From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id 2A8BE6B01E3 for ; Thu, 13 May 2010 19:55:47 -0400 (EDT) Received: from m6.gw.fujitsu.co.jp ([10.0.50.76]) by fgwmail7.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id o4DNtiMd014190 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Fri, 14 May 2010 08:55:44 +0900 Received: from smail (m6 [127.0.0.1]) by outgoing.m6.gw.fujitsu.co.jp (Postfix) with ESMTP id 2DA6C45DE4F for ; Fri, 14 May 2010 08:55:44 +0900 (JST) Received: from s6.gw.fujitsu.co.jp (s6.gw.fujitsu.co.jp [10.0.50.96]) by m6.gw.fujitsu.co.jp (Postfix) with ESMTP id 139C445DE4E for ; Fri, 14 May 2010 08:55:44 +0900 (JST) Received: from s6.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s6.gw.fujitsu.co.jp (Postfix) with ESMTP id F09CB1DB8015 for ; Fri, 14 May 2010 08:55:43 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.249.87.104]) by s6.gw.fujitsu.co.jp (Postfix) with ESMTP id A49551DB8012 for ; Fri, 14 May 2010 08:55:43 +0900 (JST) Date: Fri, 14 May 2010 08:51:35 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH] mm,migration: Avoid race between shift_arg_pages() and rmap_walk() during migration by not migrating temporary stacks Message-Id: <20100514085135.cfb5ba17.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: References: <20100511085752.GM26611@csn.ul.ie> <20100512092239.2120.A69D9226@jp.fujitsu.com> <20100512125427.d1b170ba.akpm@linux-foundation.org> <20100513091930.9b42e3b8.kamezawa.hiroyu@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Christoph Lameter Cc: Andrew Morton , KOSAKI Motohiro , Mel Gorman , Linus Torvalds , Linux-MM , LKML , Minchan Kim , Andrea Arcangeli , Rik van Riel , Peter Zijlstra List-ID: On Thu, 13 May 2010 12:22:01 -0500 (CDT) Christoph Lameter wrote: > On Thu, 13 May 2010, KAMEZAWA Hiroyuki wrote: > > > > Would it not be possible to do something similar for the temporary stack? > > > > > > > Problem here is unmap->remap. ->migratepage() function is used as > > > > unmap > > -> migratepage() > > -> failed > > -> remap > > > > Then, migratepage() itself is no help. We need some check-callback before unmap > > or lock to wait for an event we can make remapping progress. > > We could check earlier if the migrate function points to > fail_migrate_page()? If you mean checking before unmap, yes. we can avoid the race. Unmapping itself is dangerous in this case. > Where we check for PageKsm() in unmap_and_move f.e.? > I'm not sure about KSM. Thanks, -Kame -- 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