From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E62E033985 for ; Fri, 18 Jul 2025 11:06:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752836798; cv=none; b=lhhmaKgUtBHeFopWkS1iN12mZbSmhYo8Z3lRiGb0wKAeRSBrBd6WqMY1i/DNVyqUR7Wkfuys4ouSUZl9C7hGburwVOtwsK5cidN8/d0HKligqD1OW6RHnfKKnAvIGbSu772E/muyBR7HjomeSPUCNhiuroTQGv1/4QJ4LRfrHOQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752836798; c=relaxed/simple; bh=yV3C4OM0Ncg3Bd4NzNey4UabPHAiewsc05KQRlUt24g=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=JAPu3a0XJgZHtpxnyP71o04PJq3dEN5YZIuAno7T1Dj0mAR/Q33e0eEOgWQXpOaApjMzrat93b39JlJiTjOG3M7BkEZPcDIbEDV/9q8twAwiI8dZRY65heata2TWp9ijvgewRzMDoYwZCYkQxGFHF8aiNLp/VLQgYBBOVrCGXus= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=Q6ghCjhz; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Q6ghCjhz" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1752836796; 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: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=21+i6/3q/KbRZs7c78B9Zaciwq4VXi+y94ZoRHHKkFg=; b=Q6ghCjhzEf3B3ry1MH8Kp6b9+6wxKV8vZbYPgdJVItblodhrs+nhB8dppSHM8k/5Gxq93G LYMYSWRjWjinMelDistziDK4N3BEKNKMFzbqnhnbxHkAyldRNZwsedlpMRJ+bjHidtZ9yR qrGkkWxzlRCAQ7WWFEvGxWr+K4NRbaA= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-589-iVo-VQdjOdKZcKEyKEXejQ-1; Fri, 18 Jul 2025 07:06:34 -0400 X-MC-Unique: iVo-VQdjOdKZcKEyKEXejQ-1 X-Mimecast-MFC-AGG-ID: iVo-VQdjOdKZcKEyKEXejQ_1752836794 Received: by mail-wm1-f71.google.com with SMTP id 5b1f17b1804b1-45611579300so14925265e9.0 for ; Fri, 18 Jul 2025 04:06:34 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1752836793; x=1753441593; h=content-transfer-encoding:in-reply-to:organization:autocrypt :content-language:from:references:cc:to:subject:user-agent :mime-version:date:message-id:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to; bh=21+i6/3q/KbRZs7c78B9Zaciwq4VXi+y94ZoRHHKkFg=; b=wzRGiqOh0FcOIHtb3X/ObRDsK3UUUe8Biml6UkX+5B7GpD5c6Pd9JmsoiiLrUSnGH9 XL92K7EBaVQhm/Eki7YvpiS9ZMv2xnr9lS/5w+y6gEgsbsgpWCZsk5blkmyuPFln54GQ gwqFfmxnj8teYPbP1vblXCYsOdyRkTW3UISRPWrC784PzlCVouv6jBC/Eh+cDSvUet1q p9OJwae+gGpkOKLm6z+NgOFQ3c7AVU5bi6zSCbGrkWYx6DGdZ6vhjfwOKKVGCtOdjffb uCy4KgTD13mvA6Caj8OO84bVftIyTDhEWk/lomP/kn/8NFufQlrPLZhKiBTGgZf3Y3um Rp+Q== X-Forwarded-Encrypted: i=1; AJvYcCXB76Yy9tMcCReDXj5TEc2nZAFtJOEIqgU6oKcY7RarvYhBEMxOvXTu//KmamcetlDoU0dE5Vr3Rrw44j6J@vger.kernel.org X-Gm-Message-State: AOJu0YwuhBDq6p+BMnXzckK+pTXbV8xiAurVPVYPZ+Q6e4C9y2KW0eaS Ts01LzfbMjRV5oE/udbkxHWtgZuEHJbuD5IUj/ETEPe4tc6T+SIhs9Y7gGxP6tBAENuHHHifXNM biVmKfEza3Hsz80//7wW1ty+ozFSMIjo9pyNVTUilwW3a/fOVFAkgR9Km+E2xvhdMY3o= X-Gm-Gg: