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timer: Further simplify the SMP and HOTPLUG logic 

Remove one CONFIG_HOTPLUG_CPU #ifdef in trade for introducing one
CONFIG_SMP #ifdef.

The CONFIG_SMP ifdef avoids declaring the per-CPU __tvec_bases storage
on UP systems since they already have boot_tvec_bases.

Also (re)add a runtime check on the base alignment -- for the paranoid
amongst us :-)

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/fdd2d35e169bdc554ffa3fe77f77716298c75ada.1427814611.git.viresh.kumar@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2015-03-31 20:49:02 +05:30 committed by Ingo Molnar
parent 8def906044
commit 3650b57fdf
1 changed files with 15 additions and 8 deletions
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23
kernel/time/timer.c
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@ -101,7 +101,6 @@ struct tvec_base {
*/ */
struct tvec_base boot_tvec_bases; struct tvec_base boot_tvec_bases;
EXPORT_SYMBOL(boot_tvec_bases); EXPORT_SYMBOL(boot_tvec_bases);
static DEFINE_PER_CPU(struct tvec_base, __tvec_bases);
static DEFINE_PER_CPU(struct tvec_base *, tvec_bases) = &boot_tvec_bases; static DEFINE_PER_CPU(struct tvec_base *, tvec_bases) = &boot_tvec_bases;
@ -1038,6 +1037,8 @@ int try_to_del_timer_sync(struct timer_list *timer)
EXPORT_SYMBOL(try_to_del_timer_sync); EXPORT_SYMBOL(try_to_del_timer_sync);
#ifdef CONFIG_SMP #ifdef CONFIG_SMP
static DEFINE_PER_CPU(struct tvec_base, __tvec_bases);
/** /**
* del_timer_sync - deactivate a timer and wait for the handler to finish. * del_timer_sync - deactivate a timer and wait for the handler to finish.
* @timer: the timer to be deactivated * @timer: the timer to be deactivated
@ -1591,12 +1592,10 @@ static void migrate_timers(int cpu)
spin_unlock_irq(&new_base->lock); spin_unlock_irq(&new_base->lock);
put_cpu_var(tvec_bases); put_cpu_var(tvec_bases);
} }
#endif /* CONFIG_HOTPLUG_CPU */
static int timer_cpu_notify(struct notifier_block *self, static int timer_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu) unsigned long action, void *hcpu)
{ {
#ifdef CONFIG_HOTPLUG_CPU
switch (action) { switch (action) {
case CPU_DEAD: case CPU_DEAD:
case CPU_DEAD_FROZEN: case CPU_DEAD_FROZEN:
@ -1605,18 +1604,24 @@ static int timer_cpu_notify(struct notifier_block *self,
default: default:
break; break;
} }
#endif
return NOTIFY_OK; return NOTIFY_OK;
} }
static struct notifier_block timers_nb = { static inline void timer_register_cpu_notifier(void)
.notifier_call = timer_cpu_notify, {
}; cpu_notifier(timer_cpu_notify, 0);
}
#else
static inline void timer_register_cpu_notifier(void) { }
#endif /* CONFIG_HOTPLUG_CPU */
static void __init init_timer_cpu(struct tvec_base *base, int cpu) static void __init init_timer_cpu(struct tvec_base *base, int cpu)
{ {
int j; int j;
BUG_ON(base != tbase_get_base(base));
base->cpu = cpu; base->cpu = cpu;
per_cpu(tvec_bases, cpu) = base; per_cpu(tvec_bases, cpu) = base;
spin_lock_init(&base->lock); spin_lock_init(&base->lock);
@ -1643,8 +1648,10 @@ static void __init init_timer_cpus(void)
for_each_possible_cpu(cpu) { for_each_possible_cpu(cpu) {
if (cpu == local_cpu) if (cpu == local_cpu)
base = &boot_tvec_bases; base = &boot_tvec_bases;
#ifdef CONFIG_SMP
else else
base = per_cpu_ptr(&__tvec_bases, cpu); base = per_cpu_ptr(&__tvec_bases, cpu);
#endif
init_timer_cpu(base, cpu); init_timer_cpu(base, cpu);
} }
@ -1657,7 +1664,7 @@ void __init init_timers(void)
init_timer_cpus(); init_timer_cpus();
init_timer_stats(); init_timer_stats();
register_cpu_notifier(&timers_nb); timer_register_cpu_notifier();
open_softirq(TIMER_SOFTIRQ, run_timer_softirq); open_softirq(TIMER_SOFTIRQ, run_timer_softirq);
} }