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 A3ECFC021B2 for ; Tue, 25 Feb 2025 16:48:27 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1B0D96B0089; Tue, 25 Feb 2025 11:48:27 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 16138280001; Tue, 25 Feb 2025 11:48:27 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0013C6B0095; Tue, 25 Feb 2025 11:48:26 -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 D69BE6B0089 for ; Tue, 25 Feb 2025 11:48:26 -0500 (EST) Received: from smtpin28.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 711C0B1D38 for ; Tue, 25 Feb 2025 16:48:26 +0000 (UTC) X-FDA: 83159050212.28.CF47CD5 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf21.hostedemail.com (Postfix) with ESMTP id C0B011C0015 for ; Tue, 25 Feb 2025 16:48:23 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=Z4uUfH49; spf=pass (imf21.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 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=1740502104; 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=jw2CX8GJqxuLRFAFx88zTCcWlXcKTO/rHj8BJTgdWyk=; b=fcLcfABP5qMHVIwPf1wBxo1MYIIvGsF89ZHKkyZyHldfrVn+hR9d3Sipk0WCM+ZAFb7GWP YuQt+Y5XmDBws1L0/MZ0RtbC57nq2HPuHEFH+qJVc1tdptDz1FLK74fDi7d7xBDybHM0FE 4HV7lqgQfOXsmjZa33t0GsH9SVjbdfk= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=Z4uUfH49; spf=pass (imf21.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 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=1740502104; a=rsa-sha256; cv=none; b=LDM8SLMHQfngjwj8p4xbSPM7gykl+5UUAMtSS2AY1DIKDJkKGEEjTh5l7MJbN5uH+MFBYy VxXkIsj1FLsJHev7YPw/QkN2ZitvBhIlM1HYuePom97ZOeyutm5X2nRpQzzOtE8lF1wm/G 152CcqdcWcYKs0uWWl5vw+C8pA0pH+w= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1740502103; 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=jw2CX8GJqxuLRFAFx88zTCcWlXcKTO/rHj8BJTgdWyk=; b=Z4uUfH494yPKf+qWMKBmLoNxiI948PB3j16TGiZaRDoTA6wdKzq/SC/oNJzzORITsJvrYv jrissvshBpo4KYV1rZfT5nfgKJ/MOIpjtOgj94kB4S6IQB8yREvzSo5VTTbV9YuoxFZWmH HSKcZuLTKMjUm2R9EKLP069+Ypfy5v4= Received: from mail-wr1-f69.google.com (mail-wr1-f69.google.com [209.85.221.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-75--IgKxl5WOJm_bWUeNg8Tcw-1; Tue, 25 Feb 2025 11:48:21 -0500 X-MC-Unique: -IgKxl5WOJm_bWUeNg8Tcw-1 X-Mimecast-MFC-AGG-ID: -IgKxl5WOJm_bWUeNg8Tcw_1740502100 Received: by mail-wr1-f69.google.com with SMTP id ffacd0b85a97d-38f4bf0d5faso3127215f8f.0 for ; Tue, 25 Feb 2025 08:48:21 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1740502100; x=1741106900; 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=jw2CX8GJqxuLRFAFx88zTCcWlXcKTO/rHj8BJTgdWyk=; b=bUK2WGCb9zgMWdFhNbYuAYekYgd6IWQSZg6O2gDRpKzt4FuYroGR3wAYUJyzjSLCj7 UnSR6YT7Y1m06bRBvurwvJ9vIqWJGvdZaEoIKScQIilytG27o6xrRqg+BPk+J0C2V9ys MM90sqXnn/LfXx8prHUsk0AMDXV+qS5WjIsi1FwAt4MeTiWNm+XG/UjYbHnqhxhL/1ax Y+gdyH7mS4hk/S+l/E97M8BhCTkKyRaFtSS+j8c6NCFE4t83x8mU5J5cY9rJYoZ2nEK2 oyGcub+sOAv0m5lFGzLFtpV6Cirz8Bb7fb+NokFvEwrwYa0F2AiqEdmUPmPbH+9HI5a/ TSTw== X-Forwarded-Encrypted: i=1; AJvYcCW6WJvb6jnbs2Ljf+JUGIRRuaoikkP7pG/hDCEW8StG0XkvOovNcgOByGR0WCtIA1NY8QrFchHWsA==@kvack.org X-Gm-Message-State: AOJu0Yw/sYJ033cUl/yPN7w4/3MHQ6ZCNUkwvVGHyma9f3jlI/empP46 KkFq4eW200uu0ZwP5cgL+RgwxuvivKn2Z5aZeAap0tuKegnDYBy4fQ80Dm8/UxJp6mnMmwgVlgT AM/f9mc8HD0qxwwne0uEcUQxLlzW3XX/Jmdn9b/dryEfampay X-Gm-Gg: ASbGnctwWO65x0gojL0g9NruRP1vkt+Ld98KJsRwwMxitxlGxzcLe61mYj4LsTGYgYt AnO5BzsFaQge8PLtveht0L4xLf8Rsg80jX9vpi27O8CR63YWjgysEnhmHw2I2eYYnIdSY+f1+Ae reMXKTlaKRJKLvAHqVSKHmrHq9gPoDBTKYljTlgi0kWphHo5kxuFe6XPHJoH1mU59VtGyfl5OyO Dc8hz2zyzlr4+GulsB+4Ahe0SjIDO+gkOhEdDNNHYNb/rICdd6LDgzprYTh9EEN6NmXK+ViVM01 91fobUdWCl9xCClsgwIwBLDvT4yUilIQeda5OnSG+8xmQD2lzxUkzYxQya/NzKckFpZIgMh63ud WAXe10/40jVNOxPVXeloZy9Zv35wtWycvcMF6VB+eie4= X-Received: