From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1163649AbeCBADW (ORCPT ); Thu, 1 Mar 2018 19:03:22 -0500 Received: from ale.deltatee.com ([207.54.116.67]:39994 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1163541AbeCBADT (ORCPT ); Thu, 1 Mar 2018 19:03:19 -0500 To: Stephen Bates , Keith Busch Cc: Jason Gunthorpe , Sagi Grimberg , "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 , Bjorn Helgaas , Max Gurtovoy , Dan Williams , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Benjamin Herrenschmidt , Alex Williamson , Steve Wise References: <20180228234006.21093-1-logang@deltatee.com> <20180228234006.21093-11-logang@deltatee.com> <749e3752-4349-0bdf-5243-3d510c2b26db@grimberg.me> <40d69074-31a8-d06a-ade9-90de7712c553@deltatee.com> <5649098f-b775-815b-8b9a-f34628873ff4@grimberg.me> <20180301184249.GI19007@ziepe.ca> <20180301224540.GL19007@ziepe.ca> <77591162-4CCD-446E-A27C-1CDB4996ACB7@raithlin.com> <20180301234930.GG14799@localhost.localdomain> From: Logan Gunthorpe Message-ID: <9de7d9d1-3469-c315-ce47-0faa67a4e4c4@deltatee.com> Date: Thu, 1 Mar 2018 17:03:09 -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: 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: swise@opengridcomputing.com, alex.williamson@redhat.com, benh@kernel.crashing.org, jglisse@redhat.com, dan.j.williams@intel.com, maxg@mellanox.com, bhelgaas@google.com, axboe@kernel.dk, hch@lst.de, 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, sagi@grimberg.me, jgg@ziepe.ca, keith.busch@intel.com, sbates@raithlin.com X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [PATCH v2 10/10] nvmet: Optionally use PCI P2P 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 04:57 PM, Stephen Bates wrote: >> We don't want to lump these all together without knowing which region you're allocating from, right? > > In all seriousness I do agree with you on these Keith in the long term. We would consider adding property flags for the memory as it is added to the p2p core and then the allocator could evolve to intelligently dish it out. Attributes like endurance, latency and special write commit requirements could all become attributes in time. Perhaps one more reason for a central entity for p2p memory allocation so this code does not end up having to go into many different drivers? Ugh, I don't know... An allocator for PMR is going to be quite a different animal. It would probably need to look more like a filesystem given you'd need to access the same regions across reboots. I don't think it fits the p2pmem paradigm at all. I think it's something entirely new all together and who knows exactly what it will look like. Logan