From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH v10 2/9] cpuset: Add new v2 cpuset.sched.domain_root flag
Date: Thu, 21 Jun 2018 11:20:13 +0200
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To: Waiman Long <longman@redhat.com>
Cc: Tejun Heo <tj@kernel.org>, Li Zefan <lizefan@huawei.com>, Johannes Weiner <hannes@cmpxchg.org>, Ingo Molnar <mingo@redhat.com>, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, kernel-team@fb.com, pjt@google.com, luto@amacapital.net, Mike Galbraith <efault@gmx.de>, torvalds@linux-foundation.org, Roman Gushchin <guro@fb.com>, Juri Lelli <juri.lelli@redhat.com>, Patrick Bellasi <patrick.bellasi@arm.com>

On Thu, Jun 21, 2018 at 03:58:06PM +0800, Waiman Long wrote:

> As for the inconsistency between the real root and the container root,
> this is true for almost all the controllers. So it is a generic problem.
> One possible solution is to create a kind a pseudo root cgroup for the
> container that looks and feels like a real root. But is there really a
> need to do that?

I don't really know. I thought the idea was to make containers
indistinguishable from a real system. Now I know we're really rather far
away from that in reality, and I really have no clue how important all
that is.

It all depends on how exactly this works; is it like I assumed, that
this file is owned by the parent instead of the current directory? And
that if you namespace this, you have an effective read-only file?

Then fixing the inconsistency is trivial; simply provide a read-only
file for the actual root cgroup too.

And if the solution is trivial, I don't see a good reason not to do it.