From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751697AbaIKBXz (ORCPT ); Wed, 10 Sep 2014 21:23:55 -0400 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:39968 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750970AbaIKBXx (ORCPT ); Wed, 10 Sep 2014 21:23:53 -0400 X-SecurityPolicyCheck: OK by SHieldMailChecker v2.2.3 X-SHieldMailCheckerPolicyVersion: FJ-ISEC-20140219-2 Message-ID: <5410F96B.1020308@jp.fujitsu.com> Date: Thu, 11 Sep 2014 10:22:51 +0900 From: Kamezawa Hiroyuki User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Vladimir Davydov CC: Johannes Weiner , Michal Hocko , Greg Thelen , Hugh Dickins , Motohiro Kosaki , Glauber Costa , Tejun Heo , Andrew Morton , Pavel Emelianov , Konstantin Khorenko , LKML-MM , LKML-cgroups , LKML Subject: Re: [RFC] memory cgroup: my thoughts on memsw References: <20140904143055.GA20099@esperanza> <5408E1CD.3090004@jp.fujitsu.com> <20140905082846.GA25641@esperanza> <5409C6BB.7060009@jp.fujitsu.com> <20140905160029.GF25641@esperanza> <540A4420.2030504@jp.fujitsu.com> <20140908110131.GA11812@esperanza> <540DB4EC.6060100@jp.fujitsu.com> <20140910120157.GA13796@esperanza> In-Reply-To: <20140910120157.GA13796@esperanza> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit X-SecurityPolicyCheck-GC: OK by FENCE-Mail Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (2014/09/10 21:01), Vladimir Davydov wrote: > On Mon, Sep 08, 2014 at 10:53:48PM +0900, Kamezawa Hiroyuki wrote: >> (2014/09/08 20:01), Vladimir Davydov wrote: >>> On Sat, Sep 06, 2014 at 08:15:44AM +0900, Kamezawa Hiroyuki wrote: >>>> As you noticed, hitting anon+swap limit just means oom-kill. >>>> My point is that using oom-killer for "server management" just seems crazy. >>>> >>>> Let my clarify things. your proposal was. >>>> 1. soft-limit will be a main feature for server management. >>>> 2. Because of soft-limit, global memory reclaim runs. >>>> 3. Using swap at global memory reclaim can cause poor performance. >>>> 4. So, making use of OOM-Killer for avoiding swap. >>>> >>>> I can't agree "4". I think >>>> >>>> - don't configure swap. >>> >>> Suppose there are two containers, each having soft limit set to 50% of >>> total system RAM. One of the containers eats 90% of the system RAM by >>> allocating anonymous pages. Another starts using file caches and wants >>> more than 10% of RAM to work w/o issuing disk reads. So what should we >>> do then? >>> We won't be able to shrink the first container to its soft >>> limit, because there's no swap. Leaving it as is would be unfair from >>> the second container's point of view. Kill it? But the whole system is >>> going OK, because the working set of the second container is easily >>> shrinkable. Besides there may be some progress in shrinking file caches >> >from the first container. >>> >>>> - use zram >>> >>> In fact this isn't different from the previous proposal (working w/o >>> swap). ZRAM only compresses data while still storing them in RAM so we >>> eventually may get into a situation where almost all RAM is full of >>> compressed anon pages. >>> >> >> In above 2 cases, "vmpressure" works fine. > > What if a container allocates memory so fast that the userspace thread > handling its threshold notifications won't have time to react before it > eats all memory? > Softlimit is for avoiding such unfair memory scheduling, isn't it ? Thanks, -Kame