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Commit c5405a49 authored by Neil Zhang's avatar Neil Zhang Committed by Ingo Molnar
Browse files

sched: Remove redundant update_runtime notifier 



migration_call() will do all the things that update_runtime() does.
So let's remove it.

Furthermore, there is potential risk that the current code will catch
BUG_ON at line 689 of rt.c when do cpu hotplug while there are realtime
threads running because of enabling runtime twice while the rt_runtime
may already changed.

Signed-off-by: default avatarNeil Zhang <zhangwm@marvell.com>
Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1365685499-26515-1-git-send-email-zhangwm@marvell.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 41261b6a

kernel/sched/core.c

+0 −3
Original line number Diff line number Diff line
@@ -6285,9 +6285,6 @@ void __init sched_init_smp(void) 
	hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE);

	hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE);



	/* RT runtime code needs to handle some hotplug events */

	hotcpu_notifier(update_runtime, 0);



	init_hrtick();



	/* Move init over to a non-isolated CPU */

kernel/sched/rt.c

+0 −40
Original line number Diff line number Diff line
@@ -699,15 +699,6 @@ static void __disable_runtime(struct rq *rq) 
	}

}



static void disable_runtime(struct rq *rq)

{

	unsigned long flags;



	raw_spin_lock_irqsave(&rq->lock, flags);

	__disable_runtime(rq);

	raw_spin_unlock_irqrestore(&rq->lock, flags);

}



static void __enable_runtime(struct rq *rq)

{

	rt_rq_iter_t iter;
@@ -732,37 +723,6 @@ static void __enable_runtime(struct rq *rq) 
	}

}



static void enable_runtime(struct rq *rq)

{

	unsigned long flags;



	raw_spin_lock_irqsave(&rq->lock, flags);

	__enable_runtime(rq);

	raw_spin_unlock_irqrestore(&rq->lock, flags);

}



int update_runtime(struct notifier_block *nfb, unsigned long action, void *hcpu)

{

	int cpu = (int)(long)hcpu;



	switch (action) {

	case CPU_DOWN_PREPARE:

	case CPU_DOWN_PREPARE_FROZEN:

		disable_runtime(cpu_rq(cpu));

		return NOTIFY_OK;



	case CPU_DOWN_FAILED:

	case CPU_DOWN_FAILED_FROZEN:

	case CPU_ONLINE:

	case CPU_ONLINE_FROZEN:

		enable_runtime(cpu_rq(cpu));

		return NOTIFY_OK;



	default:

		return NOTIFY_DONE;

	}

}



static int balance_runtime(struct rt_rq *rt_rq)

{

	int more = 0;

kernel/sched/sched.h

+0 −1
Original line number Diff line number Diff line
@@ -1041,7 +1041,6 @@ static inline void idle_balance(int cpu, struct rq *rq) 
extern void sysrq_sched_debug_show(void);

extern void sched_init_granularity(void);

extern void update_max_interval(void);

extern int update_runtime(struct notifier_block *nfb, unsigned long action, void *hcpu);

extern void init_sched_rt_class(void);

extern void init_sched_fair_class(void);