From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751410AbeCNTe6 (ORCPT ); Wed, 14 Mar 2018 15:34:58 -0400 Received: from mail-eopbgr670098.outbound.protection.outlook.com ([40.107.67.98]:18944 "EHLO CAN01-TO1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750779AbeCNTez (ORCPT ); Wed, 14 Mar 2018 15:34:55 -0400 From: "Stephen Bates" To: Dan Williams , Logan Gunthorpe CC: Bjorn Helgaas , Sinan Kaya , "linux-kernel@vger.kernel.org" , "linux-pci@vger.kernel.org" , "linux-nvme@lists.infradead.org" , "linux-rdma@vger.kernel.org" , "linux-nvdimm@lists.01.org" , "linux-block@vger.kernel.org" , "Christoph Hellwig" , Jens Axboe , Keith Busch , Sagi Grimberg , Bjorn Helgaas , Jason Gunthorpe , Max Gurtovoy , =?utf-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Benjamin Herrenschmidt , Alex Williamson Subject: Re: [PATCH v3 01/11] PCI/P2PDMA: Support peer-to-peer memory Thread-Topic: [PATCH v3 01/11] PCI/P2PDMA: Support peer-to-peer memory Thread-Index: AQHTujlZo8bTZRn+4ECdETRRU1rPhqPNgjSAgADeTICAABJggIAAD1YAgAAHVACAAAJxAIAACW8AgAAO3oCAAAopgIAACqIA//+kE4CAAG7lAIAAA38AgAA8KICAAN/GAIAAKyWAgAADR4CAAAbOAP//nVEA Date: Wed, 14 Mar 2018 19:34:53 +0000 Message-ID: References: <3ea80992-a0fc-08f2-d93d-ae0ec4e3f4ce@codeaurora.org> <4eb6850c-df1b-fd44-3ee0-d43a50270b53@deltatee.com> <757fca36-dee4-e070-669e-f2788bd78e41@codeaurora.org> <4f761f55-4e9a-dccb-d12f-c59d2cd689db@deltatee.com> <20180313230850.GA45763@bhelgaas-glaptop.roam.corp.google.com> <8de5d3dd-a78f-02d5-0eea-4365364143b6@deltatee.com> <20180314025639.GA50067@bhelgaas-glaptop.roam.corp.google.com> <112493af-ccd0-455b-6600-b50764f7ab7e@deltatee.com> <20180314185159.GD179719@bhelgaas-glaptop.roam.corp.google.com> In-Reply-To: Accept-Language: en-CA, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: user-agent: Microsoft-MacOutlook/10.b.0.180311 authentication-results: spf=none (sender IP is ) smtp.mailfrom=sbates@raithlin.com; 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x-microsoft-antispam-message-info: e+PuAyaJEVjRBeWkTfLT+OdELBUTC5q+2ou3NLYUCa6SS86J7FMbOi08vGEtr2kVktjFkHtewwxhJYyfNuUzeg+Nl3jlSPT2yX0eHiLwOpfHc/AOFMZfzTK8N9tt76yC9a+piMaJH/ZLuK2+baYs4qEHlgKwELdHoX3QoYxJwLGzbSZCAWJt/RzIOQoVRBZC5Kv6EtmwKh2yPp1CGXHk6WjUyODmPPob9q6SQOaM8bRdnSylwi47KPv3KZiCAYZpDRgUuUbgke02teaBMT9+rzlXdMMt3jOmVSQvxkm+uiF8QcuyRGEt5/QfWcwrYXOFzG2bxVpiM6Wvc21jSZZxGg== spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM Content-Type: text/plain; charset="utf-8" Content-ID: <550690715E85424587140925CC90F10E@CANPRD01.PROD.OUTLOOK.COM> MIME-Version: 1.0 X-OriginatorOrg: raithlin.com X-MS-Exchange-CrossTenant-Network-Message-Id: 81058eac-3927-4d8f-6952-08d589e2a912 X-MS-Exchange-CrossTenant-originalarrivaltime: 14 Mar 2018 19:34:53.3869 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 18519031-7ff4-4cbb-bbcb-c3252d330f4b X-MS-Exchange-Transport-CrossTenantHeadersStamped: YTXPR0101MB1839 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id w2EJZ4Pm018710 > P2P over PCI/PCI-X is quite common in devices like raid controllers. Hi Dan Do you mean between PCIe devices below the RAID controller? Isn't it pretty novel to be able to support PCIe EPs below a RAID controller (as opposed to SCSI based devices)? > It would be useful if those configurations were not left behind so > that Linux could feasibly deploy offload code to a controller in the > PCI domain. Agreed. I think this would be great. Kind of like the XCOPY framework that was proposed a while back for SCSI devices [1] but updated to also include NVMe devices. That is definitely a use case we would like this framework to support. Stephen [1] https://lwn.net/Articles/592094/