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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 09D5310ED679 for ; Fri, 27 Mar 2026 13:58:23 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2EA4B6B0092; Fri, 27 Mar 2026 09:58:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2C22F6B0095; Fri, 27 Mar 2026 09:58:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1D8156B0096; Fri, 27 Mar 2026 09:58:23 -0400 (EDT) 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 0B5076B0092 for ; Fri, 27 Mar 2026 09:58:23 -0400 (EDT) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 46849E1801 for ; Fri, 27 Mar 2026 13:58:22 +0000 (UTC) X-FDA: 84591997644.12.00051A9 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf18.hostedemail.com (Postfix) with ESMTP id 91A191C0018 for ; Fri, 27 Mar 2026 13:58:20 +0000 (UTC) Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=SWvmhHE9; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf18.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=1774619900; 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=rV7qUqCmt9pMEfSsapby4O1NuRc/CuDUYfIgjrOR9R4=; b=n4qWi+xoQqbXlLC8/94RhuX9i0QHqobHvDiGfKbv3cgDyucTl5zZyVXhqfLcLg9cTVM2Xr OVW5eK6dUttO2q0do5lm98RVX3rTJC5XvcvHMBujc4lE2wH/VG4fc1F1QDFg+8CKn9vcK0 VAfPUPVp9UBLJiB8WH3O6T1nR3MRsuA= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1774619900; a=rsa-sha256; cv=none; b=O69SovubQaJi9Q6FNYdRsYuPFWKDOMvvqccLzTTibvuarnPT9yB0Q5pXke0ALq0BqUHFd0 LLOMbahu/pp/ig+d/hCMEGA8etrq96hXCMi9AjFTAjH1A0p8nYZe5+C0cGXEXsX3n6MZYi Asr5o6hLBdxS0Ciu8DQJrrTPAcDSBhc= ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=SWvmhHE9; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf18.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 0AFC360132; Fri, 27 Mar 2026 13:58:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9D735C19423; Fri, 27 Mar 2026 13:58:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774619899; bh=VqACtXhfTYZCQGZ04hZLNOj+ApxLBRqLokDeDdIuV6Y=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=SWvmhHE9QgoG7BeeIXiy8S/MxDrH6bLIFaNzJG3Tn0p2MnG/Io5/CWnOCyGrz2aLW geze3jKXXes3f/fa44jBQySmHCda1h0nV0OAoKNw+OX3CWBVdREOK48PnFPgHvmTVf qBqFCuR9AczmRrJNvdALxpqkDpfH7ZqC1oGWWP+3omn+BFX0U/I15Q7KJqWFWEbUIX 9qaiy1dpsnmCWXcdijGqoWkc2BrZqIK5PcpUi2Jrdb4NvRLGVkrEueTpTnzLJIUSlV 4uQpwJcszdyqiYrXKTT+BtUEbjtX6/zW00+pcfgM6YcYoQvk+eofuhty6uZaim/ZfS GTx/hySbDFbCA== Message-ID: Date: Fri, 27 Mar 2026 14:58:12 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1 03/10] mm: fs: remove filemap_nr_thps*() functions and their users To: "Lorenzo Stoakes (Oracle)" , Zi Yan Cc: "Matthew Wilcox (Oracle)" , Song Liu , Chris Mason , David Sterba , Alexander Viro , Christian Brauner , Jan Kara , Andrew Morton , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org References: <20260327014255.2058916-1-ziy@nvidia.com> <20260327014255.2058916-4-ziy@nvidia.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 X-Rspamd-Queue-Id: 91A191C0018 X-Stat-Signature: pzbzh84osm45ufsx99iocpfzmog56grb X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1774619900-826415 X-HE-Meta: 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 XSzYywYr EaSb0kQxLUUNsgJoATiG7AIQbQUlFD1JR0CTBK97THZxdklaZ3zIxgYMwUDIvN8n4xglpx9NOoU2iyn/j1jdQ464+9OKJ9nWVtme70M4nlKrspdvmSFhgmw0aHzWh4TrdHseXvr1fxzDC4+Y59oJzjOUdOMPGk5YfQqdD87NTvbtRSBlnK0KCffJjQxgEv+Y+JdyH9SxmkMb4v6sPsKNjI9SAo2AhIKyBtSPWS9dIKWt9Re6cn2sr4S9BBNOm19olWIDuEqG0BOtnVKS2YbRPjs3GUocHv1xte9W/MBPIB3ZmClyv3RtYJTgOvehdq9M7TAJ1hjVcToRuE7g= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 3/27/26 13:23, Lorenzo Stoakes (Oracle) wrote: > On Thu, Mar 26, 2026 at 09:42:48PM -0400, Zi Yan wrote: >> They are used by READ_ONLY_THP_FOR_FS to handle writes to FSes without >> large folio support, so that read-only THPs created in these FSes are not >> seen by the FSes when the underlying fd becomes writable. Now read-only PMD >> THPs only appear in a FS with large folio support and the supported orders >> include PMD_ORDRE. > > Typo: PMD_ORDRE -> PMD_ORDER > >> >> Signed-off-by: Zi Yan > > This looks obviously-correct since this stuff wouldn't have been invoked for > large folio file systems before + they already had to handle it separately, and > this function is only tied to CONFIG_READ_ONLY_THP_FOR_FS (+ a quick grep > suggests you didn't miss anything), so: There could now be a race between collapsing and the file getting opened r/w. Are we sure that all code can really deal with that? IOW, "they already had to handle it separately" -- is that true? khugepaged would have never collapse in writable files, so I wonder if all code paths are prepared for that. -- Cheers, David