From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pb0-f44.google.com (mail-pb0-f44.google.com [209.85.160.44]) by kanga.kvack.org (Postfix) with ESMTP id 9E1EA6B0035 for ; Sun, 22 Jun 2014 23:04:01 -0400 (EDT) Received: by mail-pb0-f44.google.com with SMTP id md12so5277765pbc.17 for ; Sun, 22 Jun 2014 20:04:01 -0700 (PDT) Received: from lgeamrelo02.lge.com (lgeamrelo02.lge.com. [156.147.1.126]) by mx.google.com with ESMTP id ko1si19778121pbc.100.2014.06.22.20.03.59 for ; Sun, 22 Jun 2014 20:04:00 -0700 (PDT) Date: Mon, 23 Jun 2014 12:04:48 +0900 From: Minchan Kim Subject: Re: [PATCH v3 08/13] mm, compaction: remember position within pageblock in free pages scanner Message-ID: <20140623030448.GD12413@bbox> References: <1403279383-5862-1-git-send-email-vbabka@suse.cz> <1403279383-5862-9-git-send-email-vbabka@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1403279383-5862-9-git-send-email-vbabka@suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Vlastimil Babka Cc: linux-mm@kvack.org, Andrew Morton , David Rientjes , Mel Gorman , Joonsoo Kim , Michal Nazarewicz , Naoya Horiguchi , Christoph Lameter , Rik van Riel , Zhang Yanfei , linux-kernel@vger.kernel.org On Fri, Jun 20, 2014 at 05:49:38PM +0200, Vlastimil Babka wrote: > Unlike the migration scanner, the free scanner remembers the beginning of the > last scanned pageblock in cc->free_pfn. It might be therefore rescanning pages > uselessly when called several times during single compaction. This might have > been useful when pages were returned to the buddy allocator after a failed > migration, but this is no longer the case. > > This patch changes the meaning of cc->free_pfn so that if it points to a > middle of a pageblock, that pageblock is scanned only from cc->free_pfn to the > end. isolate_freepages_block() will record the pfn of the last page it looked > at, which is then used to update cc->free_pfn. > > In the mmtests stress-highalloc benchmark, this has resulted in lowering the > ratio between pages scanned by both scanners, from 2.5 free pages per migrate > page, to 2.25 free pages per migrate page, without affecting success rates. > > Signed-off-by: Vlastimil Babka > Acked-by: David Rientjes Acked-by: Minchan Kim -- Kind regards, Minchan Kim -- 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