From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with ESMTP id 51CFE6B008A for ; Thu, 9 Dec 2010 09:42:22 -0500 (EST) Date: Thu, 9 Dec 2010 14:42:02 +0000 From: Mel Gorman Subject: Re: [patch] mm: skip rebalance of hopeless zones Message-ID: <20101209144202.GD20133@csn.ul.ie> References: <1291821419-11213-1-git-send-email-hannes@cmpxchg.org> <20101209003621.GB3796@hostway.ca> <4D00277F.9040000@redhat.com> <20101209010838.GA11758@hostway.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20101209010838.GA11758@hostway.ca> Sender: owner-linux-mm@kvack.org To: Simon Kirby Cc: Rik van Riel , Johannes Weiner , Andrew Morton , linux-mm@kvack.org List-ID: On Wed, Dec 08, 2010 at 05:08:38PM -0800, Simon Kirby wrote: > On Wed, Dec 08, 2010 at 07:49:03PM -0500, Rik van Riel wrote: > > > On 12/08/2010 07:36 PM, Simon Kirby wrote: > > > >> Mel Gorman posted a similar patch to yours, but the logic is instead to > >> consider order>0 balancing sufficient when there are other balanced zones > >> totalling at least 25% of pages on this node. This would probably fix > >> your case as well. > > > > Mel's patch addresses something very different and is unlikely > > to fix the problem this patch addresses. > > Ok, I see they're quite separate. > > Johannes' patch solves the problem of trying to balance a tiny Normal > zone which happens to be full of unclaimable slab pages by giving up in > this hopeless case, regardless of order. > > Mel's patch solves the problem of fighting allocations causing an > order>0 imbalance in the small Normal zone which happens to be full of > reclaimable pages by giving up in this not-worth-bothering case. > > The key difference is that Johannes' patch has no condition on order, so > Mel's patch probably would help (though not for intended reasons) in the > order != 0 case, and probably not in the order=0 case. > I would be interested in hearing if the patch in that series that alters how sleeping_prematurely() treats zone->all_unreclaimable makes a difference though. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org