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McKenney" , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Uladzislau Rezki , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Zqiang Cc: rcu@vger.kernel.org Subject: [PATCH v1 1/6] rcu: Remove unused expedited_need_qs field from rcu_state Date: Sat, 18 Jul 2026 13:15:32 -0400 Message-Id: <20260718171539.3781595-2-joelagnelf@nvidia.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260718171539.3781595-1-joelagnelf@nvidia.com> References: <20260718171539.3781595-1-joelagnelf@nvidia.com> Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: MN0P223CA0015.NAMP223.PROD.OUTLOOK.COM (2603:10b6:208:52b::9) To DS0PR12MB6486.namprd12.prod.outlook.com (2603:10b6:8:c5::21) 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: DS0PR12MB6486:EE_|SN7PR12MB7276:EE_ X-MS-Office365-Filtering-Correlation-Id: e78f7f40-41a6-4461-de1c-08dee4f034d0 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|23010399003|376014|7416014|1800799024|18002099003|22082099003|921020|10067099003|56012099006|5023799004|11063799006; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?T2G+i5acIGGiKS6Ar9dQRCCEU4OmiLUlURjCiwKDw6KtDpu8oq9c04jyX2Xt?= =?us-ascii?Q?zX+CDexkycFWZ+dxp7aG1I9EAT5qzWVP0NX8LLfaj29NKt2NwcBAV3R7uL5a?= =?us-ascii?Q?bXQgHodBJhBovN0SJY5Oakl5RSwKCAp1TpUv8OvdP8V2klUXF/dxmue/OZ0k?= =?us-ascii?Q?CqLoK/euW97/TTqeMlvTQpaJVOXDra8s4apoHIBoOLdQAatQm6H6KizkK6mF?= =?us-ascii?Q?wOUsqpG3xHKNS+qY1u/TnKiMjKfaOt8atIndJcH3HqzrkcVIlqhUyDWLOvwT?= =?us-ascii?Q?wfDV6i282Q68auadsMGPL77Cyt6n08xbr8O8XIij24PvqcUfkMFWscgNxD23?= =?us-ascii?Q?7GWcuEHqCzbhoULn0g3oq/A2B5B0HFAjxUsbGcMDJwOFVQ+rkuJHr/Yg9Be0?= =?us-ascii?Q?OT3gzH22630CbG4LbBvzyCQjWownsVesb4AordHIkZhVEsg5Sx1gVwZizZxM?= =?us-ascii?Q?4OBFCBfvfR20BOFd+t4MtdFbfIPi7nT+fMt1N8potP61dTXXPrmGuKBMeT8j?= =?us-ascii?Q?vIX/RkhOB+1ECK7+AZpbAReahamvE7Dr/J8G6e6H5iUIAjLTuUR50SPo7y1P?= =?us-ascii?Q?4JjHx5G54Kc8TPj3z3v0pHeV1c/vP06pEZGtv/WK/A+F1iNreeLebWa6u6UM?= =?us-ascii?Q?/gaoXkjB5azFHE6Mu3P6OVBDJ1YSqGbKvZSXHlIYKEEABwcQxFbSv1cFqpCa?= =?us-ascii?Q?GLJDFfPg1NjUlMBty7CYyOmeE8+nDafJ8UAQTvIwaeWF6hePeHpFt2MG9wZE?= =?us-ascii?Q?hAV0aOxDP6IIPynYKHeW2imLsxgo6pH/66kQ5elpUL4pFMYYeWAYx+pNzbbM?= =?us-ascii?Q?FvMFhfG/hRNW7N1LnPq5egvvNqCBLDsqWNXrEhI26s8JHWK0cZcKzyrZl0rr?= =?us-ascii?Q?9FCNOaLK+de6fZrPfoJpjV7G33UlQJ7dy3T6VpRjILEZFvOUvuK14CwLs8N3?= =?us-ascii?Q?C5foFnJJFmwL6OXsA9HFfKJ8/VZEWbGzXnOUe+rHPFiW4JUxB8IjRWnw3Ors?