From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754595Ab0D1NXE (ORCPT ); Wed, 28 Apr 2010 09:23:04 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48756 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754114Ab0D1NW7 (ORCPT ); Wed, 28 Apr 2010 09:22:59 -0400 Date: Wed, 28 Apr 2010 02:20:56 +0200 From: Andrea Arcangeli To: KAMEZAWA Hiroyuki Cc: Christoph Lameter , Mel Gorman , Linux-MM , LKML , Minchan Kim , Rik van Riel , Andrew Morton Subject: Re: [PATCH 0/3] Fix migration races in rmap_walk() V2 Message-ID: <20100428002056.GH510@random.random> References: <1272403852-10479-1-git-send-email-mel@csn.ul.ie> <20100427223242.GG8860@random.random> <20100428091345.496ca4c4.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100428091345.496ca4c4.kamezawa.hiroyu@jp.fujitsu.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 28, 2010 at 09:13:45AM +0900, KAMEZAWA Hiroyuki wrote: > Doing some check in move_ptes() after vma_adjust() is not safe. > IOW, when vma's information and information in page-table is incosistent...objrmap > is broken and migartion will cause panic. > > Then...I think there are 2 ways. > 1. use seqcounter in "mm_struct" as previous patch and lock it at mremap. > or > 2. get_user_pages_fast() when do remap. 3 take the anon_vma->lock