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authorVladimir Davydov <vdavydov@parallels.com>2014-01-21 15:49:41 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-01-21 16:19:45 -0800
commit1c98dd905ddb7552f13a3f06aa0bd9ef6affeeb7 (patch)
tree6c977f0566e6ef99ac45547a3c81017a575cd73c
parentb2f3eebe7a8ef6cd4e2ea088ac7f613793f6cad6 (diff)
downloadop-kernel-dev-1c98dd905ddb7552f13a3f06aa0bd9ef6affeeb7.zip
op-kernel-dev-1c98dd905ddb7552f13a3f06aa0bd9ef6affeeb7.tar.gz
memcg: fix kmem_account_flags check in memcg_can_account_kmem()
We should start kmem accounting for a memory cgroup only after both its kmem limit is set (KMEM_ACCOUNTED_ACTIVE) and related call sites are patched (KMEM_ACCOUNTED_ACTIVATED). Currently memcg_can_account_kmem() allows kmem accounting even if only one of the conditions is true. Fix it. This means that a page might get charged by memcg_kmem_newpage_charge which would see its static key patched already but memcg_kmem_commit_charge would still see it unpatched and so the charge won't be committed. The result would be charge inconsistency (page_cgroup not marked as PageCgroupUsed) and the charge would leak because __memcg_kmem_uncharge_pages would ignore it. [mhocko@suse.cz: augment changelog] Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Glauber Costa <glommer@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/memcontrol.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 7f1a356..3065fa8 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2959,7 +2959,8 @@ static DEFINE_MUTEX(set_limit_mutex);
static inline bool memcg_can_account_kmem(struct mem_cgroup *memcg)
{
return !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg) &&
- (memcg->kmem_account_flags & KMEM_ACCOUNTED_MASK);
+ (memcg->kmem_account_flags & KMEM_ACCOUNTED_MASK) ==
+ KMEM_ACCOUNTED_MASK;
}
/*
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