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 2C106F483F8 for ; Mon, 23 Mar 2026 21:06:02 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 909D16B0088; Mon, 23 Mar 2026 17:06:01 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8E0DF6B0089; Mon, 23 Mar 2026 17:06:01 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7F7586B008A; Mon, 23 Mar 2026 17:06:01 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 6FCB46B0088 for ; Mon, 23 Mar 2026 17:06:01 -0400 (EDT) Received: from smtpin27.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 42C791EB5E for ; Mon, 23 Mar 2026 21:06:01 +0000 (UTC) X-FDA: 84578560122.27.7E7D058 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf22.hostedemail.com (Postfix) with ESMTP id 47BA0C0003 for ; Mon, 23 Mar 2026 21:05:59 +0000 (UTC) Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=uNnOlIf9; spf=pass (imf22.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 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=1774299959; 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=pW1plpbN5b2kLbMPGpI+zFLp1dVwpXyBUxCgrFpEcb0=; b=7Mv2IY2Dy3mSbgJv43tk2WCw45OHbmV9vOsemeV3Gpk7eGvNREQGuTOQjXtUSRV9ZEqZgo j8ARznbIBx74EZj1wt0uC5d2DCMZ84PYKnRX/VpcNLKUoA891aJ5S1eW1eajFdMl91bbop sPXOoFcssC5e9zMxTrdMy5baIIgo5Yc= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1774299959; a=rsa-sha256; cv=none; b=zKJg9EOdfqGSaU4LCkyNxAHwgN377QbWP6aM409WDkU95nr3hddo00jnACSbcIbGosNXBE Qjwe41TEzQ4bRmoQWKUlnkvWyDuin9zOsTM46ZyBhyCMGlJBg0qMK7EQOW/NytWaLSbgOf xBAJmthX/CdoSLmCPAkIq2+L5yShpZQ= ARC-Authentication-Results: i=1; imf22.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=uNnOlIf9; spf=pass (imf22.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 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 sea.source.kernel.org (Postfix) with ESMTP id 4A8254176B; Mon, 23 Mar 2026 21:05:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E54D2C4CEF7; Mon, 23 Mar 2026 21:05:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774299957; bh=t5cfjJIioDyKblv+DLTJ5G7Df7yaK/d2ZJVfrVqUj34=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=uNnOlIf9NHgTcFSC2Fx+8W1oaHAtXeKVKSFhStuJICX+d9miACGoW1+lZicnFzA7k ZOdq94lWQ5rMDyDx1r9GKu1cOriauJaOjMR/KJG8LerHCcI4LWbL86S7Z8vkxYlu6h ODNrh4KA2x1M1aVVMYgSr3fJqceWZROtT5EKrDJ6Sx84QVdJkqhv+Cww8ecv54C+Fr KtMcEse3f416P3p8LufZ2HAArrp1D49S5+5od3Wu2EXl8XwYF+RVrQx/Tw2zexyjXR x3wnm9JrolLOMMnzvbNT2m8qPMooSnodI/6aGbAITEI/dSsIRkZ9eR5+ocmmfA/3aH HuakEz9FEinfw== Message-ID: <9648838a-ada7-4983-99e3-d694e803e06b@kernel.org> Date: Mon, 23 Mar 2026 22:05:50 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH 02/11] mm/khugepaged: remove READ_ONLY_THP_FOR_FS code in collapse_file() To: Matthew Wilcox , Zi Yan 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: <20260323190644.1714379-1-ziy@nvidia.com> <20260323190644.1714379-3-ziy@nvidia.com> <7382046f-7c58-4a3e-ab34-b2704355b7d5@kernel.org> <71148f2e-cceb-418e-b762-c8dbd7a7eb1f@kernel.org> 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-Server: rspam12 X-Stat-Signature: 43y9eftc4nua7dkjbtcd4iyymjqikdds X-Rspamd-Queue-Id: 47BA0C0003 X-Rspam-User: X-HE-Tag: 1774299959-546440 X-HE-Meta: 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 zMGFVwSt bTCjG8N2wqlp1jvoiDp7qypV10LT93egYalKExCs2M1CSNNvcaoQC+ahyUpyVYwWKxf+CtKAGvDCf+L0GMCfSj0inF4WJoO1RKFK9tTfe3WyDxKMc00zDoY8DGQ4wOcfq1utA/39TH/uIdPVCQM64+SCwe++U1s5vKrsj4gv5GcpXeFyw8c/Kn9T9cvpF9zlGbCv6utmD59Re/g8oPDWDVcFaH9Pe1pEJuBvcvyGw1tQuy4M5aYt5Bxlqb/QUMHd0W4XA9kvebYP8lh3H79g+89SQvMbLu/bP4/J1WYfBvNQ5psIDzSNGbKBsaw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 3/23/26 22:02, Matthew Wilcox wrote: > On Mon, Mar 23, 2026 at 04:24:26PM -0400, Zi Yan wrote: >> On 23 Mar 2026, at 16:13, David Hildenbrand (Arm) wrote: >>> I assume so, because for executables you would have to be lucky to get a >>> PMD THP? So I don't see the non-khugepaged large folio support on par >>> with khugepaged support. > > Not necessarily that lucky; if you set VM_HUGEPAGE, > do_sync_mmap_readahead() will allocate PMD-sized folios automatically. > On busy database servers (and is there any other kind?), khugepaged > takes too long to run and find opportunities to collapse text pages. > Like, days. Yes, in particular given that the default khugepaged settings are awful. > >> It is more like turning on READ_ONLY_THP_FOR_FS by default for >> FS with large folio support instead of removing it. >> >> OK, I will give it another try. > > I think the test needs to be: > > if (mapping_max_folio_order(mapping) >= PMD_ORDER) > > as there can be cases of filesystems which support up to, say, 64KiB, > but not all the way up to 2MiB. I disapprove of this situation, but > this is where we are right now. Right, that's what I had in mind. -- Cheers, David