From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759338AbYEOW2s (ORCPT ); Thu, 15 May 2008 18:28:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754201AbYEOW2i (ORCPT ); Thu, 15 May 2008 18:28:38 -0400 Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:38928 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752638AbYEOW2h (ORCPT ); Thu, 15 May 2008 18:28:37 -0400 Date: Fri, 16 May 2008 08:27:53 +1000 From: David Chinner To: Alexander Beregalov Cc: David Chinner , Kamalesh Babulal , pvp-lsts@fs.ru.acad.bg, kernel-testers@vger.kernel.org, kernel list , Ingo Molnar , peterz@infradead.org, xfs@oss.sgi.com Subject: Re: 2.6.26-rc1: possible circular locking dependency with xfs filesystem Message-ID: <20080515222753.GV155679365@sgi.com> References: <4825DF71.1030209@linux.vnet.ibm.com> <48266C77.3040102@linux.vnet.ibm.com> <20080511231002.GN103491721@sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 15, 2008 at 09:45:55PM +0400, Alexander Beregalov wrote: > 2008/5/12 David Chinner : > > On Sun, May 11, 2008 at 09:18:07AM +0530, Kamalesh Babulal wrote: > >> Kamalesh Babulal wrote: > >> > Adding the cc to kernel-list, Ingo Molnar and Peter Zijlstra > >> > > >> > Alexander Beregalov wrote: > >> >> [ INFO: possible circular locking dependency detected ] > >> >> 2.6.26-rc1-00279-g28a4acb #13 > >> >> ------------------------------------------------------- > >> >> nfsd/3087 is trying to acquire lock: > >> >> (iprune_mutex){--..}, at: [] shrink_icache_memory+0x38/0x19b > >> >> > >> >> but task is already holding lock: > >> >> (&(&ip->i_iolock)->mr_lock){----}, at: [] xfs_ilock+0xa2/0xd6 [snip] > > Oh, yeah, that. Direct inode reclaim through memory pressure. > > > > Effectively memory reclaim inverts locking order w.r.t. iprune_mutex > > when it recurses into the filesystem. False positive - can never > > cause a deadlock on XFS. Can't be solved from the XFS side of things > > without effectively turning off lockdep checking for xfs inode > > locking. > Yes, it is not a deadlock, but machine hangs for few seconds. > It still happens about once a day for me. Every kernel report looks > similar to the above. That hang is just memory reclaim running, I think you'll find. It can take some time for reclaim to find pages to use, and meanwhile everything in the machine will back up behind it.... Cheers, Dave. -- Dave Chinner Principal Engineer SGI Australian Software Group