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> - Use check_cfs_rq_runtime()'s return value in pick_task_fair() to > decide if throttle task work is needed instead of checking > throttled_hierarchy(), suggested by Peter; > - Simplify throttle_count check in tg_throtthe_down() and > tg_unthrottle_up(), suggested by Peter; > - Add enqueue_throttled_task() to speed up enqueuing a throttled task to > a throttled cfs_rq, suggested by Peter; > - Address the missing of detach_task_cfs_rq() for throttled tasks that > get migrated to a new rq, pointed out by Chengming; > - Remove cond_resched_tasks_rcu_qs() in throttle_cfs_rq_work() as > cond_resched*() is going away, pointed out by Peter. > I hope I didn't miss any comments and suggestions for v1 and if I do, > please kindly let me know, thanks! > > Base: tip/sched/core commit dabe1be4e84c("sched/smp: Use the SMP version > of double_rq_clock_clear_update()") Sorry for the delay! I gave this a spin with my nested hierarchy stress test with sched-messaging as well as with Jan's reproducer from [1] and I didn't see anything unexpected. A 2 vCPU VM running vanilla tip:sched/core (PREEMPT_RT) hangs within a few seconds when the two tasks from Jan's reproducer are pinned to the same CPU as the bandwidth timer. I haven't seen any hangs / rcu-stalls with this series applied on top of tip:sched/core. Feel free to include: Tested-by: K Prateek Nayak [1] https://lore.kernel.org/all/7483d3ae-5846-4067-b9f7-390a614ba408@siemens.com/ -- Thanks and Regards, Prateek