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[159.2.239.150]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-536c14da10csm1768631cf.0.2026.10.22.13.12.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 22 Oct 2026 13:12:29 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1xJz9J-0000000FoSN-1XEC; Thu, 22 Oct 2026 17:12:29 -0300 Date: Thu, 22 Oct 2026 17:12:29 -0300 From: Jason Gunthorpe To: Luigi Rizzo Cc: "David Hildenbrand (Arm)" , Luigi Rizzo , Joerg Roedel , Will Deacon , Robin Murphy , Christoph Hellwig , Marek Szyprowski , Andrew Morton , Vlastimil Babka , "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Greg Kroah-Hartman , "Rafael J . Wysocki" , Danilo Krummrich , Jonathan Corbet , Jesper Dangaard Brouer , Ilias Apalodimas , Willem de Bruijn , Kuniyuki Iwashima , Joshua Washington , Harshitha Ramamurthy , Saeed Mahameed , Tariq Toukan , Tony Nguyen , Przemek Kitszel , Alexander Lobakin , Michael Chan , Pavan Chebbi , iommu@lists.linux.dev, netdev@vger.kernel.org, linux-mm@kvack.org, driver-core@lists.linux.dev, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC: DMA_PMD 00/22] DMA_PMD: PMD_SIZE-backed IO buffer pools Message-ID: <20261022201229.GH3381610@ziepe.ca> References: <20261003212241.3432303-1-lrizzo@google.com> <0cc1cac1-a500-489b-9c1b-b49598b5550b@kernel.org> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 5A14518000D X-Stat-Signature: cqc7gii9ywfnnqkb6px737it581kaxqb X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=no autolearn_force=no version=4.0.1 X-Rspam-User: X-HE-Tag: 1792699951-709943 X-HE-Meta: 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 djCKj9NY atx81auQwBnlQeZlGEq9ES3T/Jj4ctRM4IL3b6od1XPT4wnOTOa//mM4udUQQ+HVRYOISJjz8DcZCxnYYxsPXz0khIwPjiq6J4STy1f9bAgl0BGL3wATORHlNoiNyaOQkXwMsi25hVUkxtkUI1UAsHDI7vXXuJjLWDCOeig6t5mq2ywjsOymrIElxKjPpICA95sA+ZLgqC9yhRpieFL4jtz0pZ5Qna4vZ+PW37OeYg5ZnYR0Z2KW1vEpp40B7TqxpYczt9JGRhECWjH1o0GV7miHkoIABKsYpvHgyn4YMXU3kIJsT2csAZrsZWpXyU/pdJI7Jz+d1XOmDUkabG1rBRzUf4aXe2xbcfLY4myJuEdGsQgPRsP50Ioc29ehGmY+SSpuoLPdi5YseVcghRsVfiMBB2NOe4j8AMZvu Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Sat, Oct 17, 2026 at 07:11:28PM +0200, Luigi Rizzo wrote: > > We should probably just find a way to describe that this is a POOL that focuses > > on physical contiguity in some configured granularity. > > Before embarking in a global renaming, I would like to get opinions on > acceptable alternative names (possibly with a short prefix usable for > identifiers in the code). I could think of the following > > DMA_PMAP (for PreMapped or Persistent Mapped) > or, ahemm... > DMA_PISA (Pooled IOMMU Superpage Allocator) > both using dmap_ for internal name prefixes Can someone explain what outside netdev would use this? And why you couldn't do this in the netdev page pool? It is not a common workload to have the DMA allocator be the one that allocates the memory. Usually we are DMA'ing from memory that was allocated someplace else. I think Robin is right, this is just a special case of the dma pool, and it certainly shouldn't be something as grandiose as a subsystem.. Jason