From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 28B0FF33A66 for ; Thu, 5 Mar 2026 14:00:37 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 54A356B0005; Thu, 5 Mar 2026 09:00:36 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 500CF6B008C; Thu, 5 Mar 2026 09:00:36 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4033C6B0092; Thu, 5 Mar 2026 09:00:36 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 2DC0E6B0005 for ; Thu, 5 Mar 2026 09:00:36 -0500 (EST) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id BE6E813902C for ; Thu, 5 Mar 2026 14:00:35 +0000 (UTC) X-FDA: 84512169630.19.5A8F170 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf28.hostedemail.com (Postfix) with ESMTP id BB170C0012 for ; Thu, 5 Mar 2026 14:00:33 +0000 (UTC) Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=LLiPPMTz; spf=pass (imf28.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1772719233; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=bLB7WOQa5oxTbNxwDfrrKUZKnAd4KHZV7UcRN3JkrTo=; b=6mDM9Q+jLL6R64JTk9WQZSnP36SyuyRBUJ2AcVw2a6QmnvjYDrqZqC98uhViDiFR/LOmfQ /p1UyT90eJ2GzuZYMM5WtTeCVGnyltJwKyQeVgWhoMU4EQJXOFtHDb4iOy5DOwebJ9aOGt ciCoJ32hIxhZnxlpE3eklQ1CbSY0QFM= ARC-Authentication-Results: i=1; imf28.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=LLiPPMTz; spf=pass (imf28.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1772719233; a=rsa-sha256; cv=none; b=O1cnQbXo3xe+hkFo87eOtbWPwqx8yV8QSfy5OkyxXqp3GRosUT7vDsViw90z+2atbvevW9 OL3OY+1VMwXYXoopbOl4kzWql2jSsDvcZoRW8sI7u2TZlJltonRPAkSaaSI+F9ghYF2RkO tTHQMs7Mmwaqy4Sda8se63t7zUDXZs4= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id AE18A43A5E; Thu, 5 Mar 2026 14:00:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1E58FC116C6; Thu, 5 Mar 2026 14:00:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772719232; bh=393qDIgoHBbCQNpTIGP+WBiCqebYKIGYINOpS7EZdyA=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=LLiPPMTzZg9/f80zQO9P/fDIaf7xVcapS/MbzaPpFA+pXw3fDPXDsl5FaO+E3F0+K e/AwWKAZC2U0+K3fQVhE48wi9M0L1hOg+hzT5GLlBoJvKlwPwy0nB/XNxCSlkA3oVi Zq5Tqg6m+9A8Um7hHXF9eEg/jNtA5iqOkWM15gP1eIg+7eezFv6GgM7tYhSpTb8EOR M+VIQjM3qFn1f+gBYvrACm1H5odHiuYaipKFvPxrAPdkk8xpNQan2YpBRq8AuPNm7l ARrox0w0CBjHRwemaDknNiPDqzDvILVTPu9EJd+tmQZOFlXsYnVgY6LfwgwCp+eVnE yuMhyx9j8yaQQ== Message-ID: <1efba81b-d4e9-405b-8ad5-0a170237902f@kernel.org> Date: Thu, 5 Mar 2026 15:00:23 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 1/4] mm/mmu_notifier: Allow two-pass struct mmu_interval_notifiers To: =?UTF-8?Q?Thomas_Hellstr=C3=B6m?= , intel-xe@lists.freedesktop.org Cc: Matthew Brost , =?UTF-8?Q?Christian_K=C3=B6nig?= , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jason Gunthorpe , Andrew Morton , Simona Vetter , Dave Airlie , Alistair Popple , dri-devel@lists.freedesktop.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260305093909.43623-1-thomas.hellstrom@linux.intel.com> <20260305093909.43623-2-thomas.hellstrom@linux.intel.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <20260305093909.43623-2-thomas.hellstrom@linux.intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: BB170C0012 X-Stat-Signature: rht8p5o6gj853u5piwodtwzomqf9nsta X-Rspam-User: X-HE-Tag: 1772719233-703874 X-HE-Meta: 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 jtSgARVv 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 3/5/26 10:39, Thomas Hellström wrote: > GPU use-cases for mmu_interval_notifiers with hmm often involve > starting a gpu operation and then waiting for it to complete. > These operations are typically context preemption or TLB flushing. > > With single-pass notifiers per GPU this doesn't scale in > multi-gpu scenarios. In those scenarios we'd want to first start > preemption- or TLB flushing on all GPUs and as a second pass wait > for them to complete. > > One can do this on per-driver basis multiplexing per-driver > notifiers but that would mean sharing the notifier "user" lock > across all GPUs and that doesn't scale well either, so adding support > for multi-pass in the core appears to be the right choice. > > Implement two-pass capability in the mmu_interval_notifier. Use a > linked list for the final passes to minimize the impact for > use-cases that don't need the multi-pass functionality by avoiding > a second interval tree walk, and to be able to easily pass data > between the two passes. > > v1: > - Restrict to two passes (Jason Gunthorpe) > - Improve on documentation (Jason Gunthorpe) > - Improve on function naming (Alistair Popple) > v2: > - Include the invalidate_finish() callback in the > struct mmu_interval_notifier_ops. > - Update documentation (GitHub Copilot:claude-sonnet-4.6) > - Use lockless list for list management. > v3: > - Update kerneldoc for the struct mmu_interval_notifier_finish::list member > (Matthew Brost) > - Add a WARN_ON_ONCE() checking for NULL invalidate_finish() op if > if invalidate_start() is non-NULL. (Matthew Brost) > v4: > - Addressed documentation review comments by David Hildenbrand. > > Cc: Matthew Brost > Cc: Christian König > Cc: David Hildenbrand > Cc: Lorenzo Stoakes > Cc: Liam R. Howlett > Cc: Vlastimil Babka > Cc: Mike Rapoport > Cc: Suren Baghdasaryan > Cc: Michal Hocko > Cc: Jason Gunthorpe > Cc: Andrew Morton > Cc: Simona Vetter > Cc: Dave Airlie > Cc: Alistair Popple > Cc: > Cc: > Cc: > > Assisted-by: GitHub Copilot:claude-sonnet-4.6 # Documentation only. > Signed-off-by: Thomas Hellström > --- LGTM, thanks! Acked-by: David Hildenbrand (Arm) -- Cheers, David