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Date: Wed, 12 Oct 2011 22:16:41 +0400
From: Cyrill Gorcunov <gorcunov@gmail.com>
To: Tejun Heo <tj@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Kay Sievers <kay.sievers@vrfy.org>, linux-kernel@vger.kernel.org,
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        Oleg Nesterov <oleg@redhat.com>, Paul Menage <paul@paulmenage.org>,
        "Rafael J. Wysocki" <rjw@sisk.pl>,
        Pavel Emelyanov <xemul@parallels.com>
Subject: Re: A =?utf-8?Q?Plumber=E2=80=99?= =?utf-8?Q?s?= Wish List for Linux
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On Wed, Oct 12, 2011 at 10:40:14AM -0700, Tejun Heo wrote:
...
> 
> In general, I think making freezer work nicely with the rest of the
> system is a good idea and have been working towards that direction.
> Allowing a frozen task to be killed is not only handy for use cases
> like above but also makes solving freezer involved deadlocks much less
> likely and easier to solve.  Another that I have in mind is allowing
> ptrace from unfrozen task to a frozen task.  This can be helpful in
> general debugging (currently attaching to multi-threaded, violently
> cloning process is quite cumbersome) and userland checkpointing.

Yeah, being able to ptrace a frozen cgroup would be great for us.
We stick with signals start/stop cycle at moment but the final target
is the cgroups and freezer of course. (btw while were poking freezer
code I noticed that there is no shortcut to move all tasks in cgroup
into the root cgroup, so I guess say "echo -1 > tasks" might be a good
addition to move all tasks from some particular cgroup to the root
by single action).

> 
> I was working toward these and had some of the patches in Rafael's
> tree but then korg went down and we lost track of the tree and I had a
> pretty long vacation.  I can't say for sure but am aiming to achieve
> the goals during the next devel cycle.
>

This is a wishlist after all, so target is pointed and only time is
needed to implement all this ;)

	Cyrill