Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756048Ab0AGHQE (ORCPT ); Thu, 7 Jan 2010 02:16:04 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754366Ab0AGHQD (ORCPT ); Thu, 7 Jan 2010 02:16:03 -0500 Received: from e23smtp04.au.ibm.com ([202.81.31.146]:56032 "EHLO e23smtp04.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753332Ab0AGHQB (ORCPT ); Thu, 7 Jan 2010 02:16:01 -0500 Date: Thu, 7 Jan 2010 12:45:54 +0530 From: Balbir Singh To: KAMEZAWA Hiroyuki Cc: "linux-mm@kvack.org" , Andrew Morton , "linux-kernel@vger.kernel.org" , "nishimura@mxp.nes.nec.co.jp" Subject: Re: [RFC] Shared page accounting for memory cgroup Message-ID: <20100107071554.GO3059@balbir.in.ibm.com> Reply-To: balbir@linux.vnet.ibm.com References: <20091229182743.GB12533@balbir.in.ibm.com> <20100104085108.eaa9c867.kamezawa.hiroyu@jp.fujitsu.com> <20100104000752.GC16187@balbir.in.ibm.com> <20100104093528.04846521.kamezawa.hiroyu@jp.fujitsu.com> <20100104005030.GG16187@balbir.in.ibm.com> <20100106130258.a918e047.kamezawa.hiroyu@jp.fujitsu.com> <20100106070150.GL3059@balbir.in.ibm.com> <20100106161211.5a7b600f.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20100106161211.5a7b600f.kamezawa.hiroyu@jp.fujitsu.com> User-Agent: Mutt/1.5.20 (2009-08-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1710 Lines: 43 * KAMEZAWA Hiroyuki [2010-01-06 16:12:11]: > On Wed, 6 Jan 2010 12:31:50 +0530 > Balbir Singh wrote: > > > No. If it takes long time, locking fork()/exit() for such long time is the bigger > > > issue. > > > I recommend you to add memacct subsystem to sum up RSS of all processes's RSS counting > > > under a cgroup. Althoght it may add huge costs in page fault path but implementation > > > will be very simple and will not hurt realtime ops. > > > There will be no terrible race, I guess. > > > > > > > But others hold that lock as well, simple thing like listing tasks and > > moving tasks, etc. I expect the usage of shared to be in the same > > range. > > > > And piles up costs ? I think cgroup guys should pay attention to fork/exit > costs more. Now, it gets slower and slower. > In that point, I never like migrate-at-task-move work in cpuset and memcg. > > My 1st objection to this patch is this "shared" doesn't mean "shared between > cgroup" but means "shared between processes". > I think it's of no use and no help to users. > So what in your opinion would help end users? My concern is that as we make progress with memcg, we account only for privately used pages with no hint/data about the real usage (shared within or with other cgroups). How do we decide if one cgroup is really heavy? > And implementation is 2nd thing. > More details on your concern, please! -- Balbir -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/