ASbGncusgx/tGEI5fruQZknJBV7yizBc81/HI8/+/Scp7CB4pikGa/rspk83B4u4oLB zQa2VoHhngu1ONkLnLuRkZHk1kTVPJCnV5FkWWfXFbwasY+tq6bZoCT7ETVp2DrZcv6q4ktZWXn SJuItvgL5cTs1isa6FXoOC+6hJgNj75PehKxH4z00qxvMVwUGEFUmXQ27ecXgtE2zbB2KYAlvgn lzwH4WPEnKX0ykHHH37HN31Z4nvirmDHPIhcRR5cbnLU+jPVXOlValAccjn1t6YNTMYWWNXp5+Z O8QlAgMuBX16NDrKMcil04yyUT8xcHjx2Avbmii4XGwQNTN9Kl8RXMIvM+qMks+T8CXy/edfrUU Dyb/ZuckPouTp5GYCFsH/6zf/HBmc3znmKcknk3NxvuLybehpuajo7tD4gHvF+wBtKto= X-Received: by 2002:a05:600c:1d20:b0:454:a37a:db67 with SMTP id 5b1f17b1804b1-4562e36c7a6mr117551415e9.17.1752836793574; Fri, 18 Jul 2025 04:06:33 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHcJiqGxI9oDWWi5nW5+YKTz9nonD/LjKsAIai1+MhX5KKmpqdahPoV4Oxx3e4BuJMcH10ZFA== X-Received: by 2002:a05:600c:1d20:b0:454:a37a:db67 with SMTP id 5b1f17b1804b1-4562e36c7a6mr117550875e9.17.1752836793013; Fri, 18 Jul 2025 04:06:33 -0700 (PDT) Received: from ?IPV6:2003:d8:2f43:8900:f364:1333:2a67:d49e? (p200300d82f438900f36413332a67d49e.dip0.t-ipconnect.de. [2003:d8:2f43:8900:f364:1333:2a67:d49e]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4563b740c51sm16819475e9.19.2025.07.18.04.06.31 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 18 Jul 2025 04:06:32 -0700 (PDT) Message-ID: <889dade6-8b3d-4cce-93ec-827886f7cb2c@redhat.com> Date: Fri, 18 Jul 2025 13:06:30 +0200 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 8/9] mm: introduce and use vm_normal_page_pud() To: Lorenzo Stoakes Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, xen-devel@lists.xenproject.org, linux-fsdevel@vger.kernel.org, nvdimm@lists.linux.dev, Andrew Morton , Juergen Gross , Stefano Stabellini , Oleksandr Tyshchenko , Dan Williams , Matthew Wilcox , Jan Kara , Alexander Viro , Christian Brauner , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Zi Yan , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Jann Horn , Pedro Falcato , Hugh Dickins , Oscar Salvador , Lance Yang References: <20250717115212.1825089-1-david@redhat.com> <20250717115212.1825089-9-david@redhat.com> <4750f39e-279b-4806-9eee-73f9fcc58187@lucifer.local> <15adb09d-4cdb-435d-927d-0c648d8239dc@lucifer.local> From: David Hildenbrand Content-Language: en-US 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/g1oFAmgsLPQFCRvGjuMACgkQTd4Q 9wD/g1o0bxAAqYC7gTyGj5rZwvy1VesF6YoQncH0yI79lvXUYOX+Nngko4v4dTlOQvrd/vhb 02e9FtpA1CxgwdgIPFKIuXvdSyXAp0xXuIuRPQYbgNriQFkaBlHe9mSf8O09J3SCVa/5ezKM OLW/OONSV/Fr2VI1wxAYj3/Rb+U6rpzqIQ3Uh/5Rjmla6pTl7Z9/o1zKlVOX1SxVGSrlXhqt kwdbjdj/csSzoAbUF/duDuhyEl11/xStm/lBMzVuf3ZhV5SSgLAflLBo4l6mR5RolpPv5wad