Return-Path: Received: from smtp.opengridcomputing.com ([72.48.136.20]:46137 "EHLO smtp.opengridcomputing.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754044AbbGUWlT (ORCPT ); Tue, 21 Jul 2015 18:41:19 -0400 Subject: Re: [PATCH v3 05/15] xprtrdma: Remove last ib_reg_phys_mr() call site To: Jason Gunthorpe References: <20150720185624.10997.51574.stgit@manet.1015granger.net> <20150720190311.10997.12636.stgit@manet.1015granger.net> <55AD5B48.3010906@talpey.com> <20150720210544.GA9655@obsidianresearch.com> <015101d0c331$69e31d10$3da95730$@opengridcomputing.com> <55AD7065.8040809@talpey.com> <015701d0c33d$36b53110$a41f9330$@opengridcomputing.com> <20150720224244.GB12278@obsidianresearch.com> Cc: "'Tom Talpey'" , "'Chuck Lever'" , linux-rdma@vger.kernel.org, linux-nfs@vger.kernel.org From: Steve Wise Message-ID: <55AECA92.3040105@opengridcomputing.com> Date: Tue, 21 Jul 2015 17:41:22 -0500 MIME-Version: 1.0 In-Reply-To: <20150720224244.GB12278@obsidianresearch.com> Content-Type: text/plain; charset=windows-1252; format=flowed Sender: linux-nfs-owner@vger.kernel.org List-ID: On 7/20/2015 5:42 PM, Jason Gunthorpe wrote: > On Mon, Jul 20, 2015 at 05:41:27PM -0500, Steve Wise wrote: >>> B) why bother to check? Are machines with <4GB interesting, and worth >>> supporting a special optimization? >> No, but cxgb3 is still interesting to user applications, and perhaps NFSRDMA using FRMRs. > Doesn't look like the NFS client will work. It requires an all > physical memory lkey for SEND and RECV buffers.. > > Jason > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html Looks like cxgb3 supports LOCAL_DMA_LKEY and MEM_MGT_EXTENSIONS so dma mrs aren't required for NFSRDMA: t4:~/linux-2.6/drivers/infiniband/hw/cxgb3 # grep IB_DEVICE_ iwch_provider.c strlcpy(dev->ibdev.name, "cxgb3_%d", IB_DEVICE_NAME_MAX); dev->device_cap_flags = IB_DEVICE_LOCAL_DMA_LKEY | IB_DEVICE_MEM_WINDOW | IB_DEVICE_MEM_MGT_EXTENSIONS; So cxgb3 can still support NFSRDMA and user verbs w/o get_dma_mr(). I'll submit a patch soon to only support get_dma_mr() if unsigned long is 4 bytes... Steve.