From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wg0-f46.google.com (mail-wg0-f46.google.com [74.125.82.46]) by kanga.kvack.org (Postfix) with ESMTP id E264A6B006E for ; Tue, 7 Oct 2014 11:34:00 -0400 (EDT) Received: by mail-wg0-f46.google.com with SMTP id l18so9572587wgh.17 for ; Tue, 07 Oct 2014 08:34:00 -0700 (PDT) Received: from mx2.suse.de (cantor2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id gf8si298547wib.72.2014.10.07.08.34.00 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 07 Oct 2014 08:34:00 -0700 (PDT) From: Vlastimil Babka Subject: [PATCH 3/5] mm, compaction: defer only on COMPACT_COMPLETE Date: Tue, 7 Oct 2014 17:33:37 +0200 Message-Id: <1412696019-21761-4-git-send-email-vbabka@suse.cz> In-Reply-To: <1412696019-21761-1-git-send-email-vbabka@suse.cz> References: <1412696019-21761-1-git-send-email-vbabka@suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Vlastimil Babka , Minchan Kim , Mel Gorman , Joonsoo Kim , Michal Nazarewicz , Naoya Horiguchi , Christoph Lameter , Rik van Riel , David Rientjes 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 --- mm/compaction.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/compaction.c b/mm/compaction.c index 4b3e0bd..9107588 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -1340,7 +1340,7 @@ unsigned long try_to_compact_pages(struct zonelist *zonelist, goto break_loop; } - if (mode != MIGRATE_ASYNC) { + if (mode != MIGRATE_ASYNC && status == COMPACT_COMPLETE) { /* * We think that allocation won't succeed in this zone * so we defer compaction there. If it ends up -- 1.8.4.5 -- 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