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]) by smtp.lore.kernel.org (Postfix) with ESMTP id 56D1CC0218C for ; Thu, 23 Jan 2025 10:20:49 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6D8186B007B; Thu, 23 Jan 2025 05:20:48 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 6611B6B0082; Thu, 23 Jan 2025 05:20:48 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4B36B6B0083; Thu, 23 Jan 2025 05:20:48 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 298066B007B for ; Thu, 23 Jan 2025 05:20:48 -0500 (EST) Received: from smtpin16.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 51797140E1D for ; Thu, 23 Jan 2025 10:20:47 +0000 (UTC) X-FDA: 83038322934.16.2540E1D Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf03.hostedemail.com (Postfix) with ESMTP id D624C20005 for ; Thu, 23 Jan 2025 10:20:44 +0000 (UTC) Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=gNcxPTu6; spf=pass (imf03.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1737627645; 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: references:dkim-signature; bh=n+wGia14dGwN29vdBo/9/2hxcBsxLnFs0mwPA3w7k88=; b=Dly8VvckY6XjJ1FmnIcsu6Pj64s57f81dvNqe5B9cHxx1/FQeuD9kZm/BoSr+arjGaQMIY o9qxwhDpC2YXbwO0PbZ+m167jtBS1aXft7NGPc0qaheMVDwY/hmCaP5tgtl2byrZ+vVxQq AEazF1ZIUSnMKqydClRpcH2tw9iFv+E= ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=gNcxPTu6; spf=pass (imf03.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1737627645; a=rsa-sha256; cv=none; b=b5GWryHxAAMzPfp4yJ6TA/Q7cdSX6tr31DSvFfy8t9q6zWWS/MeL8JMEJ/p/H8d5uGJSHu StbQRAF0jYS6GkE+3cuvKlNytJkw+0J6GdRdFd3wxjbFZYCtHU9Eb2b8FJJ4iAqCXzZ7XI VCLnmwnnN01bC8jTJXiJFmd27Df99Fc= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1737627644; h=from:from: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:autocrypt:autocrypt; bh=n+wGia14dGwN29vdBo/9/2hxcBsxLnFs0mwPA3w7k88=; b=gNcxPTu6NMuIhHNGl97/iqnzPl2EqaAojZsfTnuMjUbtholnG244NQ3A1lEk69/wTeT7RS CSf0faf8YlImm9GnYSEFdRNCtCBd2fRAmMYfM+meOSLA+C0j7FI3zh8wz+dLiqj3vdWI+S NDd2GR+HDtdBa7yywkG6BV5LEyEMJp0= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-84-JZ7_J9YuOFmdUWDrQAeJfw-1; Thu, 23 Jan 2025 05:20:42 -0500 X-MC-Unique: JZ7_J9YuOFmdUWDrQAeJfw-1 X-Mimecast-MFC-AGG-ID: JZ7_J9YuOFmdUWDrQAeJfw Received: by mail-wm1-f69.google.com with SMTP id 5b1f17b1804b1-4361ac607b6so5536365e9.0 for ; Thu, 23 Jan 2025 02:20:42 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1737627641; x=1738232441; h=content-transfer-encoding:subject:to:organization:autocrypt:cc :content-language:from:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=n+wGia14dGwN29vdBo/9/2hxcBsxLnFs0mwPA3w7k88=; b=io3FxHmJXlz+hDsgiXpz7kyHWAC3r43Yg8SiiMsPd6GFuB0BrBWPswUVkU6vLHBwgE 1j7SqFCqD8LbFbCpCW+ubfePkjmdALlVoXDF2vh+qaHt74+9+vZA++wzhUjIw8zhRFlH AQWn85wpH1aTJrJRm+tjpYGBtHQBk2qOiPDRa85rsrQF/pMSK4SqjBDjkZlmjRHQp3Oy EsiKABsEFipzTYW4BKjlR0YVE4UxjXS1YpA9BHlG6H6mQc9vLXx3LTkQL81CSeLZslXJ TIKfutElhVYK4N3HbhQ1ZCGOtmIdqWIRtjVjNVpjWSmP9q7BOC8CUGMPwybZF8GlhjJF UFUg== X-Gm-Message-State: AOJu0YyzZ92Z3vr8qjrYg5hDQps+xk1PDVHgddd37+T30QdRf3RbBu8l skCbe2WbHFJdpYcccFz1rqeWhBgNIlYZZlkMJ5mPEvdsPHOJv3ZR4ygtai/RS9JUS27yAw68zmL U2NzGLHp7zyuwRDtTplFiA9Ha2YN+GgIsrl/KWkwm3cAS5OT6+oO3xWoKUlWFsJGJDSPoQjHhS9 PrRdwJJ+W9SIAPhyzA5iRUxEqJW4NbtUA= X-Gm-Gg: