Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755982AbYCMS7I (ORCPT ); Thu, 13 Mar 2008 14:59:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751618AbYCMS64 (ORCPT ); Thu, 13 Mar 2008 14:58:56 -0400 Received: from extu-mxob-1.symantec.com ([216.10.194.28]:50310 "EHLO extu-mxob-1.symantec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751672AbYCMS6z (ORCPT ); Thu, 13 Mar 2008 14:58:55 -0400 Date: Thu, 13 Mar 2008 18:55:38 +0000 (GMT) From: Hugh Dickins X-X-Sender: hugh@blonde.site To: Jeremy Fitzhardinge cc: Martin Schwidefsky , linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, virtualization@lists.osdl.org, akpm@linux-foundation.org, nickpiggin@yahoo.com.au, zach@vmware.com, frankeh@watson.ibm.com, rusty@rustcorp.com.au, andrea@qumranet.com, clameter@sgi.com, a.p.zijlstra@chello.nl, Keir Fraser , Ian Pratt Subject: Re: [patch 0/6] Guest page hinting version 6. In-Reply-To: <47D9754B.1030509@goop.org> Message-ID: References: <20080312132132.520833247@de.ibm.com> <47D9754B.1030509@goop.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1028 Lines: 20 On Thu, 13 Mar 2008, Jeremy Fitzhardinge wrote: > > My other concern is just correctness over time on the Linux side. We already > have enough trouble keeping things like the pte and page structure state in > sync, with resulting rare data-loss bugs. Adding another layer which only > applies in specific environments raises the possibility for new bugs to be > un-noticed for a long time. How can we structure the VM changes to make sure > that its robust in the face of maintenance? Yes, that's the main concern, as whenever lots of subtlety is added. I wonder if there's any chance of a CONFIG_DEBUG mode, which could be run on anybody's x86 machine, without involving any virtualization, but in which the PAGE_STATEs become essential to the correct working of the mm. Hugh -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/