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| author | Vladimir Davydov <vdavydov@parallels.com> | 2014-01-21 15:49:41 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-01-21 16:19:45 -0800 |
| commit | 1c98dd905ddb7552f13a3f06aa0bd9ef6affeeb7 (patch) | |
| tree | 6c977f0566e6ef99ac45547a3c81017a575cd73c /mm/memcontrol.c | |
| parent | b2f3eebe7a8ef6cd4e2ea088ac7f613793f6cad6 (diff) | |
| download | lwn-1c98dd905ddb7552f13a3f06aa0bd9ef6affeeb7.tar.gz lwn-1c98dd905ddb7552f13a3f06aa0bd9ef6affeeb7.zip | |
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>
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 7f1a356153c0..3065fa80251d 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; } /* |