From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: [ofa-general] Re: [PATCH][RFC]: pte notifiers -- support for external page tables Date: Wed, 05 Sep 2007 23:42:26 +0300 Message-ID: <46DF14B2.9050402@qumranet.com> References: <11890103283456-git-send-email-avi@qumranet.com> <20070905204012.GA29272@sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm-devel , linux-mm@kvack.org, linux-kernel@vger.kernel.org, general@lists.openfabrics.org, shaohua.li@intel.com To: Jack Steiner Return-path: In-Reply-To: <20070905204012.GA29272@sgi.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: general-bounces@lists.openfabrics.org Errors-To: general-bounces@lists.openfabrics.org List-Id: kvm.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.