From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752803Ab1EEC0S (ORCPT ); Wed, 4 May 2011 22:26:18 -0400 Received: from ipmail05.adl6.internode.on.net ([150.101.137.143]:39622 "EHLO ipmail05.adl6.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752449Ab1EEC0R (ORCPT ); Wed, 4 May 2011 22:26:17 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AlQEAD8Iwk15LBzagWdsb2JhbACmHhUBARYmJcdQDoV5BJ4B Date: Thu, 5 May 2011 12:26:13 +1000 From: Dave Chinner To: linux-kernel@vger.kernel.org, Markus Trippelsdorf , Bruno =?iso-8859-1?Q?Pr=E9mont?= , xfs-masters@oss.sgi.com, xfs@oss.sgi.com, Christoph Hellwig , Alex Elder , Dave Chinner Subject: Re: 2.6.39-rc3, 2.6.39-rc4: XFS lockup - regression since 2.6.38 Message-ID: <20110505022613.GA26837@dastard> References: <20110423224403.5fd1136a@neptune.home> <20110427050850.GG12436@dastard> <20110427182622.05a068a2@neptune.home> <20110428194528.GA1627@x4.trippels.de> <20110429011929.GA13542@dastard> <20110504005736.GA2958@cucamonga.audible.transient.net> <20110505002126.GA26797@dastard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110505002126.GA26797@dastard> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 05, 2011 at 10:21:26AM +1000, Dave Chinner wrote: > On Wed, May 04, 2011 at 12:57:36AM +0000, Jamie Heilman wrote: > > Dave Chinner wrote: > > > OK, so the common elements here appears to be root filesystems > > > with small log sizes, which means they are tail pushing all the > > > time metadata operations are in progress. Definitely seems like a > > > race in the AIL workqueue trigger mechanism. I'll see if I can > > > reproduce this and cook up a patch to fix it. > > > > Is there value in continuing to post sysrq-w, sysrq-l, xfs_info, and > > other assorted feedback wrt this issue? I've had it happen twice now > > myself in the past week or so, though I have no reliable reproduction > > technique. Just wondering if more data points will help isolate the > > cause, and if so, how to be prepared to get them. > > > > For whatever its worth, my last lockup was while running > > 2.6.39-rc5-00127-g1be6a1f with a preempt config without cgroups. > > Can you all try the patch below? I've managed to trigger a couple of > xlog_wait() lockups in some controlled load tests. The lockups don't > appear to occur with the following patch to he race condition in > the AIL workqueue trigger. They are still there, just harder to hit. FWIW, I've also discovered that "echo 2 > /proc/sys/vm/drop_caches" gets the system moving again because that changes the push target. I've found two more bugs, and now my test case is now reliably reproducably a 5-10s pause at ~1M created 1byte files and then hanging at about 1.25M files. So there's yet another problem lurking that I need to get to the bottom of. Cheers, Dave. -- Dave Chinner david@fromorbit.com From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id p452Me8F107001 for ; Wed, 4 May 2011 21:22:40 -0500 Date: Thu, 5 May 2011 12:26:13 +1000 From: Dave Chinner Subject: Re: 2.6.39-rc3, 2.6.39-rc4: XFS lockup - regression since 2.6.38 Message-ID: <20110505022613.GA26837@dastard> References: <20110423224403.5fd1136a@neptune.home> <20110427050850.GG12436@dastard> <20110427182622.05a068a2@neptune.home> <20110428194528.GA1627@x4.trippels.de> <20110429011929.GA13542@dastard> <20110504005736.GA2958@cucamonga.audible.transient.net> <20110505002126.GA26797@dastard> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20110505002126.GA26797@dastard> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: linux-kernel@vger.kernel.org, Markus Trippelsdorf , Bruno =?iso-8859-1?Q?Pr=E9mont?= , xfs-masters@oss.sgi.com, xfs@oss.sgi.com, Christoph Hellwig , Alex Elder , Dave Chinner On Thu, May 05, 2011 at 10:21:26AM +1000, Dave Chinner wrote: > On Wed, May 04, 2011 at 12:57:36AM +0000, Jamie Heilman wrote: > > Dave Chinner wrote: > > > OK, so the common elements here appears to be root filesystems > > > with small log sizes, which means they are tail pushing all the > > > time metadata operations are in progress. Definitely seems like a > > > race in the AIL workqueue trigger mechanism. I'll see if I can > > > reproduce this and cook up a patch to fix it. > > > > Is there value in continuing to post sysrq-w, sysrq-l, xfs_info, and > > other assorted feedback wrt this issue? I've had it happen twice now > > myself in the past week or so, though I have no reliable reproduction > > technique. Just wondering if more data points will help isolate the > > cause, and if so, how to be prepared to get them. > > > > For whatever its worth, my last lockup was while running > > 2.6.39-rc5-00127-g1be6a1f with a preempt config without cgroups. > > Can you all try the patch below? I've managed to trigger a couple of > xlog_wait() lockups in some controlled load tests. The lockups don't > appear to occur with the following patch to he race condition in > the AIL workqueue trigger. They are still there, just harder to hit. FWIW, I've also discovered that "echo 2 > /proc/sys/vm/drop_caches" gets the system moving again because that changes the push target. I've found two more bugs, and now my test case is now reliably reproducably a 5-10s pause at ~1M created 1byte files and then hanging at about 1.25M files. So there's yet another problem lurking that I need to get to the bottom of. Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs