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 6DF3BC54E67 for ; Thu, 28 Mar 2024 10:11:10 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D8A346B0095; Thu, 28 Mar 2024 06:11:09 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D3BE16B0096; Thu, 28 Mar 2024 06:11:09 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BDBFB6B0098; Thu, 28 Mar 2024 06:11:09 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id A0E5E6B0095 for ; Thu, 28 Mar 2024 06:11:09 -0400 (EDT) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 0F3D2A065C for ; Thu, 28 Mar 2024 10:11:09 +0000 (UTC) X-FDA: 81946029858.19.B32B5F9 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 BCE5E1C000E for ; Thu, 28 Mar 2024 10:11:05 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b="D/L0wk2M"; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf21.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=1711620665; 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=hLHNuBUsHivnnoXg+gTbcgdr/MWic5w5iJ85B7qcDKo=; b=Xbp0AgKUAVIcU6g/LB+WcebVwnrjbVJUqNrbL5cnbHFZ5JgvHzmSShpfJbWbZ2JJ0bJQhP V9E1+GtBNkgQqd4hudI1nMsMIa0cmKtznWV3iZg86vmGdvMEqrNjKO8H54en6/c2HVkMYR pOU8wVQKEPslD5RBx9U15MfclVXNkMA= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b="D/L0wk2M"; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf21.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=1711620665; a=rsa-sha256; cv=none; b=MnXclq/xzhtA8Di92iZgzXEb60N7PJqrprufGCNbtdPb8b4yUGzFZdzdmZ44uSaIddDC+Y zguCzUMU9wvs8lzKJyWtVcLqNFCfGRZpB2L6IxtHao5GFcXeio9NoSR7HuUg+8tX7HBgyH nXsjZRtFiLVeBCjAvmxa2ohJYnlv7nI= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1711620665; 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=hLHNuBUsHivnnoXg+gTbcgdr/MWic5w5iJ85B7qcDKo=; b=D/L0wk2MkyB0LjwZkWIwor3H4yUh7sLFTcRUW7SpVAiAmtPhJC1cXfg4G18RvH9jYwzvlh 7ag9A+jC3Dhz9OBCl/Pk3tdjcFOEN3CAzYy9B75l06LBuboWFkHRw76bGD6Y3z88DuBQJg DgDcIFhRv8jyZ53yUaXwiqwbcB1QjLA= Received: from mail-lf1-f71.google.com (mail-lf1-f71.google.com [209.85.167.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-499-oQE_Pw2kMp6TXi2whsOsIw-1; Thu, 28 Mar 2024 06:11:03 -0400 X-MC-Unique: oQE_Pw2kMp6TXi2whsOsIw-1 Received: by mail-lf1-f71.google.com with SMTP id 2adb3069b0e04-515ab5c3738so576993e87.2 for ; Thu, 28 Mar 2024 03:11:03 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1711620662; x=1712225462; 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=hLHNuBUsHivnnoXg+gTbcgdr/MWic5w5iJ85B7qcDKo=; b=QJkSG5pgj3QucGf1hp7m6mUzXZH1/6gxzb+G29t/UNXy//amncLWU1IgWpAta0S8xw TP1/tZ0yL9JTx9+D/FNAqcUBsRxzwj2lRsJHR5B4h+/GPRX0ixFCoMBe7je8hdV0Y1TO +9X8hfKUDW6YCd4GG57AMMEgVNGeYKtbF9qlAqp8vBfY7Nu36ZK+xvtlrxaHlaqZD5Dh MBG4DfdFq3LP+fzKhhuMIC/yREr20FXUKtgh1XJV836VLcvGFrjoChvMreNTj6OMdQPp Lu3vNyu0qRbSGRlkgThl8mPhfaDNqBQd1C+eNpfSgliDd9jWbVq5LFe+JIbhL/f1C47z rrCw== X-Forwarded-Encrypted: i=1; AJvYcCXz7TE9GrLdcS2znxexwOy3aaV1F1fkkYCqnt2WF+gbBksinTG+xG91Q+NDuAMYHxRQNZ+t1Xhs7JITnkQpP4vophQ= X-Gm-Message-State: AOJu0Yyp5xzXw1lahH8gQt2w0nWRUbKtdfcLB7k0NFa6vlOZVZ4SZQNx IJSnSY4PjXl3aTuR31RUSgBgu5ex3GK1z1hdJCwd10oR6l6ThQTcKbP8oydRuCiCZOrK2ffa1uv dh+kW/I1tOofAWhbD/rW2+RKMUVGAtOReps37mCdaK1b/LkWd X-Received: by 2002:ac2:44cb:0:b0:513:a8fc:95d7 with SMTP id d11-20020ac244cb000000b00513a8fc95d7mr1360056lfm.38.1711620661945; Thu, 28 Mar 2024 03:11:01 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHHYQU8kxpYM4jVYSDvtGoR0p1IRQOO6x9SQkiA3Zc9ExgaYMDl44yGXybjHsfrkFhFyhcpwA== X-Received: