From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f41.google.com (mail-pa0-f41.google.com [209.85.220.41]) by kanga.kvack.org (Postfix) with ESMTP id 3AAE96B009A for ; Tue, 19 May 2015 03:46:57 -0400 (EDT) Received: by padbw4 with SMTP id bw4so12744027pad.0 for ; Tue, 19 May 2015 00:46:57 -0700 (PDT) Received: from lgemrelse6q.lge.com (LGEMRELSE6Q.lge.com. [156.147.1.121]) by mx.google.com with ESMTP id kd10si19795733pbd.87.2015.05.19.00.46.53 for ; Tue, 19 May 2015 00:46:56 -0700 (PDT) Date: Tue, 19 May 2015 16:47:09 +0900 From: Joonsoo Kim Subject: Re: [PATCH 2/3] mm/page_alloc: stop fallback allocation if we already get some freepage Message-ID: <20150519074708.GD12092@js1304-P5Q-DELUXE> References: <1430119421-13536-1-git-send-email-iamjoonsoo.kim@lge.com> <1430119421-13536-2-git-send-email-iamjoonsoo.kim@lge.com> <5551BB98.2040703@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5551BB98.2040703@suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Vlastimil Babka Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Mel Gorman , Johannes Weiner , Rik van Riel On Tue, May 12, 2015 at 10:36:40AM +0200, Vlastimil Babka wrote: > On 04/27/2015 09:23 AM, Joonsoo Kim wrote: > >Sometimes we try to get more freepages from buddy list than how much > >we really need, in order to refill pcp list. This may speed up following > >allocation request, but, there is a possibility to increase fragmentation > >if we steal freepages from other migratetype buddy list excessively. This > >patch changes this behaviour to stop fallback allocation in order to > >reduce fragmentation if we already get some freepages. > > > >CPU: 8 > >RAM: 512 MB with zram swap > >WORKLOAD: kernel build with -j12 > >OPTION: page owner is enabled to measure fragmentation > >After finishing the build, check fragmentation by 'cat /proc/pagetypeinfo' > > > >* Before > >Number of blocks type (movable) > >DMA32: 208.4 > > > >Number of mixed blocks (movable) > >DMA32: 139 > > > >Mixed blocks means that there is one or more allocated page for > >unmovable/reclaimable allocation in movable pageblock. Results shows that > >more than half of movable pageblock is tainted by other migratetype > >allocation. > > > >* After > >Number of blocks type (movable) > >DMA32: 207 > > > >Number of mixed blocks (movable) > >DMA32: 111.2 > > > >This result shows that non-mixed block increase by 38% in this case. > > > >Signed-off-by: Joonsoo Kim > > I agree that keeping fragmentation low is more important than > filling up the pcplists. Wouldn't expect such large difference > though. Are the results stable? Yes, I think that improvement is very stable. stdev is roughly 8 in 5 runs. Thanks. -- 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