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Shenoy" CC: Vincent Guittot , Juri Lelli , Dietmar Eggemann , "Steven Rostedt" , Ben Segall , Mel Gorman , Valentin Schneider , "Madadi Vineeth Reddy" , Hillf Danton , "Shrikanth Hegde" , Jianyong Wu , "Yangyu Chen" , Tingyin Duan , Vern Hao , Len Brown , Aubrey Li , Zhao Liu , Chen Yu , Chen Yu , Libo Chen , Adam Li , Tim Chen , References: Content-Language: en-US From: K Prateek Nayak In-Reply-To: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS3PEPF0000C37C:EE_|CYXPR12MB9319:EE_ X-MS-Office365-Filtering-Correlation-Id: cdc8a976-9485-4f29-1f33-08de15e7bb2d X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|82310400026|7416014|36860700013|32650700017|376014|1800799024; X-Microsoft-Antispam-Message-Info: =?utf-8?B?ZThJVDNLL0JTMGtEYTdxVVhPajdwYWRDZlgxSFVWZGFKZUY5c2MzRGJ1WFZO?= =?utf-8?B?NmJHdHg5WU9URWllbmJzeFl3enFnbUVOQjdnbVpweE8yUXZ4L0plaG5PSFZ5?= =?utf-8?B?YjBNUnVKTjlWNEtLTlltQURrRks1VFBqN1U2aGlXd1F4VXdSTG01MU16U3lW?= =?utf-8?B?TDlaS2g0TlpRQm5YY0p2NWp5QUF0K1BuMjNLRXNlbE80bHdKL3VFb2dlNWhI?= =?utf-8?B?c2JMRXEzZ2JTb0VQVmxnV2k5ZkFjbURoOElvU1VIdno0c09OdGFZNTJpa2tN?= =?utf-8?B?UWZTOTZNblJ5SEltNW5xOFR3U0k1d1R6UDdhUm5WSXZLeFZsVXpTV05VV0hB?= =?utf-8?B?OS9pNGxzaHJwa3F6b01PZU1ueS84bldCMTB6d1RoVlQzTVM3UStZQmRoOTJS?= =?utf-8?B?eGxpSU5pK2xnY0dNZHNzTERUOEY5UWJCRlRrMkZTbkE5M0Q2RVBhRnprZ01x?= =?utf-8?B?a2hwR1JnYWFQbUJHVDN6OFVMUmZDekExb3ZIZ0xCVGloYVNRUjMwbmhMeFRu?= =?utf-8?B?VjVtaXZac0c2aTFxNFRBU3NpL2toeHhFMHRkMG1PT0VkL0NlcHQ4eTZYeGto?= =?utf-8?B?K3RFTkx0Y3g3V0hyVHpEdXp0aTEzVzlzczVOTkpKRGhDYjBCeHVEeVAvak1N?= =?utf-8?B?dkZ3SkQrbjI1L29laXp4TExFMHNtaGFERDhsSHFhSnozSSs5cHRWTUdMMXhI?= =?utf-8?B?T09tbG9vSjJKNWpJekVoOC9WM015dXA1OS83aC9HaCtKUG9LR2hvTDBDWExy?= =?utf-8?B?T04xUCtZbEZyZDBTekY5Y0w1N2ZDQjdFUXBVZytnbHY1SVVKOVFWWXV1REtT?= =?utf-8?B?akF0VlRLQmxNbmJNRUtmRHV4MzZvbUw0bzM1aWp4c1lRU1JWRC9LSkVrY0hz?= =?utf-8?B?Nk56ZUh6N0dWNkRrZmlRUFFwR0oxaER3a20wNVI1Y2lwUTNISE50UW9TL0E4?= =?utf-8?B?L1A3ak1adUg5RmxvTmRsOXhvTFlTTGNiOVVYdHkzK0owU1VNK1JQSWx4UGd3?= =?utf-8?B?NDU5WnVtWWRIOTZDa0x0WHJEZ2hyWmhjN2JoaEhKOHB6YTYzaWZ0RCtPQmMz?= =?utf-8?B?dFRDWkZrK2pKaTRXMU9QUmxpRXJFbzdhYU00U05qeGNMYTNiSEdKOXVTaXI1?= =?utf-8?B?TEVEajVjQXI5TDlnbElPWFFlc2RVSWRHMTVEbHRaZlB1VUV6Wk5Qb2x1UHdt?= =?utf-8?B?alBpdjhJTFV6R2dxVUVDd3NZRTZvamw4OU41akdmM2xPNVdJcUJDSG8ra29I?= =?utf-8?B?Y3NEakF6SGxHY3k1M2wrTW01dHJ3U1NFZDZONXhPVFNqcnNscmdVbnIrczJl?= =?utf-8?B?NVRsTzB2ZEc0emhMWkRWZldiNlBVZ3FUdG9tUSsrZERyZWV2N1dZalNJUTZ0?= =?utf-8?B?MS92UDRpYVVFekdYRDhNUDBWNTVtN2QrYkNjVE02UWlnNGJZRFVZazdMTlhz?= =?utf-8?B?R0NTMmpJdnJBVFFzTjdmelY4UkQzZk9mZTIwQ2c1OTRWQVZkeWE5VVZZREla?= =?utf-8?B?bFBFUjZOZlgvKzhMSTIvNUdtZk1BOG5qa1ZaMnl3M2ZTWmpxRUk3clZjMTNZ?= =?utf-8?B?TE03ajVMZnR6V25OSGtLZjV2RHhMSXljVHV2NzJVWTN3amdHODlSZEdtSzlp?