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Date: Thu, 1 Nov 2012 07:52:24 -0700
Message-ID: <CAOS58YM+kRtspVUzmnSmOmrDoNS_kF6KA02zWGxqH5FUcRWo1Q@mail.gmail.com>
Subject: Re: [PATCH 3/8] cgroup: use cgroup_lock_live_group(parent) in cgroup_create()
From: Tejun Heo <tj@kernel.org>
To: Michal Hocko <mhocko@suse.cz>
Cc: lizefan@huawei.com, hannes@cmpxchg.org, bsingharora@gmail.com,
        kamezawa.hiroyu@jp.fujitsu.com, containers@lists.linux-foundation.org,
        cgroups@vger.kernel.org, linux-kernel@vger.kernel.org
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Hey, Michal.

On Thu, Nov 1, 2012 at 2:16 AM, Michal Hocko <mhocko@suse.cz> wrote:
> I am not sure I understand. What does deactivate_super has to do with
> the above suggestion? cgroup_lock_live_group will take the cgroup_mutex
> on the success or frees the previously allocated&unused memory. The
> only thing I was suggesting is to do cgroup_lock_live_group first and
> allocate the cgroup only if it doesn't fail.

It complicates updates to the error exit path. You end up having to
update a lot more and it's not like grabbing lock first is
substantially better in any way, so why bother?

Thanks.

-- 
tejun
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