1 files changed, 44 insertions, 26 deletions

diff --git a/mm/rmap.c b/mm/rmap.c
index c8454e0..5b5ad58 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -120,6 +120,21 @@ static void anon_vma_chain_free(struct anon_vma_chain *anon_vma_chain)
 	kmem_cache_free(anon_vma_chain_cachep, anon_vma_chain);
 }
 
+static void anon_vma_chain_link(struct vm_area_struct *vma,
+				struct anon_vma_chain *avc,
+				struct anon_vma *anon_vma)
+{
+	avc->vma = vma;
+	avc->anon_vma = anon_vma;
+	list_add(&avc->same_vma, &vma->anon_vma_chain);
+
+	/*
+	 * It's critical to add new vmas to the tail of the anon_vma,
+	 * see comment in huge_memory.c:__split_huge_page().
+	 */
+	list_add_tail(&avc->same_anon_vma, &anon_vma->head);
+}
+
 /**
  * anon_vma_prepare - attach an anon_vma to a memory region
  * @vma: the memory region in question
@@ -175,10 +190,7 @@ int anon_vma_prepare(struct vm_area_struct *vma)
 		spin_lock(&mm->page_table_lock);
 		if (likely(!vma->anon_vma)) {
 			vma->anon_vma = anon_vma;
-			avc->anon_vma = anon_vma;
-			avc->vma = vma;
-			list_add(&avc->same_vma, &vma->anon_vma_chain);
-			list_add_tail(&avc->same_anon_vma, &anon_vma->head);
+			anon_vma_chain_link(vma, avc, anon_vma);
 			allocated = NULL;
 			avc = NULL;
 		}
@@ -224,21 +236,6 @@ static inline void unlock_anon_vma_root(struct anon_vma *root)
 		mutex_unlock(&root->mutex);
 }
 
-static void anon_vma_chain_link(struct vm_area_struct *vma,
-				struct anon_vma_chain *avc,
-				struct anon_vma *anon_vma)
-{
-	avc->vma = vma;
-	avc->anon_vma = anon_vma;
-	list_add(&avc->same_vma, &vma->anon_vma_chain);
-
-	/*
-	 * It's critical to add new vmas to the tail of the anon_vma,
-	 * see comment in huge_memory.c:__split_huge_page().
-	 */
-	list_add_tail(&avc->same_anon_vma, &anon_vma->head);
-}
-
 /*
  * Attach the anon_vmas from src to dst.
  * Returns 0 on success, -ENOMEM on failure.
@@ -1151,10 +1148,15 @@ void page_add_new_anon_rmap(struct page *page,
  */
 void page_add_file_rmap(struct page *page)
 {
+	bool locked;
+	unsigned long flags;
+
+	mem_cgroup_begin_update_page_stat(page, &locked, &flags);
 	if (atomic_inc_and_test(&page->_mapcount)) {
 		__inc_zone_page_state(page, NR_FILE_MAPPED);
 		mem_cgroup_inc_page_stat(page, MEMCG_NR_FILE_MAPPED);
 	}
+	mem_cgroup_end_update_page_stat(page, &locked, &flags);
 }
 
 /**
@@ -1165,9 +1167,21 @@ void page_add_file_rmap(struct page *page)
  */
 void page_remove_rmap(struct page *page)
 {
+	bool anon = PageAnon(page);
+	bool locked;
+	unsigned long flags;
+
+	/*
+	 * The anon case has no mem_cgroup page_stat to update; but may
+	 * uncharge_page() below, where the lock ordering can deadlock if
+	 * we hold the lock against page_stat move: so avoid it on anon.
+	 */
+	if (!anon)
+		mem_cgroup_begin_update_page_stat(page, &locked, &flags);
+
 	/* page still mapped by someone else? */
 	if (!atomic_add_negative(-1, &page->_mapcount))
-		return;
+		goto out;
 
 	/*
 	 * Now that the last pte has gone, s390 must transfer dirty
@@ -1176,7 +1190,7 @@ void page_remove_rmap(struct page *page)
 	 * not if it's in swapcache - there might be another pte slot
 	 * containing the swap entry, but page not yet written to swap.
 	 */
-	if ((!PageAnon(page) || PageSwapCache(page)) &&
+	if ((!anon || PageSwapCache(page)) &&
 	    page_test_and_clear_dirty(page_to_pfn(page), 1))
 		set_page_dirty(page);
 	/*
@@ -1184,8 +1198,8 @@ void page_remove_rmap(struct page *page)
 	 * and not charged by memcg for now.
 	 */
 	if (unlikely(PageHuge(page)))
-		return;
-	if (PageAnon(page)) {
+		goto out;
+	if (anon) {
 		mem_cgroup_uncharge_page(page);
 		if (!PageTransHuge(page))
 			__dec_zone_page_state(page, NR_ANON_PAGES);
@@ -1205,6 +1219,9 @@ void page_remove_rmap(struct page *page)
 	 * Leaving it set also helps swapoff to reinstate ptes
 	 * faster for those pages still in swapcache.
 	 */
+out:
+	if (!anon)
+		mem_cgroup_end_update_page_stat(page, &locked, &flags);
 }
 
 /*
@@ -1282,7 +1299,7 @@ int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 			}
 			dec_mm_counter(mm, MM_ANONPAGES);
 			inc_mm_counter(mm, MM_SWAPENTS);
-		} else if (PAGE_MIGRATION) {
+		} else if (IS_ENABLED(CONFIG_MIGRATION)) {
 			/*
 			 * Store the pfn of the page in a special migration
 			 * pte. do_swap_page() will wait until the migration
@@ -1293,7 +1310,8 @@ int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 		}
 		set_pte_at(mm, address, pte, swp_entry_to_pte(entry));
 		BUG_ON(pte_file(*pte));
-	} else if (PAGE_MIGRATION && (TTU_ACTION(flags) == TTU_MIGRATION)) {
+	} else if (IS_ENABLED(CONFIG_MIGRATION) &&
+		   (TTU_ACTION(flags) == TTU_MIGRATION)) {
 		/* Establish migration entry for a file page */
 		swp_entry_t entry;
 		entry = make_migration_entry(page, pte_write(pteval));
@@ -1499,7 +1517,7 @@ static int try_to_unmap_anon(struct page *page, enum ttu_flags flags)
 		 * locking requirements of exec(), migration skips
 		 * temporary VMAs until after exec() completes.
 		 */
-		if (PAGE_MIGRATION && (flags & TTU_MIGRATION) &&
+		if (IS_ENABLED(CONFIG_MIGRATION) && (flags & TTU_MIGRATION) &&
 				is_vma_temporary_stack(vma))
 			continue;