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Date: Wed, 2 Nov 2011 16:13:54 +0100
From: Oleg Nesterov <oleg@redhat.com>
To: Jeff Layton <jlayton@redhat.com>
Cc: Tejun Heo <tj@kernel.org>, "Rafael J. Wysocki" <rjw@sisk.pl>,
        Steve French <sfrench@samba.org>, linux-kernel@vger.kernel.org,
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        "J. Bruce Fields" <bfields@fieldses.org>, Neil Brown <neilb@suse.de>,
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Subject: Re: [RFC PATCH] freezer: revert 27920651fe "PM / Freezer: Make
	fake_signal_wake_up() wake TASK_KILLABLE tasks too"
Message-ID: <20111102151354.GA28527@redhat.com>
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On 11/02, Jeff Layton wrote:
>
> On Tue, 1 Nov 2011 14:57:10 -0700
> Tejun Heo <tj@kernel.org> wrote:
>
> > For now, let's go with the count/dont_count.  Can you please write up
> > a patch for that?  Jeff, does this seem okay to you?
> >
>
> Let me make sure I understand since I don't have a great grasp of the
> freezer internals...
>
> This will set the PF_FREEZER_SKIP flag on the task, which prevents
> try_to_freeze_tasks from incrementing the "todo" var for this process
> and should let the suspend proceed.
>
> So this really makes try_to_freeze_tasks set PF_FREEZING on the task,
> but not get upset that it doesn't actually call try_to_freeze().

Yes. PF_FREEZER_SKIP means, "please count me as frozen". This task can
do nothing except refrigerator() after wakeup.

> Is that sufficient for a process that's just sleeping here?

I think this should work... but this is the question to you ;)

Oleg.