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Date: Thu, 21 Jul 2016 11:50:46 -0400
From: Tejun Heo <tj@kernel.org>
To: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Aleksa Sarai <asarai@suse.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Li Zefan <lizefan@huawei.com>, Johannes Weiner <hannes@cmpxchg.org>,
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        cgroups@vger.kernel.org, Christian Brauner <cbrauner@suse.de>,
        dev@opencontainers.org
Subject: Re: [PATCH v1 3/3] cgroup: relax common ancestor restriction for
 direct descendants
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Hello, James.

On Thu, Jul 21, 2016 at 08:34:36AM -0700, James Bottomley wrote:
> So if I as the cgroup ns owner am moving a task from A to A_subdir, the
> admin scanning tasks in all of A may miss this task in motion because
> all the tasks files can't be scanned atomically?

So, the admin just wants to move processes from A and only A to B.  It
doesn't wanna interfere with processes in the subdirs or on-going ns
operations, but if the race occurs, both A -> B migration and ns
subdir operation would succeed and the end result would be something
neither expects.

Thanks.

-- 
tejun