Return-Path: Received: from quartz.orcorp.ca ([184.70.90.242]:49126 "EHLO quartz.orcorp.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752237AbbGNT5K (ORCPT ); Tue, 14 Jul 2015 15:57:10 -0400 Date: Tue, 14 Jul 2015 13:57:00 -0600 From: Jason Gunthorpe To: "'Christoph Hellwig'" Cc: Steve Wise , "'Sagi Grimberg'" , "'Steve Wise'" , "'Tom Talpey'" , "'Doug Ledford'" , sagig@mellanox.com, ogerlitz@mellanox.com, roid@mellanox.com, linux-rdma@vger.kernel.org, eli@mellanox.com, target-devel@vger.kernel.org, linux-nfs@vger.kernel.org, trond.myklebust@primarydata.com, bfields@fieldses.org, "'Oren Duer'" Subject: Re: [PATCH V3 1/5] RDMA/core: Transport-independent access flags Message-ID: <20150714195700.GA26927@obsidianresearch.com> References: <20150708203205.GA21847@infradead.org> <20150709000337.GE16812@obsidianresearch.com> <559EF332.7060103@redhat.com> <20150709225306.GA30741@obsidianresearch.com> <559FC710.1050307@talpey.com> <20150710161108.GA19042@obsidianresearch.com> <55A24571.60902@dev.mellanox.co.il> <00e201d0be6a$e49bc910$add35b30$@opengridcomputing.com> <20150714194512.GA25887@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20150714194512.GA25887@infradead.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Tue, Jul 14, 2015 at 12:45:12PM -0700, 'Christoph Hellwig' wrote: > How does IB_DEVICE_LOCAL_DMA_LKEY (and ->local_dma_lkey) play into > this? Seems like that should be the preferred option if supported. Very good question. > Interestingly enough various iWarp driver seem to support this option, > what's the story behind that? The (to me surprising) conclusion on > the list was that iWarp would always need a memory regireations that Only for the RDMA READ lkey. All the other verbs are the same as IB, and should use a local access all physical MR lkey. Jason