6 files changed, 20 insertions, 25 deletions

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 09b449849369..c45ab3fb6e04 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -300,7 +300,7 @@ void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg,
 void mem_cgroup_uncharge(struct page *page);
 void mem_cgroup_uncharge_list(struct list_head *page_list);
 
-void mem_cgroup_replace_page(struct page *oldpage, struct page *newpage);
+void mem_cgroup_migrate(struct page *oldpage, struct page *newpage);
 
 struct lruvec *mem_cgroup_zone_lruvec(struct zone *, struct mem_cgroup *);
 struct lruvec *mem_cgroup_page_lruvec(struct page *, struct zone *);
@@ -580,7 +580,7 @@ static inline void mem_cgroup_uncharge_list(struct list_head *page_list)
 {
 }
 
-static inline void mem_cgroup_replace_page(struct page *old, struct page *new)
+static inline void mem_cgroup_migrate(struct page *old, struct page *new)
 {
 }
 
diff --git a/include/linux/mm.h b/include/linux/mm.h
index b97243d6aa49..6b471d1fc8df 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -905,20 +905,11 @@ static inline struct mem_cgroup *page_memcg(struct page *page)
 {
         return page->mem_cgroup;
 }
-
-static inline void set_page_memcg(struct page *page, struct mem_cgroup *memcg)
-{
-        page->mem_cgroup = memcg;
-}
 #else
 static inline struct mem_cgroup *page_memcg(struct page *page)
 {
         return NULL;
 }
-
-static inline void set_page_memcg(struct page *page, struct mem_cgroup *memcg)
-{
-}
 #endif
 
 /*
diff --git a/mm/filemap.c b/mm/filemap.c
index ee8140cf935d..d8317caffe85 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -577,7 +577,7 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask)
                         __inc_zone_page_state(new, NR_SHMEM);
                 spin_unlock_irqrestore(&mapping->tree_lock, flags);
                 unlock_page_memcg(memcg);
-                mem_cgroup_replace_page(old, new);
+                mem_cgroup_migrate(old, new);
                 radix_tree_preload_end();
                 if (freepage)
                         freepage(old);
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 864e237f32d9..64506b2eef34 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4457,7 +4457,7 @@ static int mem_cgroup_move_account(struct page *page,
         VM_BUG_ON(compound && !PageTransHuge(page));
 
         /*
-         * Prevent mem_cgroup_replace_page() from looking at
+         * Prevent mem_cgroup_migrate() from looking at
          * page->mem_cgroup of its source page while we change it.
          */
         ret = -EBUSY;
@@ -5486,16 +5486,17 @@ void mem_cgroup_uncharge_list(struct list_head *page_list)
 }
 
 /**
- * mem_cgroup_replace_page - migrate a charge to another page
- * @oldpage: currently charged page
- * @newpage: page to transfer the charge to
+ * mem_cgroup_migrate - charge a page's replacement
+ * @oldpage: currently circulating page
+ * @newpage: replacement page
  *
- * Migrate the charge from @oldpage to @newpage.
+ * Charge @newpage as a replacement page for @oldpage. @oldpage will
+ * be uncharged upon free.
  *
  * Both pages must be locked, @newpage->mapping must be set up.
  * Either or both pages might be on the LRU already.
  */
-void mem_cgroup_replace_page(struct page *oldpage, struct page *newpage)
+void mem_cgroup_migrate(struct page *oldpage, struct page *newpage)
 {
         struct mem_cgroup *memcg;
         unsigned int nr_pages;
diff --git a/mm/migrate.c b/mm/migrate.c
index 432ecd0172cd..848327d4a7ed 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -326,12 +326,13 @@ int migrate_page_move_mapping(struct address_space *mapping,
                         return -EAGAIN;
 
                 /* No turning back from here */
-                set_page_memcg(newpage, page_memcg(page));
                 newpage->index = page->index;
                 newpage->mapping = page->mapping;
                 if (PageSwapBacked(page))
                         SetPageSwapBacked(newpage);
 
+                mem_cgroup_migrate(page, newpage);
+
                 return MIGRATEPAGE_SUCCESS;
         }
 
@@ -373,7 +374,6 @@ int migrate_page_move_mapping(struct address_space *mapping,
          * Now we know that no one else is looking at the page:
          * no turning back from here.
          */
-        set_page_memcg(newpage, page_memcg(page));
         newpage->index = page->index;
         newpage->mapping = page->mapping;
         if (PageSwapBacked(page))
@@ -428,6 +428,8 @@ int migrate_page_move_mapping(struct address_space *mapping,
         }
         local_irq_enable();
 
+        mem_cgroup_migrate(page, newpage);
+
         return MIGRATEPAGE_SUCCESS;
 }
 
@@ -458,9 +460,9 @@ int migrate_huge_page_move_mapping(struct address_space *mapping,
                 return -EAGAIN;
         }
 
-        set_page_memcg(newpage, page_memcg(page));
         newpage->index = page->index;
         newpage->mapping = page->mapping;
+
         get_page(newpage);
 
         radix_tree_replace_slot(pslot, newpage);
@@ -468,6 +470,9 @@ int migrate_huge_page_move_mapping(struct address_space *mapping,
         page_unfreeze_refs(page, expected_count - 1);
 
         spin_unlock_irq(&mapping->tree_lock);
+
+        mem_cgroup_migrate(page, newpage);
+
         return MIGRATEPAGE_SUCCESS;
 }
 
@@ -775,7 +780,6 @@ static int move_to_new_page(struct page *newpage, struct page *page,
          * page is freed; but stats require that PageAnon be left as PageAnon.
          */
         if (rc == MIGRATEPAGE_SUCCESS) {
-                set_page_memcg(page, NULL);
                 if (!PageAnon(page))
                         page->mapping = NULL;
         }
@@ -1842,8 +1846,7 @@ fail_putback:
         }
 
         mlock_migrate_page(new_page, page);
-        set_page_memcg(new_page, page_memcg(page));
-        set_page_memcg(page, NULL);
+        mem_cgroup_migrate(page, new_page);
         page_remove_rmap(page, true);
         set_page_owner_migrate_reason(new_page, MR_NUMA_MISPLACED);
 
diff --git a/mm/shmem.c b/mm/shmem.c
index 440e2a7e6c1c..1acfdbc4bd9e 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1116,7 +1116,7 @@ static int shmem_replace_page(struct page **pagep, gfp_t gfp,
                  */
                 oldpage = newpage;
         } else {
-                mem_cgroup_replace_page(oldpage, newpage);
+                mem_cgroup_migrate(oldpage, newpage);
                 lru_cache_add_anon(newpage);
                 *pagep = newpage;
         }