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 77F3BC4829A for ; Tue, 13 Feb 2024 10:01:19 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 114B46B009D; Tue, 13 Feb 2024 05:01:19 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 09E856B009E; Tue, 13 Feb 2024 05:01:19 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E0C806B009F; Tue, 13 Feb 2024 05:01:18 -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 CC8616B009D for ; Tue, 13 Feb 2024 05:01:18 -0500 (EST) Received: from smtpin20.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 85213160BA4 for ; Tue, 13 Feb 2024 10:01:18 +0000 (UTC) X-FDA: 81786337836.20.CB1186A Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf06.hostedemail.com (Postfix) with ESMTP id 074DA180031 for ; Tue, 13 Feb 2024 10:01:15 +0000 (UTC) Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=Oh1sooYA; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf06.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1707818476; 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=eOOGhWUSnVV/mhWF+3X1dD2Ux/VRcraCiGty/87ic5E=; b=mg9vqXp34zH0Zk+2qb9KsWVq+wmvLhg9WDEZ5/CrxH8sqKhUQNdgnK/KR8wEWejIiI4pGo LzCGdu/NL6GpopZIfhYVtDjZEif7oUA8f8ZQ6WvGjstlXFpwLdY6we33lMqQTQ7DE9ZVcH ajkxsb24rVxYBEybdqIWx24/pS5zRcc= ARC-Authentication-Results: i=1; imf06.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=Oh1sooYA; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf06.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1707818476; a=rsa-sha256; cv=none; b=JNDzpEddwKjMRtHsH1YyaVc943/vM+VhWTGbctsB/ijaSrKPEx1YQEVt+O3QW/uppGaS0g 9d0u2IGCHJjuakJUZH92yQ0MN/019QLUI/CVVGooYo8WBgdmmlMzfY2YmK+xR+YlFBmvF+ jkhvKIgnkN/8Di/wiicWGNJIzSHxucM= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1707818475; 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=eOOGhWUSnVV/mhWF+3X1dD2Ux/VRcraCiGty/87ic5E=; b=Oh1sooYAxSa+rknXo0Mc6QvPzYeTnKihVgATL+AbwKuySBIAdaoOKULxjbAnavJ0IrbINV 9puV5AEs1Z54ZVVLsZIFlzDPgdS8sOK2sMmyoxxZGA3AJZc6LaguIwzDWJBYNwhFQP1TT8 blq6BYYwaZevqYXeyA5SjWUWyeFF+pM= 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-179-ZeMPfv7ANNO5oYcWmb-iLg-1; Tue, 13 Feb 2024 05:01:13 -0500 X-MC-Unique: ZeMPfv7ANNO5oYcWmb-iLg-1 Received: by mail-wr1-f69.google.com with SMTP id ffacd0b85a97d-33cd1a98261so322300f8f.0 for ; Tue, 13 Feb 2024 02:01:13 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1707818472; x=1708423272; h=content-transfer-encoding:in-reply-to:organization:autocrypt:from :references:cc:to:content-language:subject:user-agent:mime-version :date:message-id:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=eOOGhWUSnVV/mhWF+3X1dD2Ux/VRcraCiGty/87ic5E=; b=LX1yMAw2hE1mjUZEKUcCEfZd2po0uZmcHzDQciINA6b1ENETWHZXyAPlLVcckWbsPc DFPBTJiGvSL7nuFr+WGN1eTQnvVSDy4ilR6sgJPPcfBw4obPLuxImZml5k9xT2hz4+UZ MW7qe2VMQ3ItI4WBkf0B9jcKpYV4rmTeSqF4LEAOEAVNjCZt0kYWxs047ygxP8815kZY 9Tpbq7TQ8ikA0Dy3jNgN5pZWQf2+c1jvmn3k5F3FY6pERqSQ8JFnK2bbGo/EQLJTlrWy IinJaZn8fDy4wiQe6iK5kNGSnRTBZI+7MQqYvomlsA/QOfKa5bIpXzWZQsmh7LBoMQG8 vMhw== X-Gm-Message-State: AOJu0Ywut897NRsz+ugXxIKRWZt/v8CHiDOhDMlZ2aboFKvqWz2gRHmR WTbG0vmmdhZA564n8/XfXHgT4WhneDmtsoNUcanNzf7qb4yNsu8I6YA7FJvk4+TTda9W1oSzcqq eXNLC7BJZ1/lyz53PuTIxUk9RI6VSgug2kTaQTydVNU+JK6vg X-Received: by 2002:adf:f4c4:0:b0:33c:e065:992b with SMTP id h4-20020adff4c4000000b0033ce065992bmr388168wrp.59.1707818472392; Tue, 13 Feb 2024 02:01:12 -0800 (PST) X-Google-Smtp-Source: AGHT+IHo7BuC5azekhcJ4veBIbYxGMm4YlFVCwY/2ZjCujWQgpT7sZoNPy3woF9ZDl+iJe9qYXWKEw== X-Received: by 2002:adf:f4c4:0:b0:33c:e065:992b with SMTP id h4-20020adff4c4000000b0033ce065992bmr388148wrp.59.1707818471960; Tue, 13 Feb 2024 02:01:11 -0800 (PST) X-Forwarded-Encrypted: