From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755573AbYIGPdp (ORCPT ); Sun, 7 Sep 2008 11:33:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751640AbYIGPdg (ORCPT ); Sun, 7 Sep 2008 11:33:36 -0400 Received: from e28smtp04.in.ibm.com ([59.145.155.4]:48846 "EHLO e28esmtp04.in.ibm.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751531AbYIGPdg (ORCPT ); Sun, 7 Sep 2008 11:33:36 -0400 Message-ID: <48C3F444.4060908@linux.vnet.ibm.com> Date: Sun, 07 Sep 2008 21:03:24 +0530 From: Balbir Singh Reply-To: balbir@linux.vnet.ibm.com Organization: IBM User-Agent: Thunderbird 2.0.0.16 (X11/20080724) MIME-Version: 1.0 To: Paul Menage CC: KAMEZAWA Hiroyuki , Daisuke Nishimura , Andrew Morton , Hugh Dickins , Li Zefan , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH][mmotm]memcg: handle null dereference of mm->owner References: <20080905165017.b2715fe4.nishimura@mxp.nes.nec.co.jp> <20080905174021.9fa29b01.kamezawa.hiroyu@jp.fujitsu.com> <6599ad830809050903s7e1a1004i6b31660502c0dcf2@mail.gmail.com> In-Reply-To: <6599ad830809050903s7e1a1004i6b31660502c0dcf2@mail.gmail.com> 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 Paul Menage wrote: > 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. > Right, Thanks! Allocating memory is not that big a problem (we usually know the context), while freeing memory, we can't assume that current is freeing it -- Balbir