From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758718AbZCPALn (ORCPT ); Sun, 15 Mar 2009 20:11:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755084AbZCPALb (ORCPT ); Sun, 15 Mar 2009 20:11:31 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:50674 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752287AbZCPALa (ORCPT ); Sun, 15 Mar 2009 20:11:30 -0400 Date: Mon, 16 Mar 2009 09:10:02 +0900 From: KAMEZAWA Hiroyuki To: balbir@linux.vnet.ibm.com Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "nishimura@mxp.nes.nec.co.jp" , "kosaki.motohiro@jp.fujitsu.com" Subject: Re: [RFC][PATCH 0/5] memcg softlimit (Another one) v4 Message-Id: <20090316091002.e34f3eeb.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20090314185246.GT16897@balbir.in.ibm.com> References: <20090312095247.bf338fe8.kamezawa.hiroyu@jp.fujitsu.com> <20090314185246.GT16897@balbir.in.ibm.com> Organization: FUJITSU Co. LTD. X-Mailer: Sylpheed 2.5.0 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 15 Mar 2009 00:22:46 +0530 Balbir Singh wrote: > * KAMEZAWA Hiroyuki [2009-03-12 09:52:47]: > > > Hi, this is a patch for implemnt softlimit to memcg. > > > > I did some clean up and bug fixes. > > > > Anyway I have to look into details of "LRU scan algorithm" after this. > > > > How this works: > > > > (1) Set softlimit threshold to memcg. > > #echo 400M > /cgroups/my_group/memory.softlimit_in_bytes. > > > > (2) Define priority as victim. > > #echo 3 > /cgroups/my_group/memory.softlimit_priority. > > 0 is the lowest, 8 is the highest. > > If "8", softlimit feature ignore this group. > > default value is "8". > > > > (3) Add some memory pressure and make kswapd() work. > > kswapd will reclaim memory from victims paying regard to priority. > > > > Simple test on my 2cpu 86-64 box with 1.6Gbytes of memory (...vmware) > > > > While a process malloc 800MB of memory and touch it and sleep in a group, > > run kernel make -j 16 under a victim cgroup with softlimit=300M, priority=3. > > > > Without softlimit => 400MB of malloc'ed memory are swapped out. > > With softlimit => 80MB of malloc'ed memory are swapped out. > > > > I think 80MB of swap is from direct memory reclaim path. And this > > seems not to be terrible result. > > > > I'll do more test on other hosts. Any comments are welcome. > > Hi, Kamezawa-San, > > I tried some simple tests with this patch and the results are not > anywhere close to expected. > > 1. My setup is 4GB RAM with 4 CPUs and I boot with numa=fake=4 > 2. I setup my cgroups as follows > a. created /a and /b and set memory.use_hierarchy=1 > b. created /a/x and /b/x, set their memory.softlimit_priority=1 > c. set softlimit_in_bytes for a/x to 1G and b/x to 2G > d. I assigned tasks to a/x and b/x > > I expected the tasks in a/x and b/x to get memory distributed in the > ratio to 1:2. Here is what I found > > 1. The task in a/x got more memory than the task in b/x even though > I started the task in b/x first > 2. Even changing softlimit_priority (increased for b) did not help much > Thank you, I'll rewrite all. But 1G/2G usage can make kswapd() run on 4GB host ? What memory usage will be just depens on usage per-zone and if both of a/x, b/x 's usage are always over softlimit, the result will never be 1:2, because any usage over softlimit can be victim and reclaimed in round-robin. Anyway, softlimit_priority seems to be not good, I'll remove it. Thanks, -Kame