From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754991AbYEFDpE (ORCPT ); Mon, 5 May 2008 23:45:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753363AbYEFDow (ORCPT ); Mon, 5 May 2008 23:44:52 -0400 Received: from E23SMTP06.au.ibm.com ([202.81.18.175]:52794 "EHLO e23smtp06.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752751AbYEFDov (ORCPT ); Mon, 5 May 2008 23:44:51 -0400 Message-ID: <481FD3FC.4010407@linux.vnet.ibm.com> Date: Tue, 06 May 2008 09:13:56 +0530 From: Balbir Singh Reply-To: balbir@linux.vnet.ibm.com Organization: IBM User-Agent: Thunderbird 2.0.0.12 (X11/20080226) MIME-Version: 1.0 To: Andrew Morton CC: linux-mm@kvack.org, skumar@linux.vnet.ibm.com, yamamoto@valinux.co.jp, menage@google.com, lizf@cn.fujitsu.com, linux-kernel@vger.kernel.org, rientjes@google.com, xemul@openvz.org, kamezawa.hiroyu@jp.fujitsu.com Subject: Re: [-mm][PATCH 2/4] Enhance cgroup mm_owner_changed callback to add task information References: <20080503213726.3140.68845.sendpatchset@localhost.localdomain> <20080503213804.3140.26503.sendpatchset@localhost.localdomain> <20080505151504.98c28f7c.akpm@linux-foundation.org> In-Reply-To: <20080505151504.98c28f7c.akpm@linux-foundation.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Andrew Morton wrote: > On Sun, 04 May 2008 03:08:04 +0530 > Balbir Singh wrote: > >> >> This patch adds an additional field to the mm_owner callbacks. This field >> is required to get to the mm that changed. >> >> Signed-off-by: Balbir Singh >> --- >> >> include/linux/cgroup.h | 3 ++- >> kernel/cgroup.c | 2 +- >> 2 files changed, 3 insertions(+), 2 deletions(-) >> >> diff -puN kernel/cgroup.c~cgroup-add-task-to-mm--owner-callbacks kernel/cgroup.c >> --- linux-2.6.25/kernel/cgroup.c~cgroup-add-task-to-mm--owner-callbacks 2008-05-04 02:53:05.000000000 +0530 >> +++ linux-2.6.25-balbir/kernel/cgroup.c 2008-05-04 02:53:05.000000000 +0530 >> @@ -2772,7 +2772,7 @@ void cgroup_mm_owner_callbacks(struct ta >> if (oldcgrp == newcgrp) >> continue; >> if (ss->mm_owner_changed) >> - ss->mm_owner_changed(ss, oldcgrp, newcgrp); >> + ss->mm_owner_changed(ss, oldcgrp, newcgrp, new); >> } >> } >> } >> diff -puN include/linux/cgroup.h~cgroup-add-task-to-mm--owner-callbacks include/linux/cgroup.h >> --- linux-2.6.25/include/linux/cgroup.h~cgroup-add-task-to-mm--owner-callbacks 2008-05-04 02:53:05.000000000 +0530 >> +++ linux-2.6.25-balbir/include/linux/cgroup.h 2008-05-04 02:53:05.000000000 +0530 >> @@ -310,7 +310,8 @@ struct cgroup_subsys { >> */ >> void (*mm_owner_changed)(struct cgroup_subsys *ss, >> struct cgroup *old, >> - struct cgroup *new); >> + struct cgroup *new, >> + struct task_struct *p); > > If mm_owner_changed() had any documentation I'd suggest that it be updated. > Sneaky. > No, there's no documentation besides the comments. I'll go ahead and update cgroups.txt with some documentation. > The existing comment: > > /* > * This routine is called with the task_lock of mm->owner held > */ > void (*mm_owner_changed)(struct cgroup_subsys *ss, > struct cgroup *old, > struct cgroup *new); > > Is rather mysterious. To what mm does it refer? This callback is called when the mm->owner field that points to/owns a cgroup changes as a result of the owner exiting. -- Warm Regards, Balbir Singh Linux Technology Center IBM, ISTL