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 CD322ED7B96 for ; Tue, 14 Apr 2026 10:19:16 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0E98E6B0088; Tue, 14 Apr 2026 06:19:16 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 09AE96B008A; Tue, 14 Apr 2026 06:19:16 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id ECB236B0092; Tue, 14 Apr 2026 06:19:15 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id DB13E6B0088 for ; Tue, 14 Apr 2026 06:19:15 -0400 (EDT) Received: from smtpin30.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 1297EB9933 for ; Tue, 14 Apr 2026 10:19:15 +0000 (UTC) X-FDA: 84656763870.30.CA1502A Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf29.hostedemail.com (Postfix) with ESMTP id 5571712000D for ; Tue, 14 Apr 2026 10:19:13 +0000 (UTC) Authentication-Results: imf29.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=tLRQLee1; spf=pass (imf29.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1776161953; 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=zipAUA5Yaf56ZLEAskxAMpT+1BclO1sPsMVbAnC/eLI=; b=IeYKGjLjrd+aiC1jmpprPD4wyQU+9qECYQbkyo4InRUDxjwbOIzJLkihMAVtyOowNBP7J5 CnzT2eaJdsaB5gIVZ39NDDFXReTI7A6ZC5G0kP0cazaIvbMjv5y67DPGy0p061CtchzKKa W/ueLH2u6lez0gJxSQjUaN8Owp/hG1Y= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1776161953; a=rsa-sha256; cv=none; b=Nql7ov7HIQRjXrSjADwrLqRV1CkZuUUoPg2BvL+H93gNkyOn4ZSJbd7fiX6/kUK9uaCq3n VQbm1Da5Vnmoxsq2EMGQsV3eGv5OzFMJEENatGA/lQ62q+93NB6jI3elpO0diPX3qDDs+r ynAe9kd0//Y2tugvX/CwpXkXtRbq7h0= ARC-Authentication-Results: i=1; imf29.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=tLRQLee1; spf=pass (imf29.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 7AA5260131; Tue, 14 Apr 2026 10:19:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 09A33C19425; Tue, 14 Apr 2026 10:19:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776161952; bh=MDxYDpGQmy5Oxh+Of/cJzn+fi3bCoNS15eBhroroskc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=tLRQLee1YgXHJrcPplFsAm3WeFn4fNmAKXn3Y0ZZK/SsNsEVHxwzCghZjXlMEgv8f +DJOuFeqgWrsZPRaEGTNra1MaJQ6+2eobv045cs5M/9tARoAebOa6WG1cxYcYeawOB SYrA4gak03seD0kMfx8kowEkI+xf2nreknYrJv6rAwubb4Fa0bF4sKhmQiGdDYP3bG HifW8OodnnvoALRlYyAgQDRcyJ097cJvSvrsTZDwnrxFGPNb7m7bvFY1lMJ1sDJ0ZQ rEnLYH7nJmpCl6bfi+BtsewOAGiE151lEakpDBZU1bcb3K1XIMkHaO7M6DcuH2ceyu QfUzWIi7Gvvfg== Message-ID: Date: Tue, 14 Apr 2026 12:19:02 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 7.2 v2 01/12] mm/khugepaged: remove READ_ONLY_THP_FOR_FS check To: Zi Yan , Matthew Wilcox Cc: Song Liu , Chris Mason , David Sterba , Alexander Viro , Christian Brauner , Jan Kara , Andrew Morton , Lorenzo Stoakes , 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: <20260413192030.3275825-1-ziy@nvidia.com> <20260413192030.3275825-2-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: 5571712000D X-Stat-Signature: ki43k79pxutcf3j1a9em45dc56eauh5a X-Rspam-User: X-Rspamd-Server: rspam07 X-HE-Tag: 1776161953-918571 X-HE-Meta: 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 2db7Dbs2 aeLW3BRum3Y72ngr57E30PXXYBbuzp2FFFp6kEN3qE8euSmKucWv79cZm9C7bq7Ac9Jo6ddG5NoXL9I1XPrM0ZzazHJl8KwLbjn4rcFeF2zeYiwIBtd/wteZ6lqKycwPuZdgM+Cye81uDsJM/fo7vQeHoMJxsi5oLxQWqEL7A1U7FUgCHr4zizRDJBq4IJ8VIqynSP+RbAekR2O/BPgkZLYWtxHQ6hNgcKkbDl9Hvvrr9NJnLHNfDPp6TSoQbrVCMS77f9lKkbT4EHnEXvnERvovuEyLmf0UEQvG72Ju52UepqALMh+y0wTFSYw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 4/13/26 22:34, Zi Yan wrote: > On 13 Apr 2026, at 16:20, Matthew Wilcox wrote: > >> On Mon, Apr 13, 2026 at 03:20:19PM -0400, Zi Yan wrote: >>> collapse_file() requires FSes supporting large folio with at least >>> PMD_ORDER, so replace the READ_ONLY_THP_FOR_FS check with that. >>> MADV_COLLAPSE ignores shmem huge config, so exclude the check for shmem. >>> >>> While at it, replace VM_BUG_ON with VM_WARN_ON_ONCE. >> >> Why? These are bugs. I don't think we gain anything from continuing. > > The goal is to catch these issues during development. VM_BUG_ON crashes > the system and that is too much for such issues in collapse_file(). VM_BUG_ON should have never been added to the kernel. -- Cheers, David