From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=213.95.11.211 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793693380; b=1oyWwl0zrhMuhHZdDqC6f/YGNo3XGM74o25ausBtSGiEv+GJzkq3Unp3E9L1TxsXefLY LHGxR7TLQGzkw2ZzHe7IApbZopdlSMmKsPOzHqrC0+bwuTcpLp6ZXTIUl4YBChO+nCLyh WE7CmuHPD5CS2vxx00/Lv7rV+RgcKcDJ6F16RTsI1b9L/kvwZkAwhsZ4d33PUgpqyX/DH KnwKUq76Qa+TH9JohGeB1ah8OzXv9DzYg1Etl7Z97ZfnNqoVHCAbQN6qWaQVBWEPc/YNR KaPCYhvAmmnDsuBkJCDfQV86qin4l1TmU/0GwV/LeTVMiXms2oF8iMeCd0IQLSo/g4w== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793693380; h=DMARC-Filter:Received:Date:From:To:Cc:Subject:Message-ID:References: MIME-Version:Content-Type:Content-Disposition:In-Reply-To:User-Agent; bh=2on3ft6XH1eubxEl0nHP4ZK9AQjcmYaJw++Tp033neA=; b=2ZZxU1TgypeRyTKl0ARemZdE331gz08kvEQox0MfJxN4l42vkBeNyP8QzvZ1SBnhVvg6 7DuTuGLorJvtPfIdX2nL6Vk/Rt0MLjOKOJoYPQd5+hoSCTsOYvxNZtVrfzpdBSQpHC5o6 Tvh0/aPjRsSv7GhhDP1csM2wkMZq7CWvd8eYZfRSS55B02bdQnv0mAN2Snfq8Z5oiH8LP 0dp83o3osc7JlpHs4xbJy9ST5OSvh2DfO/zUZXGBDyOFkc/teJtNsb5aJHZWpwOEQFlom b6F593/vy46t0VUC77/UU1ksyhbcQhm1jMdwUNn93UVUa+D3u5tcXl49bt20Ve+87lQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=lst.de; spf=pass smtp.mailfrom=lst.de; arc=none smtp.remote-ip=213.95.11.211 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CC50F606A334; Tue, 3 Nov 2026 08:09:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org CC50F606A334 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=lst.de Received: by verein.lst.de (Postfix, from userid 2407) id 1E82268B05; Tue, 3 Nov 2026 09:09:34 +0100 (CET) Date: Tue, 3 Nov 2026 09:09:33 +0100 From: Christoph Hellwig To: Jason Gunthorpe Cc: Luigi Rizzo , "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: <20261103080933.GA4213@lst.de> References: <20261003212241.3432303-1-lrizzo@google.com> <0cc1cac1-a500-489b-9c1b-b49598b5550b@kernel.org> <20261022201229.GH3381610@ziepe.ca> <20261023140107.GC3977851@ziepe.ca> <20261023145023.GH3977851@ziepe.ca> 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: <20261023145023.GH3977851@ziepe.ca> User-Agent: Mutt/1.5.17 (2007-11-01) 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. 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.