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 ESMTP id 906C76B0082 for ; Thu, 4 Jun 2009 08:55:42 -0400 (EDT) Date: Thu, 4 Jun 2009 15:02:55 +0200 From: Andi Kleen Subject: Re: [PATCH] [6/16] HWPOISON: Add various poison checks in mm/memory.c Message-ID: <20090604130255.GB1065@one.firstfloor.org> References: <20090603846.816684333@firstfloor.org> <20090603184639.1933B1D028F@basil.firstfloor.org> <20090604042603.GA15682@localhost> <20090604051915.GN1065@one.firstfloor.org> <20090604115533.GB22118@localhost> <20090604125228.GZ1065@one.firstfloor.org> <20090604125026.GA29026@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090604125026.GA29026@localhost> Sender: owner-linux-mm@kvack.org To: Wu Fengguang Cc: Andi Kleen , "akpm@linux-foundation.org" , "npiggin@suse.de" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" List-ID: On Thu, Jun 04, 2009 at 08:50:26PM +0800, Wu Fengguang wrote: > On Thu, Jun 04, 2009 at 08:52:28PM +0800, Andi Kleen wrote: > > On Thu, Jun 04, 2009 at 07:55:33PM +0800, Wu Fengguang wrote: > > > On Thu, Jun 04, 2009 at 01:19:15PM +0800, Andi Kleen wrote: > > > > On Thu, Jun 04, 2009 at 12:26:03PM +0800, Wu Fengguang wrote: > > > > > On Thu, Jun 04, 2009 at 02:46:38AM +0800, Andi Kleen wrote: > > > > > > > > > > > > Bail out early when hardware poisoned pages are found in page fault handling. > > > > > > > > > > I suspect this patch is also not absolutely necessary: the poisoned > > > > > page will normally have been isolated already. > > > > > > > > It's needed to prevent new pages comming in when there is a parallel > > > > fault while the memory failure handling is in process. > > > > Otherwise the pages could get remapped in that small window. > > > > > > This patch makes no difference at least for file pages, including tmpfs. > > > > I was more thinking of anonymous pages with multiple mappers (e.g. > > COW after fork) > > I guess they are handled by do_anonymous_page() or do_wp_page(), > instead of do_linear_fault()/do_nonlinear_fault()? You're right. Sorry was a little confused in my earlier reply. I think what I meant is: what happens during the window when the page has just the poison bit set, but is not isolated/unmapped yet. During that window I want new mappers to not come in. That is why that check is there. -Andi -- ak@linux.intel.com -- Speaking for myself only. -- 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