From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id q7KMluOn010308 for ; Mon, 20 Aug 2012 17:47:56 -0500 Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by cuda.sgi.com with ESMTP id Zga2QXaYoyzaHmql for ; Mon, 20 Aug 2012 15:47:55 -0700 (PDT) Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q7KMltr3007704 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Mon, 20 Aug 2012 18:47:55 -0400 Received: from orion.usersys.redhat.com (vpn1-6-42.gru2.redhat.com [10.97.6.42]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id q7KMlq9Z029367 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO) for ; Mon, 20 Aug 2012 18:47:54 -0400 Date: Mon, 20 Aug 2012 19:47:51 -0300 From: Carlos Maiolino Subject: Re: [PATCH] xfs: fix race while discarding buffers [V4] Message-ID: <20120820224751.GA22096@orion.usersys.redhat.com> References: <1344621711-8049-1-git-send-email-cmaiolino@redhat.com> <20120820205134.GB29979@sgi.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20120820205134.GB29979@sgi.com> 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: xfs@oss.sgi.com Hi Ben, > > Thanks for the comments. > > What was the symptom that led to the discovery of this problem? > > Reviewed-by: Ben Myers > It started with the messages like the example below being logged by syslog: shrink_slab: xfs_buftarg_shrink+0x0/0x160 [xfs] negative objects to delete nr=-61993820 shrink_slab: xfs_buftarg_shrink+0x0/0x160 [xfs] negative objects to delete nr=-146 shrink_slab: xfs_buftarg_shrink+0x0/0x160 [xfs] negative objects to delete nr=-240601220 shrink_slab: xfs_buftarg_shrink+0x0/0x160 [xfs] negative objects to delete nr=-152 shrink_slab: xfs_buftarg_shrink+0x0/0x160 [xfs] negative objects to delete nr=-2921236993 These messages came from shrink_slab(). After that I've added a second counter into the xfs_buftarg_shrink() to check the amount of elements in list (via list_for_each() macro) to confirm the discrepancy between the counter and the real number of elements in list, and last, Eric added a second and local counter to xfs_buftarg_shrink, to account the number of buffers being added and removed from the dispose list into each call to xfs_buftarg_shrink(), where, when the problem started, we could see a wrong number of buffers beind added and/or removed from the dispose list. Cheers. -- --Carlos _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs