From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Steve Wise" Subject: RE: NFSoRDMA Fails for max_sge Less Than 18 Date: Wed, 11 Jan 2017 15:15:04 -0600 Message-ID: <042601d26c4f$c7190e90$554b2bb0$@opengridcomputing.com> References: <027101d26c2c$c94467f0$5bcd37d0$@opengridcomputing.com> <28B0D906-7BDB-4B87-94E9-6BE263BFBFF7@oracle.com> <20170111211123.GD28917@obsidianresearch.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20170111211123.GD28917-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org> Content-Language: en-us Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: 'Jason Gunthorpe' , 'Chuck Lever' Cc: "'Amrani, Ram'" , "'Elior, Ariel'" , "'Kalderon, Michal'" , linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, 'Hariprasad S' , 'Faisal Latif' , 'Doug Ledford' List-Id: linux-rdma@vger.kernel.org > > On Wed, Jan 11, 2017 at 02:40:37PM -0500, Chuck Lever wrote: > > > It might be cool to have an API similar to rdma_rw that allows ULPs > > to use a scatterlist for Send and Receive operations. It could hide > > the driver and device maximum SGE values. > > That would be good, it could bounce buffer, build temporary MRs, > or repeat RDMA WRITE/READ as appropriate.. > We're talking SEND opcodes where the ULP transfers data in the SEND that includes the command request or reply instead of having the target/server side issue RDMA opcodes. > The ULP really is not the right place to put this trade off logic > since it will be very device specific.. > A temporary REG_MR would do the trick...assuming it can contain the SGE depth as well. But issuing multiple SEND operations involves ULP protocol headers so that couldn't be done by a core service... Steve. -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html