From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794342214; b=swuSWAehc37EmTsrhHRRn2QRlYDByAnM6Y1lnZqbvjKwrr60uuqtd8Cp7bMtX15qWPui rRcSUM8ObKxdzMPaxYdFeNtG1MDhY4r56BPlbHL2l7/0g5W2c29jee2TGMdZWcSXIHQ+u j+zG8X8pB1Yc5F0ArJ8CRlF2WoXARr7EnJcsw5+G4OQGdAomvTR1DwW7gtKWE3+ne8X6U S6sVWNkdGN+g2Klv809zUPmKOzO4FX9lltBsYSfLN6UajKj+NmvqIiuWhie9uCRYYjSHN pFY/RL5EJUmo/7ZeLtkzFcjBbHhljoS0w8rPtablACVl9Q6IUxVeTRjNPGQzgbIMcBA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794342214; h=Received:DKIM-Signature:Message-ID:Date:MIME-Version:User-Agent: Subject:To:Cc:References:From:Content-Language:Autocrypt:In-Reply-To: Content-Type:Content-Transfer-Encoding; bh=Z0sgFOBOU/MeK/Ve1kAu1Sczjtdoz1FBdFO2N0G/d7U=; b=t68UPRXpzloOTldEY7qTTcx6dOduYprZkB5oDy4kggSGwjqcEicPlg7JjsQ/CgBbSFGo dOyt6ZW0MgzsFp/WUBfkWLhMhbNF2W0KDtvfUV1Sk3yxdF2/XsH5QG6GvBPMMSrC3kgPj J6FMDm4meKbChT30Nb0OHQpHI36ftr3L/Xjl4zxH1voCckYHijGb5AB47NRzPPjcOWuRf POEZd9rd20NF9uFtG5NpzlwR2BcAKGYWKRcBkWRPjoGFSlVgPuJDeg5BVEhB6aaBFJ8+M 0JyJNQsDIUBkFQHgMw2GccAve2gSXLYbmDjsHmyaB39mmYmE0IFXhai/BQm8mg81Org== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=mIRUsz35; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 16FB9606A8B8 for ; Tue, 10 Nov 2026 20:23:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=mIRUsz35 Received: by smtp.kernel.org (Postfix) with ESMTPSA id A45AF1F008A2; Tue, 10 Nov 2026 20:23:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794342213; bh=Z0sgFOBOU/MeK/Ve1kAu1Sczjtdoz1FBdFO2N0G/d7U=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=mIRUsz35IV3Zi3ISOakOHgEB/jjVCWNx2VQ0duncmJDLxeCRx1HkjV9DTwpcJbc+a 4bBl36DU6KgcJyAgXu4CC/SGGadipP6MKFGn1wbI0ObCDkbt3kbRyDDDjO1ItT/CZG ZcJdJMgONzwgBVE5SRkXNf/DRsJixuV4OFIAJoKcNKl6fuP0RijieN4T0AmYQKshtb x7LrmHKVFA3quIvpQMBdNscXLVXhV5Ip4Ek111QQDBs/oZlHE6SPje5qUWG0EkGgDa O7ToUcVYWDhRlm6lALnvv2V0M6Hi3/TJ/rlq6QVd0O4nJx7bcmCil7xWGAnneQVMKW aDBWw6QdXdcyQ== Message-ID: Date: Tue, 10 Nov 2026 21:23:23 +0100 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 5/6] mm: gup: introduce gup_unshared_pages() To: Yeoreum Yun , Rik van Riel Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Jason Gunthorpe , John Hubbard , Peter Xu , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Andrew Morton , Yuan-Hao Hsu References: <20261109-refactor_gup_fast-v3-0-2aaef02df0e1@arm.com> <20261109-refactor_gup_fast-v3-5-2aaef02df0e1@arm.com> <7627c0d90188b581e7740bf8d17c8dd07b460f89.camel@surriel.com> <699499e46ace0875fd0f32052399e665c8209ea9.camel@surriel.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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 B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 11/10/26 21:19, Yeoreum Yun wrote: > On Tue, Nov 10, 2026 at 02:21:18PM -0500, Rik van Riel wrote: >> On Tue, 2026-11-10 at 14:04 +0100, David Hildenbrand (Arm) wrote: >>> >>> Not quite the right semantics. For pagecache folios we simply don't >>> need >>> unsharing in MAP_SHARED VMAs. That does not imply that these are >>> exclusive. >>> >>> So it's all about "number of pages that don't need unsharing". >>> >> gup_no_unshare_len() ? >> >> a little awkward sounding, but it describes >> what it's doing? > > Hmm, Wouldn't this name be semantically much the same as keeping > the existing gup_unshared_page(), since both essentially convey that > no unsharing is required from GUP's perspective? > > Anyway, naming is always NP-hard problem :\ > > gup_skip_unshare_pages not sure -- Cheers, David