1 files changed, 55 insertions, 39 deletions

diff --git a/mm/rmap.c b/mm/rmap.c
index 116a5053415b..3e4c7213210c 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -274,6 +274,7 @@ int anon_vma_fork(struct vm_area_struct *vma, struct vm_area_struct *pvma)
 {
 	struct anon_vma_chain *avc;
 	struct anon_vma *anon_vma;
+	int error;
 
 	/* Don't bother if the parent process has no anon_vma here. */
 	if (!pvma->anon_vma)
@@ -283,8 +284,9 @@ int anon_vma_fork(struct vm_area_struct *vma, struct vm_area_struct *pvma)
 	 * First, attach the new VMA to the parent VMA's anon_vmas,
 	 * so rmap can find non-COWed pages in child processes.
 	 */
-	if (anon_vma_clone(vma, pvma))
-		return -ENOMEM;
+	error = anon_vma_clone(vma, pvma);
+	if (error)
+		return error;
 
 	/* Then add our own anon_vma. */
 	anon_vma = anon_vma_alloc();
@@ -1042,15 +1044,46 @@ void page_add_new_anon_rmap(struct page *page,
  */
 void page_add_file_rmap(struct page *page)
 {
-	bool locked;
+	struct mem_cgroup *memcg;
 	unsigned long flags;
+	bool locked;
 
-	mem_cgroup_begin_update_page_stat(page, &locked, &flags);
+	memcg = mem_cgroup_begin_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, MEM_CGROUP_STAT_FILE_MAPPED);
+		mem_cgroup_inc_page_stat(memcg, MEM_CGROUP_STAT_FILE_MAPPED);
 	}
-	mem_cgroup_end_update_page_stat(page, &locked, &flags);
+	mem_cgroup_end_page_stat(memcg, locked, flags);
+}
+
+static void page_remove_file_rmap(struct page *page)
+{
+	struct mem_cgroup *memcg;
+	unsigned long flags;
+	bool locked;
+
+	memcg = mem_cgroup_begin_page_stat(page, &locked, &flags);
+
+	/* page still mapped by someone else? */
+	if (!atomic_add_negative(-1, &page->_mapcount))
+		goto out;
+
+	/* Hugepages are not counted in NR_FILE_MAPPED for now. */
+	if (unlikely(PageHuge(page)))
+		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);
+	mem_cgroup_dec_page_stat(memcg, MEM_CGROUP_STAT_FILE_MAPPED);
+
+	if (unlikely(PageMlocked(page)))
+		clear_page_mlock(page);
+out:
+	mem_cgroup_end_page_stat(memcg, locked, flags);
 }
 
 /**
@@ -1061,46 +1094,33 @@ 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);
+	if (!PageAnon(page)) {
+		page_remove_file_rmap(page);
+		return;
+	}
 
 	/* page still mapped by someone else? */
 	if (!atomic_add_negative(-1, &page->_mapcount))
-		goto out;
+		return;
+
+	/* Hugepages are not counted in NR_ANON_PAGES for now. */
+	if (unlikely(PageHuge(page)))
+		return;
 
 	/*
-	 * Hugepages are not counted in NR_ANON_PAGES nor NR_FILE_MAPPED
-	 * and not charged by memcg for now.
-	 *
 	 * We use the irq-unsafe __{inc|mod}_zone_page_stat because
 	 * these counters are not modified in interrupt context, and
-	 * these counters are not modified in interrupt context, and
 	 * pte lock(a spinlock) is held, which implies preemption disabled.
 	 */
-	if (unlikely(PageHuge(page)))
-		goto out;
-	if (anon) {
-		if (PageTransHuge(page))
-			__dec_zone_page_state(page,
-					      NR_ANON_TRANSPARENT_HUGEPAGES);
-		__mod_zone_page_state(page_zone(page), NR_ANON_PAGES,
-				-hpage_nr_pages(page));
-	} else {
-		__dec_zone_page_state(page, NR_FILE_MAPPED);
-		mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_FILE_MAPPED);
-		mem_cgroup_end_update_page_stat(page, &locked, &flags);
-	}
+	if (PageTransHuge(page))
+		__dec_zone_page_state(page, NR_ANON_TRANSPARENT_HUGEPAGES);
+
+	__mod_zone_page_state(page_zone(page), NR_ANON_PAGES,
+			      -hpage_nr_pages(page));
+
 	if (unlikely(PageMlocked(page)))
 		clear_page_mlock(page);
+
 	/*
 	 * It would be tidy to reset the PageAnon mapping here,
 	 * but that might overwrite a racing page_add_anon_rmap
@@ -1110,10 +1130,6 @@ void page_remove_rmap(struct page *page)
 	 * Leaving it set also helps swapoff to reinstate ptes
 	 * faster for those pages still in swapcache.
 	 */
-	return;
-out:
-	if (!anon)
-		mem_cgroup_end_update_page_stat(page, &locked, &flags);
 }
 
 /*