From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with SMTP id D39688D0040 for ; Wed, 2 Mar 2011 12:22:07 -0500 (EST) Date: Wed, 2 Mar 2011 18:21:41 +0100 From: Andrea Arcangeli Subject: Re: [PATCH] remove compaction from kswapd Message-ID: <20110302172141.GF23911@random.random> References: <20110228222138.GP22700@random.random> <20110301223954.GI19057@random.random> <20110301164143.e44e5699.akpm@linux-foundation.org> <20110302043856.GB23911@random.random> <20110301205324.f0daaf86.akpm@linux-foundation.org> <20110302055221.GD23911@random.random> <20110301215759.f723c9bc.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110301215759.f723c9bc.akpm@linux-foundation.org> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Minchan Kim , Mel Gorman , Johannes Weiner , linux-mm@kvack.org On Tue, Mar 01, 2011 at 09:57:59PM -0800, Andrew Morton wrote: > On Wed, 2 Mar 2011 06:52:21 +0100 Andrea Arcangeli wrote: > > > These are the other two patches that are needed for both workloads to > > be better than before. > > > > mm-compaction-minimise-the-time-irqs-are-disabled-while-isolating-pages-for-migration > > mm-compaction-minimise-the-time-irqs-are-disabled-while-isolating-free-pages > > I have those queued for 2.6.39 - they didn't seem terribly critical and > no mention of NMI watchdog timeouts was made. > > Guys, this stuff matters :( Should both go into 2.6.38? If so, why? Ok: before commit 5a03b051ed87e72b959f32a86054e1142ac4cf55 it was unnoticeable problem (the above two patches are fixing longstanding bugs). But the combination of kswapd running compaction in a loop after commit 5a03b051ed87e72b959f32a86054e1142ac4cf55, and compaction keeping irqs disabled for too long (longstanding bug, but unnoticed before 5a03b051ed87e72b959f32a86054e1142ac4cf55), shows both problems. If you have a single problem you don't notice so much the other one. But kswapd calling compaction in a loop, and compaction keeping irqs disabled for too long are separate problems that shows each other. I think we want the above two patches and the patch Mel sent with Message-ID: <20110302142542.GE14162@csn.ul.ie> in 2.6.38. -- 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 internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org