1 files changed, 83 insertions, 15 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index e7eb1ab8c78a..778db5de6232 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1376,6 +1376,39 @@ static void remove_hugetlb_page(struct hstate *h, struct page *page,
 	h->nr_huge_pages_node[nid]--;
 }
 
+static void add_hugetlb_page(struct hstate *h, struct page *page,
+			     bool adjust_surplus)
+{
+	int zeroed;
+	int nid = page_to_nid(page);
+
+	VM_BUG_ON_PAGE(!HPageVmemmapOptimized(page), page);
+
+	lockdep_assert_held(&hugetlb_lock);
+
+	INIT_LIST_HEAD(&page->lru);
+	h->nr_huge_pages++;
+	h->nr_huge_pages_node[nid]++;
+
+	if (adjust_surplus) {
+		h->surplus_huge_pages++;
+		h->surplus_huge_pages_node[nid]++;
+	}
+
+	set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
+	set_page_private(page, 0);
+	SetHPageVmemmapOptimized(page);
+
+	/*
+	 * This page is now managed by the hugetlb allocator and has
+	 * no users -- drop the last reference.
+	 */
+	zeroed = put_page_testzero(page);
+	VM_BUG_ON_PAGE(!zeroed, page);
+	arch_clear_hugepage_flags(page);
+	enqueue_huge_page(h, page);
+}
+
 static void __update_and_free_page(struct hstate *h, struct page *page)
 {
 	int i;
@@ -1384,6 +1417,18 @@ static void __update_and_free_page(struct hstate *h, struct page *page)
 	if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
 		return;
 
+	if (alloc_huge_page_vmemmap(h, page)) {
+		spin_lock_irq(&hugetlb_lock);
+		/*
+		 * If we cannot allocate vmemmap pages, just refuse to free the
+		 * page and put the page back on the hugetlb free list and treat
+		 * as a surplus page.
+		 */
+		add_hugetlb_page(h, page, true);
+		spin_unlock_irq(&hugetlb_lock);
+		return;
+	}
+
 	for (i = 0; i < pages_per_huge_page(h);
 	     i++, subpage = mem_map_next(subpage, page, i)) {
 		subpage->flags &= ~(1 << PG_locked | 1 << PG_error |
@@ -1450,7 +1495,7 @@ static inline void flush_free_hpage_work(struct hstate *h)
 static void update_and_free_page(struct hstate *h, struct page *page,
 				 bool atomic)
 {
-	if (!free_vmemmap_pages_per_hpage(h) || !atomic) {
+	if (!HPageVmemmapOptimized(page) || !atomic) {
 		__update_and_free_page(h, page);
 		return;
 	}
@@ -1806,10 +1851,14 @@ static struct page *remove_pool_huge_page(struct hstate *h,
  * nothing for in-use hugepages and non-hugepages.
  * This function returns values like below:
  *
- *  -EBUSY: failed to dissolved free hugepages or the hugepage is in-use
- *          (allocated or reserved.)
- *       0: successfully dissolved free hugepages or the page is not a
- *          hugepage (considered as already dissolved)
+ *  -ENOMEM: failed to allocate vmemmap pages to free the freed hugepages
+ *           when the system is under memory pressure and the feature of
+ *           freeing unused vmemmap pages associated with each hugetlb page
+ *           is enabled.
+ *  -EBUSY:  failed to dissolved free hugepages or the hugepage is in-use
+ *           (allocated or reserved.)
+ *       0:  successfully dissolved free hugepages or the page is not a
+ *           hugepage (considered as already dissolved)
  */
 int dissolve_free_huge_page(struct page *page)
 {
@@ -1851,19 +1900,38 @@ retry:
 			goto retry;
 		}
 
-		/*
-		 * Move PageHWPoison flag from head page to the raw error page,
-		 * which makes any subpages rather than the error page reusable.
-		 */
-		if (PageHWPoison(head) && page != head) {
-			SetPageHWPoison(page);
-			ClearPageHWPoison(head);
-		}
 		remove_hugetlb_page(h, head, false);
 		h->max_huge_pages--;
 		spin_unlock_irq(&hugetlb_lock);
-		update_and_free_page(h, head, false);
-		return 0;
+
+		/*
+		 * Normally update_and_free_page will allocate required vmemmmap
+		 * before freeing the page.  update_and_free_page will fail to
+		 * free the page if it can not allocate required vmemmap.  We
+		 * need to adjust max_huge_pages if the page is not freed.
+		 * Attempt to allocate vmemmmap here so that we can take
+		 * appropriate action on failure.
+		 */
+		rc = alloc_huge_page_vmemmap(h, head);
+		if (!rc) {
+			/*
+			 * Move PageHWPoison flag from head page to the raw
+			 * error page, which makes any subpages rather than
+			 * the error page reusable.
+			 */
+			if (PageHWPoison(head) && page != head) {
+				SetPageHWPoison(page);
+				ClearPageHWPoison(head);
+			}
+			update_and_free_page(h, head, false);
+		} else {
+			spin_lock_irq(&hugetlb_lock);
+			add_hugetlb_page(h, head, false);
+			h->max_huge_pages++;
+			spin_unlock_irq(&hugetlb_lock);
+		}
+
+		return rc;
 	}
 out:
 	spin_unlock_irq(&hugetlb_lock);