From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from PH8PR06CU001.outbound.protection.outlook.com (mail-westus3azon11012019.outbound.protection.outlook.com [40.107.209.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9C98E30C630; Fri, 24 Apr 2026 02:52:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.209.19 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776999176; cv=fail; b=AlHIL3TW93Lt6qMVfEsDHwrqfs8bUFq6EcjCKmgSmrH9gm5W7QMA8TnjaVJ0Vszkhhk0mC4Fa/646efP+VeVwP/aaYMZaPi/G8zLN85ddpQ5xSGR84ZhlTWZgk9g1i8eN2xikY3ak8/Ej2zjS9uJZ3KghvqnlP1sOuip8KCe1tA= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776999176; c=relaxed/simple; bh=6u8RsVmTc/zEF2vvd9+GySSeG65hGvmT4hNCsenODw4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: Content-Type:MIME-Version; b=BLcXN2UvGms4KIMBlnlt6k+7mIC8sYLuVBHedewBwvSbvLgMcuyAjwvS8hUivV5avi4B0rpc6aH+MsHlj+Jmj80biXul7KPtkJjBITWkHhQ5UC/hPEdRMDgeW6vZb/ax5j+Cbex2+RqIg2/28n97oeNuC3nqF2l08qx9h+T4v/c= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com; spf=fail smtp.mailfrom=nvidia.com; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b=gV6rChs5; arc=fail smtp.client-ip=40.107.209.19 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=nvidia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b="gV6rChs5" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=cnteWQ7oqmyXoFsh8YlNGkW0LIqUauiiDkOZ4ImknOarFtYOc31twkAgPSPLYkOC4W1S0Qh94VXgBMYRsxg5fxxSXDgeEUi4cSyk1u+QDKQLnVFZUEhNTirB9yQoDVsHDSVy+EGqCsQ0pr9Crv4gNKtQKqqp9ioWbNZjY9hX3MI5i+6ZCrgWmVCclU6DFX96cZEa7Q0VkYve10+8rF+NaGbZQmHj8dT1fj7OB1TK4GLhhdAQxN2ijQ6eCCOadsyDW54qnj2mwwOu5s/8+PSo8gKs7sMpVLfrwiwf/gUqFGfjWo+JLFYMcSsrwZiW96wtNuPi3FMQzNprDlVaq3HPSA== 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=XUkQ9VY+MTJt6n4cWazSUfRlH2DOHqT/Skwgr3P/y3Q=; b=wxX4uOW+ZPai4OaQJ/h7LgHOLrA79Jfbp+aSFAXDyvd/nVvPa56qvmLHSYNdxJ/ZQ4bcLtwcvoekRqCBbR/rIQvaY+aNqCsxCevLinr2FXwjiMl7u4RJjAYNWWOguCaPK8UpB+EXEJIyaSYX2AgAM9os9ds6Gtdl0PrjFFcIwJ5V8up1hJ/jkWSvQlfuekKmj+3fibA5wgUsQVG9r9U2qDULhtWh+FgqUE6V3qbzJPXKc+MuCFVa7fw1SnXzC3BcUmvP9IK9VH4ZkVvHLqNhJEOLfHycEdeCcLXEXh1Gomp+77BORwE/f7u9KyaXH6w9JYxZ1b+QGgbhhcZhwFcPgQ== 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=XUkQ9VY+MTJt6n4cWazSUfRlH2DOHqT/Skwgr3P/y3Q=; b=gV6rChs5mQITajpNDk1mT7xIfKqSPvOmOt//3qlZj/NDWeyfzyrY/cEGW4/udJyDduKmZLk4gPEl9bb+eavUQN2kAlv6T+T4aDcE9HlSIIwNFVntKv3Oh7UiJ9lIwWQnrLILmrVgLvhX7Vk6CeXZo3/jrmhTRj6NoRpElV2SrOB7FZpXcwQkIU4fIbp3O2skWKt/t+y31vTAbqd7fS2oISgoe/sjm7XIFUQZNjhbHv5SXPMkPv09qNBGMwRtY2hi3tkePo9oXPcZTMfZ4rUunO0n8gGJenv4FnZlsKYtdkSTQITZWTkloruOWqgxEKMa31z6+dbIa9lzWOtnx3MrBQ== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from DS7PR12MB9473.namprd12.prod.outlook.com (2603:10b6:8:252::5) by DS4PR12MB9588.namprd12.prod.outlook.com (2603:10b6:8:282::17) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9846.16; Fri, 24 Apr 2026 02:52:16 +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 15.20.9846.021; Fri, 24 Apr 2026 02:52:16 +0000 From: Zi Yan To: Andrew Morton , "Matthew Wilcox (Oracle)" , Song Liu Cc: Chris Mason , David Sterba , Alexander Viro , Christian Brauner , Jan Kara , David Hildenbrand , Lorenzo Stoakes , Zi Yan , 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: [PATCH 7.2 v4 06/12] mm: fs: remove filemap_nr_thps*() functions and their users Date: Thu, 23 Apr 2026 22:49:09 -0400 Message-ID: <20260424024915.28758-7-ziy@nvidia.