From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Subject: Re: [PATCHSET cgroup/for-3.8] cgroup_freezer: allow migration
 regardless of freezer state and update locking
Date: Fri, 19 Oct 2012 13:02:35 -0700
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To: Matt Helsley <matthltc-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
Cc: rjw-KKrjLPT3xs0@public.gmane.org, oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org

Hey, Matt.

On Thu, Oct 18, 2012 at 06:29:45PM -0700, Matt Helsley wrote:
> Yeah, that would be a nice cleanup too. I guess the ultra-careful way to
> remove this feature would be something like:
> 
> 	Add an internal migration restriction (which may or may not be
> 		exported as a userspace interface in a subsequent
> 		patch).
> 
> 	Make the cgroup freezer use it.
> 
> 	Make the cgroup freezer WARN_ONCE() when the subsystem is first
> 		mounted. Indicates that the behavior is going to
> 		change.
> 
> 	... time passes ...
> 
> 	Remove the use of the migration "lock" from the cgroup freezer
> 		and the WARN_ONCE().
> 
> Which would also make the feature more obvious.

I don't think I'm gonna go that far for this.  I don't think we need
cgroup migration locking after all.

Thanks.

-- 
tejun