr_alert("page allocated via order %u, migratetype %s, gfp_mask %#x(%pGg)\n",
 		 page_ext->order, migratetype_names[mt], gfp_mask, &gfp_mask);
 	print_stack_trace(&trace, 0);
@@ -237,6 +332,7 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 	unsigned long pfn;
 	struct page *page;
 	struct page_ext *page_ext;
+	depot_stack_handle_t handle;
 
 	if (!static_branch_unlikely(&page_owner_inited))
 		return -EINVAL;
@@ -285,10 +381,19 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 		if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
 			continue;
 
+		/*
+		 * Access to page_ext->handle isn't synchronous so we should
+		 * be careful to access it.
+		 */
+		handle = READ_ONCE(page_ext->handle);
+		if (!handle)
+			continue;
+
 		/* Record the next PFN to read in the file offset */
 		*ppos = (pfn - min_low_pfn) + 1;
 
-		return print_page_owner(buf, count, pfn, page, page_ext);
+		return print_page_owner(buf, count, pfn, page,
+				page_ext, handle);
 	}
 
 	return 0;
diff --git a/mm/readahead.c b/mm/readahead.c
index 40be3ae0afe3..65ec288dc057 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -89,7 +89,7 @@ int read_cache_pages(struct address_space *mapping, struct list_head *pages,
 		page = lru_to_page(pages);
 		list_del(&page->lru);
 		if (add_to_page_cache_lru(page, mapping, page->index,
-				mapping_gfp_constraint(mapping, GFP_KERNEL))) {
+				readahead_gfp_mask(mapping))) {
 			read_cache_pages_invalidate_page(mapping, page);
 			continue;
 		}
@@ -108,7 +108,7 @@ int read_cache_pages(struct address_space *mapping, struct list_head *pages,
 EXPORT_SYMBOL(read_cache_pages);
 
 static int read_pages(struct address_space *mapping, struct file *filp,
-		struct list_head *pages, unsigned nr_pages)
+		struct list_head *pages, unsigned int nr_pages, gfp_t gfp)
 {
 	struct blk_plug plug;
 	unsigned page_idx;
@@ -126,10 +126,8 @@ static int read_pages(struct address_space *mapping, struct file *filp,
 	for (page_idx = 0; page_idx < nr_pages; page_idx++) {
 		struct page *page = lru_to_page(pages);
 		list_del(&page->lru);
-		if (!add_to_page_cache_lru(page, mapping, page->index,
-				mapping_gfp_constraint(mapping, GFP_KERNEL))) {
+		if (!add_to_page_cache_lru(page, mapping, page->index, gfp))
 			mapping->a_ops->readpage(filp, page);
-		}
 		put_page(page);
 	}
 	ret = 0;
@@ -159,6 +157,7 @@ int __do_page_cache_readahead(struct address_space *mapping, struct file *filp,
 	int page_idx;
 	int ret = 0;
 	loff_t isize = i_size_read(inode);
+	gfp_t gfp_mask = readahead_gfp_mask(mapping);
 
 	if (isize == 0)
 		goto out;
@@ -180,7 +179,7 @@ int __do_page_cache_readahead(struct address_space *mapping, struct file *filp,
 		if (page && !radix_tree_exceptional_entry(page))
 			continue;
 
-		page = page_cache_alloc_readahead(mapping);
+		page = __page_cache_alloc(gfp_mask);
 		if (!page)
 			break;
 		page->index = page_offset;
@@ -196,7 +195,7 @@ int __do_page_cache_readahead(struct address_space *mapping, struct file *filp,
 	 * will then handle the error.
 	 */
 	if (ret)
-		read_pages(mapping, filp, &page_pool, ret);
+		read_pages(mapping, filp, &page_pool, ret, gfp_mask);
 	BUG_ON(!list_empty(&page_pool));
 out:
 	return ret;
diff --git a/mm/rmap.c b/mm/rmap.c
index 701b93fea2a0..8a13d9f7b566 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1212,10 +1212,8 @@ void do_page_add_anon_rmap(struct page *page,
 		 * pte lock(a spinlock) is held, which implies preemption
 		 * disabled.
 		 */
-		if (compound) {
-			__inc_zone_page_state(page,
-					      NR_ANON_TRANSPARENT_HUGEPAGES);
-		}
+		if (compound)
+			__inc_zone_page_state(page, NR_ANON_THPS);
 		__mod_zone_page_state(page_zone(page), NR_ANON_PAGES, nr);
 	}
 	if (unlikely(PageKsm(page)))
@@ -1253,7 +1251,7 @@ void page_add_new_anon_rmap(struct page *page,
 		VM_BUG_ON_PAGE(!PageTransHuge(page), page);
 		/* increment count (starts at -1) */
 		atomic_set(compound_mapcount_ptr(page), 0);
-		__inc_zone_page_state(page, NR_ANON_TRANSPARENT_HUGEPAGES);
+		__inc_zone_page_state(page, NR_ANON_THPS);
 	} else {
 		/* Anon THP always mapped first with PMD */
 		VM_BUG_ON_PAGE(PageTransCompound(page), page);
@@ -1270,18 +1268,42 @@ void page_add_new_anon_rmap(struct page *page,
  *
  * The caller needs to hold the pte lock.
  */
-void page_add_file_rmap(struct page *page)
+void page_add_file_rmap(struct page *page, bool compound)
 {
+	int i, nr = 1;
+
+	VM_BUG_ON_PAGE(compound && !PageTransHuge(page), page);
 	lock_page_memcg(page);
-	if (atomic_inc_and_test(&page->_mapcount)) {
-		__inc_zone_page_state(page, NR_FILE_MAPPED);
-		mem_cgroup_inc_page_stat(page, MEM_CGROUP_STAT_FILE_MAPPED);
+	if (compound && PageTransHuge(page)) {
+		for (i = 0, nr = 0; i < HPAGE_PMD_NR; i++) {
+			if (atomic_inc_and_test(&page[i]._mapcount))
+				nr++;
+		}
+		if (!atomic_inc_and_test(compound_mapcount_ptr(page)))
+			goto out;
+		VM_BUG_ON_PAGE(!PageSwapBacked(page), page);
+		__inc_zone_page_state(page, NR_SHMEM_PMDMAPPED);
+	} else {
+		if (PageTransCompound(page)) {
+			VM_BUG_ON_PAGE(!PageLocked(page), page);
+			SetPageDoubleMap(compound_head(page));
+			if (PageMlocked(page))
+				clear_page_mlock(compound_head(page));
+		}
+		if (!atomic_inc_and_test(&page->_mapcount))
+			goto out;
 	}
+	__mod_zone_page_state(page_zone(page), NR_FILE_MAPPED, nr);
+	mem_cgroup_inc_page_stat(page, MEM_CGROUP_STAT_FILE_MAPPED);
+out:
 	unlock_page_memcg(page);
 }
 
-static void page_remove_file_rmap(struct page *page)
+static void page_remove_file_rmap(struct page *page, bool compound)
 {
+	int i, nr = 1;
+
+	VM_BUG_ON_PAGE(compound && !PageTransHuge(page), page);
 	lock_page_memcg(page);
 
 	/* Hugepages are not counted in NR_FILE_MAPPED for now. */
@@ -1292,15 +1314,26 @@ static void page_remove_file_rmap(struct page *page)
 	}
 
 	/* page still mapped by someone else? */
-	if (!atomic_add_negative(-1, &page->_mapcount))
-		goto out;
+	if (compound && PageTransHuge(page)) {
+		for (i = 0, nr = 0; i < HPAGE_PMD_NR; i++) {
+			if (atomic_add_negative(-1, &page[i]._mapcount))
+				nr++;
+		}
+		if (!atomic_add_negative(-1, compound_mapcount_ptr(page)))
+			goto out;
+		VM_BUG_ON_PAGE(!PageSwapBacked(page), page);
+		__dec_zone_page_state(page, NR_SHMEM_PMDMAPPED);
+	} else {
+		if (!atomic_add_negative(-1, &page->_mapcount))
+			goto out;
+	}
 
 	/*
 	 * We use the irq-unsafe __{inc|mod}_zone_page_stat because
 	 * these counters are not modified in interrupt context, and
 	 * pte lock(a spinlock) is held, which implies preemption disabled.
 	 */
-	__dec_zone_page_state(page, NR_FILE_MAPPED);
+	__mod_zone_page_state(page_zone(page), NR_FILE_MAPPED, -nr);
 	mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_FILE_MAPPED);
 
 	if (unlikely(PageMlocked(page)))
@@ -1323,7 +1356,7 @@ static void page_remove_anon_compound_rmap(struct page *page)
 	if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
 		return;
 
-	__dec_zone_page_state(page, NR_ANON_TRANSPARENT_HUGEPAGES);
+	__dec_zone_page_state(page, NR_ANON_THPS);
 
 	if (TestClearPageDoubleMap(page)) {
 		/*
@@ -1356,11 +1389,8 @@ static void page_remove_anon_compound_rmap(struct page *page)
  */
 void page_remove_rmap(struct page *page, bool compound)
 {
-	if (!PageAnon(page)) {
-		VM_BUG_ON_PAGE(compound && !PageHuge(page), page);
-		page_remove_file_rmap(page);
-		return;
-	}
+	if (!PageAnon(page))
+		return page_remove_file_rmap(page, compound);
 
 	if (compound)
 		return page_remove_anon_compound_rmap(page);
@@ -1436,8 +1466,14 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 	 */
 	if (!(flags & TTU_IGNORE_MLOCK)) {
 		if (vma->vm_flags & VM_LOCKED) {
-			/* Holding pte lock, we do *not* need mmap_sem here */
-			mlock_vma_page(page);
+			/* PTE-mapped THP are never mlocked */
+			if (!PageTransCompound(page)) {
+				/*
+				 * Holding pte lock, we do *not* need
+				 * mmap_sem here
+				 */
+				mlock_vma_page(page);
+			}
 			ret = SWAP_MLOCK;
 			goto out_unmap;
 		}
diff --git a/mm/shmem.c b/mm/shmem.c
index 171dee7a131f..62e42c7d544c 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -32,6 +32,7 @@
 #include <linux/export.h>
 #include <linux/swap.h>
 #include <linux/uio.h>
+#include <linux/khugepaged.h>
 
 static struct vfsmount *shm_mnt;
 
@@ -97,14 +98,6 @@ struct shmem_falloc {
 	pgoff_t nr_unswapped;	/* how often writepage refused to swap out */
 };
 
-/* Flag allocation requirements to shmem_getpage */
-enum sgp_type {
-	SGP_READ,	/* don't exceed i_size, don't allocate page */
-	SGP_CACHE,	/* don't exceed i_size, may allocate page */
-	SGP_WRITE,	/* may exceed i_size, may allocate !Uptodate page */
-	SGP_FALLOC,	/* like SGP_WRITE, but make existing page Uptodate */
-};
-
 #ifdef CONFIG_TMPFS
 static unsigned long shmem_default_max_blocks(void)
 {
@@ -124,7 +117,7 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index,
 		struct page **pagep, enum sgp_type sgp,
 		gfp_t gfp, struct mm_struct *fault_mm, int *fault_type);
 
-static inline int shmem_getpage(struct inode *inode, pgoff_t index,
+int shmem_getpage(struct inode *inode, pgoff_t index,
 		struct page **pagep, enum sgp_type sgp)
 {
 	return shmem_getpage_gfp(inode, index, pagep, sgp,
@@ -173,10 +166,13 @@ static inline int shmem_reacct_size(unsigned long flags,
  * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM,
  * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM.
  */
-static inline int shmem_acct_block(unsigned long flags)
+static inline int shmem_acct_block(unsigned long flags, long pages)
 {
-	return (flags & VM_NORESERVE) ?
-		security_vm_enough_memory_mm(current->mm, VM_ACCT(PAGE_SIZE)) : 0;
+	if (!(flags & VM_NORESERVE))
+		return 0;
+
+	return security_vm_enough_memory_mm(current->mm,
+			pages * VM_ACCT(PAGE_SIZE));
 }
 
 static inline void shmem_unacct_blocks(unsigned long flags, long pages)
@@ -192,6 +188,7 @@ static const struct inode_operations shmem_inode_operations;
 static const struct inode_operations shmem_dir_inode_operations;
 static const struct inode_operations shmem_special_inode_operations;
 static const struct vm_operations_struct shmem_vm_ops;
+static struct file_system_type shmem_fs_type;
 
 static LIST_HEAD(shmem_swaplist);
 static DEFINE_MUTEX(shmem_swaplist_mutex);
@@ -249,6 +246,53 @@ static void shmem_recalc_inode(struct inode *inode)
 	}
 }
 
+bool shmem_charge(struct inode *inode, long pages)
+{
+	struct shmem_inode_info *info = SHMEM_I(inode);
+	struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
+	unsigned long flags;
+
+	if (shmem_acct_block(info->flags, pages))
+		return false;
+	spin_lock_irqsave(&info->lock, flags);
+	info->alloced += pages;
+	inode->i_blocks += pages * BLOCKS_PER_PAGE;
+	shmem_recalc_inode(inode);
+	spin_unlock_irqrestore(&info->lock, flags);
+	inode->i_mapping->nrpages += pages;
+
+	if (!sbinfo->max_blocks)
+		return true;
+	if (percpu_counter_compare(&sbinfo->used_blocks,
+				sbinfo->max_blocks - pages) > 0) {
+		inode->i_mapping->nrpages -= pages;
+		spin_lock_irqsave(&info->lock, flags);
+		info->alloced -= pages;
+		shmem_recalc_inode(inode);
+		spin_unlock_irqrestore(&info->lock, flags);
+
+		return false;
+	}
+	percpu_counter_add(&sbinfo->used_blocks, pages);
+	return true;
+}
+
+void shmem_uncharge(struct inode *inode, long pages)
+{
+	struct shmem_inode_info *info = SHMEM_I(inode);
+	struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
+	unsigned long flags;
+
+	spin_lock_irqsave(&info->lock, flags);
+	info->alloced -= pages;
+	inode->i_blocks -= pages * BLOCKS_PER_PAGE;
+	shmem_recalc_inode(inode);
+	spin_unlock_irqrestore(&info->lock, flags);
+
+	if (sbinfo->max_blocks)
+		percpu_counter_sub(&sbinfo->used_blocks, pages);
+}
+
 /*
  * Replace item expected in radix tree by a new item, while holding tree lock.
  */
@@ -289,36 +333,256 @@ static bool shmem_confirm_swap(struct address_space *mapping,
 }
 
 /*
+ * Definitions for "huge tmpfs": tmpfs mounted with the huge= option
+ *
+ * SHMEM_HUGE_NEVER:
+ *	disables huge pages for the mount;
+ * SHMEM_HUGE_ALWAYS:
+ *	enables huge pages for the mount;
+ * SHMEM_HUGE_WITHIN_SIZE:
+ *	only allocate huge pages if the page will be fully within i_size,
+ *	also respect fadvise()/madvise() hints;
+ * SHMEM_HUGE_ADVISE:
+ *	only allocate huge pages if requested with fadvise()/madvise();
+ */
+
+#define SHMEM_HUGE_NEVER	0
+#define SHMEM_HUGE_ALWAYS	1
+#define SHMEM_HUGE_WITHIN_SIZE	2
+#define SHMEM_HUGE_ADVISE	3
+
+/*
+ * Special values.
+ * Only can be set via /sys/kernel/mm/transparent_hugepage/shmem_enabled:
+ *
+ * SHMEM_HUGE_DENY:
+ *	disables huge on shm_mnt and all mounts, for emergency use;
+ * SHMEM_HUGE_FORCE:
+ *	enables huge on shm_mnt and all mounts, w/o needing option, for testing;
+ *
+ */
+#define SHMEM_HUGE_DENY		(-1)
+#define SHMEM_HUGE_FORCE	(-2)
+
+#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
+/* ifdef here to avoid bloating shmem.o when not necessary */
+
+int shmem_huge __read_mostly;
+
+static int shmem_parse_huge(const char *str)
+{
+	if (!strcmp(str, "never"))
+		return SHMEM_HUGE_NEVER;
+	if (!strcmp(str, "always"))
+		return SHMEM_HUGE_ALWAYS;
+	if (!strcmp(str, "within_size"))
+		return SHMEM_HUGE_WITHIN_SIZE;
+	if (!strcmp(str, "advise"))
+		return SHMEM_HUGE_ADVISE;
+	if (!strcmp(str, "deny"))
+		return SHMEM_HUGE_DENY;
+	if (!strcmp(str, "force"))
+		return SHMEM_HUGE_FORCE;
+	return -EINVAL;
+}
+
+static const char *shmem_format_huge(int huge)
+{
+	switch (huge) {
+	case SHMEM_HUGE_NEVER:
+		return "never";
+	case SHMEM_HUGE_ALWAYS:
+		return "always";
+	case SHMEM_HUGE_WITHIN_SIZE:
+		return "within_size";
+	case SHMEM_HUGE_ADVISE:
+		return "advise";
+	case SHMEM_HUGE_DENY:
+		return "deny";
+	case SHMEM_HUGE_FORCE:
+		return "force";
+	default:
+		VM_BUG_ON(1);
+		return "bad_val";
+	}
+}
+
+static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo,
+		struct shrink_control *sc, unsigned long nr_to_split)
+{
+	LIST_HEAD(list), *pos, *next;
+	struct inode *inode;
+	struct shmem_inode_info *info;
+	struct page *page;
+	unsigned long batch = sc ? sc->nr_to_scan : 128;
+	int removed = 0, split = 0;
+
+	if (list_empty(&sbinfo->shrinklist))
+		return SHRINK_STOP;
+
+	spin_lock(&sbinfo->shrinklist_lock);
+	list_for_each_safe(pos, next, &sbinfo->shrinklist) {
+		info = list_entry(pos, struct shmem_inode_info, shrinklist);
+
+		/* pin the inode */
+		inode = igrab(&info->vfs_inode);
+
+		/* inode is about to be evicted */
+		if (!inode) {
+			list_del_init(&info->shrinklist);
+			removed++;
+			goto next;
+		}
+
+		/* Check if there's anything to gain */
+		if (round_up(inode->i_size, PAGE_SIZE) ==
+				round_up(inode->i_size, HPAGE_PMD_SIZE)) {
+			list_del_init(&info->shrinklist);
+			removed++;
+			iput(inode);
+			goto next;
+		}
+
+		list_move(&info->shrinklist, &list);
+next:
+		if (!--batch)
+			break;
+	}
+	spin_unlock(&sbinfo->shrinklist_lock);
+
+	list_for_each_safe(pos, next, &list) {
+		int ret;
+
+		info = list_entry(pos, struct shmem_inode_info, shrinklist);
+		inode = &info->vfs_inode;
+
+		if (nr_to_split && split >= nr_to_split) {
+			iput(inode);
+			continue;
+		}
+
+		page = find_lock_page(inode->i_mapping,
+				(inode->i_size & HPAGE_PMD_MASK) >> PAGE_SHIFT);
+		if (!page)
+			goto drop;
+
+		if (!PageTransHuge(page)) {
+			unlock_page(page);
+			put_page(page);
+			goto drop;
+		}
+
+		ret = split_huge_page(page);
+		unlock_page(page);
+		put_page(page);
+
+		if (ret) {
+			/* split failed: leave it on the list */
+			iput(inode);
+			continue;
+		}
+
+		split++;
+drop:
+		list_del_init(&info->shrinklist);
+		removed++;
+		iput(inode);
+	}
+
+	spin_lock(&sbinfo->shrinklist_lock);
+	list_splice_tail(&list, &sbinfo->shrinklist);
+	sbinfo->shrinklist_len -= removed;
+	spin_unlock(&sbinfo->shrinklist_lock);
+
+	return split;
+}
+
+static long shmem_unused_huge_scan(struct super_block *sb,
+		struct shrink_control *sc)
+{
+	struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
+
+	if (!READ_ONCE(sbinfo->shrinklist_len))
+		return SHRINK_STOP;
+
+	return shmem_unused_huge_shrink(sbinfo, sc, 0);
+}
+
+static long shmem_unused_huge_count(struct super_block *sb,
+		struct shrink_control *sc)
+{
+	struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
+	return READ_ONCE(sbinfo->shrinklist_len);
+}
+#else /* !CONFIG_TRANSPARENT_HUGE_PAGECACHE */
+
+#define shmem_huge SHMEM_HUGE_DENY
+
+static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo,
+		struct shrink_control *sc, unsigned long nr_to_split)
+{
+	return 0;
+}
+#endif /* CONFIG_TRANSPARENT_HUGE_PAGECACHE */
+
+/*
  * Like add_to_page_cache_locked, but error if expected item has gone.
  */
 static int shmem_add_to_page_cache(struct page *page,
 				   struct address_space *mapping,
 				   pgoff_t index, void *expected)
 {
-	int error;
+	int error, nr = hpage_nr_pages(page);
 
+	VM_BUG_ON_PAGE(PageTail(page), page);
+	VM_BUG_ON_PAGE(index != round_down(index, nr), page);
 	VM_BUG_ON_PAGE(!PageLocked(page), page);
 	VM_BUG_ON_PAGE(!PageSwapBacked(page), page);
+	VM_BUG_ON(expected && PageTransHuge(page));
 
-	get_page(page);
+	page_ref_add(page, nr);
 	page->mapping = mapping;
 	page->index = index;
 
 	spin_lock_irq(&mapping->tree_lock);
-	if (!expected)
+	if (PageTransHuge(page)) {
+		void __rcu **results;
+		pgoff_t idx;
+		int i;
+
+		error = 0;
+		if (radix_tree_gang_lookup_slot(&mapping->page_tree,
+					&results, &idx, index, 1) &&
+				idx < index + HPAGE_PMD_NR) {
+			error = -EEXIST;
+		}
+
+		if (!error) {
+			for (i = 0; i < HPAGE_PMD_NR; i++) {
+				error = radix_tree_insert(&mapping->page_tree,
+						index + i, page + i);
+				VM_BUG_ON(error);
+			}
+			count_vm_event(THP_FILE_ALLOC);
+		}
+	} else if (!expected) {
 		error = radix_tree_insert(&mapping->page_tree, index, page);
-	else
+	} else {
 		error = shmem_radix_tree_replace(mapping, index, expected,
 								 page);
+	}
+
 	if (!error) {
-		mapping->nrpages++;
-		__inc_zone_page_state(page, NR_FILE_PAGES);
-		__inc_zone_page_state(page, NR_SHMEM);
+		mapping->nrpages += nr;
+		if (PageTransHuge(page))
+			__inc_zone_page_state(page, NR_SHMEM_THPS);
+		__mod_zone_page_state(page_zone(page), NR_FILE_PAGES, nr);
+		__mod_zone_page_state(page_zone(page), NR_SHMEM, nr);
 		spin_unlock_irq(&mapping->tree_lock);
 	} else {
 		page->mapping = NULL;
 		spin_unlock_irq(&mapping->tree_lock);
-		put_page(page);
+		page_ref_sub(page, nr);
 	}
 	return error;
 }
@@ -331,6 +595,8 @@ static void shmem_delete_from_page_cache(struct page *page, void *radswap)
 	struct address_space *mapping = page->mapping;
 	int error;
 
+	VM_BUG_ON_PAGE(PageCompound(page), page);
+
 	spin_lock_irq(&mapping->tree_lock);
 	error = shmem_radix_tree_replace(mapping, page->index, page, radswap);
 	page->mapping = NULL;
@@ -510,10 +776,33 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
 				continue;
 			}
 
+			VM_BUG_ON_PAGE(page_to_pgoff(page) != index, page);
+
 			if (!trylock_page(page))
 				continue;
+
+			if (PageTransTail(page)) {
+				/* Middle of THP: zero out the page */
+				clear_highpage(page);
+				unlock_page(page);
+				continue;
+			} else if (PageTransHuge(page)) {
+				if (index == round_down(end, HPAGE_PMD_NR)) {
+					/*
+					 * Range ends in the middle of THP:
+					 * zero out the page
+					 */
+					clear_highpage(page);
+					unlock_page(page);
+					continue;
+				}
+				index += HPAGE_PMD_NR - 1;
+				i += HPAGE_PMD_NR - 1;
+			}
+
 			if (!unfalloc || !PageUptodate(page)) {
-				if (page->mapping == mapping) {
+				VM_BUG_ON_PAGE(PageTail(page), page);
+				if (page_mapping(page) == mapping) {
 					VM_BUG_ON_PAGE(PageWriteback(page), page);
 					truncate_inode_page(mapping, page);
 				}
@@ -589,8 +878,36 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
 			}
 
 			lock_page(page);
+
+			if (PageTransTail(page)) {
+				/* Middle of THP: zero out the page */
+				clear_highpage(page);
+				unlock_page(page);
+				/*
+				 * Partial thp truncate due 'start' in middle
+				 * of THP: don't need to look on these pages
+				 * again on !pvec.nr restart.
+				 */
+				if (index != round_down(end, HPAGE_PMD_NR))
+					start++;
+				continue;
+			} else if (PageTransHuge(page)) {
+				if (index == round_down(end, HPAGE_PMD_NR)) {
+					/*
+					 * Range ends in the middle of THP:
+					 * zero out the page
+					 */
+					clear_highpage(page);
+					unlock_page(page);
+					continue;
+				}
+				index += HPAGE_PMD_NR - 1;
+				i += HPAGE_PMD_NR - 1;
+			}
+
 			if (!unfalloc || !PageUptodate(page)) {
-				if (page->mapping == mapping) {
+				VM_BUG_ON_PAGE(PageTail(page), page);
+				if (page_mapping(page) == mapping) {
 					VM_BUG_ON_PAGE(PageWriteback(page), page);
 					truncate_inode_page(mapping, page);
 				} else {
@@ -607,10 +924,10 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
 		index++;
 	}
 
-	spin_lock(&info->lock);
+	spin_lock_irq(&info->lock);
 	info->swapped -= nr_swaps_freed;
 	shmem_recalc_inode(inode);
-	spin_unlock(&info->lock);
+	spin_unlock_irq(&info->lock);
 }
 
 void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend)
@@ -627,9 +944,9 @@ static int shmem_getattr(struct vfsmount *mnt, struct dentry *dentry,
 	struct shmem_inode_info *info = SHMEM_I(inode);
 
 	if (info->alloced - info->swapped != inode->i_mapping->nrpages) {
-		spin_lock(&info->lock);
+		spin_lock_irq(&info->lock);
 		shmem_recalc_inode(inode);
-		spin_unlock(&info->lock);
+		spin_unlock_irq(&info->lock);
 	}
 	generic_fillattr(inode, stat);
 	return 0;
@@ -639,6 +956,7 @@ static int shmem_setattr(struct dentry *dentry, struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
 	struct shmem_inode_info *info = SHMEM_I(inode);
+	struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
 	int error;
 
 	error = inode_change_ok(inode, attr);
@@ -674,6 +992,20 @@ static int shmem_setattr(struct dentry *dentry, struct iattr *attr)
 			if (oldsize > holebegin)
 				unmap_mapping_range(inode->i_mapping,
 							holebegin, 0, 1);
+
+			/*
+			 * Part of the huge page can be beyond i_size: subject
+			 * to shrink under memory pressure.
+			 */
+			if (IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE)) {
+				spin_lock(&sbinfo->shrinklist_lock);
+				if (list_empty(&info->shrinklist)) {
+					list_add_tail(&info->shrinklist,
+							&sbinfo->shrinklist);
+					sbinfo->shrinklist_len++;
+				}
+				spin_unlock(&sbinfo->shrinklist_lock);
+			}
 		}
 	}
 
@@ -686,11 +1018,20 @@ static int shmem_setattr(struct dentry *dentry, struct iattr *attr)
 static void shmem_evict_inode(struct inode *inode)
 {
 	struct shmem_inode_info *info = SHMEM_I(inode);
+	struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
 
 	if (inode->i_mapping->a_ops == &shmem_aops) {
 		shmem_unacct_size(info->flags, inode->i_size);
 		inode->i_size = 0;
 		shmem_truncate_range(inode, 0, (loff_t)-1);
+		if (!list_empty(&info->shrinklist)) {
+			spin_lock(&sbinfo->shrinklist_lock);
+			if (!list_empty(&info->shrinklist)) {
+				list_del_init(&info->shrinklist);
+				sbinfo->shrinklist_len--;
+			}
+			spin_unlock(&sbinfo->shrinklist_lock);
+		}
 		if (!list_empty(&info->swaplist)) {
 			mutex_lock(&shmem_swaplist_mutex);
 			list_del_init(&info->swaplist);
@@ -773,9 +1114,9 @@ static int shmem_unuse_inode(struct shmem_inode_info *info,
 		delete_from_swap_cache(*pagep);
 		set_page_dirty(*pagep);
 		if (!error) {
-			spin_lock(&info->lock);
+			spin_lock_irq(&info->lock);
 			info->swapped--;
-			spin_unlock(&info->lock);
+			spin_unlock_irq(&info->lock);
 			swap_free(swap);
 		}
 	}
@@ -848,6 +1189,7 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc)
 	swp_entry_t swap;
 	pgoff_t index;
 
+	VM_BUG_ON_PAGE(PageCompound(page), page);
 	BUG_ON(!PageLocked(page));
 	mapping = page->mapping;
 	index = page->index;
@@ -922,10 +1264,10 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc)
 		list_add_tail(&info->swaplist, &shmem_swaplist);
 
 	if (add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) {
-		spin_lock(&info->lock);
+		spin_lock_irq(&info->lock);
 		shmem_recalc_inode(inode);
 		info->swapped++;
-		spin_unlock(&info->lock);
+		spin_unlock_irq(&info->lock);
 
 		swap_shmem_alloc(swap);
 		shmem_delete_from_page_cache(page, swp_to_radix_entry(swap));
@@ -984,24 +1326,63 @@ static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
 #define vm_policy vm_private_data
 #endif
 
+static void shmem_pseudo_vma_init(struct vm_area_struct *vma,
+		struct shmem_inode_info *info, pgoff_t index)
+{
+	/* Create a pseudo vma that just contains the policy */
+	vma->vm_start = 0;
+	/* Bias interleave by inode number to distribute better across nodes */
+	vma->vm_pgoff = index + info->vfs_inode.i_ino;
+	vma->vm_ops = NULL;
+	vma->vm_policy = mpol_shared_policy_lookup(&info->policy, index);
+}
+
+static void shmem_pseudo_vma_destroy(struct vm_area_struct *vma)
+{
+	/* Drop reference taken by mpol_shared_policy_lookup() */
+	mpol_cond_put(vma->vm_policy);
+}
+
 static struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp,
 			struct shmem_inode_info *info, pgoff_t index)
 {
 	struct vm_area_struct pvma;
 	struct page *page;
 
-	/* Create a pseudo vma that just contains the policy */
-	pvma.vm_start = 0;
-	/* Bias interleave by inode number to distribute better across nodes */
-	pvma.vm_pgoff = index + info->vfs_inode.i_ino;
-	pvma.vm_ops = NULL;
-	pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, index);
-
+	shmem_pseudo_vma_init(&pvma, info, index);
 	page = swapin_readahead(swap, gfp, &pvma, 0);
+	shmem_pseudo_vma_destroy(&pvma);
 
-	/* Drop reference taken by mpol_shared_policy_lookup() */
-	mpol_cond_put(pvma.vm_policy);
+	return page;
+}
+
+static struct page *shmem_alloc_hugepage(gfp_t gfp,
+		struct shmem_inode_info *info, pgoff_t index)
+{
+	struct vm_area_struct pvma;
+	struct inode *inode = &info->vfs_inode;
+	struct address_space *mapping = inode->i_mapping;
+	pgoff_t idx, hindex = round_down(index, HPAGE_PMD_NR);
+	void __rcu **results;
+	struct page *page;
 
+	if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE))
+		return NULL;
+
+	rcu_read_lock();
+	if (radix_tree_gang_lookup_slot(&mapping->page_tree, &results, &idx,
+				hindex, 1) && idx < hindex + HPAGE_PMD_NR) {
+		rcu_read_unlock();
+		return NULL;
+	}
+	rcu_read_unlock();
+
+	shmem_pseudo_vma_init(&pvma, info, hindex);
+	page = alloc_pages_vma(gfp | __GFP_COMP | __GFP_NORETRY | __GFP_NOWARN,
+			HPAGE_PMD_ORDER, &pvma, 0, numa_node_id(), true);
+	shmem_pseudo_vma_destroy(&pvma);
+	if (page)
+		prep_transhuge_page(page);
 	return page;
 }
 
@@ -1011,23 +1392,51 @@ static struct page *shmem_alloc_page(gfp_t gfp,
 	struct vm_area_struct pvma;
 	struct page *page;
 
-	/* Create a pseudo vma that just contains the policy */
-	pvma.vm_start = 0;
-	/* Bias interleave by inode number to distribute better across nodes */
-	pvma.vm_pgoff = index + info->vfs_inode.i_ino;
-	pvma.vm_ops = NULL;
-	pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, index);
+	shmem_pseudo_vma_init(&pvma, info, index);
+	page = alloc_page_vma(gfp, &pvma, 0);
+	shmem_pseudo_vma_destroy(&pvma);
+
+	return page;
+}
+
+static struct page *shmem_alloc_and_acct_page(gfp_t gfp,
+		struct shmem_inode_info *info, struct shmem_sb_info *sbinfo,
+		pgoff_t index, bool huge)
+{
+	struct page *page;
+	int nr;
+	int err = -ENOSPC;
+
+	if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE))
+		huge = false;
+	nr = huge ? HPAGE_PMD_NR : 1;
+
+	if (shmem_acct_block(info->flags, nr))
+		goto failed;
+	if (sbinfo->max_blocks) {
+		if (percpu_counter_compare(&sbinfo->used_blocks,
+					sbinfo->max_blocks - nr) > 0)
+			goto unacct;
+		percpu_counter_add(&sbinfo->used_blocks, nr);
+	}
 
-	page = alloc_pages_vma(gfp, 0, &pvma, 0, numa_node_id(), false);
+	if (huge)
+		page = shmem_alloc_hugepage(gfp, info, index);
+	else
+		page = shmem_alloc_page(gfp, info, index);
 	if (page) {
 		__SetPageLocked(page);
 		__SetPageSwapBacked(page);
+		return page;
 	}
 
-	/* Drop reference taken by mpol_shared_policy_lookup() */
-	mpol_cond_put(pvma.vm_policy);
-
-	return page;
+	err = -ENOMEM;
+	if (sbinfo->max_blocks)
+		percpu_counter_add(&sbinfo->used_blocks, -nr);
+unacct:
+	shmem_unacct_blocks(info->flags, nr);
+failed:
+	return ERR_PTR(err);
 }
 
 /*
@@ -1132,12 +1541,16 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index,
 	struct mem_cgroup *memcg;
 	struct page *page;
 	swp_entry_t swap;
+	enum sgp_type sgp_huge = sgp;
+	pgoff_t hindex = index;
 	int error;
 	int once = 0;
 	int alloced = 0;
 
 	if (index > (MAX_LFS_FILESIZE >> PAGE_SHIFT))
 		return -EFBIG;
+	if (sgp == SGP_NOHUGE || sgp == SGP_HUGE)
+		sgp = SGP_CACHE;
 repeat:
 	swap.val = 0;
 	page = find_lock_entry(mapping, index);
@@ -1240,10 +1653,10 @@ repeat:
 
 		mem_cgroup_commit_charge(page, memcg, true, false);
 
-		spin_lock(&info->lock);
+		spin_lock_irq(&info->lock);
 		info->swapped--;
 		shmem_recalc_inode(inode);
-		spin_unlock(&info->lock);
+		spin_unlock_irq(&info->lock);
 
 		if (sgp == SGP_WRITE)
 			mark_page_accessed(page);
@@ -1253,51 +1666,111 @@ repeat:
 		swap_free(swap);
 
 	} else {
-		if (shmem_acct_block(info->flags)) {
-			error = -ENOSPC;
-			goto failed;
+		/* shmem_symlink() */
+		if (mapping->a_ops != &shmem_aops)
+			goto alloc_nohuge;
+		if (shmem_huge == SHMEM_HUGE_DENY || sgp_huge == SGP_NOHUGE)
+			goto alloc_nohuge;
+		if (shmem_huge == SHMEM_HUGE_FORCE)
+			goto alloc_huge;
+		switch (sbinfo->huge) {
+			loff_t i_size;
+			pgoff_t off;
+		case SHMEM_HUGE_NEVER:
+			goto alloc_nohuge;
+		case SHMEM_HUGE_WITHIN_SIZE:
+			off = round_up(index, HPAGE_PMD_NR);
+			i_size = round_up(i_size_read(inode), PAGE_SIZE);
+			if (i_size >= HPAGE_PMD_SIZE &&
+					i_size >> PAGE_SHIFT >= off)
+				goto alloc_huge;
+			/* fallthrough */
+		case SHMEM_HUGE_ADVISE:
+			if (sgp_huge == SGP_HUGE)
+				goto alloc_huge;
+			/* TODO: implement fadvise() hints */
+			goto alloc_nohuge;
 		}
-		if (sbinfo->max_blocks) {
-			if (percpu_counter_compare(&sbinfo->used_blocks,
-						sbinfo->max_blocks) >= 0) {
-				error = -ENOSPC;
-				goto unacct;
+
+alloc_huge:
+		page = shmem_alloc_and_acct_page(gfp, info, sbinfo,
+				index, true);
+		if (IS_ERR(page)) {
+alloc_nohuge:		page = shmem_alloc_and_acct_page(gfp, info, sbinfo,
+					index, false);
+		}
+		if (IS_ERR(page)) {
+			int retry = 5;
+			error = PTR_ERR(page);
+			page = NULL;
+			if (error != -ENOSPC)
+				goto failed;
+			/*
+			 * Try to reclaim some spece by splitting a huge page
+			 * beyond i_size on the filesystem.
+			 */
+			while (retry--) {
+				int ret;
+				ret = shmem_unused_huge_shrink(sbinfo, NULL, 1);
+				if (ret == SHRINK_STOP)
+					break;
+				if (ret)
+					goto alloc_nohuge;
 			}
-			percpu_counter_inc(&sbinfo->used_blocks);
+			goto failed;
 		}
 
