From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755288AbdCGN6f (ORCPT ); Tue, 7 Mar 2017 08:58:35 -0500 Received: from mx2.suse.de ([195.135.220.15]:55870 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754919AbdCGN43 (ORCPT ); Tue, 7 Mar 2017 08:56:29 -0500 Date: Tue, 7 Mar 2017 12:29:53 +0100 From: Michal Hocko To: Xishi Qiu Cc: Andrew Morton , Vlastimil Babka , Mel Gorman , Minchan Kim , Joonsoo Kim , Yisheng Xie , Linux MM , LKML Subject: Re: [RFC][PATCH 1/2] mm: use MIGRATE_HIGHATOMIC as late as possible Message-ID: <20170307112953.GF28642@dhcp22.suse.cz> References: <58BE8C91.20600@huawei.com> <20170307104758.GE28642@dhcp22.suse.cz> <58BE938B.9020908@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <58BE938B.9020908@huawei.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 07-03-17 19:03:39, Xishi Qiu wrote: > On 2017/3/7 18:47, Michal Hocko wrote: > > > On Tue 07-03-17 18:33:53, Xishi Qiu wrote: > >> MIGRATE_HIGHATOMIC page blocks are reserved for an atomic > >> high-order allocation, so use it as late as possible. > > > > Why is this better? Are you seeing any problem which this patch > > resolves? In other words the patch description should explain why not > > only what (that is usually clear from looking at the diff). > > > > Hi Michal, > > I have not see any problem yet, I think if we reserve more high order > pageblocks, the more success rate we will get when meet an atomic > high-order allocation, right? Please make sure you measure your changes under different workloads and present numbers in the changelog when you are touch such a subtle things like memory reserves. Ideas that might sound they make sense can turn out to behave differently in the real life. -- Michal Hocko SUSE Labs