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[159.2.239.150]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-5498b49dcbasm27980831cf.6.2026.11.03.07.10.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 Nov 2026 07:10:22 -0800 (PST) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1xOG9V-0000000DAq9-0szH; Tue, 03 Nov 2026 11:10:21 -0400 Date: Tue, 3 Nov 2026 11:10:21 -0400 From: Jason Gunthorpe To: Christoph Hellwig Cc: Luigi Rizzo , "David Hildenbrand (Arm)" , Luigi Rizzo , Joerg Roedel , Will Deacon , Robin Murphy , 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: <20261103151021.GK3889730@ziepe.ca> References: <0cc1cac1-a500-489b-9c1b-b49598b5550b@kernel.org> <20261022201229.GH3381610@ziepe.ca> <20261023140107.GC3977851@ziepe.ca> <20261023145023.GH3977851@ziepe.ca> <20261103080933.GA4213@lst.de> 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: <20261103080933.GA4213@lst.de> On Tue, Nov 03, 2026 at 09:09:33AM +0100, Christoph Hellwig wrote: > On Fri, Oct 23, 2026 at 11:50:23AM -0300, Jason Gunthorpe wrote: > > > Disk I/O is still potentially affected by the same problems > > > (cost if io mapping/unmapping, iotlb thrashing, bounce buffers > > > in confidential computing...) > > > > The disk folks already have a proposal to address all of this using > > io_uring and preallocated buffers. I really doubt yet another version > > is going to be interesting there. > > Huh? If you mean the dma-buf I/O it doesn't really have anything > to do with disks, except that this is the first user. Yeah > The dma-buf iovec can work for every ->read_iter/->write_iter > consumer, and should be adopted more broadly. Including by > networking instead of their own totally weird different world. I'm not holding my breath on that one.. Jason