Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753299Ab0G1Cb3 (ORCPT ); Tue, 27 Jul 2010 22:31:29 -0400 Received: from mx1.redhat.com ([209.132.183.28]:61091 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751439Ab0G1Cb1 (ORCPT ); Tue, 27 Jul 2010 22:31:27 -0400 Date: Tue, 27 Jul 2010 22:30:27 -0400 From: Vivek Goyal To: KAMEZAWA Hiroyuki Cc: "linux-mm@kvack.org" , "nishimura@mxp.nes.nec.co.jp" , "balbir@linux.vnet.ibm.com" , gthelen@google.com, m-ikeda@ds.jp.nec.com, "akpm@linux-foundation.org" , "linux-kernel@vger.kernel.org" Subject: Re: [RFC][PATCH 2/7][memcg] cgroup arbitarary ID allocation Message-ID: <20100728023027.GD12642@redhat.com> References: <20100727165155.8b458b7f.kamezawa.hiroyu@jp.fujitsu.com> <20100727165417.dacbe199.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100727165417.dacbe199.kamezawa.hiroyu@jp.fujitsu.com> User-Agent: Mutt/1.5.20 (2009-12-10) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1895 Lines: 42 On Tue, Jul 27, 2010 at 04:54:17PM +0900, KAMEZAWA Hiroyuki wrote: > From: KAMEZAWA Hiroyuki > > When a subsystem want to make use of "id" more, it's necessary to > manage the id at cgroup subsystem creation time. But, now, > because of the order of cgroup creation callback, subsystem can't > declare the id it wants. This patch allows subsystem to use customized > ID for themselves. > > Signed-off-by: KAMEZAWA Hiroyuki [..] > Index: mmotm-2.6.35-0719/Documentation/cgroups/cgroups.txt > =================================================================== > --- mmotm-2.6.35-0719.orig/Documentation/cgroups/cgroups.txt > +++ mmotm-2.6.35-0719/Documentation/cgroups/cgroups.txt > @@ -621,6 +621,15 @@ and root cgroup. Currently this will onl > the default hierarchy (which never has sub-cgroups) and a hierarchy > that is being created/destroyed (and hence has no sub-cgroups). > > +void custom_id(struct cgroup_subsys *ss, struct cgroup *cgrp) > + > +Called at assigning a new ID to cgroup subsystem state struct. This > +is called when ss->use_id == true. If this function is not provided, > +a new ID is automatically assigned. If you enable ss->use_id, > +you can use css_lookup() and css_get_next() to access "css" objects > +via IDs. > + Couple of lines to explain why a subsystem would like to assign its own ids and not be happy with generic cgroup assigned id be helpful. In this case, I think you are using this id as index into array and want to control the index, hence you seem to be doing it. But I am not sure again why do you want to control index? Vivek -- 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/