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Sun, 23 Nov 2025 20:36:07 -0800 Message-ID: Date: Mon, 24 Nov 2025 10:06:06 +0530 X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 09/17] sched/core: Add support for nohz_full CPUs To: Shrikanth Hegde , , CC: , , , , , , , , , , , , , , , , References: <20251119124449.1149616-1-sshegde@linux.ibm.com> <20251119124449.1149616-10-sshegde@linux.ibm.com> <0f9ed7ce-3839-4d2b-98b3-25cc4045aa22@amd.com> <08ff261e-7ac8-4a1d-bceb-b1bf792171ae@linux.ibm.com> Content-Language: en-US From: K Prateek Nayak In-Reply-To: <08ff261e-7ac8-4a1d-bceb-b1bf792171ae@linux.ibm.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SJ1PEPF0000231C:EE_|IA0PR12MB7531:EE_ X-MS-Office365-Filtering-Correlation-Id: 641e0f2d-c4e1-4848-c0e1-08de2b12ffb7 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|82310400026|36860700013|376014|7416014; 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X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 24 Nov 2025 04:36:13.1494 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 641e0f2d-c4e1-4848-c0e1-08de2b12ffb7 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: SJ1PEPF0000231C.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA0PR12MB7531 Hello Shrikanth, On 11/21/2025 10:10 AM, Shrikanth Hegde wrote: >> Wouldn't the task be pinned if it is running on a nohz CPU? >> We don't push out pinned tasks so this seems unnecessary. >> Am I missing something? >> > > No. Task will not be pinned if it running on nohz_full unless > user has done a taskset. They are still part of sched domains. > > Pinning is usually true for isolcpus. You need to explicity set taskset > for isolcpus since by default you won't go to those CPUs. TIL! I was under the impression that nohz_full is a superset of isolcpus but I was clearly mistaken. Thank you for clarifying. -- Thanks and Regards, Prateek