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260424024915.28758-1-ziy@nvidia.com> References: <20260424024915.28758-1-ziy@nvidia.com> Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: BLAPR03CA0126.namprd03.prod.outlook.com (2603:10b6:208:32e::11) To DS7PR12MB9473.namprd12.prod.outlook.com (2603:10b6:8:252::5) Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS7PR12MB9473:EE_|DS4PR12MB9588:EE_ X-MS-Office365-Filtering-Correlation-Id: 83480e9b-aef1-420f-4cf9-08dea1ac7ecb X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|7416014|376014|366016|56012099003|18002099003|22082099003; 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)(1800799024)(7416014)(376014)(366016)(56012099003)(18002099003)(22082099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?kxgNAgM5doLonf5SOZg1CTNtLpTfbTCp8kyDp6BULwMSX8ob9iqlvo5q4ZO5?= =?us-ascii?Q?Y6Ep9NP9yIjimDfOHF5zaPXa629NRYIiQuLOqZBDmM3x/rZEyN+EdUGgLUQm?= =?us-ascii?Q?3gnBLaiShIyOsfYOa4u+cvRKTzmJCY6i5Bf23gt0SaiDCIh8gbB2f+TSlvoA?= =?us-ascii?Q?53nga7IAvLxlxJzZMJoIZMGEhmsdQI07KJzgT2d09ACVAv+F2y2WqMobbrvo?= =?us-ascii?Q?kim7Jov7kkHmj166DfppNT8TJtPdhlz7XVHZ2KYRetpcCZu0GYqOoRBfIkrr?= =?us-ascii?Q?CyuBQpOU33gYAvy7l+2lCwSqFrSaZkPWj9xAIYJ8RY7NkZWNgg99qo4TFEf1?= =?us-ascii?Q?wUIR7Uf7hDig1EzZISw5u5oNJew7EpeV+dn+RfqGc3d2cCvYkoOGqhQ2Yx36?= =?us-ascii?Q?zsICDR8kmflKuxNf63wFzern/jABCJdnojKHZcb91IUWot4O3W9JQYSTQ1sZ?= =?us-ascii?Q?aDGeUTlGYVTSw7nmW91952OD87U1wDtd6AvloBsPHm2u6w+K+o71ObwBhejP?= =?us-ascii?Q?sDT+3YqHz5vQdY1xE9IUP5BfA6hcJIg6L/VZllIvHUoGioflYPmox/cx3um5?= =?us-ascii?Q?JX3XxwHrULzSUKP7AoIQNGlZNDa6BMF20uFknpr/dNsDoeUsi6lrEn0COp/j?= =?us-ascii?Q?wQMEz3GHdhcLuUtGEMTNE3H82LYSMNubdKnQpzpvTbNMiTSamMhDnblOBhYH?= =?us-ascii?Q?npW7nHWP0gktpDa8i7lNhBtY0bC7tTNUn+azlAsOEdoiZOJRVxvaZiMaUlh6?= =?us-ascii?Q?+NPMRCTpR5xTOEWxJipv/DanPFhMx03KiCQyq9knjutZPJ8NxjNc473Lq/kn?= =?us-ascii?Q?nFHmxx0NVj1rJ1/fXNYrpflfjZqxmsQ6zcuLoI0d2UJyTyEM2/aU9ZfdFTYj?= =?us-ascii?Q?vOb9sGKjJuoKAzq9fpa3uXwIfUl0gM7O5Q6gEsqbbDZHjvPwP2J5aYPE8QSJ?= =?us-ascii?Q?TLnWnroE3vK2LL0V9LiEWuIyRdw/8SwPJQLZB/11NidYkhL1vv0jLUu2lI1q?= =?us-ascii?Q?NtmyR6rw6dSGQeYeztC61D2TiSewBaz71AOYOQQCJqElmvO5zQfNPlLPWgxn?= =?us-ascii?Q?dAyjyIh0ZtI8Yj06YrE4TwNYuR/qo3FwVXYL2nW6MeLIWBADOhVoSp7Tf6XJ?= =?us-ascii?Q?xiTjDUBcHwdKR2yiPtiGniwswtwzM+5jVB5HDEbUIoIAFAUGu1CeAlU4xEda?= =?us-ascii?Q?fnW7/Aginbmjll0kZKkMiHSlwD4qibAg14dGSsAuRuW+8wmBkIwSWzrvhZzL?= =?us-ascii?Q?/258at8gAGRCMNS13f1Ra3TFdyMN6FiKsIYLTjfO+dmCsDE6p018hfR0367x?= =?us-ascii?Q?nRQeRZ+8ny4VnRxdM7F1NRbNmx69JOGSuXqZXwAWXs8GGU9giJqg6DmWQBmD?= =?us-ascii?Q?rvn3vnyqgosT4AcPfEnZslB45Mcqb+7MEglzvRct8v/SxPrKtsLw8U5vJta1?= =?us-ascii?Q?gldfnzv8r3jI7/TAruQViKL0y6ZjCvMpXRsKnG0YCCHQcnxK4V4GxyYOWX7Q?