6 files changed, 18 insertions, 48 deletions

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 4d34356fe644..b80de520670b 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -129,7 +129,6 @@ extern void mem_cgroup_print_oom_info(struct mem_cgroup *memcg,
 extern void mem_cgroup_replace_page_cache(struct page *oldpage,
                                         struct page *newpage);
 
-extern void mem_cgroup_reset_owner(struct page *page);
 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
 extern int do_swap_account;
 #endif
@@ -392,10 +391,6 @@ static inline void mem_cgroup_replace_page_cache(struct page *oldpage,
                                 struct page *newpage)
 {
 }
-
-static inline void mem_cgroup_reset_owner(struct page *page)
-{
-}
 #endif /* CONFIG_CGROUP_MEM_CONT */
 
 #if !defined(CONFIG_CGROUP_MEM_RES_CTLR) || !defined(CONFIG_DEBUG_VM)
diff --git a/mm/ksm.c b/mm/ksm.c
index 1925ffbfb27f..310544a379ae 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -28,7 +28,6 @@
 #include <linux/kthread.h>
 #include <linux/wait.h>
 #include <linux/slab.h>
-#include <linux/memcontrol.h>
 #include <linux/rbtree.h>
 #include <linux/memory.h>
 #include <linux/mmu_notifier.h>
@@ -1572,16 +1571,6 @@ struct page *ksm_does_need_to_copy(struct page *page,
 
         new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
         if (new_page) {
-                /*
-                 * The memcg-specific accounting when moving
-                 * pages around the LRU lists relies on the
-                 * page's owner (memcg) to be valid.  Usually,
-                 * pages are assigned to a new owner before
-                 * being put on the LRU list, but since this
-                 * is not the case here, the stale owner from
-                 * a previous allocation cycle must be reset.
-                 */
-                mem_cgroup_reset_owner(new_page);
                 copy_user_highpage(new_page, page, address, vma);
 
                 SetPageDirty(new_page);
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 1097d8098f8c..d0e57a3cda18 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1042,6 +1042,19 @@ struct lruvec *mem_cgroup_lru_add_list(struct zone *zone, struct page *page,
 
         pc = lookup_page_cgroup(page);
         memcg = pc->mem_cgroup;
+
+        /*
+         * Surreptitiously switch any uncharged page to root:
+         * an uncharged page off lru does nothing to secure
+         * its former mem_cgroup from sudden removal.
+         *
+         * Our caller holds lru_lock, and PageCgroupUsed is updated
+         * under page_cgroup lock: between them, they make all uses
+         * of pc->mem_cgroup safe.
+         */
+        if (!PageCgroupUsed(pc) && memcg != root_mem_cgroup)
+                pc->mem_cgroup = memcg = root_mem_cgroup;
+
         mz = page_cgroup_zoneinfo(memcg, page);
         /* compound_order() is stabilized through lru_lock */
         MEM_CGROUP_ZSTAT(mz, lru) += 1 << compound_order(page);
@@ -3029,23 +3042,6 @@ void mem_cgroup_uncharge_end(void)
         batch->memcg = NULL;
 }
 
-/*
- * A function for resetting pc->mem_cgroup for newly allocated pages.
- * This function should be called if the newpage will be added to LRU
- * before start accounting.
- */
-void mem_cgroup_reset_owner(struct page *newpage)
-{
-        struct page_cgroup *pc;
-
-        if (mem_cgroup_disabled())
-                return;
-
-        pc = lookup_page_cgroup(newpage);
-        VM_BUG_ON(PageCgroupUsed(pc));
-        pc->mem_cgroup = root_mem_cgroup;
-}
-
 #ifdef CONFIG_SWAP
 /*
  * called after __delete_from_swap_cache() and drop "page" account.
diff --git a/mm/migrate.c b/mm/migrate.c
index df141f60289e..1503b6b54ecb 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -839,8 +839,6 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
         if (!newpage)
                 return -ENOMEM;
 
-        mem_cgroup_reset_owner(newpage);
-
         if (page_count(page) == 1) {
                 /* page was freed from under us. So we are done. */
                 goto out;
diff --git a/mm/swap.c b/mm/swap.c
index fff1ff7fb9ad..14380e9fbe33 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -652,7 +652,7 @@ EXPORT_SYMBOL(__pagevec_release);
 void lru_add_page_tail(struct zone* zone,
                        struct page *page, struct page *page_tail)
 {
-        int active;
+        int uninitialized_var(active);
         enum lru_list lru;
         const int file = 0;
 
@@ -672,7 +672,6 @@ void lru_add_page_tail(struct zone* zone,
                         active = 0;
                         lru = LRU_INACTIVE_ANON;
                 }
-                update_page_reclaim_stat(zone, page_tail, file, active);
         } else {
                 SetPageUnevictable(page_tail);
                 lru = LRU_UNEVICTABLE;
@@ -693,6 +692,9 @@ void lru_add_page_tail(struct zone* zone,
                 list_head = page_tail->lru.prev;
                 list_move_tail(&page_tail->lru, list_head);
         }
+
+        if (!PageUnevictable(page))
+                update_page_reclaim_stat(zone, page_tail, file, active);
 }
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
@@ -710,8 +712,8 @@ static void __pagevec_lru_add_fn(struct page *page, void *arg)
         SetPageLRU(page);
         if (active)
                 SetPageActive(page);
-        update_page_reclaim_stat(zone, page, file, active);
         add_page_to_lru_list(zone, page, lru);
+        update_page_reclaim_stat(zone, page, file, active);
 }
 
 /*
diff --git a/mm/swap_state.c b/mm/swap_state.c
index 470038a91873..ea6b32d61873 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -300,16 +300,6 @@ struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
                         new_page = alloc_page_vma(gfp_mask, vma, addr);
                         if (!new_page)
                                 break;          /* Out of memory */
-                        /*
-                         * The memcg-specific accounting when moving
-                         * pages around the LRU lists relies on the
-                         * page's owner (memcg) to be valid.  Usually,
-                         * pages are assigned to a new owner before
-                         * being put on the LRU list, but since this
-                         * is not the case here, the stale owner from
-                         * a previous allocation cycle must be reset.
-                         */
-                        mem_cgroup_reset_owner(new_page);
                 }
 
                 /*