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[156.34.48.30]) by smtp.gmail.com with ESMTPSA id x29sm11148829qtv.80.2020.07.03.06.14.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 03 Jul 2020 06:14:46 -0700 (PDT) Received: from jgg by mlx with local (Exim 4.93) (envelope-from ) id 1jrLWf-003aeK-KP; Fri, 03 Jul 2020 10:14:45 -0300 Date: Fri, 3 Jul 2020 10:14:45 -0300 From: Jason Gunthorpe To: Daniel Vetter Subject: Re: [RFC PATCH v2 0/3] RDMA: add dma-buf support Message-ID: <20200703131445.GU25301@ziepe.ca> References: <20200701123904.GM25301@ziepe.ca> <34077a9f-7924-fbb3-04d9-cd20243f815c@amd.com> <20200701171524.GN25301@ziepe.ca> <20200702131000.GW3278063@phenom.ffwll.local> <20200702132953.GS25301@ziepe.ca> <11e93282-25da-841d-9be6-38b0c9703d42@amd.com> <20200702181540.GC3278063@phenom.ffwll.local> <20200703120335.GT25301@ziepe.ca> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Mailman-Approved-At: Mon, 06 Jul 2020 07:19:17 +0000 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: Leon Romanovsky , "linux-rdma@vger.kernel.org" , "dri-devel@lists.freedesktop.org" , Doug Ledford , "Vetter, Daniel" , Christian =?utf-8?B?S8O2bmln?= , "Xiong, Jianxin" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Fri, Jul 03, 2020 at 02:52:03PM +0200, Daniel Vetter wrote: > So maybe I'm just totally confused about the rdma model. I thought: > - you bind a pile of memory for various transactions, that might > happen whenever. Kernel driver doesn't have much if any insight into > when memory isn't needed anymore. I think in the rdma world that's > called registering memory, but not sure. Sure, but once registered the memory is able to be used at any moment with no visibilty from the kernel. Unlike GPU the transactions that trigger memory access do not go through the kernel - so there is no ability to interrupt a command flow and fiddle with mappings. Jason _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel