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 AF4EAF459E9 for ; Fri, 10 Apr 2026 15:18:43 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2866E6B009D; Fri, 10 Apr 2026 11:18:43 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 25CD76B009E; Fri, 10 Apr 2026 11:18:43 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 14C366B009F; Fri, 10 Apr 2026 11:18:43 -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 F41A76B009D for ; Fri, 10 Apr 2026 11:18:42 -0400 (EDT) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id A5542E317B for ; Fri, 10 Apr 2026 15:18:42 +0000 (UTC) X-FDA: 84643003284.18.0E8F3C2 Received: from SJ2PR03CU001.outbound.protection.outlook.com (mail-westusazon11012048.outbound.protection.outlook.com [52.101.43.48]) by imf06.hostedemail.com (Postfix) with ESMTP id C8373180005 for ; Fri, 10 Apr 2026 15:18:39 +0000 (UTC) Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=CS+AR1nW; spf=pass (imf06.hostedemail.com: domain of ziy@nvidia.com designates 52.101.43.48 as permitted sender) smtp.mailfrom=ziy@nvidia.com; dmarc=pass (policy=reject) header.from=nvidia.com; arc=pass ("microsoft.com:s=arcselector10001:i=1") ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1775834319; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=W96iObaU8ZHISoRxY5MArMOrG7b3TH/6ACemk4v4yOY=; b=rcqXcGobTQAFLncC+hWX/ZAstqLpIgvuHA/DKDYMk174x+WIakCAr530DlQut2BXbBCdWh CDt00S1evr+lE/+EWqFxBiYp/VygsLKIMjM+PFpvZrA5J99HGo7rQXaWY0nV90Pb73aZ6j tubNDKyR0/QsVS6CjkVlFvxUzv62AYY= ARC-Authentication-Results: i=2; imf06.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=CS+AR1nW; spf=pass (imf06.hostedemail.com: domain of ziy@nvidia.com designates 52.101.43.48 as permitted sender) smtp.mailfrom=ziy@nvidia.com; dmarc=pass (policy=reject) header.from=nvidia.com; arc=pass ("microsoft.com:s=arcselector10001:i=1") ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1775834319; a=rsa-sha256; cv=pass; b=yJYkWIaXFQnnZMpEKXKqBImbMxGhjHQqm1JLB1zgGh5jQe+AdxmTH+XF6qQqOKAfZ+rvQo s13CU7sdizVFNTUBGnOXVMk82Q36bKPBTpkOyICuzQGqK9l2ijn//4tsCjxEP1foG535Uj QLi3yQh3Ty9GYyJ4Z3N/+IXM4/C4iwk= ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=ryhuj1KC9KoWpO4jl5TfuWN3ViLT0qT0j/uyRpfaVpgT4x/5piOM4gNrIV3Fs/PLoCD7anBEMdjOYPZqDNgyqFeQAjtJtVzcb80lJTXBsilAi5dlwdUUNVjbMmUqybw2PBjN7uGt6SUKixqYPGjRsLP65OwQYLPwv3UzRJ5f5As0MT097/aYJMerQTgMJlyYntS31OFnh37TIt7Ou/W2HdUO+kEC0MXHsLfu4UtSwAenwk5SjRvQqVcYbKbPHKaT+Yzub5jeEsgHQrk9Y4XxLpvZm/UVnrNG3/U4WtA4X1DsbMrh1YQszEaGU4dohLxzDUdt1nU1SXw4kaabu2I2Fg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=W96iObaU8ZHISoRxY5MArMOrG7b3TH/6ACemk4v4yOY=; b=IdQxQlvO0uDWOW+GllZJY5LKu4X83sQA8ovVXA0LAqOhLCYFGCyqlb632aRhc7AAeVuNf1zEi8igm6il15dklXghnEk7a9R1QJzYLi0oQS6Dh7fbKaxMgLiz7MZCV1vitLcplzk9vIXnHuwj1us99GtillhYvOnwDL3AP5h5jRkW40E8C/hrBOjYRZ8Gd68XJvMbaZspEPeZZuNcMmFDt/Y1Y/WrJY+I5zJ8ngm1z6K1jyAYPjdQmE/hrCUX4UvbDhptefLq2jCl62ZjSann2iak44J4nBMIPLT7sMF73GD2780CDKG4FpQ2oz7ra1uWEXFlpG2Q8mh7q886FQGUGQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=W96iObaU8ZHISoRxY5MArMOrG7b3TH/6ACemk4v4yOY=; b=CS+AR1nW60NKKYvxAklyZtFyGUhW6IkiCise4X49w//R5Lm2FNcHdg8+XoRE3AGTFuqXSsTtvjWpmk7KccZi2PCVO3SpOr//55OxDx3tQV2F74zh4gk16YLM/aglQE78l21AI3MrzmPuGAXaLXnbBlglxZQ3SmAuMOYWh/ZqCSDzXByN7WaL2ot3LaEt9p8swHWtEviIk/2hVFOH3Uhu5AQAWlhyrpvDUOvecFRU73dWVn6AguSb+w4Naf/IP5h676oQU1XoAFaPUxmn3M9AE08c0RxVlANacDCaw6PFvv4jWBrBWHaTL8vJA9jgR6f5LUyCURNTs8km0U/WfqwBwg== Received: