From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762621AbYBAXfi (ORCPT ); Fri, 1 Feb 2008 18:35:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759603AbYBAXfa (ORCPT ); Fri, 1 Feb 2008 18:35:30 -0500 Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:56156 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1759558AbYBAXfa (ORCPT ); Fri, 1 Feb 2008 18:35:30 -0500 Date: Fri, 1 Feb 2008 17:35:28 -0600 From: Robin Holt To: Christoph Lameter Cc: Robin Holt , Andrea Arcangeli , Avi Kivity , Izik Eidus , kvm-devel@lists.sourceforge.net, Peter Zijlstra , steiner@sgi.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, daniel.blueman@quadrics.com Subject: Re: [patch 2/4] mmu_notifier: Callbacks to invalidate address ranges Message-ID: <20080201233528.GE12099@sgi.com> References: <20080201050439.009441434@sgi.com> <20080201050623.344041545@sgi.com> <20080201220952.GA3875@sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.15+20070412 (2007-04-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 01, 2008 at 03:19:32PM -0800, Christoph Lameter wrote: > On Fri, 1 Feb 2008, Robin Holt wrote: > > > We are getting this callout when we transition the pte from a read-only > > to read-write. Jack and I can not see a reason we would need that > > callout. It is causing problems for xpmem in that a write fault goes > > to get_user_pages which gets back to do_wp_page that does the callout. > > Right. You placed it there in the first place. So we can drop the code > from do_wp_page? No, we need a callout when we are becoming more restrictive, but not when becoming more permissive. I would have to guess that is the case for any of these callouts. It is for both GRU and XPMEM. I would expect the same is true for KVM, but would like a ruling from Andrea on that. Thanks, Robin From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin Holt Subject: Re: [patch 2/4] mmu_notifier: Callbacks to invalidate address ranges Date: Fri, 1 Feb 2008 17:35:28 -0600 Message-ID: <20080201233528.GE12099@sgi.com> References: <20080201050439.009441434@sgi.com> <20080201050623.344041545@sgi.com> <20080201220952.GA3875@sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Andrea Arcangeli , Peter Zijlstra , linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, steiner-sJ/iWh9BUns@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Avi Kivity , kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, daniel.blueman-xqY44rlHlBpWk0Htik3J/w@public.gmane.org, Robin Holt To: Christoph Lameter Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org On Fri, Feb 01, 2008 at 03:19:32PM -0800, Christoph Lameter wrote: > On Fri, 1 Feb 2008, Robin Holt wrote: > > > We are getting this callout when we transition the pte from a read-only > > to read-write. Jack and I can not see a reason we would need that > > callout. It is causing problems for xpmem in that a write fault goes > > to get_user_pages which gets back to do_wp_page that does the callout. > > Right. You placed it there in the first place. So we can drop the code > from do_wp_page? No, we need a callout when we are becoming more restrictive, but not when becoming more permissive. I would have to guess that is the case for any of these callouts. It is for both GRU and XPMEM. I would expect the same is true for KVM, but would like a ruling from Andrea on that. Thanks, Robin ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 1 Feb 2008 17:35:28 -0600 From: Robin Holt Subject: Re: [patch 2/4] mmu_notifier: Callbacks to invalidate address ranges Message-ID: <20080201233528.GE12099@sgi.com> References: <20080201050439.009441434@sgi.com> <20080201050623.344041545@sgi.com> <20080201220952.GA3875@sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: Robin Holt , Andrea Arcangeli , Avi Kivity , Izik Eidus , kvm-devel@lists.sourceforge.net, Peter Zijlstra , steiner@sgi.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, daniel.blueman@quadrics.com List-ID: On Fri, Feb 01, 2008 at 03:19:32PM -0800, Christoph Lameter wrote: > On Fri, 1 Feb 2008, Robin Holt wrote: > > > We are getting this callout when we transition the pte from a read-only > > to read-write. Jack and I can not see a reason we would need that > > callout. It is causing problems for xpmem in that a write fault goes > > to get_user_pages which gets back to do_wp_page that does the callout. > > Right. You placed it there in the first place. So we can drop the code > from do_wp_page? No, we need a callout when we are becoming more restrictive, but not when becoming more permissive. I would have to guess that is the case for any of these callouts. It is for both GRU and XPMEM. I would expect the same is true for KVM, but would like a ruling from Andrea on that. Thanks, Robin -- 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