Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933675AbYBNPKV (ORCPT ); Thu, 14 Feb 2008 10:10:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752023AbYBNPJ4 (ORCPT ); Thu, 14 Feb 2008 10:09:56 -0500 Received: from 209-198-142-2-host.prismnet.net ([209.198.142.2]:33617 "EHLO smtp.opengridcomputing.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751422AbYBNPJz (ORCPT ); Thu, 14 Feb 2008 10:09:55 -0500 Message-ID: <47B45994.7010805@opengridcomputing.com> Date: Thu, 14 Feb 2008 09:09:08 -0600 From: Steve Wise User-Agent: Thunderbird 2.0.0.6 (X11/20071022) MIME-Version: 1.0 To: Felix Marti CC: Roland Dreier , Christoph Lameter , Rik van Riel , steiner@sgi.com, Andrea Arcangeli , a.p.zijlstra@chello.nl, izike@qumranet.com, linux-kernel@vger.kernel.org, avi@qumranet.com, linux-mm@kvack.org, daniel.blueman@quadrics.com, Robin Holt , general@lists.openfabrics.org, Andrew Morton , kvm-devel@lists.sourceforge.net Subject: Re: [ofa-general] Re: Demand paging for memory regions References: <20080208234302.GH26564@sgi.com><20080208155641.2258ad2c.akpm@linux-foundation.org><20080209012446.GB7051@v2.random><20080209015659.GC7051@v2.random><20080209075556.63062452@bree.surriel.com><47B2174E.5000708@opengridcomputing.com> <8A71B368A89016469F72CD08050AD334026D5C23@maui.asicdesigners.com> In-Reply-To: <8A71B368A89016469F72CD08050AD334026D5C23@maui.asicdesigners.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: 1181 Lines: 28 Felix Marti wrote: > > That is correct, not a change we can make for T3. We could, in theory, > deal with changing mappings though. The change would need to be > synchronized though: the VM would need to tell us which mapping were > about to change and the driver would then need to disable DMA to/from > it, do the change and resume DMA. > Note that for T3, this involves suspending _all_ rdma connections that are in the same PD as the MR being remapped. This is because the driver doesn't know who the application advertised the rkey/stag to. So without that knowledge, all connections that _might_ rdma into the MR must be suspended. If the MR was only setup for local access, then the driver could track the connections with references to the MR and only quiesce those connections. Point being, it will stop probably all connections that an application is using (assuming the application uses a single PD). Steve. -- 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/