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sched/nohz: Convert to hotplug state machine 

Install the callbacks via the state machine.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: rt@linuxtronix.de
Link: http://lkml.kernel.org/r/20161117183541.8588-14-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Sebastian Andrzej Siewior 2016-11-17 19:35:34 +01:00 committed by Thomas Gleixner
parent 38b482929e
commit 31eff2434d
1 changed files with 14 additions and 19 deletions
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33
kernel/time/tick-sched.c
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@ -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;
/*
* 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 -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));