From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755647AbeEHTPM (ORCPT ); Tue, 8 May 2018 15:15:12 -0400 Received: from ale.deltatee.com ([207.54.116.67]:60454 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755472AbeEHTPK (ORCPT ); Tue, 8 May 2018 15:15:10 -0400 To: Alex Williamson , Bjorn Helgaas Cc: 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, Stephen Bates , Christoph Hellwig , Jens Axboe , Keith Busch , Sagi Grimberg , Bjorn Helgaas , Jason Gunthorpe , Max Gurtovoy , Dan Williams , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Benjamin Herrenschmidt , =?UTF-8?Q?Christian_K=c3=b6nig?= References: <20180423233046.21476-1-logang@deltatee.com> <20180507232346.GI161390@bhelgaas-glaptop.roam.corp.google.com> <20180508105759.7dbaa8fe@w520.home> From: Logan Gunthorpe Message-ID: <7d06df03-18ee-97c7-595e-0b25c43a6f3d@deltatee.com> Date: Tue, 8 May 2018 13:14:53 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20180508105759.7dbaa8fe@w520.home> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 172.16.1.162 X-SA-Exim-Rcpt-To: christian.koenig@amd.com, benh@kernel.crashing.org, jglisse@redhat.com, dan.j.williams@intel.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, helgaas@kernel.org, alex.williamson@redhat.com X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [PATCH v4 00/14] 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 08/05/18 10:57 AM, Alex Williamson wrote: > AIUI from previously questioning this, the change is hidden behind a > build-time config option and only custom kernels or distros optimized > for this sort of support would enable that build option. I'm more than > a little dubious though that we're not going to have a wave of distros > enabling this only to get user complaints that they can no longer make > effective use of their devices for assignment due to the resulting span > of the IOMMU groups, nor is there any sort of compromise, configure > the kernel for p2p or device assignment, not both. Is this really such > a unique feature that distro users aren't going to be asking for both > features? Thanks, I think it is. But it sounds like the majority want this to be a command line option. So we will look at doing that for v5. Logan