From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756756Ab0EKRWc (ORCPT ); Tue, 11 May 2010 13:22:32 -0400 Received: from mx1.redhat.com ([209.132.183.28]:19070 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752834Ab0EKRWa (ORCPT ); Tue, 11 May 2010 13:22:30 -0400 Message-ID: <4BE9920C.3020901@redhat.com> Date: Tue, 11 May 2010 13:21:16 -0400 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100330 Fedora/3.0.4-1.fc12 Lightning/1.0b2pre Thunderbird/3.0.4 MIME-Version: 1.0 To: Linus Torvalds CC: Mel Gorman , Andrew Morton , KAMEZAWA Hiroyuki , Linux-MM , LKML , Minchan Kim , Christoph Lameter , Andrea Arcangeli , Peter Zijlstra Subject: Re: [PATCH] mm,migration: Avoid race between shift_arg_pages() and rmap_walk() during migration by not migrating temporary stacks References: <20100511085752.GM26611@csn.ul.ie> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/11/2010 01:11 PM, Linus Torvalds wrote: > On Tue, 11 May 2010, Mel Gorman wrote: >> >> This patch closes the most important race in relation to exec and >> migration. With it applied, the swapops bug is no longer triggering for >> known problem workloads. If you pick it up, it should go with the other >> mmmigration-* fixes in mm. > > Ack. _Much_ better and clearer. > > I'm not entirely sure we need that "maybe_stack" (if we need it, that > would sound like a problem anyway), but I guess it can't hurt either. Just a heads up - I am looking at creating a patch now that allows us to _always_ lock the root anon_vma lock, when locking the anon_vma. That should take care of the other issue pretty cleanly, while still allowing us to only walk the VMAs we have to walk in places like rmap_walk. -- All rights reversed