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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 7.2 v2 12/12] selftests/mm: remove READ_ONLY_THP_FOR_FS from comments in guard-regions Date: Mon, 13 Apr 2026 16:51:28 -0400 X-Mailer: MailMate (2.0r6290) Message-ID: In-Reply-To: References: <20260413192030.3275825-1-ziy@nvidia.com> <20260413192030.3275825-13-ziy@nvidia.com> Content-Type: text/plain X-ClientProxiedBy: BL1PR13CA0018.namprd13.prod.outlook.com (2603:10b6:208:256::23) To DS7PR12MB9473.namprd12.prod.outlook.com (2603:10b6:8:252::5) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS7PR12MB9473:EE_|CYYPR12MB8871:EE_ X-MS-Office365-Filtering-Correlation-Id: a7310ce7-e331-4423-7ee2-08de999e70fe X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|366016|7416014|376014|18002099003|22082099003|56012099003; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?MTLRMkINsVJNuvGL1iVskdqWlnPsa7zQabFZX4/YdfDMtybN9FoOqqTYH3m6?= =?us-ascii?Q?h8L12uNODRDaauomMVXn80QzZDomalaLuZ8KfrjWkpsMN9J4him8Cy6nvKO/?= =?us-ascii?Q?stLRSNEobe5ENoAp8Cy0l67bDceFZ4Mzf77/9XgL/P/KLpGxlh/MBh3NGLp/?= =?us-ascii?Q?ubk08vfFgAQf3Y4yJ7SnjDGY/OedMB5dA8y22W8U2jdaR1ChUCEn9RrFg/0Q?= =?us-ascii?Q?qlg6drUIw8FN7rTODqB+S6r+yz1ZuIXvfQ8w3HzJ55OJGklf0pRexfFkHkgX?= =?us-ascii?Q?GD4upabkkxzNHNUnxp3iw6wX9IrSvlnlfl8n1SdJcUSNUQoND5ovLGhPyXFr?= =?us-ascii?Q?JvLCQYXPaQGsapjDloLmc5zG76X7sgCxQV3EtOZ6JhQdb/IL7BiYkJHu0UpE?= =?us-ascii?Q?sGEOb775aUsQscYbJvbKJYNcPnt72En7hwHPD3UmXIwSOJQqeFXlTxmdciFO?= =?us-ascii?Q?uBSa2Cc4E3htr1QRH+N2sZTT8wXtMxSHYWcYrVQbR0jFxkAFaebX9wr40R4L?= =?us-ascii?Q?B8WXrKCvSqBPclIIThWu7HF69e4thKDh1ORJieXt5nVnTq71Mym1eQBPncXP?= =?us-ascii?Q?VwQAI2iYvtiLHWTM8sdu41UvPHTt/S6fJU52toiUKUuVVLUNPP6hWx6y1ChL?= =?us-ascii?Q?VoOtCMDp5LArrUff2Q9sh0UMwt9lRBInv1r3Lbap7cN6a676yuOxXJoSe/IX?= =?us-ascii?Q?EbCAREw0RM4EC66B+UXyH2zRbr/bZa/CMWi2U9jhQLE23ftVqryfohvAb/70?= =?us-ascii?Q?7AasS9JrXlS84yUcLRKkKqjvl4EHYWHhMkevF7mG5yd7HrP4zoydWStGi8zy?= =?us-ascii?Q?D620v5T5vs69pbyPWvsRcRxfquKC29O4OVsO8Li0n9rT8yxX9p0zs9t7Z/Mn?= =?us-ascii?Q?Kp95gDVntv7u2KY1wmPy/nHOoLKx67n5/SreVFuV9Eues/SsEJXwN4MIJMuO?= =?us-ascii?Q?cmCLgZknHUuBStIJncDAnt9+rh2nvDqJsU0XXWOceB1tysr7rpwd3hJcHfMB?= =?us-ascii?Q?TK4qqrMgF0Lp97ArESKyHlRwcopkbhT+QU6tLRu19hCOa+KtBgMOCvkLBUjR?= =?us-ascii?Q?6iAbP4MlV2EkMNDTPRVJHYpTgYdLTl6OXx/jHohJlpeEhgUXATT34HulAGZG?= =?us-ascii?Q?wXvrIqBHydVaBuOIa1kAZ/ND6tID2MY/hL0hSiakCYCb0F/HEW3Lh0od/alw?= =?us-ascii?Q?kraDXAFjhaSAvmvnZGTapj6JneIBZy8Aw9MSLnf1EGzH30//GHoTeaZNoAwP?= =?us-ascii?Q?uHEBXuznVY6J0aKY/BAx1GOhguYmT4XYQmnA9MxFqa4e/M5Kg/hTM64xCaim?= =?us-ascii?Q?d+sq0kC0iX9Mf1bD2spuTgPs6BqrFmRLw5sijAm0imDpFiglBAosPTGkV6nM?= =?us-ascii?Q?UUoGIBzdPOfGTd3+HXnJLHZaAormZl9E2AmoPj6XGhdoGP4FGDeaacA2vuT5?= =?us-ascii?Q?bdpkgUlanL+Wd50WY1DNKtcYljasu76kBieK10Ph55gZtGsLKV/AaWg+HSWX?= =?us-ascii?Q?ng0zys92VfyFkqbGBVx8dUkG6BK+cb3UlZTK2aB94B1Hmb9enQCDvdMaW+DM?= =?us-ascii?Q?nLCquHO5qCgxdmRxy12W0ys9r45R/kZITNdbhL+t4jXO3yfdqXr31k9K+rg7?= =?us-ascii?Q?82ytbcOeUIPWCUz5uEQD5RdA97Mwxx5Ife6/t0VrNEvtS6w8Hed/sjMJm49W?= =?us-ascii?Q?aJuJ1isSifbmKj4IBJd/DrT2Ak0eRg2pdOVRlkD9/b5FGp6BNJ3fH8WWK2Fr?= =?us-ascii?Q?uR//FDobLA=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: a7310ce7-e331-4423-7ee2-08de999e70fe X-MS-Exchange-CrossTenant-AuthSource: DS7PR12MB9473.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 13 Apr 2026 20:51:31.3874 (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: Yo19esFsH13yure6/aQerOaVhvaCxe+G5tl1QzwgQnCqPSyV/YsKvxfOVAYG+XHp X-MS-Exchange-Transport-CrossTenantHeadersStamped: CYYPR12MB8871 On 13 Apr 2026, at 16:47, Matthew Wilcox wrote: > On Mon, Apr 13, 2026 at 03:20:30PM -0400, Zi Yan wrote: >> +++ b/tools/testing/selftests/mm/guard-regions.c >> @@ -2205,7 +2205,7 @@ TEST_F(guard_regions, collapse) >> >> /* >> * We must close and re-open local-file backed as read-only for >> - * CONFIG_READ_ONLY_THP_FOR_FS to work. >> + * MADV_COLLAPSE to work. > > Is this true? Does MADV_COLLAPSE refuse to work on writable files? > Should we delete some code here as well as fix the comment? ;-) file_thp_enabled() used by __thp_vma_allowable_orders() refuses writable files with inode_is_open_for_write(). That should prevent MADV_COLLAPSE from working on writable files. Best Regards, Yan, Zi