by 2002:a5d:59a3:0:b0:38d:e15e:17e9 with SMTP id ffacd0b85a97d-38f6f0b2161mr20087644f8f.35.1740502100268; Tue, 25 Feb 2025 08:48:20 -0800 (PST) X-Google-Smtp-Source: AGHT+IE8sdF4FkFqdZXDiyQJpYRdr9jotf0bgjSy0tUCoeN9Ynzu8FAq0ynzblVc1iJsuqV0PE3uGw== X-Received: by 2002:a5d:59a3:0:b0:38d:e15e:17e9 with SMTP id ffacd0b85a97d-38f6f0b2161mr20087605f8f.35.1740502099887; Tue, 25 Feb 2025 08:48:19 -0800 (PST) Received: from ?IPV6:2003:cb:c73e:aa00:c9db:441d:a65e:6999? (p200300cbc73eaa00c9db441da65e6999.dip0.t-ipconnect.de. [2003:cb:c73e:aa00:c9db:441d:a65e:6999]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-43ab15476f0sm32638635e9.23.2025.02.25.08.48.18 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 25 Feb 2025 08:48:19 -0800 (PST) Message-ID: <48ffe442-5015-44fe-bbd6-708ba8500505@redhat.com> Date: Tue, 25 Feb 2025 17:48:17 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 0/4] mm: permit guard regions for file-backed/shmem mappings To: Lorenzo Stoakes , Vlastimil Babka Cc: Andrew Morton , Suren Baghdasaryan , "Liam R . Howlett" , Matthew Wilcox , "Paul E . McKenney" , Jann Horn , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Shuah Khan , linux-kselftest@vger.kernel.org, linux-api@vger.kernel.org, John Hubbard , Juan Yescas , Kalesh Singh References: <8d643393-ddc0-490d-8fad-ad0b2720afb1@lucifer.local> <37b606be-f1ef-4abf-83ff-c1f34567568e@redhat.com> <0db666da-10d3-4b2c-9b33-781fb265343f@redhat.com> <62c0ba1c-7724-4033-b1de-d62a59751ca5@lucifer.local> <6eb33b5d-3040-4637-b627-48f8f78e4e28@lucifer.local> <3102ab3b-67b6-4047-9db7-e83c3b9c1c53@lucifer.local> From: David Hildenbrand 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: <3102ab3b-67b6-4047-9db7-e83c3b9c1c53@lucifer.local> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: 2G43jWRQN6gpqtGkKgxm2vg25zfkQh12qPPiGskTIwI_1740502100 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: C0B011C0015 X-Stat-Signature: 9wes633ncm8uj3wjcc9jpasfiz69itgf X-Rspam-User: X-HE-Tag: 1740502103-63169 X-HE-Meta: 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 OUUpQ0ca gFkQAe8fwDuq5M0WJWxHwJTG5XLSxV0EPnIVJ4Eml7NX9Q4yJ0Jvo77av4/E81An7e3Wbt+WrJz7ZrwAF014jAMb3Exj4PnnnMuICHkvqTAdNerB7lPYsLkVRQdJ6dlNZoFYTy+Ey6qnoFXwsvvXPl8k5uz2IGFTyez2S76rEdLKY8ylw47T6hqnRwKEiv2BkLF9bFvxWEHvqOwbqwkDE6d7rDoGApmdle2i/cz++6+xl4x6hdsNpZNnDPgA/jfP07e/6kXvpwxMd8VhKmyP/cei/+2cCVC4+pC1ag4PzQo9kAeVs4CEUDSwTxuBu7O85GSt+GYdVNLw7Hin4Aue4XY4BMO7kmJQ9l6gxuv53avHd2cW/TPada/pcSIqvJf0uYDCqe0nEJ7c5Kp0W8iZygcQtFa8lQuEw5aL1YG4gJRsj+2DlqAbzvQqi1N5lWlPm93UEBFaEEASa3/5DLPID1ZyzdIMs3VabFZCBm1zeYLE4VwQ= X-Bogosity: Ham, tests=bogofilter, spamicity=0.008000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: >> As for compatibility with VM_LOCKONFAULT, do we need a new >> MADV_GUARD_INSTALL_LOCKED or can we say MADV_GUARD_INSTALL is new enough >> that it can be just retrofitted (like you retrofit file backed mappings)? >> AFAIU the only risk would be breaking somebody that already relies on a >> failure for VM_LOCKONFAULT, and it's unlikely there's such a somebody now. >> >> > > Hmm yeah I suppose. I guess just to be consistent with the other _LOCKED > variants? (which seem to be... undocumented at least in man pages :P, and yes I > realise this is me semi-volunteering to do that obviously...). > > But on the other hand, we could also expand this if you and I see also Dave feel > this makes sense and wouldn't be confusing. Just my 2 cents: one thing that came to mind: an existing library would have to be updated to use the _LOCKED variant if the app would be using mlockall(future), which is a bit unfortunate -- and if it could be avoided, it would be great. But yeah, devil is in the detail ... -- Cheers, David / dhildenb