From: Steve Wise Subject: Re: [ofa-general] Re: [PATCH 2.6.30] xprtrdma: The frmr iova_start values are truncated by the nfs rdma client. Date: Thu, 14 May 2009 08:41:06 -0500 Message-ID: <4A0C1F72.8050503@opengridcomputing.com> References: <20090424190510.3134.90405.stgit@build.ogc.int> <49F31A16.2080806@opengridcomputing.com> <49F4AE86.4090908@opengridcomputing.com> <49f515a5.1d1e640a.1c82.6677@mx.google.com> <49F5ED55.1010607@opengridcomputing.com> <1240855510.8818.9.camel@heimdal.trondhjem.org> <1240856613.8818.16.camel@heimdal.trondhjem.org> <49F60845.4010007@opengridcomputing.com> <1240865214.8818.73.camel@heimdal.trondhjem.org> <4A08A5C6.7040003@opengridcomputing.com> <1242082203.1743.11.camel@heimdal.trondhjem.org> <4A08BF1C.2050204@opengridcomputing.com> <1242089066.1743.19.camel@heimdal.trondhjem.org> <4a08cd7b.48c3f10a.6bb1.fffff6d3@mx.google.com> <1242092150.16618.15.camel@heimdal.trondhjem.org> <4A08E7B2.1010907@opengridcomputing.com> <4A099FB8.7090603@opengridcomputing.com> <4A09A283.3090605@opengrid computing.com> <4A0BC6A6.1070002@voltaire.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Cc: Roland Dreier , Trond Myklebust , linux-nfs@vger.kernel.org, "Talpey, Thomas" , "general-ZwoEplunGu1OwGhvXhtEPSCwEArCW2h5@public.gmane.org" To: Or Gerlitz Return-path: Received: from smtp.opengridcomputing.com ([209.198.142.2]:58129 "EHLO smtp.opengridcomputing.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752468AbZENNkz (ORCPT ); Thu, 14 May 2009 09:40:55 -0400 In-Reply-To: <4A0BC6A6.1070002-smomgflXvOZWk0Htik3J/w@public.gmane.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: Or Gerlitz wrote: >> Trond Myklebust wrote >>> All I should need to know is that I can advertise either dma handles >>> or kernel VAs > > Maybe its obvious to some people here, but may I ask why there's a > need to post either dma address or kernel virtual address? is it > application need? hardware (e.g IB vs iWARP vs vendor implementation) > specific? or something else? > > Or. > > The NFSRDMA transport uses Fast Register Memory Regions. In this particular section of code, the NFSRDMA client is building a fastreg work request to bind a page list to a fastreg mr. You can read about this in the IBTA spec on memory management extensions, or in the RDMA Verbs draft. Steve.