GpYS/hm7HsmEA0PBAPNb5DvZQ7vNaX23FlgylSXyv72UVsObHsu6pT4sfoxvJ5nJxvzGi69U s1uryvlAfS6E+D5ULrV35taTwSpcBAh0/RqRbV0mTc57vvAoXofBDcs3Z30IReFS34QSpjvl Hxbe7itHGuuhEVM1qmq2U72ezOQ7MzADbwCtn+yGeISQqeFn9QMAZVAkXsc9Wp0SW/WQKb76 FkSRalBZcc2vXM0VqhFVzTb6iNqYXqVKyuPKwhBunhTt6XnIfhpRgqveCPNIasSX05VQR6/a OBHZX3seTikp7A1z9iZIsdtJxB88dGkpeMj6qJ5RLzUsPUVPodEcz1B5aTEbYK6428H8MeLq NFPwmknOlDzQNC6RND8Ez7YEhzqvw7263MojcmmPcLelYbfOwU0EVcufkQEQAOfX3n0g0fZz 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+DWgUCaCwtJQUJG8aPFAAKCRBN3hD3AP+DWlDnD/4k2TW+HyOOOePVm23F5HOhNNd7nNv3 Vq2cLcW1DteHUdxMO0X+zqrKDHI5hgnE/E2QH9jyV8mB8l/ndElobciaJcbl1cM43vVzPIWn 01vW62oxUNtEvzLLxGLPTrnMxWdZgxr7ACCWKUnMGE2E8eca0cT2pnIJoQRz242xqe/nYxBB /BAK+dsxHIfcQzl88G83oaO7vb7s/cWMYRKOg+WIgp0MJ8DO2IU5JmUtyJB+V3YzzM4cMic3 bNn8nHjTWw/9+QQ5vg3TXHZ5XMu9mtfw2La3bHJ6AybL0DvEkdGxk6YHqJVEukciLMWDWqQQ RtbBhqcprgUxipNvdn9KwNpGciM+hNtM9kf9gt0fjv79l/FiSw6KbCPX9b636GzgNy0Ev2UV m00EtcpRXXMlEpbP4V947ufWVK2Mz7RFUfU4+ETDd1scMQDHzrXItryHLZWhopPI4Z+ps0rB CQHfSpl+wG4XbJJu1D8/Ww3FsO42TMFrNr2/cmqwuUZ0a0uxrpkNYrsGjkEu7a+9MheyTzcm vyU2knz5/stkTN2LKz5REqOe24oRnypjpAfaoxRYXs+F8wml519InWlwCra49IUSxD1hXPxO WBe5lqcozu9LpNDH/brVSzHCSb7vjNGvvSVESDuoiHK8gNlf0v+epy5WYd7CGAgODPvDShGN g3eXuA== Organization: Red Hat In-Reply-To: <15adb09d-4cdb-435d-927d-0c648d8239dc@lucifer.local> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 18.07.25 12:47, Lorenzo Stoakes wrote: > On Thu, Jul 17, 2025 at 10:14:33PM +0200, David Hildenbrand wrote: >> On 17.07.25 22:03, Lorenzo Stoakes wrote: >>> On Thu, Jul 17, 2025 at 01:52:11PM +0200, David Hildenbrand wrote: >>>> Let's introduce vm_normal_page_pud(), which ends up being fairly simple >>>> because of our new common helpers and there not being a PUD-sized zero >>>> folio. >>>> >>>> Use vm_normal_page_pud() in folio_walk_start() to resolve a TODO, >>>> structuring the code like the other (pmd/pte) cases. Defer >>>> introducing vm_normal_folio_pud() until really used. >>> >>> I mean fine :P but does anybody really use this? >> >> This is a unified PFN walker (!hugetlb + hugetlb), so you can easily run >> into hugetlb PUDs, DAX PUDs and huge pfnmap (vfio) PUDs :) > > Ahhh ok. I hate hugetlb so very very much. > > Oscar is doing the Lord's work improving things but the trauma is still > there... :P > > Also yeah DAX ahem. > > I'm not familiar with huge pfnmap PUDs, could you give me a hint on this? :>) vmf_insert_pfn_pmd(), called from drivers/vfio/pci/vfio_pci_core.c Essentially, we create huge PUDs when mapping device BARs to user space. -- Cheers, David / dhildenb