From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with ESMTP id 0879F5F0001 for ; Wed, 8 Apr 2009 01:29:13 -0400 (EDT) Received: from d23relay01.au.ibm.com (d23relay01.au.ibm.com [202.81.31.243]) by e23smtp09.au.ibm.com (8.13.1/8.13.1) with ESMTP id n385ARGe026732 for ; Wed, 8 Apr 2009 01:10:27 -0400 Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay01.au.ibm.com (8.13.8/8.13.8/NCO v9.2) with ESMTP id n385TZ8i450890 for ; Wed, 8 Apr 2009 15:29:35 +1000 Received: from d23av02.au.ibm.com (loopback [127.0.0.1]) by d23av02.au.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id n385TYL4027314 for ; Wed, 8 Apr 2009 15:29:35 +1000 Date: Wed, 8 Apr 2009 10:59:04 +0530 From: Balbir Singh Subject: Re: [RFI] Shared accounting for memory resource controller Message-ID: <20090408052904.GY7082@balbir.in.ibm.com> Reply-To: balbir@linux.vnet.ibm.com References: <20090407063722.GQ7082@balbir.in.ibm.com> <20090407160014.8c545c3c.kamezawa.hiroyu@jp.fujitsu.com> <20090407071825.GR7082@balbir.in.ibm.com> <20090407163331.8e577170.kamezawa.hiroyu@jp.fujitsu.com> <20090407080355.GS7082@balbir.in.ibm.com> <20090407172419.a5f318b9.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20090407172419.a5f318b9.kamezawa.hiroyu@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org To: KAMEZAWA Hiroyuki Cc: "linux-mm@kvack.org" , Andrew Morton , "lizf@cn.fujitsu.com" , Rik van Riel , Bharata B Rao , Dhaval Giani , KOSAKI Motohiro , "linux-kernel@vger.kernel.org" List-ID: * KAMEZAWA Hiroyuki [2009-04-07 17:24:19]: > On Tue, 7 Apr 2009 13:33:55 +0530 > Balbir Singh wrote: > > > * KAMEZAWA Hiroyuki [2009-04-07 16:33:31]: > > > > > On Tue, 7 Apr 2009 12:48:25 +0530 > > > Balbir Singh wrote: > > > > > > > * KAMEZAWA Hiroyuki [2009-04-07 16:00:14]: > > > > > > > > > On Tue, 7 Apr 2009 12:07:22 +0530 > > > > > Balbir Singh wrote: > > > > > > > > > > > Hi, All, > > > > > > > > > > > > This is a request for input for the design of shared page accounting for > > > > > > the memory resource controller, here is what I have so far > > > > > > > > > > > > > > > > In my first impression, I think simple counting is impossible. > > > > > IOW, "usage count" and "shared or not" is very different problem. > > > > > > > > > > Assume a page and its page_cgroup. > > > > > > > > > > Case 1) > > > > > 1. a page is mapped by process-X under group-A > > > > > 2. its mapped by process-Y in group-B (now, shared and charged under group-A) > > > > > 3. move process-X to group-B > > > > > 4. now the page is not shared. > > > > > > > > > > > > > By shared I don't mean only between cgroups, it could be a page shared > > > > in the same cgroup > > > > > > > Hmm, is it good information ? > > > > > > Such kind of information can be calucated by > > > == > > > rss = 0; > > > for_each_process_under_cgroup() { > > > mm = tsk->mm > > > rss += mm->anon_rss; > > > } > > > some_of_all_rss = rss; > > > > > > shared_ratio = mem_cgrou->rss *100 / some_of_all_rss. > > > == > > > if 100%, all anon memory are not shared. > > > > > > > Why only anon? > > no serious intention. > Just because you wrote "expect the user to account all cached pages as shared" ;) > OK, I noticed another thing, our RSS accounting is not RSS per-se, it includes only anon RSS, file backed pages are accounted as cached. I'll send out a patch to see if we can include anon RSS as well. > > This seems like a good idea, except when we have a page > > charged to a cgroup and the task that charged it has migrated, in that > > case sum_of_all_rss will be 0. > > > Yes. But we don't move pages at task-move under expectation that moved > process will call fork() soon. > "task move" has its own problem, so ignoring it for now is a choice. > That kind of troubls can be treated when we fixes "task move". > (or fix "task move" first.) > > Thanks, > -Kame > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: email@kvack.org > > -- Balbir -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org