From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d28relay04.in.ibm.com (d28relay04.in.ibm.com [9.184.220.61]) by e28smtp01.in.ibm.com (8.13.1/8.13.1) with ESMTP id m318Hbjh009624 for ; Tue, 1 Apr 2008 13:47:37 +0530 Received: from d28av03.in.ibm.com (d28av03.in.ibm.com [9.184.220.65]) by d28relay04.in.ibm.com (8.13.8/8.13.8/NCO v8.7) with ESMTP id m318Hbb21490972 for ; Tue, 1 Apr 2008 13:47:37 +0530 Received: from d28av03.in.ibm.com (loopback [127.0.0.1]) by d28av03.in.ibm.com (8.13.1/8.13.3) with ESMTP id m318Ha2f030633 for ; Tue, 1 Apr 2008 08:17:37 GMT Message-ID: <47F1EE8F.2050508@linux.vnet.ibm.com> Date: Tue, 01 Apr 2008 13:43:03 +0530 From: Balbir Singh Reply-To: balbir@linux.vnet.ibm.com MIME-Version: 1.0 Subject: Re: [RFC][-mm] Add an owner to the mm_struct (v3) References: <20080401054324.829.4517.sendpatchset@localhost.localdomain> <6599ad830803312316m17f9e6f1mf7f068c0314a789e@mail.gmail.com> <47F1D4F3.3040207@linux.vnet.ibm.com> <6599ad830803312348u3ee4d815i2e24c130978f8e04@mail.gmail.com> <47F1E3C1.6050802@linux.vnet.ibm.com> In-Reply-To: <47F1E3C1.6050802@linux.vnet.ibm.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Paul Menage , YAMAMOTO Takashi Cc: balbir@linux.vnet.ibm.com, Pavel Emelianov , Hugh Dickins , Sudhir Kumar , lizf@cn.fujitsu.com, linux-kernel@vger.kernel.org, taka@valinux.co.jp, linux-mm@kvack.org, David Rientjes , Andrew Morton , KAMEZAWA Hiroyuki List-ID: Balbir Singh wrote: > Paul Menage wrote: >> On Mon, Mar 31, 2008 at 11:23 PM, Balbir Singh >> wrote: >>> > Here we'll want to call vm_cgroup_update_mm_owner(), to adjust the >>> > accounting. (Or if in future we end up with more than a couple of >>> > subsystems that want notification at this time, we'll want to call >>> > cgroup_update_mm_owner() and have it call any interested subsystems. >>> > >>> >>> I don't think we need to adjust accounting, since only mm->owner is changing and >>> not the cgroup to which the task/mm belongs. Do we really need to notify? I >>> don't want to do any notifications under task_lock(). >> It's possible but unlikely that the new owner is in a different cgroup. > > Hmmm... that can never happen with thread groups, since mm->owner is > p->group_leader and that never exits unless all threads are gone (it can > explicitly change groups though). Without thread groups, the new owner can > belong to a different cgroup, so we might need notification. > > Thinking out aloud If mm->owner changes and belongs to a different cgroup, we have a whole new problem. We need to determine all tasks that share the mm and belong to a particular cgroup, which changed since the new owner belongs to a different cgroup and then update the charge. -- Warm Regards, Balbir Singh Linux Technology Center IBM, ISTL -- 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