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Tue, 21 Jul 2020 00:41:59 -0700 (PDT) Date: Tue, 21 Jul 2020 09:41:57 +0200 From: Daniel Vetter To: Thomas =?iso-8859-1?Q?Hellstr=F6m_=28Intel=29?= Subject: Re: [Linaro-mm-sig] [PATCH 1/2] dma-buf.rst: Document why indefinite fences are a bad idea Message-ID: <20200721074157.GB3278063@phenom.ffwll.local> References: <20200707201229.472834-4-daniel.vetter@ffwll.ch> <20200709123339.547390-1-daniel.vetter@ffwll.ch> <93b673b7-bb48-96eb-dc2c-bd4f9304000e@shipmail.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <93b673b7-bb48-96eb-dc2c-bd4f9304000e@shipmail.org> X-Operating-System: Linux phenom 5.6.0-1-amd64 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Daniel Stone , linux-rdma@vger.kernel.org, Daniel Vetter , Intel Graphics Development , DRI Development , Christian =?iso-8859-1?Q?K=F6nig?= , linaro-mm-sig@lists.linaro.org, Steve Pronovost , amd-gfx@lists.freedesktop.org, Jason Ekstrand , Jesse Natalie , Daniel Vetter , Thomas Hellstrom , Mika Kuoppala , Felix Kuehling , linux-media@vger.kernel.org Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Mon, Jul 20, 2020 at 01:15:17PM +0200, Thomas Hellstr=F6m (Intel) wrote: > Hi, > = > On 7/9/20 2:33 PM, Daniel Vetter wrote: > > Comes up every few years, gets somewhat tedious to discuss, let's > > write this down once and for all. > > = > > What I'm not sure about is whether the text should be more explicit in > > flat out mandating the amdkfd eviction fences for long running compute > > workloads or workloads where userspace fencing is allowed. > = > Although (in my humble opinion) it might be possible to completely untang= le > kernel-introduced fences for resource management and dma-fences used for > completion- and dependency tracking and lift a lot of restrictions for the > dma-fences, including prohibiting infinite ones, I think this makes sense > describing the current state. Yeah I think a future patch needs to type up how we want to make that happen (for some cross driver consistency) and what needs to be considered. Some of the necessary parts are already there (with like the preemption fences amdkfd has as an example), but I think some clear docs on what's required from both hw, drivers and userspace would be really good. > > Reviewed-by: Thomas Hellstrom Thanks for taking a look, first 3 patches here with annotations and docs merged to drm-misc-next. I'll ask Maarten/Dave whether another pull is ok for 5.9 so that everyone can use this asap. -Daniel -- = Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel