diff options
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 21 |
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; |