From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 28B50606A32E for ; Wed, 11 Nov 2026 10:30:47 +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=JrTLwSLE Received: by kanga.kvack.org (Postfix) id A4C906B05B9; Wed, 11 Nov 2026 05:30:40 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id A24306B05BA; Wed, 11 Nov 2026 05:30:40 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 93A406B05BB; Wed, 11 Nov 2026 05:30:40 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 72D636B05B9 for ; Wed, 11 Nov 2026 05:30:40 -0500 (EST) Received: from smtpin21.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay03.hostedemail.com (Postfix) with ESMTP id EC1CBA0278 for ; Wed, 11 Nov 2026 10:30:39 +0000 (UTC) X-FDA: 85422469398.21.6134C07 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf24.hostedemail.com (Postfix) with ESMTP id 374F8180005 for ; Wed, 11 Nov 2026 10:30:38 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=JrTLwSLE; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf24.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1794393038; 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=KxrhFMa8/sp9xXjPYISbhRzyRkp2BmT2lD81VC2uH5g=; b=lU1QguqoD3RLH4BhSCCXKs3x90P7tfNrOXGSmUeu5eyXLDv1ICn23S5mH6I5xrBnwLpLxd jy3eb2z8yrcO/laftzCyjgZuths2T+mfC4HmJusyw/D4vwxz6IVXDG+GPLhDTqM0Iz699E LU3Q5nIR6vagO4zOjNdmQ5d1LFKz+cs= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=JrTLwSLE; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf24.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1794393038; b=qNfplCBeXV2K19P2ZNaZM+9HbVoeWr+wrjA6cn3K+vN8uXVyDioQjF0C3WoNv2aI9IgW4L B3AByQ6/GFGgy1xatKxNxtk3+hwz1CxOIMHN89AoojHcVRpUJU4EWi1RSXj9YpR1KMhAOT 1W2rm7Xgppta/0Ae0W0Q74e1ALIsn1A= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id B350B63C31; Wed, 11 Nov 2026 10:30:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EB69F1F00A05; Wed, 11 Nov 2026 10:30:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794393037; bh=KxrhFMa8/sp9xXjPYISbhRzyRkp2BmT2lD81VC2uH5g=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=JrTLwSLEd+YvzAemdyR51xbG4OegeC7uVGwCapD1h/0s5JMcEnFwWTDyHw8hxhFYc Yceo4rD3o841E85q5UtJ63r9LzJ+/IPSvgm54TH6mNqnP/tb0WyhsqEDBspvr1nMgU Hu4Q34UrszFwNjN+s0A0uWuX0SBJx41Hhlkwlrl2IZ2jWWBFyeM5f6ONI7me+XJd2x tDLrSIQN0h+XzgIJDmF0lUAShZ6b6bEeZ/g2Px2DPD5n88Mxnvvk5FF5+ArOFgekE3 KuBbgHWL/Op3aP1kzP2GjMevvmUd+kFCCVz2h+/uqELmyOPdyL+R577xO/dD9peHYL sFm19EJSuqEpQ== Message-ID: Date: Tue, 10 Nov 2026 14:06:23 +0100 X-Archived-By: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 5/6] mm: gup: introduce gup_unshared_pages() To: Yeoreum Yun , linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Jason Gunthorpe , John Hubbard , Peter Xu , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Andrew Morton , Rik van Riel , Yuan-Hao Hsu References: <20261109-refactor_gup_fast-v3-0-2aaef02df0e1@arm.com> <20261109-refactor_gup_fast-v3-5-2aaef02df0e1@arm.