Messages in this thread | | | Date | Thu, 20 Feb 2020 22:42:51 +0800 | From | chenqiwu <> | Subject | Re: [PATCH] sched/fair: add !se->on_rq check before dequeue entity |
| |
> > Hmm i have been too quick in my reply. I wanted to say: > AFAICT, there is no other way to dequeue a task from a cfs_rq for > which the group entity is not enqueued
But we should notice the potential racy pathes called by deactivate_task(). For example: One path is dequeue a task from its cfs_rq called by schedule(): __schedule deactivate_task dequeue_task dequeue_task_fair
Another path is trying to migrate the same task to a CPU on the preferred node: numa_migrate_preferred task_numa_migrate migrate_swap stop_two_cpus migrate_swap_stop __migrate_swap_task deactivate_task dequeue_task_fair
There could be a racy if the task is dequeued form its cfs_rq in parallel.
| |