From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Martin K. Petersen" Subject: Re: [PATCH v3 01/11] PCI/P2PDMA: Support peer-to-peer memory Date: Thu, 15 Mar 2018 00:00:27 -0400 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> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: (Stephen Bates's message of "Wed, 14 Mar 2018 19:34:53 +0000") List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-nvdimm-bounces-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org Sender: "Linux-nvdimm" To: Stephen Bates Cc: Jens Axboe , "linux-block-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Keith Busch , Alex Williamson , "linux-nvdimm-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org" , "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-nvme-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , Sinan Kaya , =?utf-8?B?SsOpcsO0bWU=?= Glisse , Jason Gunthorpe , Bjorn Helgaas , Benjamin Herrenschmidt , Bjorn Helgaas , Max Gurtovoy , Christoph Hellwig List-Id: linux-rdma@vger.kernel.org Stephen, >> 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. I'm on my umpteenth rewrite of the block/SCSI offload code. It is not as protocol-agnostic as I would like in the block layer facing downwards. It has proven quite hard to reconcile token-based and EXTENDED COPY semantics along with the desire to support stacking. But from an application/filesystem perspective everything looks the same regardless of the intricacies of the device. Nothing is preventing us from supporting other protocols... -- Martin K. Petersen Oracle Linux Engineering