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Commit 31eff243 authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Thomas Gleixner
Browse files

sched/nohz: Convert to hotplug state machine 



Install the callbacks via the state machine.

Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: rt@linuxtronix.de
Link: http://lkml.kernel.org/r/20161117183541.8588-14-bigeasy@linutronix.de


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 38b48292

kernel/time/tick-sched.c

+14 −19
Original line number Diff line number Diff line
@@ -390,24 +390,16 @@ static int __init tick_nohz_full_setup(char *str) 
}

__setup("nohz_full=", tick_nohz_full_setup);



static int tick_nohz_cpu_down_callback(struct notifier_block *nfb,

				       unsigned long action,

				       void *hcpu)

static int tick_nohz_cpu_down(unsigned int cpu)

{

	unsigned int cpu = (unsigned long)hcpu;



	switch (action & ~CPU_TASKS_FROZEN) {

	case CPU_DOWN_PREPARE:

	/*

	 * The boot CPU handles housekeeping duty (unbound timers,

	 * workqueues, timekeeping, ...) on behalf of full dynticks

	 * CPUs. It must remain online when nohz full is enabled.

	 */

	if (tick_nohz_full_running && tick_do_timer_cpu == cpu)

			return NOTIFY_BAD;

		break;

	}

	return NOTIFY_OK;

		return -EBUSY;

	return 0;

}



static int tick_nohz_init_all(void)
@@ -428,7 +420,7 @@ static int tick_nohz_init_all(void) 


void __init tick_nohz_init(void)

{

	int cpu;

	int cpu, ret;



	if (!tick_nohz_full_running) {

		if (tick_nohz_init_all() < 0)
@@ -469,7 +461,10 @@ void __init tick_nohz_init(void) 
	for_each_cpu(cpu, tick_nohz_full_mask)

		context_tracking_cpu_set(cpu);



	cpu_notifier(tick_nohz_cpu_down_callback, 0);

	ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,

					"kernel/nohz:predown", NULL,

					tick_nohz_cpu_down);

	WARN_ON(ret < 0);

	pr_info("NO_HZ: Full dynticks CPUs: %*pbl.\n",

		cpumask_pr_args(tick_nohz_full_mask));