Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759865AbXEMWQV (ORCPT ); Sun, 13 May 2007 18:16:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755415AbXEMWQO (ORCPT ); Sun, 13 May 2007 18:16:14 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:39227 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755413AbXEMWQN (ORCPT ); Sun, 13 May 2007 18:16:13 -0400 From: "Rafael J. Wysocki" To: Oleg Nesterov Subject: Re: 2.6.22-rc1: Broken suspend on SMP with tifm Date: Mon, 14 May 2007 00:21:13 +0200 User-Agent: KMail/1.9.5 Cc: Andrew Morton , LKML , Michal Piotrowski , Alex Dubov , Pierre Ossman References: <200705132132.08546.rjw@sisk.pl> <200705132350.32582.rjw@sisk.pl> <20070513215425.GA3240@tv-sign.ru> In-Reply-To: <20070513215425.GA3240@tv-sign.ru> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200705140021.14129.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1416 Lines: 39 On Sunday, 13 May 2007 23:54, Oleg Nesterov wrote: > On 05/13, Rafael J. Wysocki wrote: > > > > On Sunday, 13 May 2007 23:34, Oleg Nesterov wrote: > > > On 05/13, Rafael J. Wysocki wrote: > > > > > > > > @@ -819,20 +843,31 @@ static int __devinit workqueue_cpu_callb > > > > > > > > + > > > > + case CPU_DEAD_FROZEN: > > > > + if (wq->freezeable) { > > > > + take_over_work(wq, cpu); > > > > + thaw_process(cwq->thread); > > > > > > Suppose that PF_NOFREEZE task T does flush_workqueue(), and CPU 1 has pending > > > works. T does flush_cpu_workqueue(0), CPU_DEAD_FROZEN moves works from CPU 1 > > > to CPU 0, T does flush_cpu_workqueue(1) and finds nothing. > > > > I don't think this is possible, because we've acquired workqueue_mutex in > > _cpu_down(). > > Yes, we did... but flush_workqueue() doesn't take it? I was looking at the 2.6.21 code, sorry. Hmm, I guess we could add an additional mutex that would only be taken in flush_workqueue() and in _cpu_down()/_cpu_up() via workqueue_cpu_callback() with CPU_LOCK_ACQUIRE? It doesn't seem to be a good idea to run flush_workqueue() while CPUs are being taken up and down anyway. Greetings, Rafael - 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/