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Shenoy" , Swapnil Sapkal , Ingo Molnar , Peter Zijlstra , "Juri Lelli" , Vincent Guittot , Anna-Maria Behnsen , Frederic Weisbecker , Thomas Gleixner , References: <20250904041516.3046-1-kprateek.nayak@amd.com> <20250904041516.3046-4-kprateek.nayak@amd.com> <409bde01-720b-4602-bde9-a04262ea2c73@linux.ibm.com> Content-Language: en-US From: K Prateek Nayak In-Reply-To: <409bde01-720b-4602-bde9-a04262ea2c73@linux.ibm.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BN1PEPF00006001:EE_|MN6PR12MB8470:EE_ X-MS-Office365-Filtering-Correlation-Id: e10c8f89-8ae6-4bd1-f6b8-08ddfbd5afc0 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|7416014|36860700013|1800799024|82310400026; X-Microsoft-Antispam-Message-Info: =?utf-8?B?T1lDV2xCb0w0THA2N3o5NllkRXZGTHh0SFhuMm95dnhMVnlIbmliT0JZMlZh?= =?utf-8?B?QXRDaGhyMXRNWXBHV2ljRmFKWWhpbmdRUTk0U0ZidXBwbHVrVkVtYTBPbGxM?= =?utf-8?B?VjVPUzNEN0ZxQXlkSW13OWVQQmsrKzA2d3F5N3RNT3RiUGgvbUZkUGY5OXlY?= =?utf-8?B?UmtzZ29GVHE3RmltK3JwZElCNzlVOXFKTm1SRTdZTVhacEZaVXRlcVppeFcv?= =?utf-8?B?c1FRZDFwemJGaVJXVWJQM3laQkJOL00zTmVPeVYyQnBOOVRRVWlDUkMrN3pz?= =?utf-8?B?VFd5U2lEU29wRy9YeWhESmtVNkJDQVZ4M0ZVNW1ibmZtS250VGI3V0ozdU14?= =?utf-8?B?VUk4TXpuY3pKM3FLa2RIZy9CWWNBYkRvMjhFYWE2eVJSaXhkY0pTRWY3aCtH?= =?utf-8?B?ZzVjcXdSaTFYVlpHUzFrUXN3V0ROMWV3c1BqQW5ray82dmNmSzBzS2Rkcmxu?= =?utf-8?B?VXhtYmk3T1BMVExqcVlnWDdqK1ZFZUlXS2plbmR1bW1sK0FpYS9odE4yVldX?= =?utf-8?B?bStoVkpaaURsOFErd1BCdVVYNVc5cXdIcW50cERlNXhKaFVyRVA0Tlg4WVZI?= =?utf-8?B?UVIxODFYYldOSmFtdjFsYTY1cVczeEFQNWVFeWk0TDNSQjBJYzVyM0NmN0V2?= =?utf-8?B?blM3U3J3NlpxbmFGbDlpYm04RHliUmpCZHA2SUNVdmRaZlpIcGRmWW5aZG50?= =?utf-8?B?OHFSYWhmbHpERG9lb0s0aFRnMGhCaUo3VmlScVlJSzdlSnJ0TUVoNGJjWHI5?= =?utf-8?B?bnM3bUkyTURoWHBFTklMQjBWbzQrZlFjbFFlVXozK1RQVktHUkMwL1p0YTg4?= =?utf-8?B?SHM4K2d5ZWZtYlFuZlNsMVNuRzZpWmV2c0w0VFkyY210U1lsOS8wN2treFNk?= =?utf-8?B?VG9ENTNYOFdwcjQ4RXYwUHJuS2I2dFRLWU1SUndRK3VncUtYZGJIbHNpUCtB?= =?utf-8?B?NHpyUUxYSzN1NlpFY0VCVDdYQ2w1Y1lvNnQ0dmUrWlF6QjRBWTljOFQyejBw?= =?utf-8?B?Y1VwT3IzV0hUQVVRRlFHNFZ5R2J1WlV2L2J0UVVaOXd0OXhhOEpXbnRqUEph?= =?utf-8?B?WVZERTVYd05YanNTK0xaWTVmc1dZQ2xKYUF1c1pvVXJaemdlWG1Eei9oVllW?= =?utf-8?B?UHJxN0FpbWpFOGN5Y2FuVnBIOGdiWXlwQjFvdnVVa3lrVHNJcTJDa0J5U2Na?