From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id 9C5F55F0001 for ; Tue, 7 Apr 2009 04:25:26 -0400 (EDT) Received: from m2.gw.fujitsu.co.jp ([10.0.50.72]) by fgwmail5.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id n378PmLp018042 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Tue, 7 Apr 2009 17:25:48 +0900 Received: from smail (m2 [127.0.0.1]) by outgoing.m2.gw.fujitsu.co.jp (Postfix) with ESMTP id B612245DE62 for ; Tue, 7 Apr 2009 17:25:47 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (s2.gw.fujitsu.co.jp [10.0.50.92]) by m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 5501945DE55 for ; Tue, 7 Apr 2009 17:25:47 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 1C60CE38007 for ; Tue, 7 Apr 2009 17:25:47 +0900 (JST) Received: from m107.s.css.fujitsu.com (m107.s.css.fujitsu.com [10.249.87.107]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id BED941DB803B for ; Tue, 7 Apr 2009 17:25:46 +0900 (JST) Date: Tue, 7 Apr 2009 17:24:19 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [RFI] Shared accounting for memory resource controller Message-Id: <20090407172419.a5f318b9.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20090407080355.GS7082@balbir.in.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> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: balbir@linux.vnet.ibm.com 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: 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" ;) > 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