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[68.146.128.183]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-23e3b6efb69sm85898495ad.195.2025.07.22.20.55.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 22 Jul 2025 20:55:23 -0700 (PDT) Received: from jgg by jggl with local (Exim 4.95) (envelope-from ) id 1ueQZe-0003Gp-Gf; Wed, 23 Jul 2025 00:55:22 -0300 Date: Wed, 23 Jul 2025 00:55:22 -0300 From: Jason Gunthorpe To: Christoph Hellwig Cc: Yonatan Maman , =?utf-8?B?SsOpcsO0bWU=?= Glisse , Andrew Morton , Leon Romanovsky , Lyude Paul , Danilo Krummrich , David Airlie , Simona Vetter , Alistair Popple , Ben Skeggs , Michael Guralnik , Or Har-Toov , Daisuke Matsuda , Shay Drory , linux-mm@kvack.org, linux-rdma@vger.kernel.org, dri-devel@lists.freedesktop.org, nouveau@lists.freedesktop.org, linux-kernel@vger.kernel.org, Gal Shalom Subject: Re: [PATCH v2 4/5] RDMA/mlx5: Enable P2P DMA with fallback mechanism Message-ID: References: <20250718115112.3881129-1-ymaman@nvidia.com> <20250718115112.3881129-5-ymaman@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Stat-Signature: 3e4t9bcnupuha1grgwb7qqpwckqg4bxa X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 45140C0005 X-Rspam-User: X-HE-Tag: 1753242926-321367 X-HE-Meta: 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 NQKS8JPh 6eqWZeQ4JxXfx4TWFRw8RP6LF9ocz4LNc6lJM9GfW5Y+75ezSkdLK5L2cyRa6HfPdW6h+D2nnzuSABx+mIe5f/koCezBCs2OTn7tcaIxvOVDBOAGrxTc97jWvE5QdVvYTwHJmpVbwqxPGqtzpSEdmW3UvnS2EX0OEOboYMtSOUPrToLtArQ2UZLeQjXG1S8qcs6qt8zS46BP3odIbQmGX1Ltv4GmWie2L/8BpYJSiKrm7HXiUdF2PzdbW3Exjfci6bRJYPoMPSs2lK3YlQ+KHtqh9EkEJxztUrvKJXK6gEHcJUbXo3fwlZ3sG2A== 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: List-Subscribe: List-Unsubscribe: On Mon, Jul 21, 2025 at 12:03:41AM -0700, Christoph Hellwig wrote: > On Fri, Jul 18, 2025 at 02:51:11PM +0300, Yonatan Maman wrote: > > From: Yonatan Maman > > > > Add support for P2P for MLX5 NIC devices with automatic fallback to > > standard DMA when P2P mapping fails. > > That's now how the P2P API works. You need to check the P2P availability > higher up. How do you mean? This looks OKish to me, for ODP and HMM it has to check the P2P availability on a page by page basis because every single page can be a different origin device. There isn't really a higher up here... Jason