From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sagi Grimberg Subject: Re: kernel memory registration Date: Tue, 14 Jul 2015 11:24:26 +0300 Message-ID: <55A4C73A.7080001@dev.mellanox.co.il> References: <559BFE03.4020709@dev.mellanox.co.il> <20150707213628.GA5661@obsidianresearch.com> <559CD174.4040901@dev.mellanox.co.il> <20150708190842.GB11740@obsidianresearch.com> <559D983D.6000804@talpey.com> <20150708233604.GA20765@obsidianresearch.com> <559E54AB.2010905@dev.mellanox.co.il> <20150709170142.GA21921@obsidianresearch.com> <559F8881.7070308@dev.mellanox.co.il> <20150711103153.GC14741@infradead.org> <20150713164652.GC23832@obsidianresearch.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150713164652.GC23832-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Jason Gunthorpe , 'Christoph Hellwig' Cc: Tom Talpey , Steve Wise , dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, sagig-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org, ogerlitz-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org, roid-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org, linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, eli-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org, Oren Duer List-Id: linux-rdma@vger.kernel.org > >> Having a few schemes availabe in the core code that the driver can chose >> from seems like a much more sensible option. > > I think that makes sense, but several of the schemes we are working > with are effectively single-vendor schemes. Indirect MR and DIX are > good examples of things that only one vendor implements, and are not > standardized. > > In those cases it is hard to argue the core should provide support for > them. I'm sorry but I disagree with the statement above. T10-DIF/DIX is a standard and *not* a vendor specific feature. Other storage protocols (FC, SAS, NVME) fully support it. So yes, the core *needs* to support it. Moreover, the core stack poses memory alignment limitations for registration. The RDMA stack should allow an interface that can resolve these limitations if the device is capable of handling them. I'd say this is something all vendors should look at. Sagi. -- 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