From: Vladimir Davydov <vdavydov@parallels.com>
Date: Tue, 21 Jan 2014 23:49:41 +0000 (-0800)
Subject: memcg: fix kmem_account_flags check in memcg_can_account_kmem()
X-Git-Tag: v3.14-rc1~134^2~58
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1c98dd905ddb7552f13a3f06aa0bd9ef6affeeb7;p=pandora-kernel.git

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>
---

Reading git-diff-tree failed