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client-ip=165.204.84.17; helo=satlexmb08.amd.com; pr=C Received: from satlexmb08.amd.com (165.204.84.17) by MWH0EPF000989E8.mail.protection.outlook.com (10.167.241.135) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9115.13 via Frontend Transport; Wed, 10 Sep 2025 11:15:15 +0000 Received: from Satlexmb09.amd.com (10.181.42.218) by satlexmb08.amd.com (10.181.42.217) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.17; Wed, 10 Sep 2025 04:15:07 -0700 Received: from satlexmb07.amd.com (10.181.42.216) by satlexmb09.amd.com (10.181.42.218) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.17; Wed, 10 Sep 2025 04:15:06 -0700 Received: from [10.85.34.232] (10.180.168.240) by satlexmb07.amd.com (10.181.42.216) with Microsoft SMTP Server id 15.2.2562.17 via Frontend Transport; Wed, 10 Sep 2025 04:15:02 -0700 Message-ID: Date: Wed, 10 Sep 2025 16:45:01 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [patch 06/12] rseq: Implement sys_rseq_slice_yield() To: Thomas Gleixner , LKML CC: Arnd Bergmann , , Peter Zilstra , Mathieu Desnoyers , "Paul E. McKenney" , Boqun Feng , Jonathan Corbet , Prakash Sangappa , Madadi Vineeth Reddy , Steven Rostedt , Sebastian Andrzej Siewior References: <20250908225709.144709889@linutronix.de> <20250908225752.936257349@linutronix.de> Content-Language: en-US From: K Prateek Nayak In-Reply-To: <20250908225752.936257349@linutronix.de> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: MWH0EPF000989E8:EE_|DS0PR12MB8526:EE_ X-MS-Office365-Filtering-Correlation-Id: 71f228b9-d56e-4dca-61ea-08ddf05b51c2 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|36860700013|82310400026|1800799024|376014|7416014; X-Microsoft-Antispam-Message-Info: =?utf-8?B?dkxqd0ttRVFDTTBnNlJhZEYzZnExanZod2JmT3Zhb0ZITzcvUUc4dmRaK3pB?= =?utf-8?B?eWJEdStxV2dTMGgySUxLTFh1a2JuV2k0YURUNFVQanJsYzBnQUpHVjlQMERK?= =?utf-8?B?ZjZLZ20rM1NNQzJlMFB4eDJSWExCcHBVOFhqS0tzc2x4ekZad0RFQmxmY3RU?= =?utf-8?B?ajVPUHhnMmQyM1ZaRHRQZ0g0bjRUazEzVXdBbThDQWRQbUJxQXZpZUNTNytX?= =?utf-8?B?Q0lxWGZ5SER0d3VUaVZwa0ZFcVFnM3lhRzJKcHFWTlB0TW9wb25FS3FqTzhl?= =?utf-8?B?Z1phVytCRkROWE5ONFhkdFEvZk9Td3hRUWRFS05ObFl1SUpjY3l4QjNGNHlU?= =?utf-8?B?dzdleEpsclFzcG5zT0R2OVJha1JMVjBjVGRKQWlSZGZoTVBlTFNkdksxalJ2?= =?utf-8?B?YXFSbC96TTFqUUpFbHQwL1JrZld3elMydDF6OGtmb0xYajJXZVJUVWRKT2JG?= =?utf-8?B?ZGVXUGdWbnVmRjZGdXV4OHY3dFA5WjAwQ3p1cnFVTUg3T1YwRzYrRmgyaU1X?= =?utf-8?B?TW5UUVhIdWxJSHhSeTBTMmNoTWM0RVZlaDVJYVJwRVVNc3pBYmZUeElKQzB4?= =?utf-8?B?VHVVakxIdGpiU0MvZTBzR0RSY0V0TEJCUXRWbiswV2xzbzhlRmZUa3hwTnFV?= =?utf-8?B?dDZ6ZjRER3J4aERrdDNub2dyN1VFbW9lcWc3QWsrNFVrYXlYRFRGSUZjQWd6?= =?utf-8?B?eTE4clo4REFnUWVTdWRiS0NhOUIzSTU3MzYzNWdNRFgzdmhEeEYzZTVNemNT?= =?utf-8?B?bEI5cXViNGxZeFRZTFN6V3YrU2dZNWtNOENPVlJzdkhDQWVnK1hNUDBlK3h5?= =?utf-8?B?ckEwdWxUa1Q0NEdJNVV5QUJIREIyUXRyc0JkSElMZFVWYVM5b25VaVI5Vmk1?