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-rw-r--r--mm/memcontrol.c21
1 files changed, 20 insertions, 1 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index ce7b35d024e9..01e0c725de65 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -993,6 +993,16 @@ void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
return;
pc = lookup_page_cgroup(page);
VM_BUG_ON(PageCgroupAcctLRU(pc));
+ /*
+ * putback: charge:
+ * SetPageLRU SetPageCgroupUsed
+ * smp_mb smp_mb
+ * PageCgroupUsed && add to memcg LRU PageLRU && add to memcg LRU
+ *
+ * Ensure that one of the two sides adds the page to the memcg
+ * LRU during a race.
+ */
+ smp_mb();
if (!PageCgroupUsed(pc))
return;
/* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
@@ -1044,7 +1054,16 @@ static void mem_cgroup_lru_add_after_commit(struct page *page)
unsigned long flags;
struct zone *zone = page_zone(page);
struct page_cgroup *pc = lookup_page_cgroup(page);
-
+ /*
+ * putback: charge:
+ * SetPageLRU SetPageCgroupUsed
+ * smp_mb smp_mb
+ * PageCgroupUsed && add to memcg LRU PageLRU && add to memcg LRU
+ *
+ * Ensure that one of the two sides adds the page to the memcg
+ * LRU during a race.
+ */
+ smp_mb();
/* taking care of that the page is added to LRU while we commit it */
if (likely(!PageLRU(page)))
return;