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: <20261109-refactor_gup_fast-v3-5-2aaef02df0e1@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 374F8180005 X-Spam-Status: No, score=-16.2 required=3.0 tests=BAYES_00,DATE_IN_PAST_12_24, DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=4.0.1 X-Stat-Signature: kbbo6g9z6h3acgzzi3rdfmnp3k1sxqs9 X-HE-Tag: 1794393038-553400 X-HE-Meta: U2FsdGVkX19o6BzS8HiYwE9jP4sqSs/0z4RJMztGY8ZD++QO++OQ7IsBXEI7setnsvxQURTNuyJdAuv9k7ETUKbWc8nc7+P5ErDQrRVx3t4gPEh1H6KYPRBi+FOAit6UWGZD0oNSOmWVSkmMhnJTACN7qocdCIHSVJ0eTRA9EM9DxjahsJeOZFD3DuUPTb/oyTHxdxHS6o4JkUNKqBzyNVv4sGjoafpEcwuhShm5mk/zR6/W0b2GAcX/wRMKkiiIEHIamPJ4e7zVbIRqa+tZ//sgrYUrWHJAjKjJ5n5GNnC+jgiFGWy0+PWVUhcKkd1A1bzsAN6Tvy/Rw3edNdlwQK8e3unv5wxa/EE+t6qEdudYE/1/3dB7fo4lZ3F4WQ1k62nQ0UQli22Wxr8lsj4Rf1hpqDkqZ47NFc5UlAO3OsaXhgWYsR2tEaoeyK2UpU9QKtNjmESN1u7pY31XX8YVpdYezX7dPnOxOA296zKq6olqEgOcct9uMScNP/N1WKK4Yfl198m8rBm9IbfFffgV50u86sR1zV5xkaZ4wuEWa2E9gACaEV0OgL/cwNe+N3jaZEXtDAeec+QZ6gM0lTVjWhyfYvV1GuFg6C4AVyrhR0whNgSp0JG8IET3YYNmcDUqehyOfT6tw7V8+YjP1ey4WMV7vo8rfVgdWT53+WVsOapH/Lb2W5FIkcXElDm70jCgVwY6Im0YwPkq2n+sXuWyAFC4GTPy+WcSryQ7fqyFrxwl+lYb49kpa5bth5PiufbTdPcSHwR93NedNK2e3WL6ItVqTNFXbNsQa1d/Cp4KTB76FB9rEdMOZxmAzQmbPsEHEzv/rFWZbwnJEhs99KK4EBdwOAVo2sgz26D8JazGLdhBv9p7GE/jVa3GTY3YltLhpVGApVQ4OiFATpXr5yTyANfsSl4UzyghHSMwBB3/svJF7HnBEwzNjdrgztMXE2df8zOyUSuBIi/vfUTSX6t lfG3H9hs M2ACSOVFj7spwMcqxSE7BSzvZZMohcPK7PRyCUIYXk+bFWkD4Yq6OVeyCPxmUzXR0WWwzEoMwPHh9u9uoBw19fTO0cqYgH1YzkanIg3vZltFumGcHA0V189u3nZsB1vWOS1Po9aOVdwZ+rBFp8IUTouDV4JdKJgQeMwxmMBfD4zql/CnX72U9Z159qylZ+4Hn56732w5Gr04gIDTQ+9HnCqUaM8IrmlqRvWGXHhH8j3MLqwjerqkK88Ckwwl4ZZzW71uv5W1UMupC/7VB3ibs+a0JIL68ogRsYFnUKEEkWDgnI/xaJhsFOXapQjbAzc7m2+rcuuS7HPefyas5vhcikUNOcGQoYxuGt7KQo2Ui/PXvn4c= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On 11/9/26 13:32, Yeoreum Yun wrote: > This is preparatory patch to make gup_fast_pte_range() batchable. > > Introduce gup_unshared_pages() to count consecutive pages within a folio > that do not require unsharing, and use it to implement gup_must_unshare(). > > Also add a folio argument to gup_must_unshare() so callers can reuse an > existing folio and avoid the compound_head() call implicit in PageAnon(). > > There is no functional change. > > Signed-off-by: Yeoreum Yun > --- > mm/gup.c | 111 +++++++++++++++++++++++++++++++++++++-------------------------- > 1 file changed, 66 insertions(+), 45 deletions(-) > > diff --git a/mm/gup.c b/mm/gup.c > index bfe83ce1411d5..c863bae33e2f1 100644 > --- a/mm/gup.c > +++ b/mm/gup.c > @@ -633,58 +633,39 @@ static struct page *no_page_table(struct vm_area_struct *vma, > return NULL; > } > > -/* > - * Indicates for which pages that are write-protected in the page table, > - * whether GUP has to trigger unsharing via FAULT_FLAG_UNSHARE such that the > - * GUP pin will remain consistent with the pages mapped into the page tables > - * of the MM. > - * > - * Temporary unmapping of PageAnonExclusive() pages or clearing of > - * PageAnonExclusive() has to protect against concurrent GUP: > - * * Ordinary GUP: Using the PT lock > - * * GUP-fast and fork(): mm->write_protect_seq > - * * GUP-fast and KSM or temporary unmapping (swap, migration): see > - * folio_try_share_anon_rmap_*() > - * > - * Must be called with the (sub)page that's actually referenced via the > - * page table entry, which might not necessarily be the head page for a > - * PTE-mapped THP. > - * > - * If the vma is NULL, we're coming from the GUP-fast path and might have > - * to fallback to the slow path just to lookup the vma. > - */ > -static inline bool gup_must_unshare(struct vm_area_struct *vma, > - unsigned int flags, struct page *page) > +static unsigned long gup_unshared_pages(struct vm_area_struct *vma, Besides the function name, LGTM. gup_pages_requiring_unsharing() ? Don't quite like it, but something along those lines. -- Cheers, David