Date: Mon, 4 May 2015 12:15:00 -0400
From: Tejun Heo <tj@kernel.org>
To: Zefan Li <lizefan@huawei.com>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>, Cgroups <cgroups@vger.kernel.org>
Subject: Re: [RFC][PATCH] cgroup: disallow subtree controller enable/disable
 while there are tasks
Message-ID: <20150504161500.GC1971@htj.duckdns.org>
References: <554745D1.1000206@huawei.com>
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On Mon, May 04, 2015 at 06:11:29PM +0800, Zefan Li wrote:
> It's not safe if we enable/disable some controllers while there are
> tasks in the substree, because task migration can fail.
> 
> For example rt bandwidth controller disallow having rt tasks in the
> cgroup if no bandwidth has been allocated, which is the case when
> a cgroup is just created.
> 
> A kernel warning is triggered immediately by doing:

Well, the whole thing is behind the devel flag for a reason.  Let's
see how we can resolve the RT case and then determine what to do.

Thanks.

-- 
tejun
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