From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757136AbYDGWKk (ORCPT ); Mon, 7 Apr 2008 18:10:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752710AbYDGWKc (ORCPT ); Mon, 7 Apr 2008 18:10:32 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:41592 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751973AbYDGWKb (ORCPT ); Mon, 7 Apr 2008 18:10:31 -0400 Date: Mon, 7 Apr 2008 15:09:56 -0700 From: Andrew Morton To: Balbir Singh Cc: menage@google.com, xemul@openvz.org, hugh@veritas.com, skumar@linux.vnet.ibm.com, yamamoto@valinux.co.jp, lizf@cn.fujitsu.com, linux-kernel@vger.kernel.org, taka@valinux.co.jp, linux-mm@kvack.org, rientjes@google.com, balbir@linux.vnet.ibm.com, kamezawa.hiroyu@jp.fujitsu.com Subject: Re: [-mm] Add an owner to the mm_struct (v8) Message-Id: <20080407150956.9a29573a.akpm@linux-foundation.org> In-Reply-To: <20080404080544.26313.38199.sendpatchset@localhost.localdomain> References: <20080404080544.26313.38199.sendpatchset@localhost.localdomain> X-Mailer: Sylpheed version 2.2.4 (GTK+ 2.8.20; i486-pc-linux-gnu) 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 Fri, 04 Apr 2008 13:35:44 +0530 Balbir Singh wrote: > 1. Add mm->owner change callbacks using cgroups > > ... > > +config MM_OWNER > + bool "Enable ownership of mm structure" > + help > + This option enables mm_struct's to have an owner. The advantage > + of this approach is that it allows for several independent memory > + based cgroup controllers to co-exist independently without too > + much space overhead > + > + This feature adds fork/exit overhead. So enable this only if > + you need resource controllers Do we really want to offer this option to people? It's rather a low-level thing and it's likely to cause more confusion than it's worth. Remember that most kernels get to our users via kernel vendors - to what will they be setting this config option? > config CGROUP_MEM_RES_CTLR > bool "Memory Resource Controller for Control Groups" > depends on CGROUPS && RESOURCE_COUNTERS > + select MM_OWNER Presumably they'll always be setting it to "y" if they are enabling cgroups at all. > --- linux-2.6.25-rc8/kernel/cgroup.c~memory-controller-add-mm-owner 2008-04-03 22:43:27.000000000 +0530 > +++ linux-2.6.25-rc8-balbir/kernel/cgroup.c 2008-04-03 22:43:27.000000000 +0530 > @@ -118,6 +118,7 @@ static int root_count; > * be called. > */ > static int need_forkexit_callback; > +static int need_mm_owner_callback; I suppose these should be __read_mostly.