From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932369AbXIEUpl (ORCPT ); Wed, 5 Sep 2007 16:45:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757846AbXIEUpZ (ORCPT ); Wed, 5 Sep 2007 16:45:25 -0400 Received: from il.qumranet.com ([82.166.9.18]:60868 "EHLO il.qumranet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757808AbXIEUpX (ORCPT ); Wed, 5 Sep 2007 16:45:23 -0400 Message-ID: <46DF14B2.9050402@qumranet.com> Date: Wed, 05 Sep 2007 23:42:26 +0300 From: Avi Kivity User-Agent: Thunderbird 2.0.0.5 (X11/20070719) MIME-Version: 1.0 To: Jack Steiner CC: linux-kernel@vger.kernel.org, linux-mm@kvack.org, shaohua.li@intel.com, kvm-devel , general@lists.openfabrics.org Subject: Re: [PATCH][RFC]: pte notifiers -- support for external page tables References: <11890103283456-git-send-email-avi@qumranet.com> <20070905204012.GA29272@sgi.com> In-Reply-To: <20070905204012.GA29272@sgi.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org [resend due to broken cc list in my original post] Jack Steiner wrote: > On Wed, Sep 05, 2007 at 07:38:48PM +0300, Avi Kivity wrote: > >> Some hardware and software systems maintain page tables outside the normal >> Linux page tables, which reference userspace memory. This includes >> Infiniband, other RDMA-capable devices, and kvm (with a pending patch). >> >> > > I like it. > > We have 2 special devices with external TLBs that can > take advantage of this. > > One suggestion - at least for what we need. Can the notifier be > registered against the mm_struct instead of (or in addition to) the > vma? > Yes. It's a lot simpler since this way we don't have to support vma creation/splitting/merging/destruction. There's a tiny performance hit for kvm, but it isn't worth the bother. Will implement for v2 of this patch. -- Any sufficiently difficult bug is indistinguishable from a feature.