From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1162011AbeCAVXP (ORCPT ); Thu, 1 Mar 2018 16:23:15 -0500 Received: from ale.deltatee.com ([207.54.116.67]:38684 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161923AbeCAVXK (ORCPT ); Thu, 1 Mar 2018 16:23:10 -0500 To: Jerome Glisse Cc: benh@au1.ibm.com, Dan Williams , Linux Kernel Mailing List , linux-pci@vger.kernel.org, linux-nvme@lists.infradead.org, linux-rdma , linux-nvdimm , linux-block@vger.kernel.org, Stephen Bates , Christoph Hellwig , Jens Axboe , Keith Busch , Sagi Grimberg , Bjorn Helgaas , Jason Gunthorpe , Max Gurtovoy , Alex Williamson , Oliver OHalloran References: <20180228234006.21093-1-logang@deltatee.com> <1519876489.4592.3.camel@kernel.crashing.org> <1519876569.4592.4.camel@au1.ibm.com> <1519938210.4592.30.camel@au1.ibm.com> <1de70207-40ce-29f0-6093-337112852475@deltatee.com> <20180301211817.GC6742@redhat.com> From: Logan Gunthorpe Message-ID: <25034ee7-de03-ed77-78e0-2333f46897cc@deltatee.com> Date: Thu, 1 Mar 2018 14:22:56 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <20180301211817.GC6742@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 172.16.1.162 X-SA-Exim-Rcpt-To: oliveroh@au1.ibm.com, alex.williamson@redhat.com, maxg@mellanox.com, jgg@mellanox.com, bhelgaas@google.com, sagi@grimberg.me, keith.busch@intel.com, axboe@kernel.dk, hch@lst.de, sbates@raithlin.com, linux-block@vger.kernel.org, linux-nvdimm@lists.01.org, linux-rdma@vger.kernel.org, linux-nvme@lists.infradead.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, dan.j.williams@intel.com, benh@au1.ibm.com, jglisse@redhat.com X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [PATCH v2 00/10] Copy Offload in NVMe Fabrics with P2P PCI Memory X-SA-Exim-Version: 4.2.1 (built Tue, 02 Aug 2016 21:08:31 +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 On 01/03/18 02:18 PM, Jerome Glisse wrote: > This is pretty easy to do with HMM: > > unsigned long hmm_page_to_phys_pfn(struct page *page) This is not useful unless you want to go through all the kernel paths we are using and replace page_to_phys() and friends with something else that calls an HMM function when appropriate... The problem isn't getting the physical address from a page, it's that we are passing these pages through various kernel interfaces which expect pages that work in the usual manner. (Look at the code: we quite simply provide a way to get the PCI bus address from a page when necessary). Logan