From: Mel Gorman Subject: Re: [BUG] fatal hang untarring 90GB file, possibly writeback related. Date: Thu, 28 Apr 2011 15:07:25 +0100 Message-ID: <20110428140725.GX4658@suse.de> References: <1303920553.2583.7.camel@mulgrave.site> <1303921583-sup-4021@think> <1303923000.2583.8.camel@mulgrave.site> <1303923177-sup-2603@think> <1303924902.2583.13.camel@mulgrave.site> <1303925374-sup-7968@think> <1303926637.2583.17.camel@mulgrave.site> <1303934716.2583.22.camel@mulgrave.site> <1303990590.2081.9.camel@lenovo> <20110428135228.GC1696@quack.suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Cc: colin.king@canonical.com, James Bottomley , Chris Mason , linux-fsdevel , linux-mm , linux-kernel , linux-ext4 , mgorman@novell.com To: Jan Kara Return-path: Received: from cantor.suse.de ([195.135.220.2]:56550 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760397Ab1D1OH3 (ORCPT ); Thu, 28 Apr 2011 10:07:29 -0400 Content-Disposition: inline In-Reply-To: <20110428135228.GC1696@quack.suse.cz> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Thu, Apr 28, 2011 at 03:52:28PM +0200, Jan Kara wrote: > On Thu 28-04-11 12:36:30, Colin Ian King wrote: > > One more data point to add, I've been looking at an identical issue when > > copying large amounts of data. I bisected this - and the lockups occur > > with commit > > 3e7d344970673c5334cf7b5bb27c8c0942b06126 - before that I don't see the > > issue. With this commit, my file copy test locks up after ~8-10 > > iterations, before this commit I can copy > 100 times and don't see the > > lockup. > Adding Mel to CC, I guess he'll be interested. Mel, it seems this commit > of yours causes kswapd on non-preempt kernels spin for a *long* time... > I'm still thinking about the traces which do not point the finger directly at compaction per-se but it's possible that the change means kswapd is not reclaiming like it should be. To test this theory, does applying [d527caf2: mm: compaction: prevent kswapd compacting memory to reduce CPU usage] help? -- Mel Gorman SUSE Labs