-		page = shmem_alloc_page(gfp, info, index);
-		if (!page) {
-			error = -ENOMEM;
-			goto decused;
-		}
+		if (PageTransHuge(page))
+			hindex = round_down(index, HPAGE_PMD_NR);
+		else
+			hindex = index;
+
 		if (sgp == SGP_WRITE)
 			__SetPageReferenced(page);
 
 		error = mem_cgroup_try_charge(page, charge_mm, gfp, &memcg,
-				false);
+				PageTransHuge(page));
 		if (error)
-			goto decused;
-		error = radix_tree_maybe_preload(gfp & GFP_RECLAIM_MASK);
+			goto unacct;
+		error = radix_tree_maybe_preload_order(gfp & GFP_RECLAIM_MASK,
+				compound_order(page));
 		if (!error) {
-			error = shmem_add_to_page_cache(page, mapping, index,
+			error = shmem_add_to_page_cache(page, mapping, hindex,
 							NULL);
 			radix_tree_preload_end();
 		}
 		if (error) {
-			mem_cgroup_cancel_charge(page, memcg, false);
-			goto decused;
+			mem_cgroup_cancel_charge(page, memcg,
+					PageTransHuge(page));
+			goto unacct;
 		}
-		mem_cgroup_commit_charge(page, memcg, false, false);
+		mem_cgroup_commit_charge(page, memcg, false,
+				PageTransHuge(page));
 		lru_cache_add_anon(page);
 
-		spin_lock(&info->lock);
-		info->alloced++;
-		inode->i_blocks += BLOCKS_PER_PAGE;
+		spin_lock_irq(&info->lock);
+		info->alloced += 1 << compound_order(page);
+		inode->i_blocks += BLOCKS_PER_PAGE << compound_order(page);
 		shmem_recalc_inode(inode);
-		spin_unlock(&info->lock);
+		spin_unlock_irq(&info->lock);
 		alloced = true;
 
+		if (PageTransHuge(page) &&
+				DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE) <
+				hindex + HPAGE_PMD_NR - 1) {
+			/*
+			 * Part of the huge page is beyond i_size: subject
+			 * to shrink under memory pressure.
+			 */
+			spin_lock(&sbinfo->shrinklist_lock);
+			if (list_empty(&info->shrinklist)) {
+				list_add_tail(&info->shrinklist,
+						&sbinfo->shrinklist);
+				sbinfo->shrinklist_len++;
+			}
+			spin_unlock(&sbinfo->shrinklist_lock);
+		}
+
 		/*
 		 * Let SGP_FALLOC use the SGP_WRITE optimization on a new page.
 		 */
@@ -1309,10 +1782,15 @@ clear:
 		 * but SGP_FALLOC on a page fallocated earlier must initialize
 		 * it now, lest undo on failure cancel our earlier guarantee.
 		 */
-		if (sgp != SGP_WRITE) {
-			clear_highpage(page);
-			flush_dcache_page(page);
-			SetPageUptodate(page);
+		if (sgp != SGP_WRITE && !PageUptodate(page)) {
+			struct page *head = compound_head(page);
+			int i;
+
+			for (i = 0; i < (1 << compound_order(head)); i++) {
+				clear_highpage(head + i);
+				flush_dcache_page(head + i);
+			}
+			SetPageUptodate(head);
 		}
 	}
 
@@ -1322,24 +1800,30 @@ clear:
 		if (alloced) {
 			ClearPageDirty(page);
 			delete_from_page_cache(page);
-			spin_lock(&info->lock);
+			spin_lock_irq(&info->lock);
 			shmem_recalc_inode(inode);
-			spin_unlock(&info->lock);
+			spin_unlock_irq(&info->lock);
 		}
 		error = -EINVAL;
 		goto unlock;
 	}
-	*pagep = page;
+	*pagep = page + index - hindex;
 	return 0;
 
 	/*
 	 * Error recovery.
 	 */
-decused:
-	if (sbinfo->max_blocks)
-		percpu_counter_add(&sbinfo->used_blocks, -1);
 unacct:
-	shmem_unacct_blocks(info->flags, 1);
+	if (sbinfo->max_blocks)
+		percpu_counter_sub(&sbinfo->used_blocks,
+				1 << compound_order(page));
+	shmem_unacct_blocks(info->flags, 1 << compound_order(page));
+
+	if (PageTransHuge(page)) {
+		unlock_page(page);
+		put_page(page);
+		goto alloc_nohuge;
+	}
 failed:
 	if (swap.val && !shmem_confirm_swap(mapping, index, swap))
 		error = -EEXIST;
@@ -1350,9 +1834,9 @@ unlock:
 	}
 	if (error == -ENOSPC && !once++) {
 		info = SHMEM_I(inode);
-		spin_lock(&info->lock);
+		spin_lock_irq(&info->lock);
 		shmem_recalc_inode(inode);
-		spin_unlock(&info->lock);
+		spin_unlock_irq(&info->lock);
 		goto repeat;
 	}
 	if (error == -EEXIST)	/* from above or from radix_tree_insert */
@@ -1364,6 +1848,7 @@ static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
 	struct inode *inode = file_inode(vma->vm_file);
 	gfp_t gfp = mapping_gfp_mask(inode->i_mapping);
+	enum sgp_type sgp;
 	int error;
 	int ret = VM_FAULT_LOCKED;
 
@@ -1425,13 +1910,107 @@ static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 		spin_unlock(&inode->i_lock);
 	}
 
-	error = shmem_getpage_gfp(inode, vmf->pgoff, &vmf->page, SGP_CACHE,
+	sgp = SGP_CACHE;
+	if (vma->vm_flags & VM_HUGEPAGE)
+		sgp = SGP_HUGE;
+	else if (vma->vm_flags & VM_NOHUGEPAGE)
+		sgp = SGP_NOHUGE;
+
+	error = shmem_getpage_gfp(inode, vmf->pgoff, &vmf->page, sgp,
 				  gfp, vma->vm_mm, &ret);
 	if (error)
 		return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS);
 	return ret;
 }
 
+unsigned long shmem_get_unmapped_area(struct file *file,
+				      unsigned long uaddr, unsigned long len,
+				      unsigned long pgoff, unsigned long flags)
+{
+	unsigned long (*get_area)(struct file *,
+		unsigned long, unsigned long, unsigned long, unsigned long);
+	unsigned long addr;
+	unsigned long offset;
+	unsigned long inflated_len;
+	unsigned long inflated_addr;
+	unsigned long inflated_offset;
+
+	if (len > TASK_SIZE)
+		return -ENOMEM;
+
+	get_area = current->mm->get_unmapped_area;
+	addr = get_area(file, uaddr, len, pgoff, flags);
+
+	if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE))
+		return addr;
+	if (IS_ERR_VALUE(addr))
+		return addr;
+	if (addr & ~PAGE_MASK)
+		return addr;
+	if (addr > TASK_SIZE - len)
+		return addr;
+
+	if (shmem_huge == SHMEM_HUGE_DENY)
+		return addr;
+	if (len < HPAGE_PMD_SIZE)
+		return addr;
+	if (flags & MAP_FIXED)
+		return addr;
+	/*
+	 * Our priority is to support MAP_SHARED mapped hugely;
+	 * and support MAP_PRIVATE mapped hugely too, until it is COWed.
+	 * But if caller specified an address hint, respect that as before.
+	 */
+	if (uaddr)
+		return addr;
+
+	if (shmem_huge != SHMEM_HUGE_FORCE) {
+		struct super_block *sb;
+
+		if (file) {
+			VM_BUG_ON(file->f_op != &shmem_file_operations);
+			sb = file_inode(file)->i_sb;
+		} else {
+			/*
+			 * Called directly from mm/mmap.c, or drivers/char/mem.c
+			 * for "/dev/zero", to create a shared anonymous object.
+			 */
+			if (IS_ERR(shm_mnt))
+				return addr;
+			sb = shm_mnt->mnt_sb;
+		}
+		if (SHMEM_SB(sb)->huge != SHMEM_HUGE_NEVER)
+			return addr;
+	}
+
+	offset = (pgoff << PAGE_SHIFT) & (HPAGE_PMD_SIZE-1);
+	if (offset && offset + len < 2 * HPAGE_PMD_SIZE)
+		return addr;
+	if ((addr & (HPAGE_PMD_SIZE-1)) == offset)
+		return addr;
+
+	inflated_len = len + HPAGE_PMD_SIZE - PAGE_SIZE;
+	if (inflated_len > TASK_SIZE)
+		return addr;
+	if (inflated_len < len)
+		return addr;
+
+	inflated_addr = get_area(NULL, 0, inflated_len, 0, flags);
+	if (IS_ERR_VALUE(inflated_addr))
+		return addr;
+	if (inflated_addr & ~PAGE_MASK)
+		return addr;
+
+	inflated_offset = inflated_addr & (HPAGE_PMD_SIZE-1);
+	inflated_addr += offset - inflated_offset;
+	if (inflated_offset > offset)
+		inflated_addr += HPAGE_PMD_SIZE;
+
+	if (inflated_addr > TASK_SIZE - len)
+		return addr;
+	return inflated_addr;
+}
+
 #ifdef CONFIG_NUMA
 static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol)
 {
@@ -1456,7 +2035,7 @@ int shmem_lock(struct file *file, int lock, struct user_struct *user)
 	struct shmem_inode_info *info = SHMEM_I(inode);
 	int retval = -ENOMEM;
 
-	spin_lock(&info->lock);
+	spin_lock_irq(&info->lock);
 	if (lock && !(info->flags & VM_LOCKED)) {
 		if (!user_shm_lock(inode->i_size, user))
 			goto out_nomem;
@@ -1471,7 +2050,7 @@ int shmem_lock(struct file *file, int lock, struct user_struct *user)
 	retval = 0;
 
 out_nomem:
-	spin_unlock(&info->lock);
+	spin_unlock_irq(&info->lock);
 	return retval;
 }
 
@@ -1479,6 +2058,11 @@ static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	file_accessed(file);
 	vma->vm_ops = &shmem_vm_ops;
+	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE) &&
+			((vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK) <
+			(vma->vm_end & HPAGE_PMD_MASK)) {
+		khugepaged_enter(vma, vma->vm_flags);
+	}
 	return 0;
 }
 
@@ -1504,6 +2088,7 @@ static struct inode *shmem_get_inode(struct super_block *sb, const struct inode
 		spin_lock_init(&info->lock);
 		info->seals = F_SEAL_SEAL;
 		info->flags = flags & VM_NORESERVE;
+		INIT_LIST_HEAD(&info->shrinklist);
 		INIT_LIST_HEAD(&info->swaplist);
 		simple_xattrs_init(&info->xattrs);
 		cache_no_acl(inode);
@@ -1589,12 +2174,23 @@ shmem_write_end(struct file *file, struct address_space *mapping,
 		i_size_write(inode, pos + copied);
 
 	if (!PageUptodate(page)) {
+		struct page *head = compound_head(page);
+		if (PageTransCompound(page)) {
+			int i;
+
+			for (i = 0; i < HPAGE_PMD_NR; i++) {
+				if (head + i == page)
+					continue;
+				clear_highpage(head + i);
+				flush_dcache_page(head + i);
+			}
+		}
 		if (copied < PAGE_SIZE) {
 			unsigned from = pos & (PAGE_SIZE - 1);
 			zero_user_segments(page, 0, from,
 					from + copied, PAGE_SIZE);
 		}
-		SetPageUptodate(page);
+		SetPageUptodate(head);
 	}
 	set_page_dirty(page);
 	unlock_page(page);
@@ -2860,11 +3456,24 @@ static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo,
 			sbinfo->gid = make_kgid(current_user_ns(), gid);
 			if (!gid_valid(sbinfo->gid))
 				goto bad_val;
+#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
+		} else if (!strcmp(this_char, "huge")) {
+			int huge;
+			huge = shmem_parse_huge(value);
+			if (huge < 0)
+				goto bad_val;
+			if (!has_transparent_hugepage() &&
+					huge != SHMEM_HUGE_NEVER)
+				goto bad_val;
+			sbinfo->huge = huge;
+#endif
+#ifdef CONFIG_NUMA
 		} else if (!strcmp(this_char,"mpol")) {
 			mpol_put(mpol);
 			mpol = NULL;
 			if (mpol_parse_str(value, &mpol))
 				goto bad_val;
+#endif
 		} else {
 			pr_err("tmpfs: Bad mount option %s\n", this_char);
 			goto error;
@@ -2910,6 +3519,7 @@ static int shmem_remount_fs(struct super_block *sb, int *flags, char *data)
 		goto out;
 
 	error = 0;
+	sbinfo->huge = config.huge;
 	sbinfo->max_blocks  = config.max_blocks;
 	sbinfo->max_inodes  = config.max_inodes;
 	sbinfo->free_inodes = config.max_inodes - inodes;
@@ -2943,6 +3553,11 @@ static int shmem_show_options(struct seq_file *seq, struct dentry *root)
 	if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID))
 		seq_printf(seq, ",gid=%u",
 				from_kgid_munged(&init_user_ns, sbinfo->gid));
+#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
+	/* Rightly or wrongly, show huge mount option unmasked by shmem_huge */
+	if (sbinfo->huge)
+		seq_printf(seq, ",huge=%s", shmem_format_huge(sbinfo->huge));
+#endif
 	shmem_show_mpol(seq, sbinfo->mpol);
 	return 0;
 }
@@ -3072,6 +3687,8 @@ int shmem_fill_super(struct super_block *sb, void *data, int silent)
 	if (percpu_counter_init(&sbinfo->used_blocks, 0, GFP_KERNEL))
 		goto failed;
 	sbinfo->free_inodes = sbinfo->max_inodes;
+	spin_lock_init(&sbinfo->shrinklist_lock);
+	INIT_LIST_HEAD(&sbinfo->shrinklist);
 
 	sb->s_maxbytes = MAX_LFS_FILESIZE;
 	sb->s_blocksize = PAGE_SIZE;
@@ -3161,6 +3778,7 @@ static const struct address_space_operations shmem_aops = {
 
 static const struct file_operations shmem_file_operations = {
 	.mmap		= shmem_mmap,
+	.get_unmapped_area = shmem_get_unmapped_area,
 #ifdef CONFIG_TMPFS
 	.llseek		= shmem_file_llseek,
 	.read_iter	= shmem_file_read_iter,
@@ -3233,6 +3851,10 @@ static const struct super_operations shmem_ops = {
 	.evict_inode	= shmem_evict_inode,
 	.drop_inode	= generic_delete_inode,
 	.put_super	= shmem_put_super,
+#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
+	.nr_cached_objects	= shmem_unused_huge_count,
+	.free_cached_objects	= shmem_unused_huge_scan,
+#endif
 };
 
 static const struct vm_operations_struct shmem_vm_ops = {
@@ -3282,6 +3904,13 @@ int __init shmem_init(void)
 		pr_err("Could not kern_mount tmpfs\n");
 		goto out1;
 	}
+
+#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
+	if (has_transparent_hugepage() && shmem_huge < SHMEM_HUGE_DENY)
+		SHMEM_SB(shm_mnt->mnt_sb)->huge = shmem_huge;
+	else
+		shmem_huge = 0; /* just in case it was patched */
+#endif
 	return 0;
 
 out1:
@@ -3293,6 +3922,91 @@ out3:
 	return error;
 }
 
+#if defined(CONFIG_TRANSPARENT_HUGE_PAGECACHE) && defined(CONFIG_SYSFS)
+static ssize_t shmem_enabled_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	int values[] = {
+		SHMEM_HUGE_ALWAYS,
+		SHMEM_HUGE_WITHIN_SIZE,
+		SHMEM_HUGE_ADVISE,
+		SHMEM_HUGE_NEVER,
+		SHMEM_HUGE_DENY,
+		SHMEM_HUGE_FORCE,
+	};
+	int i, count;
+
+	for (i = 0, count = 0; i < ARRAY_SIZE(values); i++) {
+		const char *fmt = shmem_huge == values[i] ? "[%s] " : "%s ";
+
+		count += sprintf(buf + count, fmt,
+				shmem_format_huge(values[i]));
+	}
+	buf[count - 1] = '\n';
+	return count;
+}
+
+static ssize_t shmem_enabled_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	char tmp[16];
+	int huge;
+
+	if (count + 1 > sizeof(tmp))
+		return -EINVAL;
+	memcpy(tmp, buf, count);
+	tmp[count] = '\0';
+	if (count && tmp[count - 1] == '\n')
+		tmp[count - 1] = '\0';
+
+	huge = shmem_parse_huge(tmp);
+	if (huge == -EINVAL)
+		return -EINVAL;
+	if (!has_transparent_hugepage() &&
+			huge != SHMEM_HUGE_NEVER && huge != SHMEM_HUGE_DENY)
+		return -EINVAL;
+
+	shmem_huge = huge;
+	if (shmem_huge < SHMEM_HUGE_DENY)
+		SHMEM_SB(shm_mnt->mnt_sb)->huge = shmem_huge;
+	return count;
+}
+
+struct kobj_attribute shmem_enabled_attr =
+	__ATTR(shmem_enabled, 0644, shmem_enabled_show, shmem_enabled_store);
+
+bool shmem_huge_enabled(struct vm_area_struct *vma)
+{
+	struct inode *inode = file_inode(vma->vm_file);
+	struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
+	loff_t i_size;
+	pgoff_t off;
+
+	if (shmem_huge == SHMEM_HUGE_FORCE)
+		return true;
+	if (shmem_huge == SHMEM_HUGE_DENY)
+		return false;
+	switch (sbinfo->huge) {
+		case SHMEM_HUGE_NEVER:
+			return false;
+		case SHMEM_HUGE_ALWAYS:
+			return true;
+		case SHMEM_HUGE_WITHIN_SIZE:
+			off = round_up(vma->vm_pgoff, HPAGE_PMD_NR);
+			i_size = round_up(i_size_read(inode), PAGE_SIZE);
+			if (i_size >= HPAGE_PMD_SIZE &&
+					i_size >> PAGE_SHIFT >= off)
+				return true;
+		case SHMEM_HUGE_ADVISE:
+			/* TODO: implement fadvise() hints */
+			return (vma->vm_flags & VM_HUGEPAGE);
+		default:
+			VM_BUG_ON(1);
+			return false;
+	}
+}
+#endif /* CONFIG_TRANSPARENT_HUGE_PAGECACHE && CONFIG_SYSFS */
+
 #else /* !CONFIG_SHMEM */
 
 /*
@@ -3335,6 +4049,15 @@ void shmem_unlock_mapping(struct address_space *mapping)
 {
 }
 
