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 56A0A6B004F for ; Thu, 28 May 2009 03:46:56 -0400 (EDT) Date: Thu, 28 May 2009 09:54:16 +0200 From: Andi Kleen Subject: Re: [PATCH] [1/16] HWPOISON: Add page flag for poisoned pages Message-ID: <20090528075416.GY1065@one.firstfloor.org> References: <200905271012.668777061@firstfloor.org> <20090527201226.CCCBB1D028F@basil.firstfloor.org> <20090527221510.5e418e97@lxorguk.ukuu.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090527221510.5e418e97@lxorguk.ukuu.org.uk> Sender: owner-linux-mm@kvack.org To: Alan Cox Cc: Andi Kleen , akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, fengguang.wu@intel.com List-ID: On Wed, May 27, 2009 at 10:15:10PM +0100, Alan Cox wrote: > On Wed, 27 May 2009 22:12:26 +0200 (CEST) > Andi Kleen wrote: > > > > > Hardware poisoned pages need special handling in the VM and shouldn't be > > touched again. This requires a new page flag. Define it here. > > Why can't you use PG_reserved ? That already indicates the page may not > even be present (which is effectively your situation at that point). Right now a page must be present with PG_reserved, otherwise /dev/mem, /proc/kcore lots of other things will explode. > Given lots of other hardware platforms we support bus error, machine > check, explode or do random undefined fun things when you touch pages > that don't exist I'm not sure I see why poisoned is different here ? It's really a special case for lots of things and mixing it up with PG_reserved is not very useful I think. Also page flags are not that tight a resource anymore anyways. I think it's better to have it separated. However I would expect that other architectures would use poisoned pages too for their own similar issues. It's not really a x86 specific concept. -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