From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qc0-f171.google.com (mail-qc0-f171.google.com [209.85.216.171]) by kanga.kvack.org (Postfix) with ESMTP id 70DA06B0070 for ; Mon, 20 Oct 2014 11:18:50 -0400 (EDT) Received: by mail-qc0-f171.google.com with SMTP id i17so3906490qcy.30 for ; Mon, 20 Oct 2014 08:18:50 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id g6si16788873qgf.49.2014.10.20.08.18.49 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 20 Oct 2014 08:18:49 -0700 (PDT) Message-ID: <544527CE.8090607@redhat.com> Date: Mon, 20 Oct 2014 11:18:38 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH 3/5] mm, compaction: defer only on COMPACT_COMPLETE References: <1412696019-21761-1-git-send-email-vbabka@suse.cz> <1412696019-21761-4-git-send-email-vbabka@suse.cz> In-Reply-To: <1412696019-21761-4-git-send-email-vbabka@suse.cz> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Vlastimil Babka , Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Minchan Kim , Mel Gorman , Joonsoo Kim , Michal Nazarewicz , Naoya Horiguchi , Christoph Lameter , David Rientjes On 10/07/2014 11:33 AM, Vlastimil Babka wrote: > Deferred compaction is employed to avoid compacting zone where sync direct > compaction has recently failed. As such, it makes sense to only defer when > a full zone was scanned, which is when compact_zone returns with > COMPACT_COMPLETE. It's less useful to defer when compact_zone returns with > apparent success (COMPACT_PARTIAL), followed by a watermark check failure, > which can happen due to parallel allocation activity. It also does not make > much sense to defer compaction which was completely skipped (COMPACT_SKIP) for > being unsuitable in the first place. > > This patch therefore makes deferred compaction trigger only when > COMPACT_COMPLETE is returned from compact_zone(). Results of stress-highalloc > becnmark show the difference is within measurement error, so the issue is > rather cosmetic. > > Signed-off-by: Vlastimil Babka > Cc: Minchan Kim > Cc: Mel Gorman > Cc: Joonsoo Kim > Cc: Michal Nazarewicz > Cc: Naoya Horiguchi > Cc: Christoph Lameter > Cc: Rik van Riel > Cc: David Rientjes Acked-by: Rik van Riel -- 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/ . Don't email: email@kvack.org