+#ifdef CONFIG_MMU
+unsigned long shmem_get_unmapped_area(struct file *file,
+				      unsigned long addr, unsigned long len,
+				      unsigned long pgoff, unsigned long flags)
+{
+	return current->mm->get_unmapped_area(file, addr, len, pgoff, flags);
+}
+#endif
+
 void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend)
 {
 	truncate_inode_pages_range(inode->i_mapping, lstart, lend);
@@ -3461,6 +4184,13 @@ int shmem_zero_setup(struct vm_area_struct *vma)
 		fput(vma->vm_file);
 	vma->vm_file = file;
 	vma->vm_ops = &shmem_vm_ops;
+
+	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE) &&
+			((vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK) <
+			(vma->vm_end & HPAGE_PMD_MASK)) {
+		khugepaged_enter(vma, vma->vm_flags);
+	}
+
 	return 0;
 }
 
diff --git a/mm/slab.c b/mm/slab.c
index cc8bbc1e6bc9..09771ed3e693 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1236,61 +1236,6 @@ static void __init set_up_node(struct kmem_cache *cachep, int index)
 	}
 }
 
-#ifdef CONFIG_SLAB_FREELIST_RANDOM
-static void freelist_randomize(struct rnd_state *state, freelist_idx_t *list,
-			size_t count)
-{
-	size_t i;
-	unsigned int rand;
-
-	for (i = 0; i < count; i++)
-		list[i] = i;
-
-	/* Fisher-Yates shuffle */
-	for (i = count - 1; i > 0; i--) {
-		rand = prandom_u32_state(state);
-		rand %= (i + 1);
-		swap(list[i], list[rand]);
-	}
-}
-
-/* Create a random sequence per cache */
-static int cache_random_seq_create(struct kmem_cache *cachep, gfp_t gfp)
-{
-	unsigned int seed, count = cachep->num;
-	struct rnd_state state;
-
-	if (count < 2)
-		return 0;
-
-	/* If it fails, we will just use the global lists */
-	cachep->random_seq = kcalloc(count, sizeof(freelist_idx_t), gfp);
-	if (!cachep->random_seq)
-		return -ENOMEM;
-
-	/* Get best entropy at this stage */
-	get_random_bytes_arch(&seed, sizeof(seed));
-	prandom_seed_state(&state, seed);
-
-	freelist_randomize(&state, cachep->random_seq, count);
-	return 0;
-}
-
-/* Destroy the per-cache random freelist sequence */
-static void cache_random_seq_destroy(struct kmem_cache *cachep)
-{
-	kfree(cachep->random_seq);
-	cachep->random_seq = NULL;
-}
-#else
-static inline int cache_random_seq_create(struct kmem_cache *cachep, gfp_t gfp)
-{
-	return 0;
-}
-static inline void cache_random_seq_destroy(struct kmem_cache *cachep) { }
-#endif /* CONFIG_SLAB_FREELIST_RANDOM */
-
-
 /*
  * Initialisation.  Called after the page allocator have been initialised and
  * before smp_init().
@@ -2535,7 +2480,7 @@ static void cache_init_objs_debug(struct kmem_cache *cachep, struct page *page)
 union freelist_init_state {
 	struct {
 		unsigned int pos;
-		freelist_idx_t *list;
+		unsigned int *list;
 		unsigned int count;
 		unsigned int rand;
 	};
@@ -2554,7 +2499,7 @@ static bool freelist_state_initialize(union freelist_init_state *state,
 	unsigned int rand;
 
 	/* Use best entropy available to define a random shift */
-	get_random_bytes_arch(&rand, sizeof(rand));
+	rand = get_random_int();
 
 	/* Use a random state if the pre-computed list is not available */
 	if (!cachep->random_seq) {
@@ -2576,13 +2521,20 @@ static freelist_idx_t next_random_slot(union freelist_init_state *state)
 	return (state->list[state->pos++] + state->rand) % state->count;
 }
 
+/* Swap two freelist entries */
+static void swap_free_obj(struct page *page, unsigned int a, unsigned int b)
+{
+	swap(((freelist_idx_t *)page->freelist)[a],
+		((freelist_idx_t *)page->freelist)[b]);
+}
+
 /*
  * Shuffle the freelist initialization state based on pre-computed lists.
  * return true if the list was successfully shuffled, false otherwise.
  */
 static bool shuffle_freelist(struct kmem_cache *cachep, struct page *page)
 {
-	unsigned int objfreelist = 0, i, count = cachep->num;
+	unsigned int objfreelist = 0, i, rand, count = cachep->num;
 	union freelist_init_state state;
 	bool precomputed;
 
@@ -2607,7 +2559,15 @@ static bool shuffle_freelist(struct kmem_cache *cachep, struct page *page)
 	 * Later use a pre-computed list for speed.
 	 */
 	if (!precomputed) {
-		freelist_randomize(&state.rnd_state, page->freelist, count);
+		for (i = 0; i < count; i++)
+			set_free_obj(page, i, i);
+
+		/* Fisher-Yates shuffle */
+		for (i = count - 1; i > 0; i--) {
+			rand = prandom_u32_state(&state.rnd_state);
+			rand %= (i + 1);
+			swap_free_obj(page, i, rand);
+		}
 	} else {
 		for (i = 0; i < count; i++)
 			set_free_obj(page, i, next_random_slot(&state));
@@ -2726,8 +2686,11 @@ static struct page *cache_grow_begin(struct kmem_cache *cachep,
 	 * critical path in kmem_cache_alloc().
 	 */
 	if (unlikely(flags & GFP_SLAB_BUG_MASK)) {
-		pr_emerg("gfp: %u\n", flags & GFP_SLAB_BUG_MASK);
-		BUG();
+		gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK;
+		flags &= ~GFP_SLAB_BUG_MASK;
+		pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
+				invalid_mask, &invalid_mask, flags, &flags);
+		dump_stack();
 	}
 	local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
 
@@ -3489,8 +3452,7 @@ static void free_block(struct kmem_cache *cachep, void **objpp,
 		n->free_objects -= cachep->num;
 
 		page = list_last_entry(&n->slabs_free, struct page, lru);
-		list_del(&page->lru);
-		list_add(&page->lru, list);
+		list_move(&page->lru, list);
 	}
 }
 
@@ -3979,7 +3941,7 @@ static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp)
 	int shared = 0;
 	int batchcount = 0;
 
-	err = cache_random_seq_create(cachep, gfp);
+	err = cache_random_seq_create(cachep, cachep->num, gfp);
 	if (err)
 		goto end;
 
diff --git a/mm/slab.h b/mm/slab.h
index dedb1a920fb8..f33980ab0406 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -42,6 +42,7 @@ struct kmem_cache {
 #include <linux/kmemcheck.h>
 #include <linux/kasan.h>
 #include <linux/kmemleak.h>
+#include <linux/random.h>
 
 /*
  * State of the slab allocator.
@@ -253,8 +254,7 @@ static __always_inline int memcg_charge_slab(struct page *page,
 	if (is_root_cache(s))
 		return 0;
 
-	ret = __memcg_kmem_charge_memcg(page, gfp, order,
-					s->memcg_params.memcg);
+	ret = memcg_kmem_charge_memcg(page, gfp, order, s->memcg_params.memcg);
 	if (ret)
 		return ret;
 
@@ -268,6 +268,9 @@ static __always_inline int memcg_charge_slab(struct page *page,
 static __always_inline void memcg_uncharge_slab(struct page *page, int order,
 						struct kmem_cache *s)
 {
+	if (!memcg_kmem_enabled())
+		return;
+
 	memcg_kmem_update_page_stat(page,
 			(s->flags & SLAB_RECLAIM_ACCOUNT) ?
 			MEMCG_SLAB_RECLAIMABLE : MEMCG_SLAB_UNRECLAIMABLE,
@@ -390,7 +393,11 @@ static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s,
 	if (should_failslab(s, flags))
 		return NULL;
 
-	return memcg_kmem_get_cache(s, flags);
+	if (memcg_kmem_enabled() &&
+	    ((flags & __GFP_ACCOUNT) || (s->flags & SLAB_ACCOUNT)))
+		return memcg_kmem_get_cache(s);
+
+	return s;
 }
 
 static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
@@ -407,7 +414,9 @@ static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
 					 s->flags, flags);
 		kasan_slab_alloc(s, object, flags);
 	}
-	memcg_kmem_put_cache(s);
+
+	if (memcg_kmem_enabled())
+		memcg_kmem_put_cache(s);
 }
 
 #ifndef CONFIG_SLOB
@@ -464,4 +473,17 @@ int memcg_slab_show(struct seq_file *m, void *p);
 
 void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr);
 
+#ifdef CONFIG_SLAB_FREELIST_RANDOM
+int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
+			gfp_t gfp);
+void cache_random_seq_destroy(struct kmem_cache *cachep);
+#else
+static inline int cache_random_seq_create(struct kmem_cache *cachep,
+					unsigned int count, gfp_t gfp)
+{
+	return 0;
+}
+static inline void cache_random_seq_destroy(struct kmem_cache *cachep) { }
+#endif /* CONFIG_SLAB_FREELIST_RANDOM */
+
 #endif /* MM_SLAB_H */
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 82317abb03ed..71f0b28a1bec 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -1012,7 +1012,7 @@ void *kmalloc_order(size_t size, gfp_t flags, unsigned int order)
 	struct page *page;
 
 	flags |= __GFP_COMP;
-	page = alloc_kmem_pages(flags, order);
+	page = alloc_pages(flags, order);
 	ret = page ? page_address(page) : NULL;
 	kmemleak_alloc(ret, size, 1, flags);
 	kasan_kmalloc_large(ret, size, flags);
@@ -1030,6 +1030,53 @@ void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
 EXPORT_SYMBOL(kmalloc_order_trace);
 #endif
 
+#ifdef CONFIG_SLAB_FREELIST_RANDOM
+/* Randomize a generic freelist */
+static void freelist_randomize(struct rnd_state *state, unsigned int *list,
+			size_t count)
+{
+	size_t i;
+	unsigned int rand;
+
+	for (i = 0; i < count; i++)
+		list[i] = i;
+
+	/* Fisher-Yates shuffle */
+	for (i = count - 1; i > 0; i--) {
+		rand = prandom_u32_state(state);
+		rand %= (i + 1);
+		swap(list[i], list[rand]);
+	}
+}
+
+/* Create a random sequence per cache */
+int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
+				    gfp_t gfp)
+{
+	struct rnd_state state;
+
+	if (count < 2 || cachep->random_seq)
+		return 0;
+
+	cachep->random_seq = kcalloc(count, sizeof(unsigned int), gfp);
+	if (!cachep->random_seq)
+		return -ENOMEM;
+
+	/* Get best entropy at this stage of boot */
+	prandom_seed_state(&state, get_random_long());
+
+	freelist_randomize(&state, cachep->random_seq, count);
+	return 0;
+}
+
+/* Destroy the per-cache random freelist sequence */
+void cache_random_seq_destroy(struct kmem_cache *cachep)
+{
+	kfree(cachep->random_seq);
+	cachep->random_seq = NULL;
+}
+#endif /* CONFIG_SLAB_FREELIST_RANDOM */
+
 #ifdef CONFIG_SLABINFO
 
 #ifdef CONFIG_SLAB
diff --git a/mm/slub.c b/mm/slub.c
index 825ff4505336..f9da8716b8b3 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1405,6 +1405,109 @@ static inline struct page *alloc_slab_page(struct kmem_cache *s,
 	return page;
 }
 
+#ifdef CONFIG_SLAB_FREELIST_RANDOM
+/* Pre-initialize the random sequence cache */
+static int init_cache_random_seq(struct kmem_cache *s)
+{
+	int err;
+	unsigned long i, count = oo_objects(s->oo);
+
+	err = cache_random_seq_create(s, count, GFP_KERNEL);
+	if (err) {
+		pr_err("SLUB: Unable to initialize free list for %s\n",
+			s->name);
+		return err;
+	}
+
+	/* Transform to an offset on the set of pages */
+	if (s->random_seq) {
+		for (i = 0; i < count; i++)
+			s->random_seq[i] *= s->size;
+	}
+	return 0;
+}
+
+/* Initialize each random sequence freelist per cache */
+static void __init init_freelist_randomization(void)
+{
+	struct kmem_cache *s;
+
+	mutex_lock(&slab_mutex);
+
+	list_for_each_entry(s, &slab_caches, list)
+		init_cache_random_seq(s);
+
+	mutex_unlock(&slab_mutex);
+}
+
+/* Get the next entry on the pre-computed freelist randomized */
+static void *next_freelist_entry(struct kmem_cache *s, struct page *page,
+				unsigned long *pos, void *start,
+				unsigned long page_limit,
+				unsigned long freelist_count)
+{
+	unsigned int idx;
+
+	/*
+	 * If the target page allocation failed, the number of objects on the
+	 * page might be smaller than the usual size defined by the cache.
+	 */
+	do {
+		idx = s->random_seq[*pos];
+		*pos += 1;
+		if (*pos >= freelist_count)
+			*pos = 0;
+	} while (unlikely(idx >= page_limit));
+
+	return (char *)start + idx;
+}
+
+/* Shuffle the single linked freelist based on a random pre-computed sequence */
+static bool shuffle_freelist(struct kmem_cache *s, struct page *page)
+{
+	void *start;
+	void *cur;
+	void *next;
+	unsigned long idx, pos, page_limit, freelist_count;
+
+	if (page->objects < 2 || !s->random_seq)
+		return false;
+
+	freelist_count = oo_objects(s->oo);
+	pos = get_random_int() % freelist_count;
+
+	page_limit = page->objects * s->size;
+	start = fixup_red_left(s, page_address(page));
+
+	/* First entry is used as the base of the freelist */
+	cur = next_freelist_entry(s, page, &pos, start, page_limit,
+				freelist_count);
+	page->freelist = cur;
+
+	for (idx = 1; idx < page->objects; idx++) {
+		setup_object(s, page, cur);
+		next = next_freelist_entry(s, page, &pos, start, page_limit,
+			freelist_count);
+		set_freepointer(s, cur, next);
+		cur = next;
+	}
+	setup_object(s, page, cur);
+	set_freepointer(s, cur, NULL);
+
+	return true;
+}
+#else
+static inline int init_cache_random_seq(struct kmem_cache *s)
+{
+	return 0;
+}
+static inline void init_freelist_randomization(void) { }
+static inline bool shuffle_freelist(struct kmem_cache *s, struct page *page)
+{
+	return false;
+}
+#endif /* CONFIG_SLAB_FREELIST_RANDOM */
+
 static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
 {
 	struct page *page;
@@ -1412,6 +1515,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
 	gfp_t alloc_gfp;
 	void *start, *p;
 	int idx, order;
+	bool shuffle;
 
 	flags &= gfp_allowed_mask;
 
@@ -1473,15 +1577,19 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
 
 	kasan_poison_slab(page);
 
-	for_each_object_idx(p, idx, s, start, page->objects) {
-		setup_object(s, page, p);
-		if (likely(idx < page->objects))
-			set_freepointer(s, p, p + s->size);
-		else
-			set_freepointer(s, p, NULL);
+	shuffle = shuffle_freelist(s, page);
+
+	if (!shuffle) {
+		for_each_object_idx(p, idx, s, start, page->objects) {
+			setup_object(s, page, p);
+			if (likely(idx < page->objects))
+				set_freepointer(s, p, p + s->size);
+			else
+				set_freepointer(s, p, NULL);
+		}
+		page->freelist = fixup_red_left(s, start);
 	}
 
-	page->freelist = fixup_red_left(s, start);
 	page->inuse = page->objects;
 	page->frozen = 1;
 
@@ -1504,8 +1612,10 @@ out:
 static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
 {
 	if (unlikely(flags & GFP_SLAB_BUG_MASK)) {
-		pr_emerg("gfp: %u\n", flags & GFP_SLAB_BUG_MASK);
-		BUG();
+		gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK;
+		flags &= ~GFP_SLAB_BUG_MASK;
+		pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
+				invalid_mask, &invalid_mask, flags, &flags);
 	}
 
 	return allocate_slab(s,
@@ -2867,7 +2977,7 @@ int build_detached_freelist(struct kmem_cache *s, size_t size,
 		if (unlikely(!PageSlab(page))) {
 			BUG_ON(!PageCompound(page));
 			kfree_hook(object);
-			__free_kmem_pages(page, compound_order(page));
+			__free_pages(page, compound_order(page));
 			p[size] = NULL; /* mark object processed */
 			return size;
 		}
@@ -3207,6 +3317,7 @@ static void free_kmem_cache_nodes(struct kmem_cache *s)
 
 void __kmem_cache_release(struct kmem_cache *s)
 {
+	cache_random_seq_destroy(s);
 	free_percpu(s->cpu_slab);
 	free_kmem_cache_nodes(s);
 }
@@ -3431,6 +3542,13 @@ static int kmem_cache_open(struct kmem_cache *s, unsigned long flags)
 #ifdef CONFIG_NUMA
 	s->remote_node_defrag_ratio = 1000;
 #endif
+
+	/* Initialize the pre-computed randomized freelist if slab is up */
+	if (slab_state >= UP) {
+		if (init_cache_random_seq(s))
+			goto error;
+	}
+
 	if (!init_kmem_cache_nodes(s))
 		goto error;
 
@@ -3575,7 +3693,7 @@ static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
 	void *ptr = NULL;
 
 	flags |= __GFP_COMP | __GFP_NOTRACK;
-	page = alloc_kmem_pages_node(node, flags, get_order(size));
+	page = alloc_pages_node(node, flags, get_order(size));
 	if (page)
 		ptr = page_address(page);
 
@@ -3656,7 +3774,7 @@ void kfree(const void *x)
 	if (unlikely(!PageSlab(page))) {
 		BUG_ON(!PageCompound(page));
 		kfree_hook(x);
-		__free_kmem_pages(page, compound_order(page));
+		__free_pages(page, compound_order(page));
 		return;
 	}
 	slab_free(page->slab_cache, page, object, NULL, 1, _RET_IP_);
@@ -3947,6 +4065,9 @@ void __init kmem_cache_init(void)
 	setup_kmalloc_cache_index_table();
 	create_kmalloc_caches(0);
 
+	/* Setup random freelists for each cache */
+	init_freelist_randomization();
+
 #ifdef CONFIG_SMP
 	register_cpu_notifier(&slab_notifier);
 #endif
diff --git a/mm/swap.c b/mm/swap.c
index 90530ff8ed16..616df4ddd870 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -292,6 +292,7 @@ static bool need_activate_page_drain(int cpu)
 
 void activate_page(struct page *page)
 {
+	page = compound_head(page);
 	if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
 		struct pagevec *pvec = &get_cpu_var(activate_page_pvecs);
 
@@ -316,6 +317,7 @@ void activate_page(struct page *page)
 {
 	struct zone *zone = page_zone(page);
 