from DS7PR12MB9473.namprd12.prod.outlook.com (2603:10b6:8:252::5) by DM4PR12MB5868.namprd12.prod.outlook.com (2603:10b6:8:67::17) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9791.34; Fri, 10 Apr 2026 15:18:31 +0000 Received: from DS7PR12MB9473.namprd12.prod.outlook.com ([fe80::f01d:73d2:2dda:c7b2]) by DS7PR12MB9473.namprd12.prod.outlook.com ([fe80::f01d:73d2:2dda:c7b2%4]) with mapi id 15.20.9769.041; Fri, 10 Apr 2026 15:18:29 +0000 From: Zi Yan To: Andres Freund Cc: "Matthew Wilcox (Oracle)" , Song Liu , Chris Mason , David Sterba , Alexander Viro , Christian Brauner , Jan Kara , Andrew Morton , David Hildenbrand , 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 Subject: Re: [PATCH v1 05/10] mm/huge_memory: remove READ_ONLY_THP_FOR_FS from file_thp_enabled() Date: Fri, 10 Apr 2026 11:18:24 -0400 X-Mailer: MailMate (2.0r6290) Message-ID: In-Reply-To: References: <20260327014255.2058916-1-ziy@nvidia.com> <20260327014255.2058916-6-ziy@nvidia.com> Content-Type: text/plain X-ClientProxiedBy: MN2PR03CA0027.namprd03.prod.outlook.com (2603:10b6:208:23a::32) To DS7PR12MB9473.namprd12.prod.outlook.com (2603:10b6:8:252::5) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS7PR12MB9473:EE_|DM4PR12MB5868:EE_ X-MS-Office365-Filtering-Correlation-Id: be8c2c48-f030-4886-0553-08de97146b37 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|376014|1800799024|366016|18002099003|22082099003|56012099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DS7PR12MB9473.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(7416014)(376014)(1800799024)(366016)(18002099003)(22082099003)(56012099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?Vq/XAecwvZ4mFVG3eAebuZs1rOdUwPcPzvKJTaqtS+mldN4seMPZKVTfka7+?= =?us-ascii?Q?FcGu5+dmWEeg3S1xgN2S9CH8Ye5VQ+zr9ZPK/lJYD5WClwjfQ2SiPPlGqGPA?= =?us-ascii?Q?Jx5wrSNH4T8oZ/+Y6GACQ2U0UI3EFwO7cHAeOH74lozyQt+fnrlI+uhiO1Ap?= =?us-ascii?Q?UsyQAMM67CdLqjKeGHMI11OAgDEo5lZ/3bVCVLumCA+D95i9nm2bfaEh0Ijr?= =?us-ascii?Q?U5uIr/1xkOrS6r7NxF/YuzQOHrCnBC6OOACEZohRQ69EgukPXsghSgB1lO8m?= =?us-ascii?Q?hDZqhGks2ZGsn1wAUPKnpkT5KMEuBbg8iTPvclBiwjbrVqec6didc9nDkVGL?= =?us-ascii?Q?gshVwx7TAyocNbEfoVXoFG8VQo9X/pOftdxNRr3oyg356USMHQwUmruTB070?= =?us-ascii?Q?j5fp1O2qdIXgfd2vngQg3rDPRDhrG4/O/PhckvMv1E8a2sFVsLwCUEywKTIi?= =?us-ascii?Q?nGfG5nT137LfLkXP5xWd8yldILgnytmnBPqz2MUlSLPK4VIldish2JtTLZ6n?= =?us-ascii?Q?mraKWHk0+aeUP59L6nSJCrIizvLTLRXcs5uFMVxrpyW0hm41Gko7rT7exrGk?= =?us-ascii?Q?y6TUT5RH6qg45jlAl9klLbXt33tpmjmfK6PC59J8XLEuG2bPviI8wBe0nHx+?= =?us-ascii?Q?LpEkxiZ9v1kt5aAPY8hPfqZ2K2fxPTS3BnUrnUK3bQKqh53Z05HSdVyjByGS?= =?us-ascii?Q?d52Cjbs6URYZcrcZO9ysmrY9jpSPLXdUIqUAesvXTarsvR94oBN0/YvRSiRg?= =?us-ascii?Q?oJP9SG5zML9DAiByWBjUGYN2jSgWgtNLsTCnCFizt61lWdYdz9DcEnI/5kpY?= =?us-ascii?Q?vMpFPrSRwxrzM/9GBxLI+4VWH1MLB7LJ6didGSz7Xfd+hqZdLu97Busik56J?= =?us-ascii?Q?8nel/wwvBgsqFZqbySMJU8y+V950qFSISGOcUB9QPhUqXEEzXmDmJf6Mnc7T?= =?us-ascii?Q?DzOiDrY0JDs8rDwM7+NiaGNPhH2szdu0/513vBQIh4+9B39agd9XCY4obYcV?= =?us-ascii?Q?aGg+9B314o0Y2I6usReOX6U3fL91JCFR7K0mjaQoPBBxpUmg/rkMlg3PV8oi?= =?us-ascii?Q?