= =?utf-8?B?aXhwS0piTndnM1dWUXBleVVxWlNRWUZRMktBaDJtVHBNbWZ4NnROU0Nlempx?= =?utf-8?B?N1FvcHh3Qm1VeDhzWnk5MEpjWmg5VTJUTGE1ejBsM0xlaHhMVVYxdmNiajlN?= =?utf-8?B?dVFHcEFheXV5Q2hneE0xR1pzOFdmQkx1bVd2VW5UNWRTZkdVZ2pNaWl5eWtw?= =?utf-8?B?UzlMY3l3VWs2TVlqdzZ4L0dLUUtVaWF5VGtGNjk4dWw5M2pFQzB6MEVrZGpv?= =?utf-8?B?MnJheFphai9zTjhrc2xSVzB4b2pTd3h2TEJlMUtQT3JhRVFKc0I1eVJWWUxV?= =?utf-8?B?Ym9uaWlFd0FrVllNTk54eXlRT1VGa2c3b0RKVHFIOHNQVFRkd1FXSU54ek4x?= =?utf-8?B?V25xWnAzNVMwN1BjMjRRTWpPRWMxSDhnZWtLRElBQlNNK1R5RTlzWE9Rb0pW?= =?utf-8?B?WnRLb25EdCtqZ0JhRGt6Q2NDSmJGdlJodE9FUC8rNWlFenFwZkpUMDlrVzJl?= =?utf-8?B?S0xWRVZ5YkFOanVjUWlVdmEwb0k3OVAya2NGeDUyWE9HZHZteGlFN3IxL0dK?= =?utf-8?B?STJySGtRSmQxR0RzRDMvSDY0R3duUlpUOGNsZDB4WC9BajJGa2VoWUJVbU1J?= =?utf-8?B?T2FkSy9MVU9pdTJIdFVZQi9tVnBBNElNV1UvQUVvZHY3OUJDQkF4UDIwZWV2?= =?utf-8?B?NUdRTWRZRzhFMnFvM3o3Vmt3Zmoxa3NzQlR6SEJxc2dyU0JIbTZBYWp6VUdm?= =?utf-8?B?aG9ZaXhIVUpPcHJUS2pON3lYYW1MOHhnbVZjbzFSWHNuT3AzTHdXR3NUZjh4?= =?utf-8?B?dmhXMTc4YjNFbUdTL24xQVh1RlAzWUJjZE0zUUJaYTJXZnFKU21Wa3ZlYjg4?= =?utf-8?B?ejVXYzZ3Y0ZwK2xwaHpISlBHZVBjbXdSN0xpcUgzcTl2WUsrbUhSdEQyU2Rq?= =?utf-8?B?eitWcWtyYmhVYk1NaTB3bFoxbWMwUk56U1BZOGVuR3ZoNkROaU9HdzNPNE9Q?= =?utf-8?B?VGRBV29wUmtoSzFZTjFocGZQTTYyWGMvZ0VyN2dvbEFSSGtiZmRSWWJxaGVP?= =?utf-8?B?RFRKUm9Hdk5mN244S0NkckJxWmxLZVJTcnZzN3FiNVRPWU5VZE00MHAvRTNq?= =?utf-8?B?QXQ1Z0NPMTl5dzQwMEpZeVNGcVo2T05Hc1pqVjN6bWp5bWpldTJDM0VYbUow?= =?utf-8?Q?t7PW5O?= X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:CAL;SFV:NSPM;H:satlexmb08.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(36860700013)(82310400026)(1800799024)(376014)(7416014);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Sep 2025 11:15:15.9522 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 71f228b9-d56e-4dca-61ea-08ddf05b51c2 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[satlexmb08.amd.com] X-MS-Exchange-CrossTenant-AuthSource: MWH0EPF000989E8.namprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS0PR12MB8526 Hello Thomas, On 9/9/2025 4:30 AM, Thomas Gleixner wrote: > --- a/kernel/rseq.c > +++ b/kernel/rseq.c > @@ -542,6 +542,15 @@ int rseq_slice_extension_prctl(unsigned > return -EFAULT; > } > nit. Perhaps a small note here to highlight how need_resched() is true for tasks who had the slice extension granted. Something like: /** * sys_rseq_slice_yield - yield the current processor if a task granted with * slice extension is done with the critical work before being forced out. * * This syscall entry work ensures NEED_RESCHED is set if the task was granted * a slice extension before arriving here. * * Return: 1 if the task successfully yielded the CPU within the granted slice. * 0 if the slice extension was either never granted or was revoked by * going over the granted extension. */ > +SYSCALL_DEFINE0(rseq_slice_yield) > +{ > + if (need_resched()) { > + schedule(); > + return 1; > + } > + return 0; > +} -- Thanks and Regards, Prateek