+	page = compound_head(page);
 	spin_lock_irq(&zone->lru_lock);
 	__activate_page(page, mem_cgroup_page_lruvec(page, zone), NULL);
 	spin_unlock_irq(&zone->lru_lock);
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 031713ab40ce..78cfa292a29a 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -2493,7 +2493,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 		goto bad_swap;
 	}
 	/* frontswap enabled? set up bit-per-page map for frontswap */
-	if (frontswap_enabled)
+	if (IS_ENABLED(CONFIG_FRONTSWAP))
 		frontswap_map = vzalloc(BITS_TO_LONGS(maxpages) * sizeof(long));
 
 	if (p->bdev &&(swap_flags & SWAP_FLAG_DISCARD) && swap_discardable(p)) {
diff --git a/mm/truncate.c b/mm/truncate.c
index 4064f8f53daa..a01cce450a26 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -155,10 +155,14 @@ invalidate_complete_page(struct address_space *mapping, struct page *page)
 
 int truncate_inode_page(struct address_space *mapping, struct page *page)
 {
+	loff_t holelen;
+	VM_BUG_ON_PAGE(PageTail(page), page);
+
+	holelen = PageTransHuge(page) ? HPAGE_PMD_SIZE : PAGE_SIZE;
 	if (page_mapped(page)) {
 		unmap_mapping_range(mapping,
 				   (loff_t)page->index << PAGE_SHIFT,
-				   PAGE_SIZE, 0);
+				   holelen, 0);
 	}
 	return truncate_complete_page(mapping, page);
 }
@@ -279,7 +283,7 @@ void truncate_inode_pages_range(struct address_space *mapping,
 
 			if (!trylock_page(page))
 				continue;
-			WARN_ON(page->index != index);
+			WARN_ON(page_to_pgoff(page) != index);
 			if (PageWriteback(page)) {
 				unlock_page(page);
 				continue;
@@ -367,7 +371,7 @@ void truncate_inode_pages_range(struct address_space *mapping,
 			}
 
 			lock_page(page);
-			WARN_ON(page->index != index);
+			WARN_ON(page_to_pgoff(page) != index);
 			wait_on_page_writeback(page);
 			truncate_inode_page(mapping, page);
 			unlock_page(page);
@@ -487,7 +491,21 @@ unsigned long invalidate_mapping_pages(struct address_space *mapping,
 
 			if (!trylock_page(page))
 				continue;
-			WARN_ON(page->index != index);
+
+			WARN_ON(page_to_pgoff(page) != index);
+
+			/* Middle of THP: skip */
+			if (PageTransTail(page)) {
+				unlock_page(page);
+				continue;
+			} else if (PageTransHuge(page)) {
+				index += HPAGE_PMD_NR - 1;
+				i += HPAGE_PMD_NR - 1;
+				/* 'end' is in the middle of THP */
+				if (index ==  round_down(end, HPAGE_PMD_NR))
+					continue;
+			}
+
 			ret = invalidate_inode_page(page);
 			unlock_page(page);
 			/*
@@ -594,7 +612,7 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
 			}
 
 			lock_page(page);
-			WARN_ON(page->index != index);
+			WARN_ON(page_to_pgoff(page) != index);
 			if (page->mapping != mapping) {
 				unlock_page(page);
 				continue;
diff --git a/mm/util.c b/mm/util.c
index 917e0e3d0f8e..8d010ef2ce1c 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -399,10 +399,12 @@ struct address_space *page_mapping(struct page *page)
 	}
 
 	mapping = page->mapping;
-	if ((unsigned long)mapping & PAGE_MAPPING_FLAGS)
+	if ((unsigned long)mapping & PAGE_MAPPING_ANON)
 		return NULL;
-	return mapping;
+
+	return (void *)((unsigned long)mapping & ~PAGE_MAPPING_FLAGS);
 }
+EXPORT_SYMBOL(page_mapping);
 
 /* Slow path of page_mapcount() for compound pages */
 int __page_mapcount(struct page *page)
@@ -410,6 +412,12 @@ int __page_mapcount(struct page *page)
 	int ret;
 
 	ret = atomic_read(&page->_mapcount) + 1;
+	/*
+	 * For file THP page->_mapcount contains total number of mapping
+	 * of the page: no need to look into compound_mapcount.
+	 */
+	if (!PageAnon(page) && !PageHuge(page))
+		return ret;
 	page = compound_head(page);
 	ret += atomic_read(compound_mapcount_ptr(page)) + 1;
 	if (PageDoubleMap(page))
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index e11475cdeb7a..91f44e78c516 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1501,7 +1501,7 @@ static void __vunmap(const void *addr, int deallocate_pages)
 			struct page *page = area->pages[i];
 
 			BUG_ON(!page);
-			__free_kmem_pages(page, 0);
+			__free_pages(page, 0);
 		}
 
 		kvfree(area->pages);
@@ -1629,9 +1629,9 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
 		struct page *page;
 
 		if (node == NUMA_NO_NODE)
-			page = alloc_kmem_pages(alloc_mask, order);
+			page = alloc_pages(alloc_mask, order);
 		else
-			page = alloc_kmem_pages_node(node, alloc_mask, order);
+			page = alloc_pages_node(node, alloc_mask, order);
 
 		if (unlikely(!page)) {
 			/* Successfully allocated i pages, free them in __vunmap() */
diff --git a/mm/vmscan.c b/mm/vmscan.c
index c4a2f4512fca..21d417ccff69 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1055,8 +1055,14 @@ static unsigned long shrink_page_list(struct list_head *page_list,
 
 			/* Adding to swap updated mapping */
 			mapping = page_mapping(page);
+		} else if (unlikely(PageTransHuge(page))) {
+			/* Split file THP */
+			if (split_huge_page_to_list(page, page_list))
+				goto keep_locked;
 		}
 
+		VM_BUG_ON_PAGE(PageTransHuge(page), page);
+
 		/*
 		 * The page is mapped into the page tables of one or more
 		 * processes. Try to unmap it here.
@@ -1254,7 +1260,7 @@ unsigned long reclaim_clean_pages_from_list(struct zone *zone,
 
 	list_for_each_entry_safe(page, next, page_list, lru) {
 		if (page_is_file_cache(page) && !PageDirty(page) &&
-		    !isolated_balloon_page(page)) {
+		    !__PageMovable(page)) {
 			ClearPageActive(page);
 			list_move(&page->lru, &clean_pages);
 		}
diff --git a/mm/vmstat.c b/mm/vmstat.c
index cb2a67bb4158..7997f52935c9 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -718,7 +718,9 @@ const char * const vmstat_text[] = {
 	"nr_dirtied",
 	"nr_written",
 	"nr_pages_scanned",
-
+#if IS_ENABLED(CONFIG_ZSMALLOC)
+	"nr_zspages",
+#endif
 #ifdef CONFIG_NUMA
 	"numa_hit",
 	"numa_miss",
@@ -731,6 +733,8 @@ const char * const vmstat_text[] = {
 	"workingset_activate",
 	"workingset_nodereclaim",
 	"nr_anon_transparent_hugepages",
+	"nr_shmem_hugepages",
+	"nr_shmem_pmdmapped",
 	"nr_free_cma",
 
 	/* enum writeback_stat_item counters */
@@ -815,6 +819,8 @@ const char * const vmstat_text[] = {
 	"thp_fault_fallback",
 	"thp_collapse_alloc",
 	"thp_collapse_alloc_failed",
+	"thp_file_alloc",
+	"thp_file_mapped",
 	"thp_split_page",
 	"thp_split_page_failed",
 	"thp_deferred_split_page",
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index b6d4f258cb53..04176de6df70 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -16,32 +16,15 @@
  * struct page(s) to form a zspage.
  *
  * Usage of struct page fields:
- *	page->private: points to the first component (0-order) page
- *	page->index (union with page->freelist): offset of the first object
- *		starting in this page. For the first page, this is
- *		always 0, so we use this field (aka freelist) to point
- *		to the first free object in zspage.
- *	page->lru: links together all component pages (except the first page)
- *		of a zspage
- *
- *	For _first_ page only:
- *
- *	page->private: refers to the component page after the first page
- *		If the page is first_page for huge object, it stores handle.
- *		Look at size_class->huge.
- *	page->freelist: points to the first free object in zspage.
- *		Free objects are linked together using in-place
- *		metadata.
- *	page->objects: maximum number of objects we can store in this
- *		zspage (class->zspage_order * PAGE_SIZE / class->size)
- *	page->lru: links together first pages of various zspages.
- *		Basically forming list of zspages in a fullness group.
- *	page->mapping: class index and fullness group of the zspage
- *	page->inuse: the number of objects that are used in this zspage
+ *	page->private: points to zspage
+ *	page->freelist(index): links together all component pages of a zspage
+ *		For the huge page, this is always 0, so we use this field
+ *		to store handle.
  *
  * Usage of struct page flags:
  *	PG_private: identifies the first component page
  *	PG_private2: identifies the last component page
+ *	PG_owner_priv_1: indentifies the huge component page
  *
  */
 
@@ -66,6 +49,11 @@
 #include <linux/debugfs.h>
 #include <linux/zsmalloc.h>
 #include <linux/zpool.h>
+#include <linux/mount.h>
+#include <linux/migrate.h>
+#include <linux/pagemap.h>
+
+#define ZSPAGE_MAGIC	0x58
 
 /*
  * This must be power of 2 and greater than of equal to sizeof(link_free).
@@ -88,9 +76,7 @@
  * Object location (<PFN>, <obj_idx>) is encoded as
  * as single (unsigned long) handle value.
  *
- * Note that object index <obj_idx> is relative to system
- * page <PFN> it is stored in, so for each sub-page belonging
- * to a zspage, obj_idx starts with 0.
+ * Note that object index <obj_idx> starts from 0.
  *
  * This is made more complicated by various memory models and PAE.
  */
@@ -149,33 +135,29 @@
  *  ZS_MIN_ALLOC_SIZE and ZS_SIZE_CLASS_DELTA must be multiple of ZS_ALIGN
  *  (reason above)
  */
-#define ZS_SIZE_CLASS_DELTA	(PAGE_SIZE >> 8)
+#define ZS_SIZE_CLASS_DELTA	(PAGE_SIZE >> CLASS_BITS)
 
 /*
  * We do not maintain any list for completely empty or full pages
  */
 enum fullness_group {
-	ZS_ALMOST_FULL,
-	ZS_ALMOST_EMPTY,
-	_ZS_NR_FULLNESS_GROUPS,
-
 	ZS_EMPTY,
-	ZS_FULL
+	ZS_ALMOST_EMPTY,
+	ZS_ALMOST_FULL,
+	ZS_FULL,
+	NR_ZS_FULLNESS,
 };
 
 enum zs_stat_type {
+	CLASS_EMPTY,
+	CLASS_ALMOST_EMPTY,
+	CLASS_ALMOST_FULL,
+	CLASS_FULL,
 	OBJ_ALLOCATED,
 	OBJ_USED,
-	CLASS_ALMOST_FULL,
-	CLASS_ALMOST_EMPTY,
+	NR_ZS_STAT_TYPE,
 };
 
-#ifdef CONFIG_ZSMALLOC_STAT
-#define NR_ZS_STAT_TYPE	(CLASS_ALMOST_EMPTY + 1)
-#else
-#define NR_ZS_STAT_TYPE	(OBJ_USED + 1)
-#endif
-
 struct zs_size_stat {
 	unsigned long objs[NR_ZS_STAT_TYPE];
 };
@@ -184,6 +166,10 @@ struct zs_size_stat {
 static struct dentry *zs_stat_root;
 #endif
 
+#ifdef CONFIG_COMPACTION
+static struct vfsmount *zsmalloc_mnt;
+#endif
+
 /*
  * number of size_classes
  */
@@ -207,35 +193,49 @@ static const int fullness_threshold_frac = 4;
 
 struct size_class {
 	spinlock_t lock;
-	struct page *fullness_list[_ZS_NR_FULLNESS_GROUPS];
+	struct list_head fullness_list[NR_ZS_FULLNESS];
 	/*
 	 * Size of objects stored in this class. Must be multiple
 	 * of ZS_ALIGN.
 	 */
 	int size;
-	unsigned int index;
-
-	struct zs_size_stat stats;
-
+	int objs_per_zspage;
 	/* Number of PAGE_SIZE sized pages to combine to form a 'zspage' */
 	int pages_per_zspage;
-	/* huge object: pages_per_zspage == 1 && maxobj_per_zspage == 1 */
-	bool huge;
+
+	unsigned int index;
+	struct zs_size_stat stats;
 };
 
+/* huge object: pages_per_zspage == 1 && maxobj_per_zspage == 1 */
+static void SetPageHugeObject(struct page *page)
+{
+	SetPageOwnerPriv1(page);
+}
+
+static void ClearPageHugeObject(struct page *page)
+{
+	ClearPageOwnerPriv1(page);
+}
+
+static int PageHugeObject(struct page *page)
+{
+	return PageOwnerPriv1(page);
+}
+
 /*
  * Placed within free objects to form a singly linked list.
- * For every zspage, first_page->freelist gives head of this list.
+ * For every zspage, zspage->freeobj gives head of this list.
  *
  * This must be power of 2 and less than or equal to ZS_ALIGN
  */
 struct link_free {
 	union {
 		/*
-		 * Position of next free chunk (encodes <PFN, obj_idx>)
+		 * Free object index;
 		 * It's valid for non-allocated object
 		 */
-		void *next;
+		unsigned long next;
 		/*
 		 * Handle of allocated object.
 		 */
@@ -248,6 +248,7 @@ struct zs_pool {
 
 	struct size_class **size_class;
 	struct kmem_cache *handle_cachep;
+	struct kmem_cache *zspage_cachep;
 
 	atomic_long_t pages_allocated;
 
@@ -263,16 +264,36 @@ struct zs_pool {
 #ifdef CONFIG_ZSMALLOC_STAT
 	struct dentry *stat_dentry;
 #endif
+#ifdef CONFIG_COMPACTION
+	struct inode *inode;
+	struct work_struct free_work;
+#endif
 };
 
 /*
  * A zspage's class index and fullness group
  * are encoded in its (first)page->mapping
  */
-#define CLASS_IDX_BITS	28
-#define FULLNESS_BITS	4
-#define CLASS_IDX_MASK	((1 << CLASS_IDX_BITS) - 1)
-#define FULLNESS_MASK	((1 << FULLNESS_BITS) - 1)
+#define FULLNESS_BITS	2
+#define CLASS_BITS	8
+#define ISOLATED_BITS	3
+#define MAGIC_VAL_BITS	8
+
+struct zspage {
+	struct {
+		unsigned int fullness:FULLNESS_BITS;
+		unsigned int class:CLASS_BITS;
+		unsigned int isolated:ISOLATED_BITS;
+		unsigned int magic:MAGIC_VAL_BITS;
+	};
+	unsigned int inuse;
+	unsigned int freeobj;
+	struct page *first_page;
+	struct list_head list; /* fullness list */
+#ifdef CONFIG_COMPACTION
+	rwlock_t lock;
+#endif
+};
 
 struct mapping_area {
 #ifdef CONFIG_PGTABLE_MAPPING
@@ -284,29 +305,74 @@ struct mapping_area {
 	enum zs_mapmode vm_mm; /* mapping mode */
 };
 
-static int create_handle_cache(struct zs_pool *pool)
+#ifdef CONFIG_COMPACTION
+static int zs_register_migration(struct zs_pool *pool);
+static void zs_unregister_migration(struct zs_pool *pool);
+static void migrate_lock_init(struct zspage *zspage);
+static void migrate_read_lock(struct zspage *zspage);
+static void migrate_read_unlock(struct zspage *zspage);
+static void kick_deferred_free(struct zs_pool *pool);
+static void init_deferred_free(struct zs_pool *pool);
+static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage);
+#else
+static int zsmalloc_mount(void) { return 0; }
+static void zsmalloc_unmount(void) {}
+static int zs_register_migration(struct zs_pool *pool) { return 0; }
+static void zs_unregister_migration(struct zs_pool *pool) {}
+static void migrate_lock_init(struct zspage *zspage) {}
+static void migrate_read_lock(struct zspage *zspage) {}
+static void migrate_read_unlock(struct zspage *zspage) {}
+static void kick_deferred_free(struct zs_pool *pool) {}
+static void init_deferred_free(struct zs_pool *pool) {}
+static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage) {}
+#endif
+
+static int create_cache(struct zs_pool *pool)
 {
 	pool->handle_cachep = kmem_cache_create("zs_handle", ZS_HANDLE_SIZE,
 					0, 0, NULL);
-	return pool->handle_cachep ? 0 : 1;
+	if (!pool->handle_cachep)
+		return 1;
+
+	pool->zspage_cachep = kmem_cache_create("zspage", sizeof(struct zspage),
+					0, 0, NULL);
+	if (!pool->zspage_cachep) {
+		kmem_cache_destroy(pool->handle_cachep);
+		pool->handle_cachep = NULL;
+		return 1;
+	}
+
+	return 0;
 }
 
-static void destroy_handle_cache(struct zs_pool *pool)
+static void destroy_cache(struct zs_pool *pool)
 {
 	kmem_cache_destroy(pool->handle_cachep);
+	kmem_cache_destroy(pool->zspage_cachep);
 }
 
-static unsigned long alloc_handle(struct zs_pool *pool, gfp_t gfp)
+static unsigned long cache_alloc_handle(struct zs_pool *pool, gfp_t gfp)
 {
 	return (unsigned long)kmem_cache_alloc(pool->handle_cachep,
-			gfp & ~__GFP_HIGHMEM);
+			gfp & ~(__GFP_HIGHMEM|__GFP_MOVABLE));
 }
 
-static void free_handle(struct zs_pool *pool, unsigned long handle)
+static void cache_free_handle(struct zs_pool *pool, unsigned long handle)
 {
 	kmem_cache_free(pool->handle_cachep, (void *)handle);
 }
 
+static struct zspage *cache_alloc_zspage(struct zs_pool *pool, gfp_t flags)
+{
+	return kmem_cache_alloc(pool->zspage_cachep,
+			flags & ~(__GFP_HIGHMEM|__GFP_MOVABLE));
+};
+
+static void cache_free_zspage(struct zs_pool *pool, struct zspage *zspage)
+{
+	kmem_cache_free(pool->zspage_cachep, zspage);
+}
+
 static void record_obj(unsigned long handle, unsigned long obj)
 {
 	/*
@@ -409,38 +475,76 @@ static unsigned int get_maxobj_per_zspage(int size, int pages_per_zspage)
 /* per-cpu VM mapping areas for zspage accesses that cross page boundaries */
 static DEFINE_PER_CPU(struct mapping_area, zs_map_area);
 
+static bool is_zspage_isolated(struct zspage *zspage)
+{
+	return zspage->isolated;
+}
+
 static int is_first_page(struct page *page)
 {
 	return PagePrivate(page);
 }
 
-static int is_last_page(struct page *page)
+/* Protected by class->lock */
+static inline int get_zspage_inuse(struct zspage *zspage)
+{
+	return zspage->inuse;
+}
+
+static inline void set_zspage_inuse(struct zspage *zspage, int val)
+{
+	zspage->inuse = val;
+}
+
+static inline void mod_zspage_inuse(struct zspage *zspage, int val)
+{
+	zspage->inuse += val;
+}
+
+static inline struct page *get_first_page(struct zspage *zspage)
+{
+	struct page *first_page = zspage->first_page;
+
+	VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
+	return first_page;
+}
+
+static inline int get_first_obj_offset(struct page *page)
+{
+	return page->units;
+}
+
+static inline void set_first_obj_offset(struct page *page, int offset)
+{
+	page->units = offset;
+}
+
+static inline unsigned int get_freeobj(struct zspage *zspage)
+{
+	return zspage->freeobj;
+}
+
+static inline void set_freeobj(struct zspage *zspage, unsigned int obj)
 {
-	return PagePrivate2(page);
+	zspage->freeobj = obj;
 }
 
