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 8F6A613B590 for ; Fri, 11 Jul 2025 18:57:40 +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=1752260262; cv=none; b=ebMLnhXiUw3AotXp2DkcL20xlXjdq6qzmJt+7S9WxqGWAfHTRDzr+B3d5O8LKZwpGanAaQRtENtKIU9Fulptw8ibxc/k7y7NnTDvW5TTTFa8Y5Ud/Xu6iMyhHl2+f6PFpOPyUgHg3+GiVTzbvj/YiKZhnrLgB79Ha6N15oAIChs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752260262; c=relaxed/simple; bh=R4KOVvt/FCWP6gRCC0GZxjeyZOsKBBBECyJoWTZIt5U=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=eJCTyYRxJwS1+hRvN4Z3UD+Vg8fhgeA6tnqPk2mI8u3lWr+MoEw2oJRJ00pMInfR+PqDZW3egZLE42ZBJffNxNU7ZA9qND9KgKTJr3xYO2ygYb5GTtL5SOX6t5udbblKjlrhrvCuDLISYAF/+2YNaXyzqE2E/PpJQFY76mG1RH8= 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=gALLjl2/; 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="gALLjl2/" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1752260259; 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=VbL3LlciXrx5usUof/F7sG/X7kZUjQJ0y4avrgolLvM=; b=gALLjl2/69KpLdydwNZte7ubVKX4YlwqVCF5pnfGIuhp0/Gm0rQKwtkkeFMca7aC8yNq8J TLRhLh9FLJCFfqRW0G+XFg4xUaMJWB6aA7ZnzsT77BIeeQeVL3a3tZusx19PesaXl9/Oio wu/YOZ6Uj5kFf7SviP40KSzz/y4POls= 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-617-MV_-vLl5Niqcgkc1-PucHw-1; Fri, 11 Jul 2025 14:57:38 -0400 X-MC-Unique: MV_-vLl5Niqcgkc1-PucHw-1 X-Mimecast-MFC-AGG-ID: MV_-vLl5Niqcgkc1-PucHw_1752260257 Received: by mail-wm1-f69.google.com with SMTP id 5b1f17b1804b1-455d95e711cso3768365e9.0 for ; Fri, 11 Jul 2025 11:57:38 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1752260257; x=1752865057; 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=VbL3LlciXrx5usUof/F7sG/X7kZUjQJ0y4avrgolLvM=; b=Jv8+PSFZhuCJQ+LT3j2NvWnFQxCaaE7ffv9QLC+slYgAkJDYMQ30f783hgH9E/hf3S UGAUK+t6CwHIA9028KXyVIkuiImZfhKpBiOyD3MvejTInfYqlup8RIoLl3FzSv7UGUcF osqyw/4nFdrtPqkyxbDGWPb/SzdraOpd+dBgFo14Ak6bouDVr7TcpIi/mBqXyoCnwhUp BGCphb/KP5L4Ym4GCfD0dPctXgApIi6v8LnhrJUd4oAnyDNabPDeXdpj3YGDeekGTia9 NoCw6WliIOxgLRAdb1YlWJ5cu8VmnVZeO6EMOmLMpFull20+cDwTGDe1P5gGNiuXWja0 3ZaQ== X-Forwarded-Encrypted: i=1; AJvYcCXQe5foN1+QrlPNmjS7lgRjjCeV3LBIU+wDI4kdDkk62dN91DLf8GMFG70a5ZJLuadMA3OIYgtfuV1cXdAJ@vger.kernel.org X-Gm-Message-State: AOJu0YyqCf33gSJvtZdq6ewtP2GDEt/JQm68gAFXVElNRm6j79owTeju JRxmkj3YNNXAtC2oRrZXfVO3Q4ZDOxTYH58FfttaDZP7PRYLWnnX1WX5vNPP1mg0/3fwPRdFA9i NvNsiefJz2YjW9k6TFmSAM1F7V35KcQt+0DjzUnXjH2LwRo4NPyQ5uv7O/WQz9ZOLE1Y= X-Gm-Gg: ASbGnct0G/0SHmew/FKmtBiqfC70QtrFlascj6jdXEkrS8WgjYSKNwKdBsaEmO+eTX8 Z5mXtb3UwAncRprUzdxBkgkeAZBbmhDDOndvQ2D6VnsodbBjvoaJHKfdQEJJUlW2z4gEaHDAkrP WZX0gT3yHyui9nwpL4QfqJA7D6Ct4s0m8lvUGmseG0mcAOF3jxzkb1K/uwR1b3jjJhe7+t2ieqp /nW0eNKw3WTTnriTJdkoZnQsCCIZd2S+iO8YdJ9rU93+Bb5oR5F1fvqMRhilVMRuECBfFQpsTYy FxPP76c+ydGRh4cmp75rscitFUHz9BJecWpQ/psszSWy4D43A51zCnyfgdYlkzVkaJOZH5y3IS6 rYOPnJs3kHkQQEHBzLR0ct0iLXR/6+LMZDeLSEik7T2XQVHs+yItAkVGt8fBC/vXyfg0= X-Received: by 2002:a05:6000:2c0f:b0:3a5:3993:3427 with SMTP id ffacd0b85a97d-3b5f1e95fb8mr4724523f8f.26.1752260257156; Fri, 11 Jul 