Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757487Ab1FVLb2 (ORCPT ); Wed, 22 Jun 2011 07:31:28 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35603 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755582Ab1FVLb1 (ORCPT ); Wed, 22 Jun 2011 07:31:27 -0400 Message-ID: <4E01D27F.8080304@redhat.com> Date: Wed, 22 Jun 2011 14:31:11 +0300 From: Avi Kivity User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110428 Fedora/3.1.10-1.fc15 Thunderbird/3.1.10 MIME-Version: 1.0 To: Izik Eidus CC: nai.xia@gmail.com, Andrew Morton , Andrea Arcangeli , Hugh Dickins , Chris Wright , Rik van Riel , linux-mm , Johannes Weiner , linux-kernel , kvm Subject: Re: [PATCH] mmu_notifier, kvm: Introduce dirty bit tracking in spte and mmu notifier to help KSM dirty bit tracking References: <201106212055.25400.nai.xia@gmail.com> <201106212132.39311.nai.xia@gmail.com> <4E01C752.10405@redhat.com> <4E01CC77.10607@ravellosystems.com> <4E01CDAD.3070202@redhat.com> <4E01CFD2.6000404@ravellosystems.com> <4E01D0E3.9080508@redhat.com> <4E01D1C8.2050707@redhat.com> In-Reply-To: <4E01D1C8.2050707@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 872 Lines: 24 On 06/22/2011 02:28 PM, Avi Kivity wrote: > > Actually, this is dangerous. If we use the dirty bit for other > things, we will get data corruption. > > For example we might want to map clean host pages as writeable-clean > in the spte on a read fault so that we don't get a page fault when > they get eventually written. > Another example - we can use the dirty bit for dirty page loggging. So I think we can get away with a conditional tlb flush - only flush if the page was dirty. That should be rare after the first pass, at least with small pages. -- error compiling committee.c: too many arguments to function -- 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/