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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-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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