2025 11:57:37 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHGwKEUQLbh/zY6545eP9xFg7a7s2kPU1xUA4JG52ouaTweDCumvMrk6zcF1Opz8ywnEmQoVg== X-Received: by 2002:a05:6000:2c0f:b0:3a5:3993:3427 with SMTP id ffacd0b85a97d-3b5f1e95fb8mr4724490f8f.26.1752260256647; Fri, 11 Jul 2025 11:57:36 -0700 (PDT) Received: from ?IPV6:2003:d8:2f0a:2e00:89cb:c7f0:82f2:e43c? (p200300d82f0a2e0089cbc7f082f2e43c.dip0.t-ipconnect.de. [2003:d8:2f0a:2e00:89cb:c7f0:82f2:e43c]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3b5e8e1e8b1sm5171588f8f.82.2025.07.11.11.57.34 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 11 Jul 2025 11:57:35 -0700 (PDT) Message-ID: Date: Fri, 11 Jul 2025 20:57:33 +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 RFC 01/14] mm/memory: drop highest_memmap_pfn sanity check in vm_normal_page() To: Hugh Dickins Cc: Lance Yang , Oscar Salvador , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, nvdimm@lists.linux.dev, Andrew Morton , Juergen Gross , Stefano Stabellini , Oleksandr Tyshchenko , Dan Williams , Alistair Popple , Matthew Wilcox , Jan Kara , Alexander Viro , Christian Brauner , Zi Yan , Baolin Wang , Lorenzo Stoakes , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jann Horn , Pedro Falcato , Lance Yang References: <20250617154345.2494405-1-david@redhat.com> <20250617154345.2494405-2-david@redhat.com> <5e5e8d79-61b1-465d-ab5a-4fa82d401215@redhat.com> <36dd6b12-f683-48a2-8b9c-c8cd0949dfdc@redhat.com> <0b1cb496-4e50-252e-5bcf-74a89a78a8c0@google.com> <056787ba-eed1-4517-89cd-20c7cc9935dc@redhat.com> <5e439af4-6281-43b2-cbd2-616f5d115fdf@google.com> 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/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 In-Reply-To: <5e439af4-6281-43b2-cbd2-616f5d115fdf@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 11.07.25 20:49, Hugh Dickins wrote: > On Fri, 11 Jul 2025, David Hildenbrand wrote: >> On 08.07.25 04:52, Hugh Dickins wrote: >>> >>> Of course it's limited in what it can catch (and won't even get called >>> if the present bit was not set - a more complete patch might unify with >>> those various "Bad swap" messages). Of course. But it's still useful for >>> stopping pfn_to_page() veering off the end of the memmap[] (in some >>> configs). >> >> Right, probably in the configs we both don't care that much about nowadays :) > > I thought it was the other way round: it's useful for stopping > pfn_to_page() veering off the end of the memmap[] if it's a memory model > where pfn_to_page() is a simple linear conversion. > > As with SPARSEMEM_VMEMMAP, which I thought was the favourite nowadays. Yes, you're right, I had the !SPARSEMEM model in mind, but obviously, the same applies for the SPARSEMEM_VMEMMAP case as well. Only the SPARSEMEM && !SPARSEMEM_VMEMMAP model is weird. IIRC, it will dereference NULL when given a non-existant PFN. (__nr_to_section returning NULL and pfn_to_section_nr() not beeing happy about that) -- Cheers, David / dhildenb