= =?us-ascii?Q?gYKaTCUD1TuG3k2t5sndHKrQl3H3X59VjrgXxjGhvZ+fp8ZW4q47DgSrDzRh?= =?us-ascii?Q?Hf0q3YAaCg1TVXiAcBxb+ywByOyP3jTMbR80d4zl68swYOnkVF20OYkVHJPQ?= =?us-ascii?Q?5rRbFFHC37JOcjKHEY3HmlBYO/jKi20nTjcES6/sJSL5DojnksY4/CwtX6UX?= =?us-ascii?Q?BarS8oZ6Eo68pu2+lOruLxd+xGdhE7WCHxC/3Cue9BVsnTmz?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 83480e9b-aef1-420f-4cf9-08dea1ac7ecb X-MS-Exchange-CrossTenant-AuthSource: DS7PR12MB9473.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 24 Apr 2026 02:52:16.8195 (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: yzIJu8jCK1zXbGbWqSYrMkh9feOq1s+mwAuhmXtz6AT7jmGO61dS6oPbybmALyE7 X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS4PR12MB9588 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. READ_ONLY_THP_FOR_FS was using mapping->nr_thps, inode->i_writecount, and smp_mb() to prevent writes to a read-only THP and collapsing writable folios into a THP. In collapse_file(), mapping->nr_thps is increased, then smp_mb(), and if inode->i_writecount > 0, collapse is stopped, while do_dentry_open() first increases inode->i_writecount, then a full memory fence, and if mapping->nr_thps > 0, all read-only THPs are truncated. Now this mechanism can be removed along with READ_ONLY_THP_FOR_FS code, since a dirty folio check has been added after try_to_unmap() in collapse_file() to make sure no writable folio can be collapsed. Signed-off-by: Zi Yan Reviewed-by: Matthew Wilcox (Oracle) Acked-by: David Hildenbrand (Arm) Reviewed-by: Baolin Wang --- fs/open.c | 27 --------------------------- include/linux/pagemap.h | 29 ----------------------------- mm/filemap.c | 1 - mm/huge_memory.c | 1 - mm/khugepaged.c | 28 ---------------------------- 5 files changed, 86 deletions(-) diff --git a/fs/open.c b/fs/open.c index 681d405bc61e..c321b80027f1 100644 --- a/fs/open.c +++ b/fs/open.c @@ -968,33 +968,6 @@ static int do_dentry_open(struct file *f, if ((f->f_flags & O_DIRECT) && !(f->f_mode & FMODE_CAN_ODIRECT)) return -EINVAL; - /* - * XXX: Huge page cache doesn't support writing yet. Drop all page - * cache for this file before processing writes. - */ - if (f->f_mode & FMODE_WRITE) { - /* - * Depends on full fence from get_write_access() to synchronize - * against collapse_file() regarding i_writecount and nr_thps - * updates. Ensures subsequent insertion of THPs into the page - * cache will fail. - */ - if (filemap_nr_thps(inode->i_mapping)) { - struct address_space *mapping = inode->i_mapping; - - filemap_invalidate_lock(inode->i_mapping); - /* - * unmap_mapping_range just need to be called once - * here, because the private pages is not need to be - * unmapped mapping (e.g. data segment of dynamic - * shared libraries here). - */ - unmap_mapping_range(mapping, 0, 0, 0); - truncate_inode_pages(mapping, 0); - filemap_invalidate_unlock(inode->i_mapping); - } - } - return 0; cleanup_all: diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 5b4313d91137..88e58ca79bb5 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -528,35 +528,6 @@ static inline size_t mapping_max_folio_size(const struct address_space *mapping) return PAGE_SIZE << mapping_max_folio_order(mapping); } -static inline int filemap_nr_thps(const struct address_space *mapping) -{ -#ifdef CONFIG_READ_ONLY_THP_FOR_FS - return atomic_read(&mapping->nr_thps); -#else - return 0; -#endif -} - -static inline void filemap_nr_thps_inc(struct address_space *mapping) -{ -#ifdef CONFIG_READ_ONLY_THP_FOR_FS - if (!mapping_large_folio_support(mapping)) - atomic_inc(&mapping->nr_thps); -#else - WARN_ON_ONCE(mapping_large_folio_support(mapping) == 0); -#endif -} - -static inline void filemap_nr_thps_dec(struct address_space *mapping) -{ -#ifdef CONFIG_READ_ONLY_THP_FOR_FS - if (!mapping_large_folio_support(mapping)) - atomic_dec(&mapping->nr_thps); -#else - WARN_ON_ONCE(mapping_large_folio_support(mapping) == 0); -#endif -} - struct address_space *folio_mapping(const struct folio *folio); /** diff --git a/mm/filemap.c b/mm/filemap.c index 4e636647100c..d3cd4d2f3734 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -189,7 +189,6 @@ static void filemap_unaccount_folio(struct address_space *mapping, lruvec_stat_mod_folio(folio, NR_SHMEM_THPS, -nr); } else if (folio_test_pmd_mappable(folio)) { lruvec_stat_mod_folio(folio, NR_FILE_THPS, -nr); - filemap_nr_thps_dec(mapping); } if (test_bit(AS_KERNEL_FILE, &folio->mapping->flags)) mod_node_page_state(folio_pgdat(folio), diff --git a/mm/huge_memory.c b/mm/huge_memory.c index f0db1390a18f..8b85a3e58b00 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3937,7 +3937,6 @@ static int __folio_freeze_and_split_unmapped(struct folio *folio, unsigned int n } else { lruvec_stat_mod_folio(folio, NR_FILE_THPS, -nr); - filemap_nr_thps_dec(mapping); } } } diff --git a/mm/khugepaged.c b/mm/khugepaged.c index cdd4b37e4a68..4de7e30c4b71 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -2469,21 +2469,6 @@ static enum scan_result collapse_file(struct mm_struct *mm, unsigned long addr, goto xa_unlocked; } - if (!is_shmem) { - filemap_nr_thps_inc(mapping); - /* - * Paired with the fence in do_dentry_open() -> get_write_access() - * to ensure i_writecount is up to date and the update to nr_thps - * is visible. Ensures the page cache will be truncated if the - * file is opened writable. - */ - smp_mb(); - if (inode_is_open_for_write(mapping->host)) { - result = SCAN_FAIL; - filemap_nr_thps_dec(mapping); - } - } - xa_locked: xas_unlock_irq(&xas); xa_unlocked: @@ -2661,19 +2646,6 @@ static enum scan_result collapse_file(struct mm_struct *mm, unsigned long addr, folio_putback_lru(folio); folio_put(folio); } - /* - * Undo the updates of filemap_nr_thps_inc for non-SHMEM - * file only. This undo is not needed unless failure is - * due to SCAN_COPY_MC. - */ - if (!is_shmem && result == SCAN_COPY_MC) { - filemap_nr_thps_dec(mapping); - /* - * Paired with the fence in do_dentry_open() -> get_write_access() - * to ensure the update to nr_thps is visible. - */ - smp_mb(); - } new_folio->mapping = NULL; -- 2.43.0