Messages in this thread | | | Subject | Re: [PATCH 4/5] sched/fair: Remove double_lock_balance() from active_load_balance_cpu_stop() | From | Tim Chen <> | Date | Thu, 24 Jul 2014 17:04:11 -0700 |
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On Tue, 2014-07-22 at 15:30 +0400, Kirill Tkhai wrote: > Bad situation: > > double_lock_balance() drops busiest_rq lock. The busiest_rq is *busiest*, > and a lot of tasks and context switches there. We are dropping the lock > and waiting for it again. > > Let's just detach the task and once finally unlock it! > > Warning: this admits unlocked using of can_migrate_task(), throttled_lb_pair(), > and task_hot(). I added comments about that. >
Wonder if we should also consider removing double_lock_balance usage from rt.c and deadline.c? Then those two schedulers will also not lock both the source and destination queues at the same time for load balancing.
Tim
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