From 3650b57fdf208bc0e36cbe7b5e0744bd0e0cf34d Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 31 Mar 2015 20:49:02 +0530 Subject: [PATCH] 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) Acked-by: Viresh Kumar Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/fdd2d35e169bdc554ffa3fe77f77716298c75ada.1427814611.git.viresh.kumar@linaro.org Signed-off-by: Ingo Molnar --- kernel/time/timer.c | 23 +++++++++++++++-------- 1 file changed, 15 insertions(+), 8 deletions(-) diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 1feb9c7035c0..2ece3aa5069c 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -101,7 +101,6 @@ struct tvec_base { */ struct tvec_base 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; @@ -1038,6 +1037,8 @@ int try_to_del_timer_sync(struct timer_list *timer) EXPORT_SYMBOL(try_to_del_timer_sync); #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. * @timer: the timer to be deactivated @@ -1591,12 +1592,10 @@ static void migrate_timers(int cpu) spin_unlock_irq(&new_base->lock); put_cpu_var(tvec_bases); } -#endif /* CONFIG_HOTPLUG_CPU */ static int timer_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) { -#ifdef CONFIG_HOTPLUG_CPU switch (action) { case CPU_DEAD: case CPU_DEAD_FROZEN: @@ -1605,18 +1604,24 @@ static int timer_cpu_notify(struct notifier_block *self, default: break; } -#endif + return NOTIFY_OK; } -static struct notifier_block timers_nb = { - .notifier_call = timer_cpu_notify, -}; +static inline void timer_register_cpu_notifier(void) +{ + 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) { int j; + BUG_ON(base != tbase_get_base(base)); + base->cpu = cpu; per_cpu(tvec_bases, cpu) = base; spin_lock_init(&base->lock); @@ -1643,8 +1648,10 @@ static void __init init_timer_cpus(void) for_each_possible_cpu(cpu) { if (cpu == local_cpu) base = &boot_tvec_bases; +#ifdef CONFIG_SMP else base = per_cpu_ptr(&__tvec_bases, cpu); +#endif init_timer_cpu(base, cpu); } @@ -1657,7 +1664,7 @@ void __init init_timers(void) init_timer_cpus(); init_timer_stats(); - register_cpu_notifier(&timers_nb); + timer_register_cpu_notifier(); open_softirq(TIMER_SOFTIRQ, run_timer_softirq); } -- 2.20.1