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Date: Tue, 2 Apr 2013 12:43:46 +0400
From: Glauber Costa <glommer@parallels.com>
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To: Li Zefan <lizefan@huawei.com>
CC: Michal Hocko <mhocko@suse.cz>, Johannes Weiner <hannes@cmpxchg.org>,
        KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
        LKML <linux-kernel@vger.kernel.org>, Cgroups <cgroups@vger.kernel.org>,
        <linux-mm@kvack.org>
Subject: Re: [PATCH] memcg: don't do cleanup manually if mem_cgroup_css_online()
 fails
References: <515A8A40.6020406@huawei.com>
In-Reply-To: <515A8A40.6020406@huawei.com>
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On 04/02/2013 11:35 AM, Li Zefan wrote:
> If memcg_init_kmem() returns -errno when a memcg is being created,
> mem_cgroup_css_online() will decrement memcg and its parent's refcnt,
> (but strangely there's no mem_cgroup_put() for mem_cgroup_get() called
> in memcg_propagate_kmem()).
> 
> But then cgroup core will call mem_cgroup_css_free() to do cleanup...
> 

Not a kmemcg bug, but a real bug. Tested by forcing an ENOMEM condition
to happen manually, and Li patch fixes it.
> Signed-off-by: Li Zefan <lizefan@huawei.com>

Acked-by: Glauber Costa <glommer@parallels.com>