From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from zps76.corp.google.com (zps76.corp.google.com [172.25.146.76]) by smtp-out.google.com with ESMTP id m85G3opI014098 for ; Fri, 5 Sep 2008 17:03:51 +0100 Received: from gxk14 (gxk14.prod.google.com [10.202.11.14]) by zps76.corp.google.com with ESMTP id m85Fwr0X021386 for ; Fri, 5 Sep 2008 09:03:50 -0700 Received: by gxk14 with SMTP id 14so7064339gxk.20 for ; Fri, 05 Sep 2008 09:03:49 -0700 (PDT) Message-ID: <6599ad830809050903s7e1a1004i6b31660502c0dcf2@mail.gmail.com> Date: Fri, 5 Sep 2008 09:03:49 -0700 From: "Paul Menage" Subject: Re: [PATCH][mmotm]memcg: handle null dereference of mm->owner In-Reply-To: <20080905174021.9fa29b01.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20080905165017.b2715fe4.nishimura@mxp.nes.nec.co.jp> <20080905174021.9fa29b01.kamezawa.hiroyu@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org Return-Path: To: KAMEZAWA Hiroyuki Cc: Daisuke Nishimura , Andrew Morton , Balbir Singh , Hugh Dickins , Li Zefan , linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: On Fri, Sep 5, 2008 at 1:40 AM, KAMEZAWA Hiroyuki wrote: > > BTW, I have a question to Balbir and Paul. (I'm sorry I missed the discussion.) > Recently I wonder why we need MM_OWNER. > > - What's bad with thread's cgroup ? Because lots of mm operations take place in a context where we don't have a thread pointer, and hence no cgroup. > - Why we can't disallow per-thread cgroup under memcg ?) We can, but that's orthogonal - we still need to be able to get to some thread (or a pointer directly in the mm to the cgroup, but with multiple cgroup subsystems popping up that needed such a pointer, it seems cleaner to have the owner pointer rather than adding multiple separate cgroup subsystem pointers to mm. Paul -- 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