From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id 2880F6B002E for ; Tue, 10 May 2011 10:35:16 -0400 (EDT) Date: Tue, 10 May 2011 15:35:09 +0100 From: Mel Gorman Subject: Re: [BUG] fatal hang untarring 90GB file, possibly writeback related. Message-ID: <20110510143509.GD4146@suse.de> References: <1304025145.2598.24.camel@mulgrave.site> <1304030629.2598.42.camel@mulgrave.site> <20110503091320.GA4542@novell.com> <1304431982.2576.5.camel@mulgrave.site> <1304432553.2576.10.camel@mulgrave.site> <20110506074224.GB6591@suse.de> <20110506080728.GC6591@suse.de> <1304964980.4865.53.camel@mulgrave.site> <20110510102141.GA4149@novell.com> <1305036064.6737.8.camel@mulgrave.site> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="vkogqOf2sHV7VnPd" Content-Disposition: inline In-Reply-To: <1305036064.6737.8.camel@mulgrave.site> Sender: owner-linux-mm@kvack.org List-ID: To: James Bottomley Cc: Mel Gorman , Jan Kara , colin.king@canonical.com, Chris Mason , linux-fsdevel , linux-mm , linux-kernel , linux-ext4 --vkogqOf2sHV7VnPd Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline On Tue, May 10, 2011 at 09:01:04AM -0500, James Bottomley wrote: > On Tue, 2011-05-10 at 11:21 +0100, Mel Gorman wrote: > > I really would like to hear if the fix makes a big difference or > > if we need to consider forcing SLUB high-order allocations bailing > > at the first sign of trouble (e.g. by masking out __GFP_WAIT in > > allocate_slab). Even with the fix applied, kswapd might be waking up > > less but processes will still be getting stalled in direct compaction > > and direct reclaim so it would still be jittery. > > "the fix" being this > > https://lkml.org/lkml/2011/3/5/121 > Drop this for the moment. It was a long shot at best and there is little evidence the problem is in this area. I'm attaching two patches. The first is the NO_KSWAPD one to stop kswapd being woken up by SLUB using speculative high-orders. The second one is more drastic and prevents slub entering direct reclaim or compaction. It applies on top of patch 1. These are both untested and afraid are a bit rushed as well :( -- Mel Gorman SUSE Labs --vkogqOf2sHV7VnPd Content-Type: text/x-patch; charset=iso-8859-15 Content-Disposition: attachment; filename="mm-slub-do-not-wake-kswapd-for-slub-high-orders.patch" --vkogqOf2sHV7VnPd--