-static void get_zspage_mapping(struct page *first_page,
+static void get_zspage_mapping(struct zspage *zspage,
 				unsigned int *class_idx,
 				enum fullness_group *fullness)
 {
-	unsigned long m;
-	VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
+	BUG_ON(zspage->magic != ZSPAGE_MAGIC);
 
-	m = (unsigned long)first_page->mapping;
-	*fullness = m & FULLNESS_MASK;
-	*class_idx = (m >> FULLNESS_BITS) & CLASS_IDX_MASK;
+	*fullness = zspage->fullness;
+	*class_idx = zspage->class;
 }
 
-static void set_zspage_mapping(struct page *first_page,
+static void set_zspage_mapping(struct zspage *zspage,
 				unsigned int class_idx,
 				enum fullness_group fullness)
 {
-	unsigned long m;
-	VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
-
-	m = ((class_idx & CLASS_IDX_MASK) << FULLNESS_BITS) |
-			(fullness & FULLNESS_MASK);
-	first_page->mapping = (struct address_space *)m;
+	zspage->class = class_idx;
+	zspage->fullness = fullness;
 }
 
 /*
@@ -464,23 +568,19 @@ static int get_size_class_index(int size)
 static inline void zs_stat_inc(struct size_class *class,
 				enum zs_stat_type type, unsigned long cnt)
 {
-	if (type < NR_ZS_STAT_TYPE)
-		class->stats.objs[type] += cnt;
+	class->stats.objs[type] += cnt;
 }
 
 static inline void zs_stat_dec(struct size_class *class,
 				enum zs_stat_type type, unsigned long cnt)
 {
-	if (type < NR_ZS_STAT_TYPE)
-		class->stats.objs[type] -= cnt;
+	class->stats.objs[type] -= cnt;
 }
 
 static inline unsigned long zs_stat_get(struct size_class *class,
 				enum zs_stat_type type)
 {
-	if (type < NR_ZS_STAT_TYPE)
-		return class->stats.objs[type];
-	return 0;
+	return class->stats.objs[type];
 }
 
 #ifdef CONFIG_ZSMALLOC_STAT
@@ -624,6 +724,7 @@ static inline void zs_pool_stat_destroy(struct zs_pool *pool)
 }
 #endif
 
+
 /*
  * For each size class, zspages are divided into different groups
  * depending on how "full" they are. This was done so that we could
@@ -631,21 +732,20 @@ static inline void zs_pool_stat_destroy(struct zs_pool *pool)
  * the pool (not yet implemented). This function returns fullness
  * status of the given page.
  */
-static enum fullness_group get_fullness_group(struct page *first_page)
+static enum fullness_group get_fullness_group(struct size_class *class,
+						struct zspage *zspage)
 {
-	int inuse, max_objects;
+	int inuse, objs_per_zspage;
 	enum fullness_group fg;
 
-	VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
-
-	inuse = first_page->inuse;
-	max_objects = first_page->objects;
+	inuse = get_zspage_inuse(zspage);
+	objs_per_zspage = class->objs_per_zspage;
 
 	if (inuse == 0)
 		fg = ZS_EMPTY;
-	else if (inuse == max_objects)
+	else if (inuse == objs_per_zspage)
 		fg = ZS_FULL;
-	else if (inuse <= 3 * max_objects / fullness_threshold_frac)
+	else if (inuse <= 3 * objs_per_zspage / fullness_threshold_frac)
 		fg = ZS_ALMOST_EMPTY;
 	else
 		fg = ZS_ALMOST_FULL;
@@ -660,32 +760,25 @@ static enum fullness_group get_fullness_group(struct page *first_page)
  * identified by <class, fullness_group>.
  */
 static void insert_zspage(struct size_class *class,
-				enum fullness_group fullness,
-				struct page *first_page)
+				struct zspage *zspage,
+				enum fullness_group fullness)
 {
-	struct page **head;
-
-	VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
-
-	if (fullness >= _ZS_NR_FULLNESS_GROUPS)
-		return;
-
-	zs_stat_inc(class, fullness == ZS_ALMOST_EMPTY ?
-			CLASS_ALMOST_EMPTY : CLASS_ALMOST_FULL, 1);
-
-	head = &class->fullness_list[fullness];
-	if (!*head) {
-		*head = first_page;
-		return;
-	}
+	struct zspage *head;
 
+	zs_stat_inc(class, fullness, 1);
+	head = list_first_entry_or_null(&class->fullness_list[fullness],
+					struct zspage, list);
 	/*
-	 * We want to see more ZS_FULL pages and less almost
-	 * empty/full. Put pages with higher ->inuse first.
+	 * We want to see more ZS_FULL pages and less almost empty/full.
+	 * Put pages with higher ->inuse first.
 	 */
-	list_add_tail(&first_page->lru, &(*head)->lru);
-	if (first_page->inuse >= (*head)->inuse)
-		*head = first_page;
+	if (head) {
+		if (get_zspage_inuse(zspage) < get_zspage_inuse(head)) {
+			list_add(&zspage->list, &head->list);
+			return;
+		}
+	}
+	list_add(&zspage->list, &class->fullness_list[fullness]);
 }
 
 /*
@@ -693,27 +786,14 @@ static void insert_zspage(struct size_class *class,
  * by <class, fullness_group>.
  */
 static void remove_zspage(struct size_class *class,
-				enum fullness_group fullness,
-				struct page *first_page)
+				struct zspage *zspage,
+				enum fullness_group fullness)
 {
-	struct page **head;
-
-	VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
-
-	if (fullness >= _ZS_NR_FULLNESS_GROUPS)
-		return;
-
-	head = &class->fullness_list[fullness];
-	VM_BUG_ON_PAGE(!*head, first_page);
-	if (list_empty(&(*head)->lru))
-		*head = NULL;
-	else if (*head == first_page)
-		*head = (struct page *)list_entry((*head)->lru.next,
-					struct page, lru);
+	VM_BUG_ON(list_empty(&class->fullness_list[fullness]));
+	VM_BUG_ON(is_zspage_isolated(zspage));
 
-	list_del_init(&first_page->lru);
-	zs_stat_dec(class, fullness == ZS_ALMOST_EMPTY ?
-			CLASS_ALMOST_EMPTY : CLASS_ALMOST_FULL, 1);
+	list_del_init(&zspage->list);
+	zs_stat_dec(class, fullness, 1);
 }
 
 /*
@@ -726,19 +806,22 @@ static void remove_zspage(struct size_class *class,
  * fullness group.
  */
 static enum fullness_group fix_fullness_group(struct size_class *class,
-						struct page *first_page)
+						struct zspage *zspage)
 {
 	int class_idx;
 	enum fullness_group currfg, newfg;
 
-	get_zspage_mapping(first_page, &class_idx, &currfg);
-	newfg = get_fullness_group(first_page);
+	get_zspage_mapping(zspage, &class_idx, &currfg);
+	newfg = get_fullness_group(class, zspage);
 	if (newfg == currfg)
 		goto out;
 
-	remove_zspage(class, currfg, first_page);
-	insert_zspage(class, newfg, first_page);
-	set_zspage_mapping(first_page, class_idx, newfg);
+	if (!is_zspage_isolated(zspage)) {
+		remove_zspage(class, zspage, currfg);
+		insert_zspage(class, zspage, newfg);
+	}
+
+	set_zspage_mapping(zspage, class_idx, newfg);
 
 out:
 	return newfg;
@@ -780,64 +863,49 @@ static int get_pages_per_zspage(int class_size)
 	return max_usedpc_order;
 }
 
-/*
- * A single 'zspage' is composed of many system pages which are
- * linked together using fields in struct page. This function finds
- * the first/head page, given any component page of a zspage.
- */
-static struct page *get_first_page(struct page *page)
+static struct zspage *get_zspage(struct page *page)
 {
-	if (is_first_page(page))
-		return page;
-	else
-		return (struct page *)page_private(page);
+	struct zspage *zspage = (struct zspage *)page->private;
+
+	BUG_ON(zspage->magic != ZSPAGE_MAGIC);
+	return zspage;
 }
 
 static struct page *get_next_page(struct page *page)
 {
-	struct page *next;
+	if (unlikely(PageHugeObject(page)))
+		return NULL;
 
-	if (is_last_page(page))
-		next = NULL;
-	else if (is_first_page(page))
-		next = (struct page *)page_private(page);
-	else
-		next = list_entry(page->lru.next, struct page, lru);
+	return page->freelist;
+}
 
-	return next;
+/**
+ * obj_to_location - get (<page>, <obj_idx>) from encoded object value
+ * @page: page object resides in zspage
+ * @obj_idx: object index
+ */
+static void obj_to_location(unsigned long obj, struct page **page,
+				unsigned int *obj_idx)
+{
+	obj >>= OBJ_TAG_BITS;
+	*page = pfn_to_page(obj >> OBJ_INDEX_BITS);
+	*obj_idx = (obj & OBJ_INDEX_MASK);
 }
 
-/*
- * Encode <page, obj_idx> as a single handle value.
- * We use the least bit of handle for tagging.
+/**
+ * location_to_obj - get obj value encoded from (<page>, <obj_idx>)
+ * @page: page object resides in zspage
+ * @obj_idx: object index
  */
-static void *location_to_obj(struct page *page, unsigned long obj_idx)
+static unsigned long location_to_obj(struct page *page, unsigned int obj_idx)
 {
 	unsigned long obj;
 
-	if (!page) {
-		VM_BUG_ON(obj_idx);
-		return NULL;
-	}
-
 	obj = page_to_pfn(page) << OBJ_INDEX_BITS;
-	obj |= ((obj_idx) & OBJ_INDEX_MASK);
+	obj |= obj_idx & OBJ_INDEX_MASK;
 	obj <<= OBJ_TAG_BITS;
 
-	return (void *)obj;
-}
-
-/*
- * Decode <page, obj_idx> pair from the given object handle. We adjust the
- * decoded obj_idx back to its original value since it was adjusted in
- * location_to_obj().
- */
-static void obj_to_location(unsigned long obj, struct page **page,
-				unsigned long *obj_idx)
-{
-	obj >>= OBJ_TAG_BITS;
-	*page = pfn_to_page(obj >> OBJ_INDEX_BITS);
-	*obj_idx = (obj & OBJ_INDEX_MASK);
+	return obj;
 }
 
 static unsigned long handle_to_obj(unsigned long handle)
@@ -845,109 +913,147 @@ static unsigned long handle_to_obj(unsigned long handle)
 	return *(unsigned long *)handle;
 }
 
-static unsigned long obj_to_head(struct size_class *class, struct page *page,
-			void *obj)
+static unsigned long obj_to_head(struct page *page, void *obj)
 {
-	if (class->huge) {
+	if (unlikely(PageHugeObject(page))) {
 		VM_BUG_ON_PAGE(!is_first_page(page), page);
-		return page_private(page);
+		return page->index;
 	} else
 		return *(unsigned long *)obj;
 }
 
-static unsigned long obj_idx_to_offset(struct page *page,
-				unsigned long obj_idx, int class_size)
+static inline int testpin_tag(unsigned long handle)
 {
-	unsigned long off = 0;
-
-	if (!is_first_page(page))
-		off = page->index;
-
-	return off + obj_idx * class_size;
+	return bit_spin_is_locked(HANDLE_PIN_BIT, (unsigned long *)handle);
 }
 
 static inline int trypin_tag(unsigned long handle)
 {
-	unsigned long *ptr = (unsigned long *)handle;
-
-	return !test_and_set_bit_lock(HANDLE_PIN_BIT, ptr);
+	return bit_spin_trylock(HANDLE_PIN_BIT, (unsigned long *)handle);
 }
 
 static void pin_tag(unsigned long handle)
 {
-	while (!trypin_tag(handle));
+	bit_spin_lock(HANDLE_PIN_BIT, (unsigned long *)handle);
 }
 
 static void unpin_tag(unsigned long handle)
 {
-	unsigned long *ptr = (unsigned long *)handle;
-
-	clear_bit_unlock(HANDLE_PIN_BIT, ptr);
+	bit_spin_unlock(HANDLE_PIN_BIT, (unsigned long *)handle);
 }
 
 static void reset_page(struct page *page)
 {
+	__ClearPageMovable(page);
 	clear_bit(PG_private, &page->flags);
 	clear_bit(PG_private_2, &page->flags);
 	set_page_private(page, 0);
-	page->mapping = NULL;
-	page->freelist = NULL;
 	page_mapcount_reset(page);
+	ClearPageHugeObject(page);
+	page->freelist = NULL;
+}
+
+/*
+ * To prevent zspage destroy during migration, zspage freeing should
+ * hold locks of all pages in the zspage.
+ */
+void lock_zspage(struct zspage *zspage)
+{
+	struct page *page = get_first_page(zspage);
+
+	do {
+		lock_page(page);
+	} while ((page = get_next_page(page)) != NULL);
 }
 
-static void free_zspage(struct page *first_page)
+int trylock_zspage(struct zspage *zspage)
 {
-	struct page *nextp, *tmp, *head_extra;
+	struct page *cursor, *fail;
 
-	VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
-	VM_BUG_ON_PAGE(first_page->inuse, first_page);
+	for (cursor = get_first_page(zspage); cursor != NULL; cursor =
+					get_next_page(cursor)) {
+		if (!trylock_page(cursor)) {
+			fail = cursor;
+			goto unlock;
+		}
+	}
 
-	head_extra = (struct page *)page_private(first_page);
+	return 1;
+unlock:
+	for (cursor = get_first_page(zspage); cursor != fail; cursor =
+					get_next_page(cursor))
+		unlock_page(cursor);
 
-	reset_page(first_page);
-	__free_page(first_page);
+	return 0;
+}
 
-	/* zspage with only 1 system page */
-	if (!head_extra)
-		return;
+static void __free_zspage(struct zs_pool *pool, struct size_class *class,
+				struct zspage *zspage)
+{
+	struct page *page, *next;
+	enum fullness_group fg;
+	unsigned int class_idx;
 
-	list_for_each_entry_safe(nextp, tmp, &head_extra->lru, lru) {
-		list_del(&nextp->lru);
-		reset_page(nextp);
-		__free_page(nextp);
+	get_zspage_mapping(zspage, &class_idx, &fg);
+
+	assert_spin_locked(&class->lock);
+
+	VM_BUG_ON(get_zspage_inuse(zspage));
+	VM_BUG_ON(fg != ZS_EMPTY);
+
+	next = page = get_first_page(zspage);
+	do {
+		VM_BUG_ON_PAGE(!PageLocked(page), page);
+		next = get_next_page(page);
+		reset_page(page);
+		unlock_page(page);
+		dec_zone_page_state(page, NR_ZSPAGES);
+		put_page(page);
+		page = next;
+	} while (page != NULL);
+
+	cache_free_zspage(pool, zspage);
+
+	zs_stat_dec(class, OBJ_ALLOCATED, get_maxobj_per_zspage(
+			class->size, class->pages_per_zspage));
+	atomic_long_sub(class->pages_per_zspage,
+					&pool->pages_allocated);
+}
+
+static void free_zspage(struct zs_pool *pool, struct size_class *class,
+				struct zspage *zspage)
+{
+	VM_BUG_ON(get_zspage_inuse(zspage));
+	VM_BUG_ON(list_empty(&zspage->list));
+
+	if (!trylock_zspage(zspage)) {
+		kick_deferred_free(pool);
+		return;
 	}
-	reset_page(head_extra);
-	__free_page(head_extra);
+
+	remove_zspage(class, zspage, ZS_EMPTY);
+	__free_zspage(pool, class, zspage);
 }
 
 /* Initialize a newly allocated zspage */
-static void init_zspage(struct size_class *class, struct page *first_page)
+static void init_zspage(struct size_class *class, struct zspage *zspage)
 {
+	unsigned int freeobj = 1;
 	unsigned long off = 0;
-	struct page *page = first_page;
-
-	VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
+	struct page *page = get_first_page(zspage);
 
 	while (page) {
 		struct page *next_page;
 		struct link_free *link;
-		unsigned int i = 1;
 		void *vaddr;
 
-		/*
-		 * page->index stores offset of first object starting
-		 * in the page. For the first page, this is always 0,
-		 * so we use first_page->index (aka ->freelist) to store
-		 * head of corresponding zspage's freelist.
-		 */
-		if (page != first_page)
-			page->index = off;
+		set_first_obj_offset(page, off);
 
 		vaddr = kmap_atomic(page);
 		link = (struct link_free *)vaddr + off / sizeof(*link);
 
 		while ((off += class->size) < PAGE_SIZE) {
-			link->next = location_to_obj(page, i++);
+			link->next = freeobj++ << OBJ_TAG_BITS;
 			link += class->size / sizeof(*link);
 		}
 
@@ -957,87 +1063,112 @@ static void init_zspage(struct size_class *class, struct page *first_page)
 		 * page (if present)
 		 */
 		next_page = get_next_page(page);
-		link->next = location_to_obj(next_page, 0);
+		if (next_page) {
+			link->next = freeobj++ << OBJ_TAG_BITS;
+		} else {
+			/*
+			 * Reset OBJ_TAG_BITS bit to last link to tell
+			 * whether it's allocated object or not.
+			 */
+			link->next = -1 << OBJ_TAG_BITS;
+		}
 		kunmap_atomic(vaddr);
 		page = next_page;
 		off %= PAGE_SIZE;
 	}
+
+	set_freeobj(zspage, 0);
 }
 
-/*
- * Allocate a zspage for the given size class
- */
-static struct page *alloc_zspage(struct size_class *class, gfp_t flags)
+static void create_page_chain(struct size_class *class, struct zspage *zspage,
+				struct page *pages[])
 {
-	int i, error;
-	struct page *first_page = NULL, *uninitialized_var(prev_page);
+	int i;
+	struct page *page;
+	struct page *prev_page = NULL;
+	int nr_pages = class->pages_per_zspage;
 
