diff options
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index e2996b80601f..b66512771167 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -358,6 +358,10 @@ void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru) return; pc = lookup_page_cgroup(page); + /* + * Used bit is set without atomic ops but after smp_wmb(). + * For making pc->mem_cgroup visible, insert smp_rmb() here. + */ smp_rmb(); /* unused page is not rotated. */ if (!PageCgroupUsed(pc)) @@ -374,7 +378,10 @@ void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru) if (mem_cgroup_disabled()) return; pc = lookup_page_cgroup(page); - /* barrier to sync with "charge" */ + /* + * Used bit is set without atomic ops but after smp_wmb(). + * For making pc->mem_cgroup visible, insert smp_rmb() here. + */ smp_rmb(); if (!PageCgroupUsed(pc)) return; @@ -559,6 +566,14 @@ mem_cgroup_get_reclaim_stat_from_page(struct page *page) return NULL; pc = lookup_page_cgroup(page); + /* + * Used bit is set without atomic ops but after smp_wmb(). + * For making pc->mem_cgroup visible, insert smp_rmb() here. + */ + smp_rmb(); + if (!PageCgroupUsed(pc)) + return NULL; + mz = page_cgroup_zoneinfo(pc); if (!mz) return NULL; |