i=1; AJvYcCV4tSd4c2cvHc+FSJzNu6I7YvcbiHAeITmgqMQ3v+uu5dkbtyL7ZejfS8SydmKrGVYVI2NoCvNYUbEbiI2/0cM8PWHPebKFv+CRqnZtkzRtV0M3l7eJqzDIBIyZsTwg86hCU/idzEZ8xm0w2hHOdL2Unqn/a8DAACEel2WyRfZCNfdBB+aXGbCI8kBf4Yhuzvi1YbkLomBQ65xtidyNBdyn7qaWSyXeWicJEyaMQvDaobQrPvNHIiHUVtGOZ0XeEH7J6N86VHiL3pX4cjkCbrwbrH3Pu9GcmjyFNgfrjGXjFIP80s0i5KbqYWPtYHA5/zu+K/iZCF5jqBX+TlnazLvlAuM0eytMQVg0EFjAEdCK1eRVTMZDmBV1T3T7GondGz/ZhJft+3e5eeb/krH8LUWwbDx32ZqdVYzOYtC2YVKXa0QNJq3hmtNIob4ezPKmUz1yvt1j9hgt2kYc9ivPAl5NWGmqI8HJkfuTudMqAtsOfV8MPbWNvUpP700Svv/T8/iKcvSKli0CHL7ni2ncgFgfYadBMHMq/6QO+vGYquDvkk+GjqFFPkBGui72sm/eLmDvGH3G9oQKORJdhNTznQcn/QWIk+Z1obvehZbENa9XU2nYKVqp4Ae8FHBGVcCfZ7H2u3OCsLxmZtPheE9+Br5w/49IZYpK0LYnWDd30g05ewHkKIP2ZkXz8jI/FzkIQgyZ5OVzSQV0KoJj1NcoJm2O41RjgF9VSixn8ugypffHOlTELXkayKidOEI/rQtHN/llW35IwV+4Cp2Dyhl4Lxc+PdveXT8qWEnqLz3H7BqNOruDonASCgQftc8lOJJdRkOunN5CloXVwj2TusSxIAmmAGIiQfScWHKK5RbeXyuboKr+yhYHm0O6w3BzpQ== Received: from ?IPV6:2003:cb:c70a:4d00:b968:9e7a:af8b:adf7? (p200300cbc70a4d00b9689e7aaf8badf7.dip0.t-ipconnect.de. [2003:cb:c70a:4d00:b968:9e7a:af8b:adf7]) by smtp.gmail.com with ESMTPSA id h16-20020a056000001000b0033cdedb3e84sm659589wrx.18.2024.02.13.02.01.10 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 13 Feb 2024 02:01:11 -0800 (PST) Message-ID: <39ee7f6b-082e-4bab-98e1-dc2130131160@redhat.com> Date: Tue, 13 Feb 2024 11:01:09 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 19/25] arm64/mm: Wire up PTE_CONT for user mappings To: Ryan Roberts , Mark Rutland Cc: Catalin Marinas , Will Deacon , Ard Biesheuvel , Marc Zyngier , James Morse , Andrey Ryabinin , Andrew Morton , Matthew Wilcox , Kefeng Wang , John Hubbard , Zi Yan , Barry Song <21cnbao@gmail.com>, Alistair Popple , Yang Shi , Nicholas Piggin , Christophe Leroy , "Aneesh Kumar K.V" , "Naveen N. Rao" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , linux-arm-kernel@lists.infradead.org, x86@kernel.org, linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20240202080756.1453939-1-ryan.roberts@arm.com> <20240202080756.1453939-20-ryan.roberts@arm.com> <64395ae4-3a7d-45dd-8f1d-ea6b232829c5@arm.com> 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: <64395ae4-3a7d-45dd-8f1d-ea6b232829c5@arm.com> X-Mimecast-Spam-Score: 0 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: rspam09 X-Rspamd-Queue-Id: 074DA180031 X-Stat-Signature: 6tnmmrgqewo7tor4kam3uaa673hqrmh7 X-Rspam-User: X-HE-Tag: 1707818475-873245 X-HE-Meta: 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 7aGOVM0I 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 12.02.24 21:38, Ryan Roberts wrote: > [...] > >>>>> +static inline bool mm_is_user(struct mm_struct *mm) >>>>> +{ >>>>> + /* >>>>> + * Don't attempt to apply the contig bit to kernel mappings, because >>>>> + * dynamically adding/removing the contig bit can cause page faults. >>>>> + * These racing faults are ok for user space, since they get serialized >>>>> + * on the PTL. But kernel mappings can't tolerate faults. >>>>> + */ >>>>> + return mm != &init_mm; >>>>> +} >>>> >>>> We also have the efi_mm as a non-user mm, though I don't think we manipulate >>>> that while it is live, and I'm not sure if that needs any special handling. >>> >>> Well we never need this function in the hot (order-0 folio) path, so I think I >>> could add a check for efi_mm here with performance implication. It's probably >>> safest to explicitly exclude it? What do you think? >> >> Oops: This should have read "I think I could add a check for efi_mm here >> *without* performance implication" > > It turns out that efi_mm is only defined when CONFIG_EFI is enabled. I can do this: > > return mm != &init_mm && (!IS_ENABLED(CONFIG_EFI) || mm != &efi_mm); Please use all the lines you need ;) if (IS_ENABLED(CONFIG_EFI) && unlikely(mm == &efi_mm)) return false; return mm != &init_mm; > > Is that acceptable? This is my preference, but nothing else outside of efi > references this symbol currently. We could also mark MMs in some way to be special. return mm->is_user; Then it's easy to extend. -- Cheers, David / dhildenb