ASbGncvJBrWWFyUzaf48WC3HM2DQ9XlBd4tZ5G9vvad0f54KI4NUbECe/6eLqLAouZp odchl8REu3GW/D1bIEwCbDbllFMp/ZtnwWb+N0ITFxtL2uCV/PdRL1QJWN8f3sOBQolaQaiibaA LtslU0q07kCVb9OPZH2y+ztQgnpi9ggzHjZGWqKqnx0Z80ebq0aHHvCclYeiRxdxJDQZ7jej6ui XY5Vm7ZnlGboioWXrNrote1sMBBIHyA9Py5E8RQ7F0copHVEtXjGC3Oh3E4Mu3AK6EI2X8up5vC kM/bU1DQaktXAGg9Zz32l9WBalLc0vJ5XbsFzkY3wnjR81SYf3Ofu3y7BeJEvqu+eY/7wfwdkNn GA29P4JqrXQNQVDmnsPScMA== X-Received: by 2002:a05:600c:4743:b0:434:ff25:199f with SMTP id 5b1f17b1804b1-438914309a8mr187505525e9.26.1737627641595; Thu, 23 Jan 2025 02:20:41 -0800 (PST) X-Google-Smtp-Source: AGHT+IGK5UH+INgn+5/Di/pesvq9JHyNkB/a1MNPTzn1K8rJZwYB4w9bxe2GWdXEeN+ysaBUTXCdpw== X-Received: by 2002:a05:600c:4743:b0:434:ff25:199f with SMTP id 5b1f17b1804b1-438914309a8mr187505185e9.26.1737627641130; Thu, 23 Jan 2025 02:20:41 -0800 (PST) Received: from ?IPV6:2003:cb:c70b:b400:e20a:6d03:7ac8:f97d? (p200300cbc70bb400e20a6d037ac8f97d.dip0.t-ipconnect.de. [2003:cb:c70b:b400:e20a:6d03:7ac8:f97d]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-438b31b1618sm58827435e9.24.2025.01.23.02.20.38 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 23 Jan 2025 02:20:39 -0800 (PST) Message-ID: <346518a4-a090-4eaa-bc04-634388fd4ca3@redhat.com> Date: Thu, 23 Jan 2025 11:20:37 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird From: David Hildenbrand Cc: John Hubbard , nouveau@lists.freedesktop.org, Jason Gunthorpe , Alistair Popple , DRI Development , Karol Herbst , Lyude Paul , Danilo Krummrich Autocrypt: addr=david@redhat.com; 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 B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63XOwU0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat To: "linux-mm@kvack.org" Subject: [Question] Are "device exclusive non-swap entries" / "SVM atomics in Nouveau" still getting used in practice? X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: KFPr0etmC4f71rGJthk2MgstpsglsJnaQ4cM7HGXn6A_1737627642 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: D624C20005 X-Rspam-User: X-Rspamd-Server: rspam11 X-Stat-Signature: cko7npdktqxg8xojekxcxfh6xgkj38mj X-HE-Tag: 1737627644-110800 X-HE-Meta: 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 JxRslWVK 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.070358, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi, I keep finding issues in our implementation of "device exclusive non-swap entries", and the way it messes with mapcounts is disgusting. As a reminder, what we do here is to replace a PTE pointing to an anonymous page by a "device exclusive non-swap entry". As long as the original PTE is in place, the only CPU can access it, as soon as the "device exclusive non-swap entry" is in place, only the device can access it. Conversion back and forth is triggered by CPU / device faults. I have fixes/reworks/simplifications for most things, but as there is only a "real" single user in-tree of make_device_exclusive(): drivers/gpu/drm/nouveau/nouveau_svm.c to "support SVM atomics in Nouveau [1]" naturally I am wondering: is this still a thing on actual hardware, or is it already stale on recent hardware and not really required anymore? [1] https://lore.kernel.org/linux-kernel//6621654.gmDyfcmpjF@nvdebian/T/ -- Cheers, David / dhildenb