= =?us-ascii?Q?yKogWBuYoLFbNKFVu4KyUBi7EUlWYA/o8VOurVi4DF7IojcT6wJVgXdFIleo?= =?us-ascii?Q?C4Q7LdznnOB6HMeYp8/RVKtLqoPinE3x81I2fx8tySzRFzPdCGHWMLB8vCS/?= =?us-ascii?Q?8Y+6TeNT+sJWb+mipmIv65+DfU3Cv1EcxTg7xek+tBzewTH7Y6cV9i4OmBM9?= =?us-ascii?Q?wluw4AJLS/5qp0rrxSBOkJMSrS6rOpuztjuZMhUl9SzQ4WjEsq9unrDa3gHd?= =?us-ascii?Q?EXYNV926UAH9fFohypyYKI30zUl5dfqukPHR2I1mwurUB+q5maqWUwT4Md+g?= =?us-ascii?Q?tUGqOpiatlOn4vvZw71fC7+40qo6RPnueeKP+QOe4bJtSC8IRxtdoFfpfhnR?= =?us-ascii?Q?nFe0AXwXRyMjEQWIZkZvv+qfR4yco8j2FJL3PIZytwALGFRb3DLmaHSntmCw?= =?us-ascii?Q?1RVLtoDM/Dyy/qhASHvv2jkjXo/ooFsINnc9B6Au5tTTXpILufaYstu9729N?= =?us-ascii?Q?SSo0g4IeitfpMs48EFwxYgZFGngQpgbhRTDrvOjwqSXjlgcZUMXs2fFsgXQm?= =?us-ascii?Q?eLyq2lzdHul0HbYu1TzhNCYWlHb9KK0dal/BvIcWDVhmRkVJTuhFBpAbEobx?= =?us-ascii?Q?0Y10GtQme5sT9blfVxRMlRgMe12kowAnuCm+f9beNBS4MOiHE3Hf1knu7tvH?= =?us-ascii?Q?i9m+4CtGq89CMt+BqPQgiW3UkkoK73aoghG4FzaA2NIIcKe0tSLtqURJjJA1?= =?us-ascii?Q?QKdj3+rtZQ=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: e78f7f40-41a6-4461-de1c-08dee4f034d0 X-MS-Exchange-CrossTenant-AuthSource: DS0PR12MB6486.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Jul 2026 17:15:46.3373 (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: UjFKDBxzFLfJEdSAY46gYAgqqef6SKLDkJ0JI7LN+nO/su4Y3gG8bQ+qxKNK0UDCl2GlkPiIF5n98UbZY8zm6g== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN7PR12MB7276 The ->expedited_need_qs counter was part of the old expedited grace-period machinery that spun waiting for each CPU to check in. The current implementation instead tracks holdout CPUs via the rcu_node structures' ->expmask fields and waits on the ->exp_wq[] wait queues, so nothing reads or writes ->expedited_need_qs any longer. Remove the field to avoid wasting space in rcu_state and to keep readers of the expedited code from searching for nonexistent users. Signed-off-by: Joel Fernandes --- kernel/rcu/tree.h | 1 - 1 file changed, 1 deletion(-) diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index 7dfc57e9adb1..beb86e39909a 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -386,7 +386,6 @@ struct rcu_state { struct mutex exp_mutex; /* Serialize expedited GP. */ struct mutex exp_wake_mutex; /* Serialize wakeup. */ unsigned long expedited_sequence; /* Take a ticket. */ - atomic_t expedited_need_qs; /* # CPUs left to check in. */ struct swait_queue_head expedited_wq; /* Wait for check-ins. */ int ncpus_snap; /* # CPUs seen last time. */ u8 cbovld; /* Callback overload now? */ -- 2.34.1