Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758567Ab1ELUEU (ORCPT ); Thu, 12 May 2011 16:04:20 -0400 Received: from bedivere.hansenpartnership.com ([66.63.167.143]:46090 "EHLO bedivere.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757573Ab1ELUET (ORCPT ); Thu, 12 May 2011 16:04:19 -0400 Subject: Re: [PATCH 3/3] mm: slub: Default slub_max_order to 0 From: James Bottomley To: Pekka Enberg Cc: Christoph Lameter , Mel Gorman , Andrew Morton , Colin King , Raghavendra D Prabhu , Jan Kara , Chris Mason , Rik van Riel , Johannes Weiner , linux-fsdevel , linux-mm , linux-kernel , linux-ext4 In-Reply-To: <1305229447.2575.71.camel@mulgrave.site> References: <1305127773-10570-1-git-send-email-mgorman@suse.de> <1305127773-10570-4-git-send-email-mgorman@suse.de> <1305213359.2575.46.camel@mulgrave.site> <1305214993.2575.50.camel@mulgrave.site> <1305215742.27848.40.camel@jaguar> <1305225467.2575.66.camel@mulgrave.site> <1305229447.2575.71.camel@mulgrave.site> Content-Type: text/plain; charset="UTF-8" Date: Thu, 12 May 2011 15:04:12 -0500 Message-ID: <1305230652.2575.72.camel@mulgrave.site> Mime-Version: 1.0 X-Mailer: Evolution 2.32.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1527 Lines: 35 On Thu, 2011-05-12 at 14:44 -0500, James Bottomley wrote: > On Thu, 2011-05-12 at 13:37 -0500, James Bottomley wrote: > > On Thu, 2011-05-12 at 18:55 +0300, Pekka Enberg wrote: > > > On Thu, 2011-05-12 at 10:43 -0500, James Bottomley wrote: > > > > However, since you admit even you see problems, let's concentrate on > > > > fixing them rather than recriminations? > > > > > > Yes, please. So does dropping max_order to 1 help? > > > PAGE_ALLOC_COSTLY_ORDER is set to 3 in 2.6.39-rc7. > > > > Just booting with max_slab_order=1 (and none of the other patches > > applied) I can still get the machine to go into kswapd at 99%, so it > > doesn't seem to make much of a difference. > > > > Do you want me to try with the other two patches and max_slab_order=1? > > OK, so patches 1 + 2 plus setting slub_max_order=1 still manages to > trigger the problem (kswapd spinning at 99%). This is still with > PREEMPT; it's possible that non-PREEMPT might be better, so I'll try > patches 1+2+3 with PREEMPT just to see if the perturbation is caused by > it. Confirmed, I'm afraid ... I can trigger the problem with all three patches under PREEMPT. It's not a hang this time, it's just kswapd taking 100% system time on 1 CPU and it won't calm down after I unload the system. James -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/