From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753356AbcGLGdJ (ORCPT ); Tue, 12 Jul 2016 02:33:09 -0400 Received: from out4133-2.mail.aliyun.com ([42.120.133.2]:32406 "EHLO out4133-2.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753209AbcGLGdI (ORCPT ); Tue, 12 Jul 2016 02:33:08 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R161e4;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e02c03296;MF=hillf.zj@alibaba-inc.com;NM=1;PH=DS;RN=6;SR=0;TI=SMTPD_----50LgOkD_1468305165; Reply-To: "Hillf Danton" From: "Hillf Danton" To: "'Andrew Morton'" Cc: "'Mel Gorman'" , "'Johannes Weiner'" , "'Vlastimil Babka'" , "'linux-kernel'" , References: <00ed01d1d1c8$fcb12ff0$f6138fd0$@alibaba-inc.com> <20160711152015.e3be8be7702fb0ca4625040d@linux-foundation.org> In-Reply-To: <20160711152015.e3be8be7702fb0ca4625040d@linux-foundation.org> Subject: Re: [PATCH] mm, vmscan: Give up balancing node for high order allocations earlier Date: Tue, 12 Jul 2016 14:32:45 +0800 Message-ID: <013d01d1dc07$33896860$9a9c3920$@alibaba-inc.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Outlook 14.0 Thread-Index: AQIjHdIxSD+aa8LumyDVvPFUA7jL6gHAokUpn2OeB7A= Content-Language: zh-cn Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > To avoid excessive reclaim, we give up rebalancing for high order > > allocations right after reclaiming enough pages. > > hm. What are the observed runtime effects of this change? Any testing > results? > This work was based on Mel's work, Sir, "[PATCH 00/27] Move LRU page reclaim from zones to nodes v7". In "[PATCH 06/27] mm, vmscan: Make kswapd reclaim in terms of nodes", fragmentation detection is introduced to avoid excessive reclaim. We bail out of balancing for high-order allocations if the pages reclaimed at the __current__ reclaim priority are two times more than required. In this work we give up reclaiming for high-order allocations if the __total__ number of pages reclaimed, from the first priority to the current priority, is more than needed, and in net result we reclaim less pages. Given " [PATCH 00/34] Move LRU page reclaim from zones to nodes v9" is delivered, I will send this work if necessary, after Mel's work landing in the -mm tree. thanks Hillf