From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay3.corp.sgi.com [198.149.34.15]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id q7OIhvVJ097341 for ; Fri, 24 Aug 2012 13:43:57 -0500 Date: Fri, 24 Aug 2012 13:44:41 -0500 From: Ben Myers Subject: Re: [PATCH] xfs: fix race while discarding buffers [V4] Message-ID: <20120824184441.GA3274@sgi.com> References: <1344621711-8049-1-git-send-email-cmaiolino@redhat.com> <20120820205134.GB29979@sgi.com> <20120820224751.GA22096@orion.usersys.redhat.com> <20120820232110.GM19235@dastard> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20120820232110.GM19235@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: Dave Chinner , Carlos Maiolino Cc: xfs@oss.sgi.com Carlos and Dave, On Tue, Aug 21, 2012 at 09:21:10AM +1000, Dave Chinner wrote: > On Mon, Aug 20, 2012 at 07:47:51PM -0300, Carlos Maiolino wrote: > > 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(). > > Worth noting is that this warning came from a RHEL kernel, not a > mainline kernel. The mainline kernels don't screw up the nr_to_scan > calculations when a negative object count is returned to them. > Hence mainline kernels are not impacted by the accounting bug at > all... Thanks for the additional information. Sometimes it is helpful to know the symptom along with the fix. Regards, Ben _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs