From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mike Galbraith <umgwanakikbuti@gmail.com>
Subject: Re: [PATCH] sched: Relax a restriction in sched_rt_can_attach()
Date: Mon, 04 May 2015 16:09:42 +0200
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To: Peter Zijlstra <peterz@infradead.org>
Cc: Zefan Li <lizefan@huawei.com>, Ingo Molnar <mingo@kernel.org>, Tejun Heo <tj@kernel.org>, LKML <linux-kernel@vger.kernel.org>, Cgroups <cgroups@vger.kernel.org>

On Mon, 2015-05-04 at 14:37 +0200, Peter Zijlstra wrote:
> On Mon, May 04, 2015 at 05:11:10PM +0800, Zefan Li wrote:
> 
> > Some degree of flexibility is provided so that you may disable some controllers
> > in a subtree. For example:
> >
> > root                  ---> child1
> > (cpuset,memory,cpu)        (cpuset,memory)
> >                       \
> >                        \-> child2
> >                            (cpu)
> 
> Uhm, how does that work? Would a task their effective cgroup be the
> first parent that has a controller enabled?
> 
> In particular, in your example, if T were part of child1, would its cpu
> controller be root?

That's what I'd hope for.  I wanted to try that cgroup.subtree_control
gizmo to see for myself, but I don't have one, and probably won't get
one until I introduce systemd to my axe (again, it's a slow learner).

	-Mike