Date: Fri, 17 Jul 2009 09:20:01 -0700
From: Matt Helsley <matthltc@us.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Matt Helsley <matthltc@us.ibm.com>, Thomas Gleixner <tglx@linutronix.de>,
       LKML <linux-kernel@vger.kernel.org>,
       Andrew Morton <akpm@linux-foundation.org>, Rafael Wysocki <rjw@sisk.pl>,
       Ingo Molnar <mingo@elte.hu>, Nathan Lynch <ntl@pobox.com>,
       Nigel Cunningham <nigel@tuxonice.net>, stable@kernel.org,
       containers@lists.linux-foundation.org,
       linux-pm@lists.linux-foundation.org
Subject: Re: [patch 2/2] sched: fix nr_uninterruptible accounting of frozen
	tasks really
Message-ID: <20090717162001.GC5878@count0.beaverton.ibm.com>
References: <20090717121545.489258927@linutronix.de> <20090717122103.225652146@linutronix.de> <20090717155116.GB5878@count0.beaverton.ibm.com> <1247846127.6522.21.camel@laptop>
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On Fri, Jul 17, 2009 at 05:55:27PM +0200, Peter Zijlstra wrote:
> On Fri, 2009-07-17 at 08:51 -0700, Matt Helsley wrote:
> 
> > So it's not clear to me how adding PF_FREEZING fixes anything. Am I
> > missing something?
> 
> Yep, PF_FROZEN is only observed going into schedule(), on the way back
> out thaw_process() will already have cleared the flag.
> 
> So we don't increment in deactivate_task(), but we do decrement in
> activate_task(), yielding for some very unbalanced accounting.

Ahhh, right!

OK, so the fix looks good then.

Cheers,
	-Matt Helsley
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