 	/*
 	 * Allocate individual pages and link them together as:
-	 * 1. first page->private = first sub-page
-	 * 2. all sub-pages are linked together using page->lru
-	 * 3. each sub-page is linked to the first page using page->private
+	 * 1. all pages are linked together using page->freelist
+	 * 2. each sub-page point to zspage using page->private
 	 *
-	 * For each size class, First/Head pages are linked together using
-	 * page->lru. Also, we set PG_private to identify the first page
-	 * (i.e. no other sub-page has this flag set) and PG_private_2 to
-	 * identify the last page.
+	 * we set PG_private to identify the first page (i.e. no other sub-page
+	 * has this flag set) and PG_private_2 to identify the last page.
 	 */
-	error = -ENOMEM;
-	for (i = 0; i < class->pages_per_zspage; i++) {
-		struct page *page;
-
-		page = alloc_page(flags);
-		if (!page)
-			goto cleanup;
-
-		INIT_LIST_HEAD(&page->lru);
-		if (i == 0) {	/* first page */
+	for (i = 0; i < nr_pages; i++) {
+		page = pages[i];
+		set_page_private(page, (unsigned long)zspage);
+		page->freelist = NULL;
+		if (i == 0) {
+			zspage->first_page = page;
 			SetPagePrivate(page);
-			set_page_private(page, 0);
-			first_page = page;
-			first_page->inuse = 0;
+			if (unlikely(class->objs_per_zspage == 1 &&
+					class->pages_per_zspage == 1))
+				SetPageHugeObject(page);
+		} else {
+			prev_page->freelist = page;
 		}
-		if (i == 1)
-			set_page_private(first_page, (unsigned long)page);
-		if (i >= 1)
-			set_page_private(page, (unsigned long)first_page);
-		if (i >= 2)
-			list_add(&page->lru, &prev_page->lru);
-		if (i == class->pages_per_zspage - 1)	/* last page */
+		if (i == nr_pages - 1)
 			SetPagePrivate2(page);
 		prev_page = page;
 	}
+}
+
+/*
+ * Allocate a zspage for the given size class
+ */
+static struct zspage *alloc_zspage(struct zs_pool *pool,
+					struct size_class *class,
+					gfp_t gfp)
+{
+	int i;
+	struct page *pages[ZS_MAX_PAGES_PER_ZSPAGE];
+	struct zspage *zspage = cache_alloc_zspage(pool, gfp);
+
+	if (!zspage)
+		return NULL;
 
-	init_zspage(class, first_page);
+	memset(zspage, 0, sizeof(struct zspage));
+	zspage->magic = ZSPAGE_MAGIC;
+	migrate_lock_init(zspage);
 
-	first_page->freelist = location_to_obj(first_page, 0);
-	/* Maximum number of objects we can store in this zspage */
-	first_page->objects = class->pages_per_zspage * PAGE_SIZE / class->size;
+	for (i = 0; i < class->pages_per_zspage; i++) {
+		struct page *page;
 
-	error = 0; /* Success */
+		page = alloc_page(gfp);
+		if (!page) {
+			while (--i >= 0) {
+				dec_zone_page_state(pages[i], NR_ZSPAGES);
+				__free_page(pages[i]);
+			}
+			cache_free_zspage(pool, zspage);
+			return NULL;
+		}
 
-cleanup:
-	if (unlikely(error) && first_page) {
-		free_zspage(first_page);
-		first_page = NULL;
+		inc_zone_page_state(page, NR_ZSPAGES);
+		pages[i] = page;
 	}
 
-	return first_page;
+	create_page_chain(class, zspage, pages);
+	init_zspage(class, zspage);
+
+	return zspage;
 }
 
-static struct page *find_get_zspage(struct size_class *class)
+static struct zspage *find_get_zspage(struct size_class *class)
 {
 	int i;
-	struct page *page;
+	struct zspage *zspage;
 
-	for (i = 0; i < _ZS_NR_FULLNESS_GROUPS; i++) {
-		page = class->fullness_list[i];
-		if (page)
+	for (i = ZS_ALMOST_FULL; i >= ZS_EMPTY; i--) {
+		zspage = list_first_entry_or_null(&class->fullness_list[i],
+				struct zspage, list);
+		if (zspage)
 			break;
 	}
 
-	return page;
+	return zspage;
 }
 
 #ifdef CONFIG_PGTABLE_MAPPING
@@ -1242,11 +1373,9 @@ static bool can_merge(struct size_class *prev, int size, int pages_per_zspage)
 	return true;
 }
 
-static bool zspage_full(struct page *first_page)
+static bool zspage_full(struct size_class *class, struct zspage *zspage)
 {
-	VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
-
-	return first_page->inuse == first_page->objects;
+	return get_zspage_inuse(zspage) == class->objs_per_zspage;
 }
 
 unsigned long zs_get_total_pages(struct zs_pool *pool)
@@ -1272,8 +1401,10 @@ EXPORT_SYMBOL_GPL(zs_get_total_pages);
 void *zs_map_object(struct zs_pool *pool, unsigned long handle,
 			enum zs_mapmode mm)
 {
+	struct zspage *zspage;
 	struct page *page;
-	unsigned long obj, obj_idx, off;
+	unsigned long obj, off;
+	unsigned int obj_idx;
 
 	unsigned int class_idx;
 	enum fullness_group fg;
@@ -1294,9 +1425,14 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle,
 
 	obj = handle_to_obj(handle);
 	obj_to_location(obj, &page, &obj_idx);
-	get_zspage_mapping(get_first_page(page), &class_idx, &fg);
+	zspage = get_zspage(page);
+
+	/* migration cannot move any subpage in this zspage */
+	migrate_read_lock(zspage);
+
+	get_zspage_mapping(zspage, &class_idx, &fg);
 	class = pool->size_class[class_idx];
-	off = obj_idx_to_offset(page, obj_idx, class->size);
+	off = (class->size * obj_idx) & ~PAGE_MASK;
 
 	area = &get_cpu_var(zs_map_area);
 	area->vm_mm = mm;
@@ -1314,7 +1450,7 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle,
 
 	ret = __zs_map_object(area, pages, off, class->size);
 out:
-	if (!class->huge)
+	if (likely(!PageHugeObject(page)))
 		ret += ZS_HANDLE_SIZE;
 
 	return ret;
@@ -1323,8 +1459,10 @@ EXPORT_SYMBOL_GPL(zs_map_object);
 
 void zs_unmap_object(struct zs_pool *pool, unsigned long handle)
 {
+	struct zspage *zspage;
 	struct page *page;
-	unsigned long obj, obj_idx, off;
+	unsigned long obj, off;
+	unsigned int obj_idx;
 
 	unsigned int class_idx;
 	enum fullness_group fg;
@@ -1333,9 +1471,10 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle)
 
 	obj = handle_to_obj(handle);
 	obj_to_location(obj, &page, &obj_idx);
-	get_zspage_mapping(get_first_page(page), &class_idx, &fg);
+	zspage = get_zspage(page);
+	get_zspage_mapping(zspage, &class_idx, &fg);
 	class = pool->size_class[class_idx];
-	off = obj_idx_to_offset(page, obj_idx, class->size);
+	off = (class->size * obj_idx) & ~PAGE_MASK;
 
 	area = this_cpu_ptr(&zs_map_area);
 	if (off + class->size <= PAGE_SIZE)
@@ -1350,38 +1489,50 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle)
 		__zs_unmap_object(area, pages, off, class->size);
 	}
 	put_cpu_var(zs_map_area);
+
+	migrate_read_unlock(zspage);
 	unpin_tag(handle);
 }
 EXPORT_SYMBOL_GPL(zs_unmap_object);
 
 static unsigned long obj_malloc(struct size_class *class,
-				struct page *first_page, unsigned long handle)
+				struct zspage *zspage, unsigned long handle)
 {
+	int i, nr_page, offset;
 	unsigned long obj;
 	struct link_free *link;
 
 	struct page *m_page;
-	unsigned long m_objidx, m_offset;
+	unsigned long m_offset;
 	void *vaddr;
 
 	handle |= OBJ_ALLOCATED_TAG;
-	obj = (unsigned long)first_page->freelist;
-	obj_to_location(obj, &m_page, &m_objidx);
-	m_offset = obj_idx_to_offset(m_page, m_objidx, class->size);
+	obj = get_freeobj(zspage);
+
+	offset = obj * class->size;
+	nr_page = offset >> PAGE_SHIFT;
+	m_offset = offset & ~PAGE_MASK;
+	m_page = get_first_page(zspage);
+
+	for (i = 0; i < nr_page; i++)
+		m_page = get_next_page(m_page);
 
 	vaddr = kmap_atomic(m_page);
 	link = (struct link_free *)vaddr + m_offset / sizeof(*link);
-	first_page->freelist = link->next;
-	if (!class->huge)
+	set_freeobj(zspage, link->next >> OBJ_TAG_BITS);
+	if (likely(!PageHugeObject(m_page)))
 		/* record handle in the header of allocated chunk */
 		link->handle = handle;
 	else
-		/* record handle in first_page->private */
-		set_page_private(first_page, handle);
+		/* record handle to page->index */
+		zspage->first_page->index = handle;
+
 	kunmap_atomic(vaddr);
-	first_page->inuse++;
+	mod_zspage_inuse(zspage, 1);
 	zs_stat_inc(class, OBJ_USED, 1);
 
+	obj = location_to_obj(m_page, obj);
+
 	return obj;
 }
 
@@ -1399,12 +1550,13 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t size, gfp_t gfp)
 {
 	unsigned long handle, obj;
 	struct size_class *class;
-	struct page *first_page;
+	enum fullness_group newfg;
+	struct zspage *zspage;
 
 	if (unlikely(!size || size > ZS_MAX_ALLOC_SIZE))
 		return 0;
 
-	handle = alloc_handle(pool, gfp);
+	handle = cache_alloc_handle(pool, gfp);
 	if (!handle)
 		return 0;
 
@@ -1413,29 +1565,38 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t size, gfp_t gfp)
 	class = pool->size_class[get_size_class_index(size)];
 
 	spin_lock(&class->lock);
-	first_page = find_get_zspage(class);
-
-	if (!first_page) {
+	zspage = find_get_zspage(class);
+	if (likely(zspage)) {
+		obj = obj_malloc(class, zspage, handle);
+		/* Now move the zspage to another fullness group, if required */
+		fix_fullness_group(class, zspage);
+		record_obj(handle, obj);
 		spin_unlock(&class->lock);
-		first_page = alloc_zspage(class, gfp);
-		if (unlikely(!first_page)) {
-			free_handle(pool, handle);
-			return 0;
-		}
 
-		set_zspage_mapping(first_page, class->index, ZS_EMPTY);
-		atomic_long_add(class->pages_per_zspage,
-					&pool->pages_allocated);
+		return handle;
+	}
 
-		spin_lock(&class->lock);
-		zs_stat_inc(class, OBJ_ALLOCATED, get_maxobj_per_zspage(
-				class->size, class->pages_per_zspage));
+	spin_unlock(&class->lock);
+
+	zspage = alloc_zspage(pool, class, gfp);
+	if (!zspage) {
+		cache_free_handle(pool, handle);
+		return 0;
 	}
 
-	obj = obj_malloc(class, first_page, handle);
-	/* Now move the zspage to another fullness group, if required */
-	fix_fullness_group(class, first_page);
+	spin_lock(&class->lock);
+	obj = obj_malloc(class, zspage, handle);
+	newfg = get_fullness_group(class, zspage);
+	insert_zspage(class, zspage, newfg);
+	set_zspage_mapping(zspage, class->index, newfg);
 	record_obj(handle, obj);
+	atomic_long_add(class->pages_per_zspage,
+				&pool->pages_allocated);
+	zs_stat_inc(class, OBJ_ALLOCATED, get_maxobj_per_zspage(
+			class->size, class->pages_per_zspage));
+
+	/* We completely set up zspage so mark them as movable */
+	SetZsPageMovable(pool, zspage);
 	spin_unlock(&class->lock);
 
 	return handle;
@@ -1445,36 +1606,38 @@ EXPORT_SYMBOL_GPL(zs_malloc);
 static void obj_free(struct size_class *class, unsigned long obj)
 {
 	struct link_free *link;
-	struct page *first_page, *f_page;
-	unsigned long f_objidx, f_offset;
+	struct zspage *zspage;
+	struct page *f_page;
+	unsigned long f_offset;
+	unsigned int f_objidx;
 	void *vaddr;
 
 	obj &= ~OBJ_ALLOCATED_TAG;
 	obj_to_location(obj, &f_page, &f_objidx);
-	first_page = get_first_page(f_page);
-
-	f_offset = obj_idx_to_offset(f_page, f_objidx, class->size);
+	f_offset = (class->size * f_objidx) & ~PAGE_MASK;
+	zspage = get_zspage(f_page);
 
 	vaddr = kmap_atomic(f_page);
 
 	/* Insert this object in containing zspage's freelist */
 	link = (struct link_free *)(vaddr + f_offset);
-	link->next = first_page->freelist;
-	if (class->huge)
-		set_page_private(first_page, 0);
+	link->next = get_freeobj(zspage) << OBJ_TAG_BITS;
 	kunmap_atomic(vaddr);
-	first_page->freelist = (void *)obj;
-	first_page->inuse--;
+	set_freeobj(zspage, f_objidx);
+	mod_zspage_inuse(zspage, -1);
 	zs_stat_dec(class, OBJ_USED, 1);
 }
 
 void zs_free(struct zs_pool *pool, unsigned long handle)
 {
-	struct page *first_page, *f_page;
-	unsigned long obj, f_objidx;
+	struct zspage *zspage;
+	struct page *f_page;
+	unsigned long obj;
+	unsigned int f_objidx;
 	int class_idx;
 	struct size_class *class;
 	enum fullness_group fullness;
+	bool isolated;
 
 	if (unlikely(!handle))
 		return;
@@ -1482,25 +1645,31 @@ void zs_free(struct zs_pool *pool, unsigned long handle)
 	pin_tag(handle);
 	obj = handle_to_obj(handle);
 	obj_to_location(obj, &f_page, &f_objidx);
-	first_page = get_first_page(f_page);
+	zspage = get_zspage(f_page);
 
-	get_zspage_mapping(first_page, &class_idx, &fullness);
+	migrate_read_lock(zspage);
+
+	get_zspage_mapping(zspage, &class_idx, &fullness);
 	class = pool->size_class[class_idx];
 
 	spin_lock(&class->lock);
 	obj_free(class, obj);
-	fullness = fix_fullness_group(class, first_page);
-	if (fullness == ZS_EMPTY) {
-		zs_stat_dec(class, OBJ_ALLOCATED, get_maxobj_per_zspage(
-				class->size, class->pages_per_zspage));
-		atomic_long_sub(class->pages_per_zspage,
-				&pool->pages_allocated);
-		free_zspage(first_page);
+	fullness = fix_fullness_group(class, zspage);
+	if (fullness != ZS_EMPTY) {
+		migrate_read_unlock(zspage);
+		goto out;
 	}
+
+	isolated = is_zspage_isolated(zspage);
+	migrate_read_unlock(zspage);
+	/* If zspage is isolated, zs_page_putback will free the zspage */
+	if (likely(!isolated))
+		free_zspage(pool, class, zspage);
+out:
+
 	spin_unlock(&class->lock);
 	unpin_tag(handle);
-
-	free_handle(pool, handle);
+	cache_free_handle(pool, handle);
 }
 EXPORT_SYMBOL_GPL(zs_free);
 
@@ -1508,7 +1677,7 @@ static void zs_object_copy(struct size_class *class, unsigned long dst,
 				unsigned long src)
 {
 	struct page *s_page, *d_page;
-	unsigned long s_objidx, d_objidx;
+	unsigned int s_objidx, d_objidx;
 	unsigned long s_off, d_off;
 	void *s_addr, *d_addr;
 	int s_size, d_size, size;
@@ -1519,8 +1688,8 @@ static void zs_object_copy(struct size_class *class, unsigned long dst,
 	obj_to_location(src, &s_page, &s_objidx);
 	obj_to_location(dst, &d_page, &d_objidx);
 
-	s_off = obj_idx_to_offset(s_page, s_objidx, class->size);
-	d_off = obj_idx_to_offset(d_page, d_objidx, class->size);
+	s_off = (class->size * s_objidx) & ~PAGE_MASK;
+	d_off = (class->size * d_objidx) & ~PAGE_MASK;
 
 	if (s_off + class->size > PAGE_SIZE)
 		s_size = PAGE_SIZE - s_off;
@@ -1579,12 +1748,11 @@ static unsigned long find_alloced_obj(struct size_class *class,
 	unsigned long handle = 0;
 	void *addr = kmap_atomic(page);
 
-	if (!is_first_page(page))
-		offset = page->index;
+	offset = get_first_obj_offset(page);
 	offset += class->size * index;
 
 	while (offset < PAGE_SIZE) {
-		head = obj_to_head(class, page, addr + offset);
+		head = obj_to_head(page, addr + offset);
 		if (head & OBJ_ALLOCATED_TAG) {
 			handle = head & ~OBJ_ALLOCATED_TAG;
 			if (trypin_tag(handle))
@@ -1601,7 +1769,7 @@ static unsigned long find_alloced_obj(struct size_class *class,
 }
 
 struct zs_compact_control {
-	/* Source page for migration which could be a subpage of zspage. */
+	/* Source spage for migration which could be a subpage of zspage */
 	struct page *s_page;
 	/* Destination page for migration which should be a first page
 	 * of zspage. */
@@ -1632,14 +1800,14 @@ static int migrate_zspage(struct zs_pool *pool, struct size_class *class,
 		}
 
 		/* Stop if there is no more space */
-		if (zspage_full(d_page)) {
+		if (zspage_full(class, get_zspage(d_page))) {
 			unpin_tag(handle);
 			ret = -ENOMEM;
 			break;
 		}
 
 		used_obj = handle_to_obj(handle);
-		free_obj = obj_malloc(class, d_page, handle);
+		free_obj = obj_malloc(class, get_zspage(d_page), handle);
 		zs_object_copy(class, free_obj, used_obj);
 		index++;
 		/*
@@ -1661,68 +1829,422 @@ static int migrate_zspage(struct zs_pool *pool, struct size_class *class,
 	return ret;
 }
 
-static struct page *isolate_target_page(struct size_class *class)
+static struct zspage *isolate_zspage(struct size_class *class, bool source)
 {
 	int i;
-	struct page *page;
+	struct zspage *zspage;
+	enum fullness_group fg[2] = {ZS_ALMOST_EMPTY, ZS_ALMOST_FULL};
 
-	for (i = 0; i < _ZS_NR_FULLNESS_GROUPS; i++) {
-		page = class->fullness_list[i];
-		if (page) {
-			remove_zspage(class, i, page);
-			break;
+	if (!source) {
+		fg[0] = ZS_ALMOST_FULL;
+		fg[1] = ZS_ALMOST_EMPTY;
+	}
+
+	for (i = 0; i < 2; i++) {
+		zspage = list_first_entry_or_null(&class->fullness_list[fg[i]],
+							struct zspage, list);
+		if (zspage) {
+			VM_BUG_ON(is_zspage_isolated(zspage));
+			remove_zspage(class, zspage, fg[i]);
+			return zspage;
 		}
 	}
 
-	return page;
+	return zspage;
 }
 
 /*
- * putback_zspage - add @first_page into right class's fullness list
- * @pool: target pool
+ * putback_zspage - add @zspage into right class's fullness list
  * @class: destination class
- * @first_page: target page
+ * @zspage: target page
  *
- * Return @fist_page's fullness_group
+ * Return @zspage's fullness_group
  */
-static enum fullness_group putback_zspage(struct zs_pool *pool,
-			struct size_class *class,
-			struct page *first_page)
+static enum fullness_group putback_zspage(struct size_class *class,
+			struct zspage *zspage)
 {
 	enum fullness_group fullness;
 
