Messages in this thread | | | Date | Tue, 28 Oct 2014 16:22:55 -0400 | From | Tejun Heo <> | Subject | Re: blk-mq vs cpu hotplug performance (due to percpu_ref_put performance) |
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On Tue, Oct 28, 2014 at 09:20:55PM +0100, Christian Borntraeger wrote: > I have not verified this, but I guess what happens is: > hotplug > -> notify > -> blk_mq_queue_reinit_notify > -> blk_mq_queue_reinit > -> blk_mq_freeze_queue > -> percpu_ref_kill > -> percpu_ref_kill_and_confirm > -> __percpu_ref_switch_to_atomic > -> call_rcu_sched
But call_rcu_sched() wouldn't show up as latency. It's an async call unlike synchronize_*().
Thanks.
-- tejun
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