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McKenney" , Metin Kaya , Xuewen Yan , Thomas Gleixner , Daniel Lezcano , "Suleiman Souhlal" , kuyo chang , hupu , References: <20260313023022.2902479-1-jstultz@google.com> <20260313023022.2902479-2-jstultz@google.com> <20ea3670-c30a-433b-a07f-c4ff98ae2379@amd.com> <20260318125522.GH3738010@noisy.programming.kicks-ass.net> Content-Language: en-US From: K Prateek Nayak In-Reply-To: <20260318125522.GH3738010@noisy.programming.kicks-ass.net> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Received-SPF: None (SATLEXMB03.amd.com: kprateek.nayak@amd.com does not designate permitted sender hosts) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS2PEPF000061C6:EE_|IA1PR12MB8263:EE_ X-MS-Office365-Filtering-Correlation-Id: 56f43956-5930-4307-c77d-08de851887b1 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|82310400026|376014|36860700016|7416014|1800799024|18002099003|56012099003|22082099003|13003099007; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:satlexmb07.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(82310400026)(376014)(36860700016)(7416014)(1800799024)(18002099003)(56012099003)(22082099003)(13003099007);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: N5s8qxi7Z+Us4qjK6KoAe98NEh1/zXCUU7JlVNkcj+E+j9IDwnrYSjQchX690oFqsiXq8iQwCDrZaON6mJulkk0hxzl+5EbXJmn/LfhJU4zKEO/KGDgrlVU1J8LOMhN8Ys7qoQZwefrVt5JQMVPAteTtzxX6f4I+u8jjExY5n01/kQJ5dr2EtNX6oOBFTbgwFc1HWZBijIhUBPtz/ovpjjwyUUY52CnBsXTic1Trv4gAKw3Xk4mSG9oD+Lj/olJ15Q5L4imMauKKT7dwMFH3uLnignl5MyPMjBP+xoPcZtkcTf/UudDd5Sdy0oGHBTSrKGoNDYL74Ld9SR2SZstU6r/gMOkkOlXZeRUTqPGj22qDrZUq1lslRiTRwNJjCIA+4GnL2SIK/Wp7hPlgejjN9wS0PM2pwDfufwqbvhV8iq3x5r2BRZuijDZErnGo4sfZ X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Mar 2026 18:02:33.4839 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 56f43956-5930-4307-c77d-08de851887b1 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: DS2PEPF000061C6.namprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA1PR12MB8263 On 3/18/2026 6:25 PM, Peter Zijlstra wrote: > On Tue, Mar 17, 2026 at 11:11:20AM +0530, K Prateek Nayak wrote: > >> Also, deadline, RT, fair, and idle don't really care about the "next" >> argument of put_prev_task() and the only one that does care is >> put_prev_task_scx() to call switch_class() callback so putting it as >> either NULL or "rq->donor" should be safe. > > https://lkml.kernel.org/r/20260317104343.225156112@infradead.org > > Makes fair care about the @next argument to put_prev_task_fair(). Ack! In this case, using "rq->donor" is better since we skip traversing the entire cgroup hierarchy and bail-out at the common parent which is the immediate next entity. -- Thanks and Regards, Prateek