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Date: Mon, 29 Aug 2011 19:21:32 +0200
From: Oleg Nesterov <oleg@redhat.com>
To: Tejun Heo <tj@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>, Paul Menage <paul@paulmenage.org>,
        containers@lists.linux-foundation.org,
        linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH pm-freezer 3/4] freezer: check freezing() before
	leaving FROZEN state
Message-ID: <20110829172132.GA12191@redhat.com>
References: <20110829140418.GB18871@mtj.dyndns.org> <20110829140509.GC18871@mtj.dyndns.org> <20110829140549.GD18871@mtj.dyndns.org> <20110829163533.GB9973@redhat.com> <20110829171228.GA11339@redhat.com>
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On 08/29, Oleg Nesterov wrote:
>
> Hmm. But I got lost a bit. Why do we need freezer_lock to set/clear
> PF_FROZEN ? OK, the code below takes freezer_lock for freezing().
> Is there any other reason?

Ah, at least we need it to serialize with __thaw_task() which does
"if (frozen) wake_up()".

Oleg.