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X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 Nov 2024 03:02:45.0633 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: b48366b8-3916-41b6-9625-08dcfe0f7cf3 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=[SATLEXMB04.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: SA1PR12MB8965 Hello Mike, On 11/5/2024 12:16 PM, Mike Galbraith wrote: > On Tue, 2024-11-05 at 09:52 +0530, K Prateek Nayak wrote: >> Hello Mike, > > Greetings, > >> Would checking "p->nr_cpus_allowed > 1" be enough instead of doing a >> "cpumask_weight(p->cpus_ptr) > 1"? > > Yeah (thwap). > >> I was thinking, since the task is indeed delayed, there has to be more >> than one task on the runqueue right since a single task by itself cannot >> be ineligible and be marked for delayed dequeue? > > But they migrate via LB, and idle balance unlocks the rq. > trace_printk() just verified that they do still both land with > sched_delayed intact and with nr_running = 1. Ah! You are right! thank you for clarifying. Since the sharp stick seems to be working, let me go thrown a bunch of workloads at it and report back :) -- Thanks and Regards, Prateek > >> The only time we >> encounter a delayed task with "rq->nr_running == 1" is if the other >> tasks have been fully dequeued and pick_next_task() is in the process of >> picking off all the delayed task, but since that is done with the rq >> lock held in schedule(), it is even possible for the >> "rq->nr_running > 1" to be false here? > > I don't see how, the rq being looked at is locked. > > -Mike