= =?utf-8?B?bzM4RTNaM2MvSk1GZVJqUk42N25peTAzTm1NcGtRbzA4TURKK09WR3FWKy9S?= =?utf-8?B?RmNzQmI1K3lKb3JFb0tuMkE4SVRCanZiTEpvLzRkSXEyMEljNUUxOXpaYjJN?= =?utf-8?B?WnpzQUhJVjhJUHpsMGY2WlNKYUM2TGpOZG5IVnc2MzdzRzI0bDJHQlhlRHlk?= =?utf-8?B?UzdGVy9vS1ZFQkRLQmNHRjNUaWZNK2pBS0hDK1RYSVNnVHRvbklEb0p0ditq?= =?utf-8?B?YlErVFptRXY1cUlTSVh2NzBDTzJhd2RtbjQvSC9zSWxENTFaWU43VHFsZzBZ?= =?utf-8?B?VVB2QkVZWFJ6eVZUSCtBKytRa0JNdWVvNi93TjJielFwYzdwR29MN2Fnb0Mr?= =?utf-8?B?ZThUSWd2M24rSWx4K3ZvbFYwZnhPa0dTeXZ5K3hITkpLSHcrYVJ0K0V2ckxG?= =?utf-8?B?WW9aOU5Mc2NsY21FeksvL2E5Z2VVRHFEMHR3RmtUUTZydUFBUG94cjJhQVho?= =?utf-8?B?dzFoM0I2eUxxdTdnT1lNYlBTWkJ0bmJvZ0FsNEdQdXpHeFQrYmZyeE1LZHBQ?= =?utf-8?B?eGxQRGxzdzJHUTZCUTJJLzArVjFDaElPMm5OQWlIRDR1cEpSalNQNGZLR3pS?= =?utf-8?B?SjZHRit5ZTRwVUhOdXhXN3FEZzZKZG56REZpNU9KdGhoOEVXb0RUb0lxR2hI?= =?utf-8?B?QzVwbDhJZTZxM2xFNVY3TitmclZ3UTRzbkovdHFWSzZmTTlVeWo2blAyZDBj?= =?utf-8?B?MTM3NzBZZU81THlmUDRySDdQVm5vTGlWT2tPTlJwU2tWSjVBQUFIeDlUYWVj?= =?utf-8?B?bFRYU0tkQXg5QVBTTFFpa0FSOVU1dXRwMG40dUR0VGJ4YlFYd0FVVHhHbEtx?= =?utf-8?Q?TyQtEz?= X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:CAL;SFV:NSPM;H:satlexmb07.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(376014)(7416014)(36860700013)(1800799024)(82310400026);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 25 Sep 2025 01:48:55.1323 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: e10c8f89-8ae6-4bd1-f6b8-08ddfbd5afc0 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=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: BN1PEPF00006001.namprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN6PR12MB8470 Hello Shrikanth, On 9/25/2025 1:47 AM, Shrikanth Hegde wrote: > > > On 9/4/25 9:44 AM, K Prateek Nayak wrote: >> "rq->nohz_tick_stopped" always follows the state of CPU on >> "nohz.idle_cpus_mask". Use the local rq indicator instead of checking >> for the CPU on the "idle_cpus_mask". >> >> Use READ_ONCE() and WRITE_ONCE() for "rq->nohz_tick_stopped" to ensure >> update_nohz_stats() always sees the latest value. >> > > Is this ever called by remote CPU? If not, is READ/WRITE ONCE is necessary? Patch 6 looks at "rq->nohz_tick_stopped" to correct the idle mask in the sched domain rebuild path which is done from a remote CPU. -- Thanks and Regards, Prateek