From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A2549C0044D for ; Mon, 16 Mar 2020 18:58:27 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4E7AD20719 for ; Mon, 16 Mar 2020 18:58:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4E7AD20719 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 993326B0003; Mon, 16 Mar 2020 14:58:26 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 944C16B0005; Mon, 16 Mar 2020 14:58:26 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 833E26B0007; Mon, 16 Mar 2020 14:58:26 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0009.hostedemail.com [216.40.44.9]) by kanga.kvack.org (Postfix) with ESMTP id 6AF586B0003 for ; Mon, 16 Mar 2020 14:58:26 -0400 (EDT) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 0FDBC180AD81A for ; Mon, 16 Mar 2020 18:58:26 +0000 (UTC) X-FDA: 76602136212.24.price48_f5fc8543e063 X-HE-Tag: price48_f5fc8543e063 X-Filterd-Recvd-Size: 2380 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf23.hostedemail.com (Postfix) with ESMTP for ; Mon, 16 Mar 2020 18:58:25 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 12B8E68BFE; Mon, 16 Mar 2020 19:58:23 +0100 (CET) Date: Mon, 16 Mar 2020 19:58:22 +0100 From: Christoph Hellwig To: Ralph Campbell Cc: Christoph Hellwig , Jason Gunthorpe , Dan Williams , Bharata B Rao , Christian =?iso-8859-1?Q?K=F6nig?= , Ben Skeggs , Jerome Glisse , kvm-ppc@vger.kernel.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, nouveau@lists.freedesktop.org, linux-mm@kvack.org Subject: Re: [PATCH 2/2] mm: remove device private page support from hmm_range_fault Message-ID: <20200316185822.GA25473@lst.de> References: <20200316175259.908713-1-hch@lst.de> <20200316175259.908713-3-hch@lst.de> <20200316184935.GA25322@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200316184935.GA25322@lst.de> User-Agent: Mutt/1.5.17 (2007-11-01) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Mar 16, 2020 at 07:49:35PM +0100, Christoph Hellwig wrote: > On Mon, Mar 16, 2020 at 11:42:19AM -0700, Ralph Campbell wrote: > > > > On 3/16/20 10:52 AM, Christoph Hellwig wrote: > >> No driver has actually used properly wire up and support this feature. > >> There is various code related to it in nouveau, but as far as I can tell > >> it never actually got turned on, and the only changes since the initial > >> commit are global cleanups. > > > > This is not actually true. OpenCL 2.x does support SVM with nouveau and > > device private memory via clEnqueueSVMMigrateMem(). > > Also, Ben Skeggs has accepted a set of patches to map GPU memory after being > > migrated and this change would conflict with that. > > Can you explain me how we actually invoke this code? > > For that we'd need HMM_PFN_DEVICE_PRIVATE NVIF_VMM_PFNMAP_V0_VRAM > set in ->pfns before calling hmm_range_fault, which isn't happening. Ok, looks like the fault side is unused, but we need to keep the non-fault path in place. I'll fix up the patch.