Re: [RFC][PATCH 1/2] mm: use MIGRATE_HIGHATOMIC as late as possible

Path	csiph.com!news.mixmin.net!news.unit0.net!news.panservice.it!bofh.it!news.nic.it!robomod
From	Michal Hocko <mhocko@kernel.org>
Newsgroups	linux.kernel
Subject	Re: [RFC][PATCH 1/2] mm: use MIGRATE_HIGHATOMIC as late as possible
Date	Tue, 07 Mar 2017 15:00:02 +0100
Message-ID	<tinOG-8fM-11@gated-at.bofh.it> (permalink)
References	<tikH7-6ao-1@gated-at.bofh.it> <tikQO-6fF-11@gated-at.bofh.it> <tilab-6G6-43@gated-at.bofh.it>
MIME-Version	1.0
Content-Type	text/plain; charset=us-ascii
Content-Disposition	inline
User-Agent	Mutt/1.5.23 (2014-03-12)
Sender	robomod@news.nic.it
List-ID	<linux-kernel.vger.kernel.org>
X-Mailing-List	linux-kernel@vger.kernel.org
Approved	robomod@news.nic.it
Lines	25
Organization	linux.* mail to news gateway
X-Original-Cc	Andrew Morton <akpm@linux-foundation.org>, Vlastimil Babka <vbabka@suse.cz>, Mel Gorman <mgorman@techsingularity.net>, Minchan Kim <minchan@kernel.org>, Joonsoo Kim <iamjoonsoo.kim@lge.com>, Yisheng Xie <xieyisheng1@huawei.com>, Linux MM <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>
X-Original-Date	Tue, 7 Mar 2017 12:29:53 +0100
X-Original-Message-ID	<20170307112953.GF28642@dhcp22.suse.cz>
X-Original-References	<58BE8C91.20600@huawei.com> <20170307104758.GE28642@dhcp22.suse.cz> <58BE938B.9020908@huawei.com>
X-Original-Sender	linux-kernel-owner@vger.kernel.org
Xref	csiph.com linux.kernel:1594250

Show key headers only | View raw

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

Thread

[RFC][PATCH 1/2] mm: use MIGRATE_HIGHATOMIC as late as possible Xishi Qiu <qiuxishi@huawei.com> - 2017-03-07 11:40 +0100
  Re: [RFC][PATCH 1/2] mm: use MIGRATE_HIGHATOMIC as late as possible Michal Hocko <mhocko@kernel.org> - 2017-03-07 11:50 +0100
    Re: [RFC][PATCH 1/2] mm: use MIGRATE_HIGHATOMIC as late as possible Xishi Qiu <qiuxishi@huawei.com> - 2017-03-07 12:10 +0100
      Re: [RFC][PATCH 1/2] mm: use MIGRATE_HIGHATOMIC as late as possible Michal Hocko <mhocko@kernel.org> - 2017-03-07 15:00 +0100
  [RFC][PATCH 2/2] mm: unreserve highatomic pageblock if direct reclaim  failed Xishi Qiu <qiuxishi@huawei.com> - 2017-03-07 11:50 +0100

csiph-web