1 files changed, 19 insertions, 50 deletions

diff --git a/mm/ksm.c b/mm/ksm.c
index 2d162c5625f6..ca6d2a06a615 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -441,20 +441,6 @@ static void break_cow(struct rmap_item *rmap_item)
 	up_read(&mm->mmap_sem);
 }
 
-static struct page *page_trans_compound_anon(struct page *page)
-{
-	if (PageTransCompound(page)) {
-		struct page *head = compound_head(page);
-		/*
-		 * head may actually be splitted and freed from under
-		 * us but it's ok here.
-		 */
-		if (PageAnon(head))
-			return head;
-	}
-	return NULL;
-}
-
 static struct page *get_mergeable_page(struct rmap_item *rmap_item)
 {
 	struct mm_struct *mm = rmap_item->mm;
@@ -470,7 +456,7 @@ static struct page *get_mergeable_page(struct rmap_item *rmap_item)
 	page = follow_page(vma, addr, FOLL_GET);
 	if (IS_ERR_OR_NULL(page))
 		goto out;
-	if (PageAnon(page) || page_trans_compound_anon(page)) {
+	if (PageAnon(page)) {
 		flush_anon_page(vma, page, addr);
 		flush_dcache_page(page);
 	} else {
@@ -956,13 +942,13 @@ static int replace_page(struct vm_area_struct *vma, struct page *page,
 	}
 
 	get_page(kpage);
-	page_add_anon_rmap(kpage, vma, addr);
+	page_add_anon_rmap(kpage, vma, addr, false);
 
 	flush_cache_page(vma, addr, pte_pfn(*ptep));
 	ptep_clear_flush_notify(vma, addr, ptep);
 	set_pte_at_notify(mm, addr, ptep, mk_pte(kpage, vma->vm_page_prot));
 
-	page_remove_rmap(page);
+	page_remove_rmap(page, false);
 	if (!page_mapped(page))
 		try_to_free_swap(page);
 	put_page(page);
@@ -975,33 +961,6 @@ out:
 	return err;
 }
 
-static int page_trans_compound_anon_split(struct page *page)
-{
-	int ret = 0;
-	struct page *transhuge_head = page_trans_compound_anon(page);
-	if (transhuge_head) {
-		/* Get the reference on the head to split it. */
-		if (get_page_unless_zero(transhuge_head)) {
-			/*
-			 * Recheck we got the reference while the head
-			 * was still anonymous.
-			 */
-			if (PageAnon(transhuge_head))
-				ret = split_huge_page(transhuge_head);
-			else
-				/*
-				 * Retry later if split_huge_page run
-				 * from under us.
-				 */
-				ret = 1;
-			put_page(transhuge_head);
-		} else
-			/* Retry later if split_huge_page run from under us. */
-			ret = 1;
-	}
-	return ret;
-}
-
 /*
  * try_to_merge_one_page - take two pages and merge them into one
  * @vma: the vma that holds the pte pointing to page
@@ -1020,9 +979,6 @@ static int try_to_merge_one_page(struct vm_area_struct *vma,
 	if (page == kpage)			/* ksm page forked */
 		return 0;
 
-	if (PageTransCompound(page) && page_trans_compound_anon_split(page))
-		goto out;
-	BUG_ON(PageTransCompound(page));
 	if (!PageAnon(page))
 		goto out;
 
@@ -1035,6 +991,13 @@ static int try_to_merge_one_page(struct vm_area_struct *vma,
 	 */
 	if (!trylock_page(page))
 		goto out;
+
+	if (PageTransCompound(page)) {
+		err = split_huge_page(page);
+		if (err)
+			goto out_unlock;
+	}
+
 	/*
 	 * If this anonymous page is mapped only here, its pte may need
 	 * to be write-protected.  If it's mapped elsewhere, all of its
@@ -1050,6 +1013,12 @@ static int try_to_merge_one_page(struct vm_area_struct *vma,
 			 */
 			set_page_stable_node(page, NULL);
 			mark_page_accessed(page);
+			/*
+			 * Page reclaim just frees a clean page with no dirty
+			 * ptes: make sure that the ksm page would be swapped.
+			 */
+			if (!PageDirty(page))
+				SetPageDirty(page);
 			err = 0;
 		} else if (pages_identical(page, kpage))
 			err = replace_page(vma, page, kpage, orig_pte);
@@ -1065,6 +1034,7 @@ static int try_to_merge_one_page(struct vm_area_struct *vma,
 		}
 	}
 
+out_unlock:
 	unlock_page(page);
 out:
 	return err;
@@ -1635,8 +1605,7 @@ next_mm:
 				cond_resched();
 				continue;
 			}
-			if (PageAnon(*page) ||
-			    page_trans_compound_anon(*page)) {
+			if (PageAnon(*page)) {
 				flush_anon_page(vma, *page, ksm_scan.address);
 				flush_dcache_page(*page);
 				rmap_item = get_next_rmap_item(slot,
@@ -1899,7 +1868,7 @@ struct page *ksm_might_need_to_copy(struct page *page,
 
 		SetPageDirty(new_page);
 		__SetPageUptodate(new_page);
-		__set_page_locked(new_page);
+		__SetPageLocked(new_page);
 	}
 
 	return new_page;