From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756153AbYDUGZl (ORCPT ); Mon, 21 Apr 2008 02:25:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751110AbYDUGZd (ORCPT ); Mon, 21 Apr 2008 02:25:33 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:33561 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750976AbYDUGZc (ORCPT ); Mon, 21 Apr 2008 02:25:32 -0400 Date: Sun, 20 Apr 2008 23:24:27 -0700 From: Andrew Morton To: KAMEZAWA Hiroyuki Cc: hugh@veritas.com, menage@google.com, balbir@linux.vnet.ibm.com, xemul@openvz.org, shiwh@cn.fujitsu.com, mel@csn.ul.ie, linux-kernel@vger.kernel.org Subject: Re: -mm merge plans for 2.6.26 (memcgroup) Message-Id: <20080420232427.1b399104.akpm@linux-foundation.org> In-Reply-To: <20080421093059.57a61bc3.kamezawa.hiroyu@jp.fujitsu.com> References: <20080420072053.6bcb7884.akpm@linux-foundation.org> <20080421093059.57a61bc3.kamezawa.hiroyu@jp.fujitsu.com> X-Mailer: Sylpheed version 2.2.4 (GTK+ 2.8.19; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On Mon, 21 Apr 2008 09:30:59 +0900 KAMEZAWA Hiroyuki wrote: > On Mon, 21 Apr 2008 00:51:30 +0100 (BST) > Hugh Dickins wrote: > > > disable-the-memory-controller-by-default-v3.patch > > > disable-the-memory-controller-by-default-v3-fix.patch > > > > If those are to go in, then the sooner the better, yes. > > > > But though I argued for cgroup_disable=memory (or some such), > > I think myself that taking it even further now (requiring an > > additional cgroup_enable=memory at boottime to get the memcg > > stuff you chose with CGROUP_MEM_RES_CTLR=y at build time) is > > confusing overkill, just messing around. Yes, it does sound a bit silly. I'd say just enable it, and provide a cgroup_disable. > > Others think differently. A compromise would be to improve the > > helptext for CGROUP_MEM_RES_CTLR (some of it is presently nonsense, > > isn't it? Certainly there's a significant overhead, but it's the > > 32-bit struct page not the 64-bit which then suffers from crossing > > cacheline boundaries). Not much point in mentioning > > cgroup_disable=memory if those patches go in, but needs to say > > cgroup_enable=memory bootoption also needed. > > > My concern around this is "default" action of cgroups may be different > from each otther. It's confusing... > > > > > memcgroup-check-and-initialize-page-cgroup-in-memmap_init_zone.patch > > > > No, it was a good find from Shi, but you were right to think the patch > > fishy, and Kame put in lots of work (thank you!) to identify the actual > > culprit: he and Mel are discussing what the actual fix should be; and > > we might want to choose a different fix for stable than for 2.6.26. > > > > I think you should drop that memmap_init_zone patch: the cgroup > > pointer is not the only field we assume is zeroed, both flags and > > mapping can cause trouble if they were not originally zeroed. > > Re-zero the whole struct page? No, far better to fix the > > root of the corruption, that Kame and Mel are working on. > > > I'll test and repodt Mel's patch later. I think Shi's patch will be > unnecessary. OK, I'll drop that one. Thanks - it helps.