= =?utf-8?B?dGtyZU85Z3ZjUS9hYWdOYUpkNWxjSjVUOHdFdk1SSkFHWWswOVE5elA2aHdE?= =?utf-8?B?bDR4dHpMRVZDdStNZnN3bkFQcWJrNXdpZnhNcGVnMm9LMkNHMjcrRkFGT1R1?= =?utf-8?B?OVpmNkxndHRUR1p0ZHR5N3JBb1VtRG9TdkNQdHhaU3J0VFZiTFl3QzYxUkZL?= =?utf-8?B?ZjVsaTlvT1hvRi82K3Q4YVlFbW5kb3pzemt0V3NZWnlxRkZETVhLY2Z0eExX?= =?utf-8?B?eGwyNVFrQ2E0dFVVUkVGTUpqWFFOZ0dFR1ZTRCtqb0Z4Z0o3SUNVV21VemtO?= =?utf-8?B?MEtDRGp3MTBva2FmcnF4bHlJaVB6T0g5TkVtYW44VFMyUm4zcVdGTTN1ZTRh?= =?utf-8?B?bDB5TFlpQUtTNHFPVnRaUTVKZ3JiZGt3YndXd0hrbFlabUc1VEhvY3RYMWdj?= =?utf-8?B?alI4cnVNakViSW0zZGVQd083VTNwaHlGRkczV0J2Q1UrdDNwOW1GeElqOHYv?= =?utf-8?Q?BukA=3D?= 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)(82310400026)(7416014)(36860700013)(32650700017)(376014)(1800799024);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 28 Oct 2025 06:03:35.4650 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: cdc8a976-9485-4f29-1f33-08de15e7bb2d 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: DS3PEPF0000C37C.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: CYXPR12MB9319 Hello Tim, On 10/11/2025 11:54 PM, Tim Chen wrote: > @@ -9969,6 +9969,12 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env) > if (env->flags & LBF_ACTIVE_LB) > return 1; > > +#ifdef CONFIG_SCHED_CACHE > + if (sched_cache_enabled() && > + can_migrate_llc_task(env->src_cpu, env->dst_cpu, p) == mig_forbid) > + return 0; > +#endif > + > degrades = migrate_degrades_locality(p, env); > if (!degrades) > hot = task_hot(p, env); Should we care for task_hot() w.r.t. migration cost if a task is being moved to a preferred LLC? Also, should we leave out tasks under core scheduling from the llc aware lb? Even discount them when calculating "mm->nr_running_avg"? > @@ -10227,6 +10233,20 @@ static int detach_tasks(struct lb_env *env) > if (env->imbalance <= 0) > break; > > +#ifdef CONFIG_SCHED_CACHE > + /* > + * Don't detach more tasks if the remaining tasks want > + * to stay. We know the remaining tasks all prefer the > + * current LLC, because after order_tasks_by_llc(), the > + * tasks that prefer the current LLC are at the tail of > + * the list. The inhibition of detachment is to avoid too > + * many tasks being migrated out of the preferred LLC. > + */ > + if (sched_cache_enabled() && detached && p->preferred_llc != -1 && > + llc_id(env->src_cpu) == p->preferred_llc) > + break; In all cases? Should we check can_migrate_llc() wrt to util migrated and then make a call if we should move the preferred LLC tasks or not? Perhaps disallow it the first time if "nr_balance_failed" is 0 but subsequent failed attempts should perhaps explore breaking the preferred llc restriction if there is an imbalance and we are under "mig_unrestricted" conditions. > +#endif > + > continue; > next: > if (p->sched_task_hot) -- Thanks and Regards, Prateek