Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934728AbZGQQMj (ORCPT ); Fri, 17 Jul 2009 12:12:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964861AbZGQQMi (ORCPT ); Fri, 17 Jul 2009 12:12:38 -0400 Received: from casper.infradead.org ([85.118.1.10]:42209 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934708AbZGQQMi (ORCPT ); Fri, 17 Jul 2009 12:12:38 -0400 Subject: Re: [patch 2/2] sched: fix nr_uninterruptible accounting of frozen tasks really From: Peter Zijlstra To: Matt Helsley Cc: Thomas Gleixner , LKML , Andrew Morton , Rafael Wysocki , Ingo Molnar , Nathan Lynch , Nigel Cunningham , stable@kernel.org, containers@lists.linux-foundation.org, linux-pm@lists.linux-foundation.org In-Reply-To: <20090717155116.GB5878@count0.beaverton.ibm.com> References: <20090717121545.489258927@linutronix.de> <20090717122103.225652146@linutronix.de> <20090717155116.GB5878@count0.beaverton.ibm.com> Content-Type: text/plain Date: Fri, 17 Jul 2009 17:55:27 +0200 Message-Id: <1247846127.6522.21.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.26.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 651 Lines: 16 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. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/