Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760256AbXFRGoL (ORCPT ); Mon, 18 Jun 2007 02:44:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757320AbXFRGn6 (ORCPT ); Mon, 18 Jun 2007 02:43:58 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:51351 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756279AbXFRGn5 (ORCPT ); Mon, 18 Jun 2007 02:43:57 -0400 Date: Mon, 18 Jun 2007 08:43:43 +0200 From: Ingo Molnar To: Miklos Szeredi Cc: cebbert@redhat.com, chris@atlee.ca, linux-kernel@vger.kernel.org, tglx@linutronix.de, torvalds@linux-foundation.org, akpm@linux-foundation.org Subject: Re: [BUG] long freezes on thinkpad t60 Message-ID: <20070618064343.GA31113@elte.hu> References: <20070524141059.GA19872@elte.hu> <20070524144447.GA25068@elte.hu> <20070524210153.GB19672@elte.hu> <20070616103707.GA28096@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.14 (2007-02-12) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.1.7 -2.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1126 Lines: 32 * Miklos Szeredi wrote: > > could you try the quick hack below, ontop of cfs-v17? It adds two > > things to wait_task_inactive(): > > > > - a cond_resched() [in case you are running !PREEMPT] > > > > - use MONITOR+MWAIT to monitor memory transactions to the rq->curr > > cacheline. This should make the polling loop definitely fair. > > Is it not possible for the mwait to get stuck? it is - when the other CPU does nothing. > > If this solves the problem on your box then i'll do a proper fix and > > introduce a cpu_relax_memory_change(*addr) type of API to around > > monitor/mwait. This patch boots fine on my T60 - but i never saw > > your problem. > > Yes, the patch does make the pauses go away. In fact just the > smp_mb() seems to suffice. cool! Could you send me the smallest patch you tried that still made the hangs go away? Ingo - 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/