+1Ha1FNyXErLQS2oy+YfgPKnEaudYCD365A2bRa5skgmP92QfNpX/oZG4CVF?= =?us-ascii?Q?ERJ3/+DNAwWIHqw0Etb7pizFuAQIkEJ44u+KYpa6vTUM3/IxRUYS5ELqjs2n?= =?us-ascii?Q?YMGqXn9rHxFIc/yrLHaXq5CZENyDTHcn0tinEW5RyZJT28nF5ZJ2EaMdQdqT?= =?us-ascii?Q?zggL1YSQxBOA57/qv79dJ5IZyDYHS/R/yq4iTPVK1Ex8PgPF8LSHpahmMXbr?= =?us-ascii?Q?emQCbi3VaBRuJ4tThtG0p/o6NTcfENUfCCTT4Ci8dMnZEzynlVLF0XEBSz75?= =?us-ascii?Q?gMI3fR4ZZEg0XZEICbk23fSiMeBNKIOyiIpQStLlAtfNZOkRmo3jKTz8vUGF?= =?us-ascii?Q?DQQWcNq9oR6FA0vIiybrE9cKbQP4v7aHymtSAhbuElo76S181kFpG52cRmJG?= =?us-ascii?Q?V05dJ00aW0tGGkrXt0dP7ZVHHALcyFJDrEb8x24c6Iwmo2hHI0nXIkW5+BCA?= =?us-ascii?Q?bFXa6/qvcgpmu3P02XpX/7ZJSc8Oee9Mq+pdoP0W53xOwwIPbUcgQiyz4+2p?= =?us-ascii?Q?MIoWGfWIZ5Z1tbvE1fgcYcbFmQd1Ur+LpC/RjnKlxZu+B1X40nWemJX946jt?= =?us-ascii?Q?OLH24Je/Zz3U1ce/umxsDvkpJ8UXioJj98NpKnQk6is+VeEM?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: be8c2c48-f030-4886-0553-08de97146b37 X-MS-Exchange-CrossTenant-AuthSource: DS7PR12MB9473.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Apr 2026 15:18:28.9409 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: EVslQhxvUhOBO03QJ6yCv8XFXxyl/TM3S6MpPcoR1RpI2k3xDpsDM7VgQmeYFrO6 X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM4PR12MB5868 X-Rspam-User: X-Rspamd-Queue-Id: C8373180005 X-Stat-Signature: 4szrupz7momnsn1gshrwqizy55ybdc17 X-Rspamd-Server: rspam06 X-HE-Tag: 1775834319-891265 X-HE-Meta: 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 8EkzALiK 6YSZfES9CxZ81/czWW6oLVRtr5neGq5szqtOfInMMeu+DmyU9CX69v97p8sXSGZ7ODiSJWEuvxV54RZKgtr/auhzHEFB8z2Qdr5mmrWExP2iKK125gxaIQURHp8U0tskAns0Fxl/PS25usLU5dvuhGnB7nWWoCJhoW9RPOPe4ZTxrw5CcvqRyXTJhw6MIsMUDl1hut0hyaKEU3djlaE/XUnFmuDEr4mwjx50qFPuXQgxlUPKysBPMljp8j5dWVIMyEx4TPgixEZZ3ZQ5/bXJ79+H0D+YJkSLczk5PMoblif8J5tb3RpYlgV8ZP4FfIjPeIkF87PAUqrXfAFQtlphCYFVLplqYni0wHMoImwmrKBw0Wha/jzwNZP0V9W6GMN5MdGgm+iTnEWqRIMnnHNvS2HkxaCxe1ED5MBF4Oyw1/hwUA0ilk+rcK0ngsPbVikFKDtgxcTEziVPF8Ro= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 10 Apr 2026, at 11:06, Andres Freund wrote: > Hi, > > On 2026-03-26 21:42:50 -0400, Zi Yan wrote: >> Replace it with a check on the max folio order of the file's address space >> mapping, making sure PMD_ORDER is supported. > > Question from a user space developer (who learned of this via LWN [1]): > > Right now MADV_COlLAPSE on file mappings appears to only only work with > CONFIG_READ_ONLY_THP_FOR_FS. > > That's pretty sad, because I see quite consistent gains (~15%) from doing > madvise(MADV_COLLAPSE) on e.g. postgres' .text - but because > CONFIG_READ_ONLY_THP_FOR_FS is not enabled default (or at least not commonly, > I think?) in distro kernels, it never quite seemed worth the fiddliness. > > > Do I understand correctly that by replacing the check here (and the > predecessor commits), madvise(MADV_COLLAPSE) on file mappings might actually > start working in more situations on typical distro kernels? Yes, assuming your file system supports PMD THPs. Based on[1], ext4 and xfs have the support, btrfs supports large folio but not up to PMD order. I have not checked other FSes supporting large folio[2]. [1] https://lore.kernel.org/all/20260330160942.173324-1-r@hev.cc/ [2] https://lore.kernel.org/all/aTJg9vOijOGVTnVt@casper.infradead.org/ Best Regards, Yan, Zi