Messages in this thread | | | Date | Tue, 29 Jul 2014 18:19:28 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCH v2 2/5] sched: Teach scheduler to understand ONRQ_MIGRATING state |
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On 07/29, Kirill Tkhai wrote: > > How about this? Everything is inside task_rq_lock() now. The patch > became much less.
And with this change task_migrating() is not possible under task_rq_lock() or __task_rq_lock(). This means that 1/5 can be simplified too.
__migrate_swap_task() is probably the notable exception...
Off-topic, but it takes 2 ->pi_lock's. This means it can deadlock with try_to_wake_up_local() (if a 3rd process does ttwu() and waits for ->on_cpu == 0). But I guess __migrate_swap_task() should not play with PF_WQ_WORKER threads.
Oleg.
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