-	fullness = get_fullness_group(first_page);
-	insert_zspage(class, fullness, first_page);
-	set_zspage_mapping(first_page, class->index, fullness);
+	VM_BUG_ON(is_zspage_isolated(zspage));
 
-	if (fullness == ZS_EMPTY) {
-		zs_stat_dec(class, OBJ_ALLOCATED, get_maxobj_per_zspage(
-			class->size, class->pages_per_zspage));
-		atomic_long_sub(class->pages_per_zspage,
-				&pool->pages_allocated);
+	fullness = get_fullness_group(class, zspage);
+	insert_zspage(class, zspage, fullness);
+	set_zspage_mapping(zspage, class->index, fullness);
+
+	return fullness;
+}
+
+#ifdef CONFIG_COMPACTION
+static struct dentry *zs_mount(struct file_system_type *fs_type,
+				int flags, const char *dev_name, void *data)
+{
+	static const struct dentry_operations ops = {
+		.d_dname = simple_dname,
+	};
+
+	return mount_pseudo(fs_type, "zsmalloc:", NULL, &ops, ZSMALLOC_MAGIC);
+}
+
+static struct file_system_type zsmalloc_fs = {
+	.name		= "zsmalloc",
+	.mount		= zs_mount,
+	.kill_sb	= kill_anon_super,
+};
+
+static int zsmalloc_mount(void)
+{
+	int ret = 0;
 
-		free_zspage(first_page);
+	zsmalloc_mnt = kern_mount(&zsmalloc_fs);
+	if (IS_ERR(zsmalloc_mnt))
+		ret = PTR_ERR(zsmalloc_mnt);
+
+	return ret;
+}
+
+static void zsmalloc_unmount(void)
+{
+	kern_unmount(zsmalloc_mnt);
+}
+
+static void migrate_lock_init(struct zspage *zspage)
+{
+	rwlock_init(&zspage->lock);
+}
+
+static void migrate_read_lock(struct zspage *zspage)
+{
+	read_lock(&zspage->lock);
+}
+
+static void migrate_read_unlock(struct zspage *zspage)
+{
+	read_unlock(&zspage->lock);
+}
+
+static void migrate_write_lock(struct zspage *zspage)
+{
+	write_lock(&zspage->lock);
+}
+
+static void migrate_write_unlock(struct zspage *zspage)
+{
+	write_unlock(&zspage->lock);
+}
+
+/* Number of isolated subpage for *page migration* in this zspage */
+static void inc_zspage_isolation(struct zspage *zspage)
+{
+	zspage->isolated++;
+}
+
+static void dec_zspage_isolation(struct zspage *zspage)
+{
+	zspage->isolated--;
+}
+
+static void replace_sub_page(struct size_class *class, struct zspage *zspage,
+				struct page *newpage, struct page *oldpage)
+{
+	struct page *page;
+	struct page *pages[ZS_MAX_PAGES_PER_ZSPAGE] = {NULL, };
+	int idx = 0;
+
+	page = get_first_page(zspage);
+	do {
+		if (page == oldpage)
+			pages[idx] = newpage;
+		else
+			pages[idx] = page;
+		idx++;
+	} while ((page = get_next_page(page)) != NULL);
+
+	create_page_chain(class, zspage, pages);
+	set_first_obj_offset(newpage, get_first_obj_offset(oldpage));
+	if (unlikely(PageHugeObject(oldpage)))
+		newpage->index = oldpage->index;
+	__SetPageMovable(newpage, page_mapping(oldpage));
+}
+
+bool zs_page_isolate(struct page *page, isolate_mode_t mode)
+{
+	struct zs_pool *pool;
+	struct size_class *class;
+	int class_idx;
+	enum fullness_group fullness;
+	struct zspage *zspage;
+	struct address_space *mapping;
+
+	/*
+	 * Page is locked so zspage couldn't be destroyed. For detail, look at
+	 * lock_zspage in free_zspage.
+	 */
+	VM_BUG_ON_PAGE(!PageMovable(page), page);
+	VM_BUG_ON_PAGE(PageIsolated(page), page);
+
+	zspage = get_zspage(page);
+
+	/*
+	 * Without class lock, fullness could be stale while class_idx is okay
+	 * because class_idx is constant unless page is freed so we should get
+	 * fullness again under class lock.
+	 */
+	get_zspage_mapping(zspage, &class_idx, &fullness);
+	mapping = page_mapping(page);
+	pool = mapping->private_data;
+	class = pool->size_class[class_idx];
+
+	spin_lock(&class->lock);
+	if (get_zspage_inuse(zspage) == 0) {
+		spin_unlock(&class->lock);
+		return false;
 	}
 
-	return fullness;
+	/* zspage is isolated for object migration */
+	if (list_empty(&zspage->list) && !is_zspage_isolated(zspage)) {
+		spin_unlock(&class->lock);
+		return false;
+	}
+
+	/*
+	 * If this is first time isolation for the zspage, isolate zspage from
+	 * size_class to prevent further object allocation from the zspage.
+	 */
+	if (!list_empty(&zspage->list) && !is_zspage_isolated(zspage)) {
+		get_zspage_mapping(zspage, &class_idx, &fullness);
+		remove_zspage(class, zspage, fullness);
+	}
+
+	inc_zspage_isolation(zspage);
+	spin_unlock(&class->lock);
+
+	return true;
 }
 
-static struct page *isolate_source_page(struct size_class *class)
+int zs_page_migrate(struct address_space *mapping, struct page *newpage,
+		struct page *page, enum migrate_mode mode)
+{
+	struct zs_pool *pool;
+	struct size_class *class;
+	int class_idx;
+	enum fullness_group fullness;
+	struct zspage *zspage;
+	struct page *dummy;
+	void *s_addr, *d_addr, *addr;
+	int offset, pos;
+	unsigned long handle, head;
+	unsigned long old_obj, new_obj;
+	unsigned int obj_idx;
+	int ret = -EAGAIN;
+
+	VM_BUG_ON_PAGE(!PageMovable(page), page);
+	VM_BUG_ON_PAGE(!PageIsolated(page), page);
+
+	zspage = get_zspage(page);
+
+	/* Concurrent compactor cannot migrate any subpage in zspage */
+	migrate_write_lock(zspage);
+	get_zspage_mapping(zspage, &class_idx, &fullness);
+	pool = mapping->private_data;
+	class = pool->size_class[class_idx];
+	offset = get_first_obj_offset(page);
+
+	spin_lock(&class->lock);
+	if (!get_zspage_inuse(zspage)) {
+		ret = -EBUSY;
+		goto unlock_class;
+	}
+
+	pos = offset;
+	s_addr = kmap_atomic(page);
+	while (pos < PAGE_SIZE) {
+		head = obj_to_head(page, s_addr + pos);
+		if (head & OBJ_ALLOCATED_TAG) {
+			handle = head & ~OBJ_ALLOCATED_TAG;
+			if (!trypin_tag(handle))
+				goto unpin_objects;
+		}
+		pos += class->size;
+	}
+
+	/*
+	 * Here, any user cannot access all objects in the zspage so let's move.
+	 */
+	d_addr = kmap_atomic(newpage);
+	memcpy(d_addr, s_addr, PAGE_SIZE);
+	kunmap_atomic(d_addr);
+
+	for (addr = s_addr + offset; addr < s_addr + pos;
+					addr += class->size) {
+		head = obj_to_head(page, addr);
+		if (head & OBJ_ALLOCATED_TAG) {
+			handle = head & ~OBJ_ALLOCATED_TAG;
+			if (!testpin_tag(handle))
+				BUG();
+
+			old_obj = handle_to_obj(handle);
+			obj_to_location(old_obj, &dummy, &obj_idx);
+			new_obj = (unsigned long)location_to_obj(newpage,
+								obj_idx);
+			new_obj |= BIT(HANDLE_PIN_BIT);
+			record_obj(handle, new_obj);
+		}
+	}
+
+	replace_sub_page(class, zspage, newpage, page);
+	get_page(newpage);
+
+	dec_zspage_isolation(zspage);
+
+	/*
+	 * Page migration is done so let's putback isolated zspage to
+	 * the list if @page is final isolated subpage in the zspage.
+	 */
+	if (!is_zspage_isolated(zspage))
+		putback_zspage(class, zspage);
+
+	reset_page(page);
+	put_page(page);
+	page = newpage;
+
+	ret = MIGRATEPAGE_SUCCESS;
+unpin_objects:
+	for (addr = s_addr + offset; addr < s_addr + pos;
+						addr += class->size) {
+		head = obj_to_head(page, addr);
+		if (head & OBJ_ALLOCATED_TAG) {
+			handle = head & ~OBJ_ALLOCATED_TAG;
+			if (!testpin_tag(handle))
+				BUG();
+			unpin_tag(handle);
+		}
+	}
+	kunmap_atomic(s_addr);
+unlock_class:
+	spin_unlock(&class->lock);
+	migrate_write_unlock(zspage);
+
+	return ret;
+}
+
+void zs_page_putback(struct page *page)
+{
+	struct zs_pool *pool;
+	struct size_class *class;
+	int class_idx;
+	enum fullness_group fg;
+	struct address_space *mapping;
+	struct zspage *zspage;
+
+	VM_BUG_ON_PAGE(!PageMovable(page), page);
+	VM_BUG_ON_PAGE(!PageIsolated(page), page);
+
+	zspage = get_zspage(page);
+	get_zspage_mapping(zspage, &class_idx, &fg);
+	mapping = page_mapping(page);
+	pool = mapping->private_data;
+	class = pool->size_class[class_idx];
+
+	spin_lock(&class->lock);
+	dec_zspage_isolation(zspage);
+	if (!is_zspage_isolated(zspage)) {
+		fg = putback_zspage(class, zspage);
+		/*
+		 * Due to page_lock, we cannot free zspage immediately
+		 * so let's defer.
+		 */
+		if (fg == ZS_EMPTY)
+			schedule_work(&pool->free_work);
+	}
+	spin_unlock(&class->lock);
+}
+
+const struct address_space_operations zsmalloc_aops = {
+	.isolate_page = zs_page_isolate,
+	.migratepage = zs_page_migrate,
+	.putback_page = zs_page_putback,
+};
+
+static int zs_register_migration(struct zs_pool *pool)
+{
+	pool->inode = alloc_anon_inode(zsmalloc_mnt->mnt_sb);
+	if (IS_ERR(pool->inode)) {
+		pool->inode = NULL;
+		return 1;
+	}
+
+	pool->inode->i_mapping->private_data = pool;
+	pool->inode->i_mapping->a_ops = &zsmalloc_aops;
+	return 0;
+}
+
+static void zs_unregister_migration(struct zs_pool *pool)
+{
+	flush_work(&pool->free_work);
+	if (pool->inode)
+		iput(pool->inode);
+}
+
+/*
+ * Caller should hold page_lock of all pages in the zspage
+ * In here, we cannot use zspage meta data.
+ */
+static void async_free_zspage(struct work_struct *work)
 {
 	int i;
-	struct page *page = NULL;
+	struct size_class *class;
+	unsigned int class_idx;
+	enum fullness_group fullness;
+	struct zspage *zspage, *tmp;
+	LIST_HEAD(free_pages);
+	struct zs_pool *pool = container_of(work, struct zs_pool,
+					free_work);
 
-	for (i = ZS_ALMOST_EMPTY; i >= ZS_ALMOST_FULL; i--) {
-		page = class->fullness_list[i];
-		if (!page)
+	for (i = 0; i < zs_size_classes; i++) {
+		class = pool->size_class[i];
+		if (class->index != i)
 			continue;
 
-		remove_zspage(class, i, page);
-		break;
+		spin_lock(&class->lock);
+		list_splice_init(&class->fullness_list[ZS_EMPTY], &free_pages);
+		spin_unlock(&class->lock);
+	}
+
+
+	list_for_each_entry_safe(zspage, tmp, &free_pages, list) {
+		list_del(&zspage->list);
+		lock_zspage(zspage);
+
+		get_zspage_mapping(zspage, &class_idx, &fullness);
+		VM_BUG_ON(fullness != ZS_EMPTY);
+		class = pool->size_class[class_idx];
+		spin_lock(&class->lock);
+		__free_zspage(pool, pool->size_class[class_idx], zspage);
+		spin_unlock(&class->lock);
 	}
+};
+
+static void kick_deferred_free(struct zs_pool *pool)
+{
+	schedule_work(&pool->free_work);
+}
+
+static void init_deferred_free(struct zs_pool *pool)
+{
+	INIT_WORK(&pool->free_work, async_free_zspage);
+}
+
+static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage)
+{
+	struct page *page = get_first_page(zspage);
 
-	return page;
+	do {
+		WARN_ON(!trylock_page(page));
+		__SetPageMovable(page, pool->inode->i_mapping);
+		unlock_page(page);
+	} while ((page = get_next_page(page)) != NULL);
 }
+#endif
 
 /*
  *
@@ -1748,20 +2270,20 @@ static unsigned long zs_can_compact(struct size_class *class)
 static void __zs_compact(struct zs_pool *pool, struct size_class *class)
 {
 	struct zs_compact_control cc;
-	struct page *src_page;
-	struct page *dst_page = NULL;
+	struct zspage *src_zspage;
+	struct zspage *dst_zspage = NULL;
 
 	spin_lock(&class->lock);
-	while ((src_page = isolate_source_page(class))) {
+	while ((src_zspage = isolate_zspage(class, true))) {
 
 		if (!zs_can_compact(class))
 			break;
 
 		cc.index = 0;
-		cc.s_page = src_page;
+		cc.s_page = get_first_page(src_zspage);
 
-		while ((dst_page = isolate_target_page(class))) {
-			cc.d_page = dst_page;
+		while ((dst_zspage = isolate_zspage(class, false))) {
+			cc.d_page = get_first_page(dst_zspage);
 			/*
 			 * If there is no more space in dst_page, resched
 			 * and see if anyone had allocated another zspage.
@@ -1769,23 +2291,25 @@ static void __zs_compact(struct zs_pool *pool, struct size_class *class)
 			if (!migrate_zspage(pool, class, &cc))
 				break;
 
-			putback_zspage(pool, class, dst_page);
+			putback_zspage(class, dst_zspage);
 		}
 
 		/* Stop if we couldn't find slot */
-		if (dst_page == NULL)
+		if (dst_zspage == NULL)
 			break;
 
-		putback_zspage(pool, class, dst_page);
-		if (putback_zspage(pool, class, src_page) == ZS_EMPTY)
+		putback_zspage(class, dst_zspage);
+		if (putback_zspage(class, src_zspage) == ZS_EMPTY) {
+			free_zspage(pool, class, src_zspage);
 			pool->stats.pages_compacted += class->pages_per_zspage;
+		}
 		spin_unlock(&class->lock);
 		cond_resched();
 		spin_lock(&class->lock);
 	}
 
-	if (src_page)
-		putback_zspage(pool, class, src_page);
+	if (src_zspage)
+		putback_zspage(class, src_zspage);
 
 	spin_unlock(&class->lock);
 }
@@ -1892,6 +2416,7 @@ struct zs_pool *zs_create_pool(const char *name)
 	if (!pool)
 		return NULL;
 
+	init_deferred_free(pool);
 	pool->size_class = kcalloc(zs_size_classes, sizeof(struct size_class *),
 			GFP_KERNEL);
 	if (!pool->size_class) {
@@ -1903,7 +2428,7 @@ struct zs_pool *zs_create_pool(const char *name)
 	if (!pool->name)
 		goto err;
 
-	if (create_handle_cache(pool))
+	if (create_cache(pool))
 		goto err;
 
 	/*
@@ -1914,6 +2439,7 @@ struct zs_pool *zs_create_pool(const char *name)
 		int size;
 		int pages_per_zspage;
 		struct size_class *class;
+		int fullness = 0;
 
 		size = ZS_MIN_ALLOC_SIZE + i * ZS_SIZE_CLASS_DELTA;
 		if (size > ZS_MAX_ALLOC_SIZE)
@@ -1943,11 +2469,13 @@ struct zs_pool *zs_create_pool(const char *name)
 		class->size = size;
 		class->index = i;
 		class->pages_per_zspage = pages_per_zspage;
-		if (pages_per_zspage == 1 &&
-			get_maxobj_per_zspage(size, pages_per_zspage) == 1)
-			class->huge = true;
+		class->objs_per_zspage = class->pages_per_zspage *
+						PAGE_SIZE / class->size;
 		spin_lock_init(&class->lock);
 		pool->size_class[i] = class;
+		for (fullness = ZS_EMPTY; fullness < NR_ZS_FULLNESS;
+							fullness++)
+			INIT_LIST_HEAD(&class->fullness_list[fullness]);
 
 		prev_class = class;
 	}
@@ -1955,6 +2483,9 @@ struct zs_pool *zs_create_pool(const char *name)
 	/* debug only, don't abort if it fails */
 	zs_pool_stat_create(pool, name);
 
+	if (zs_register_migration(pool))
+		goto err;
+
 	/*
 	 * Not critical, we still can use the pool
 	 * and user can trigger compaction manually.
@@ -1974,6 +2505,7 @@ void zs_destroy_pool(struct zs_pool *pool)
 	int i;
 
 	zs_unregister_shrinker(pool);
+	zs_unregister_migration(pool);
 	zs_pool_stat_destroy(pool);
 
 	for (i = 0; i < zs_size_classes; i++) {
@@ -1986,8 +2518,8 @@ void zs_destroy_pool(struct zs_pool *pool)
 		if (class->index != i)
 			continue;
 
-		for (fg = 0; fg < _ZS_NR_FULLNESS_GROUPS; fg++) {
-			if (class->fullness_list[fg]) {
+		for (fg = ZS_EMPTY; fg < NR_ZS_FULLNESS; fg++) {
+			if (!list_empty(&class->fullness_list[fg])) {
 				pr_info("Freeing non-empty class with size %db, fullness group %d\n",
 					class->size, fg);
 			}
@@ -1995,7 +2527,7 @@ void zs_destroy_pool(struct zs_pool *pool)
 		kfree(class);
 	}
 
-	destroy_handle_cache(pool);
+	destroy_cache(pool);
 	kfree(pool->size_class);
 	kfree(pool->name);
 	kfree(pool);
@@ -2004,7 +2536,13 @@ EXPORT_SYMBOL_GPL(zs_destroy_pool);
 
 static int __init zs_init(void)
 {
-	int ret = zs_register_cpu_notifier();
+	int ret;
+
+	ret = zsmalloc_mount();
+	if (ret)
+		goto out;
+
+	ret = zs_register_cpu_notifier();
 
 	if (ret)
 		goto notifier_fail;
@@ -2021,7 +2559,8 @@ static int __init zs_init(void)
 
 notifier_fail:
 	zs_unregister_cpu_notifier();
-
+	zsmalloc_unmount();
+out:
 	return ret;
 }
 
@@ -2030,6 +2569,7 @@ static void __exit zs_exit(void)
 #ifdef CONFIG_ZPOOL
 	zpool_unregister_driver(&zs_zpool_driver);
 #endif
+	zsmalloc_unmount();
 	zs_unregister_cpu_notifier();
 
 	zs_stat_exit();