From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423256AbXBUXVA (ORCPT ); Wed, 21 Feb 2007 18:21:00 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1423257AbXBUXVA (ORCPT ); Wed, 21 Feb 2007 18:21:00 -0500 Received: from ozlabs.org ([203.10.76.45]:39471 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423256AbXBUXU7 (ORCPT ); Wed, 21 Feb 2007 18:20:59 -0500 Subject: Re: [patch 05/24] Xen-paravirt_ops: Add pagetable accessors to pack and unpack pagetable entries From: Rusty Russell To: Andi Kleen Cc: virtualization@lists.osdl.org, Chris Wright , xen-devel@lists.xensource.com, Andrew Morton , linux-kernel@vger.kernel.org In-Reply-To: <200702212315.12883.ak@suse.de> References: <20070221205254.169835700@goop.org> <20070221205322.869165491@goop.org> <200702212315.12883.ak@suse.de> Content-Type: text/plain Date: Thu, 22 Feb 2007 10:20:02 +1100 Message-Id: <1172100002.13378.42.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.8.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2007-02-21 at 23:15 +0100, Andi Kleen wrote: > On Wednesday 21 February 2007 21:52, Jeremy Fitzhardinge wrote: > > Add a set of accessors to pack, unpack and modify page table entries > > (at all levels). This allows a paravirt implementation to control the > > contents of pgd/pmd/pte entries. For example, Xen uses this to > > convert the (pseudo-)physical address into a machine address when > > populating a pagetable entry, and converting back to pphys address > > when an entry is read. > > Do you have some lmbench numbers before/after this change? > iirc at least fork and exit do a lot of pte accesses in various forms. > If it's measurable it might be needed to patch those for the native case. Yes, __mkpte must be patched to avoid performance embarrassment. Jeremy, did you want me to do this, or are you happy to? Rusty. PS. I really must revise my "paravirt-ops counter" patch which tallies how much each op is getting called.