From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id 638516B002D for ; Fri, 7 Oct 2011 18:42:51 -0400 (EDT) Message-ID: <4E8F8062.2080105@redhat.com> Date: Fri, 07 Oct 2011 18:42:42 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH 2/2] mm: Abort reclaim/compaction if compaction can proceed References: <1318000643-27996-1-git-send-email-mgorman@suse.de> <1318000643-27996-3-git-send-email-mgorman@suse.de> <4E8F5BEA.3040502@redhat.com> <20111007202417.GD6418@suse.de> In-Reply-To: <20111007202417.GD6418@suse.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: Johannes Weiner , akpm@linux-foundation.org, Josh Boyer , aarcange@redhat.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org On 10/07/2011 04:24 PM, Mel Gorman wrote: > On Fri, Oct 07, 2011 at 04:07:06PM -0400, Rik van Riel wrote: >> On 10/07/2011 11:17 AM, Mel Gorman wrote: >>> If compaction can proceed, shrink_zones() stops doing any work but >>> the callers still shrink_slab(), raises the priority and potentially >>> sleeps. This patch aborts direct reclaim/compaction entirely if >>> compaction can proceed. >>> >>> Signed-off-by: Mel Gorman >> >> This patch makes sense to me, but I have not tested it like >> the first one. >> > > Do if you can. I'll probably build a kernel with your patch in it on Sunday - I'll be walking across a mountain tomorrow :) > It's marginal and could be confirmation bias on my part. Basically, > there is noise when this path is being exercised but there were fewer > slabs scanned. However, I don't know what the variances are and > whether the reduction was within the noise or not but it makes sense > that it would scan less. If I profiled carefully, I might be able > to show that a few additional cycles are spent raising the priority > but it would be marginal. This seems clear enough. > While patch 1 is very clear, patch 2 depends on reviewers deciding it > "makes sense". > >> Having said that, I'm pretty sure the patch is ok :) >> > > Care to ack? Sure. Acked-by: Rik van Riel -- All rights reversed -- 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