by 2002:ac2:44cb:0:b0:513:a8fc:95d7 with SMTP id d11-20020ac244cb000000b00513a8fc95d7mr1360023lfm.38.1711620661535; Thu, 28 Mar 2024 03:11:01 -0700 (PDT) Received: from ?IPV6:2003:cb:c714:3600:8033:4189:6bd4:ea29? (p200300cbc7143600803341896bd4ea29.dip0.t-ipconnect.de. [2003:cb:c714:3600:8033:4189:6bd4:ea29]) by smtp.gmail.com with ESMTPSA id i4-20020adfefc4000000b0033b6e26f0f9sm1344502wrp.42.2024.03.28.03.10.59 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 28 Mar 2024 03:11:01 -0700 (PDT) Message-ID: <372a9331-6d95-4083-9a8f-a4f714868bea@redhat.com> Date: Thu, 28 Mar 2024 11:10:59 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 06/13] mm/gup: Drop folio_fast_pin_allowed() in hugepd processing To: peterx@redhat.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Yang Shi , "Kirill A . Shutemov" , Mike Kravetz , John Hubbard , Michael Ellerman , Andrew Jones , Muchun Song , linux-riscv@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, Christophe Leroy , Andrew Morton , Christoph Hellwig , Lorenzo Stoakes , Matthew Wilcox , Rik van Riel , linux-arm-kernel@lists.infradead.org, Andrea Arcangeli , "Aneesh Kumar K . V" , Vlastimil Babka , James Houghton , Jason Gunthorpe , Mike Rapoport , Axel Rasmussen References: <20240327152332.950956-1-peterx@redhat.com> <20240327152332.950956-7-peterx@redhat.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: <20240327152332.950956-7-peterx@redhat.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-Rspam-User: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: BCE5E1C000E X-Stat-Signature: i9gskap1fprs6ab467sm4u53jnz4nchh X-HE-Tag: 1711620665-109508 X-HE-Meta: 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 vZzuQF8v 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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 27.03.24 16:23, peterx@redhat.com wrote: > From: Peter Xu > > Hugepd format for GUP is only used in PowerPC with hugetlbfs. There are > some kernel usage of hugepd (can refer to hugepd_populate_kernel() for > PPC_8XX), however those pages are not candidates for GUP. > > Commit a6e79df92e4a ("mm/gup: disallow FOLL_LONGTERM GUP-fast writing to > file-backed mappings") added a check to fail gup-fast if there's potential > risk of violating GUP over writeback file systems. That should never apply > to hugepd. Considering that hugepd is an old format (and even > software-only), there's no plan to extend hugepd into other file typed > memories that is prone to the same issue. > > Drop that check, not only because it'll never be true for hugepd per any > known plan, but also it paves way for reusing the function outside > fast-gup. > > To make sure we'll still remember this issue just in case hugepd will be > extended to support non-hugetlbfs memories, add a rich comment above > gup_huge_pd(), explaining the issue with proper references. > > Cc: Christoph Hellwig > Cc: Lorenzo Stoakes > Cc: Michael Ellerman > Cc: linuxppc-dev@lists.ozlabs.org > Signed-off-by: Peter Xu > --- @Andrew, you properly adjusted the code to remove the gup_fast_folio_allowed() call instead of the folio_fast_pin_allowed() call, but (1) the commit subject (2) comment for gup_huge_pd() Still mention folio_fast_pin_allowed(). The patch "mm/gup: handle hugepd for follow_page()" then moves that (outdated) comment. -- Cheers, David / dhildenb