Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161170AbcK3SC0 (ORCPT ); Wed, 30 Nov 2016 13:02:26 -0500 Received: from ale.deltatee.com ([207.54.116.67]:58272 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933196AbcK3SBw (ORCPT ); Wed, 30 Nov 2016 13:01:52 -0500 To: Jason Gunthorpe , Haggai Eran References: <20161123215510.GA16311@obsidianresearch.com> <91d28749-bc64-622f-56a1-26c00e6b462a@deltatee.com> <20161124164249.GD20818@obsidianresearch.com> <3f2d2db3-fb75-2422-2a18-a8497fd5d70e@amd.com> <20161125193252.GC16504@obsidianresearch.com> <20161128165751.GB28381@obsidianresearch.com> <1480357179.19407.13.camel@mellanox.com> <20161128190244.GA21975@obsidianresearch.com> <20161130162353.GA24639@obsidianresearch.com> Cc: "linux-kernel@vger.kernel.org" , "linux-rdma@vger.kernel.org" , "linux-nvdimm@ml01.01.org" , "christian.koenig@amd.com" , "Suravee.Suthikulpanit@amd.com" , "John.Bridgman@amd.com" , "Alexander.Deucher@amd.com" , "Linux-media@vger.kernel.org" , "dan.j.williams@intel.com" , "dri-devel@lists.freedesktop.org" , Max Gurtovoy , "linux-pci@vger.kernel.org" , "serguei.sagalovitch@amd.com" , "Paul.Blinzer@amd.com" , "Felix.Kuehling@amd.com" , "ben.sander@amd.com" From: Logan Gunthorpe Message-ID: <5f5b7989-84f5-737e-47c8-831f752d6280@deltatee.com> Date: Wed, 30 Nov 2016 11:01:09 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Icedove/45.4.0 MIME-Version: 1.0 In-Reply-To: <20161130162353.GA24639@obsidianresearch.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 172.16.1.111 X-SA-Exim-Rcpt-To: ben.sander@amd.com, Felix.Kuehling@amd.com, Paul.Blinzer@amd.com, serguei.sagalovitch@amd.com, linux-pci@vger.kernel.org, maxg@mellanox.com, dri-devel@lists.freedesktop.org, dan.j.williams@intel.com, Linux-media@vger.kernel.org, Alexander.Deucher@amd.com, John.Bridgman@amd.com, Suravee.Suthikulpanit@amd.com, christian.koenig@amd.com, linux-nvdimm@ml01.01.org, linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, haggaie@mellanox.com, jgunthorpe@obsidianresearch.com X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: Enabling peer to peer device transactions for PCIe devices X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:24:06 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 507 Lines: 15 On 30/11/16 09:23 AM, Jason Gunthorpe wrote: >> Two cases I can think of are RDMA access to an NVMe device's controller >> memory buffer, > > I'm not sure on the use model there.. The NVMe fabrics stuff could probably make use of this. It's an in-kernel system to allow remote access to an NVMe device over RDMA. So they ought to be able to optimize their transfers by DMAing directly to the NVMe's CMB -- no userspace interface would be required but there would need some kernel infrastructure. Logan