Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752368Ab0K2PIl (ORCPT ); Mon, 29 Nov 2010 10:08:41 -0500 Received: from gir.skynet.ie ([193.1.99.77]:59598 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751069Ab0K2PIk (ORCPT ); Mon, 29 Nov 2010 10:08:40 -0500 Date: Mon, 29 Nov 2010 15:08:24 +0000 From: Mel Gorman To: Kyle McMartin Cc: Andrew Morton , Shaohua Li , KOSAKI Motohiro , Christoph Lameter , David Rientjes , KAMEZAWA Hiroyuki , LKML , Linux-MM Subject: Re: [PATCH 1/2] mm: page allocator: Adjust the per-cpu counter threshold when memory is low Message-ID: <20101129150824.GF13268@csn.ul.ie> References: <1288169256-7174-1-git-send-email-mel@csn.ul.ie> <1288169256-7174-2-git-send-email-mel@csn.ul.ie> <20101126160619.GP22651@bombadil.infradead.org> <20101129095618.GB13268@csn.ul.ie> <20101129131626.GF15818@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20101129131626.GF15818@bombadil.infradead.org> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1837 Lines: 38 On Mon, Nov 29, 2010 at 08:16:26AM -0500, Kyle McMartin wrote: > On Mon, Nov 29, 2010 at 09:56:19AM +0000, Mel Gorman wrote: > > Can you point me at a relevant bugzilla entry or forward me the bug report > > and I'll take a look? > > > > https://bugzilla.redhat.com/show_bug.cgi?id=649694 > Ouch! I have been unable to create an exact copy of your kernel source as I'm not running Fedora. From a partial conversion of a source RPM, I saw no changes related to mm/vmscan.c. Is this accurate? I'm trying to establish if this is a mainline bug as well. Second, I see all the stack traces are marked with "?" making them unreliable. Is that anything to be concerned about? I see that one user has reported that the patches fixed the problem for him but I fear that this might be a co-incidence or that the patches close a race of some description. Specifically, I'm trying to identify if there is a situation where kswapd() constantly loops checking watermarks and never calling cond_resched(). This could conceivably happen if kswapd() is always checking sleeping_prematurely() at a higher order where as balance_pgdat() is always checks the watermarks at the lower order. I'm not seeing how this could happen in 2.6.35.6 though. If Fedora doesn't have special changes, it might mean that these patches do need to go into -stable as the cost of zone_page_state_snapshot() is far higher on larger machines than previously reported. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- 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/