diff options
Diffstat (limited to 'kernel/time/hrtimer.c')
| -rw-r--r-- | kernel/time/hrtimer.c | 36 |
1 files changed, 22 insertions, 14 deletions
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index 5c7ae4b641c4..457a373e2181 100644 --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -183,7 +183,7 @@ struct hrtimer_cpu_base *get_target_base(struct hrtimer_cpu_base *base, int pinned) { if (pinned || !base->migration_enabled) - return this_cpu_ptr(&hrtimer_bases); + return base; return &per_cpu(hrtimer_bases, get_nohz_timer_target()); } #else @@ -191,23 +191,32 @@ static inline struct hrtimer_cpu_base *get_target_base(struct hrtimer_cpu_base *base, int pinned) { - return this_cpu_ptr(&hrtimer_bases); + return base; } #endif /* - * Switch the timer base to the current CPU when possible. + * We switch the timer base to a power-optimized selected CPU target, + * if: + * - NO_HZ_COMMON is enabled + * - timer migration is enabled + * - the timer callback is not running + * - the timer is not the first expiring timer on the new target + * + * If one of the above requirements is not fulfilled we move the timer + * to the current CPU or leave it on the previously assigned CPU if + * the timer callback is currently running. */ static inline struct hrtimer_clock_base * switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base, int pinned) { - struct hrtimer_cpu_base *new_cpu_base, *this_base; + struct hrtimer_cpu_base *new_cpu_base, *this_cpu_base; struct hrtimer_clock_base *new_base; int basenum = base->index; - this_base = this_cpu_ptr(&hrtimer_bases); - new_cpu_base = get_target_base(this_base, pinned); + this_cpu_base = this_cpu_ptr(&hrtimer_bases); + new_cpu_base = get_target_base(this_cpu_base, pinned); again: new_base = &new_cpu_base->clock_base[basenum]; @@ -229,19 +238,19 @@ again: raw_spin_unlock(&base->cpu_base->lock); raw_spin_lock(&new_base->cpu_base->lock); - if (new_cpu_base != this_base && + if (new_cpu_base != this_cpu_base && hrtimer_check_target(timer, new_base)) { raw_spin_unlock(&new_base->cpu_base->lock); raw_spin_lock(&base->cpu_base->lock); - new_cpu_base = this_base; + new_cpu_base = this_cpu_base; timer->base = base; goto again; } timer->base = new_base; } else { - if (new_cpu_base != this_base && + if (new_cpu_base != this_cpu_base && hrtimer_check_target(timer, new_base)) { - new_cpu_base = this_base; + new_cpu_base = this_cpu_base; goto again; } } @@ -679,14 +688,14 @@ static void retrigger_next_event(void *arg) /* * Switch to high resolution mode */ -static int hrtimer_switch_to_hres(void) +static void hrtimer_switch_to_hres(void) { struct hrtimer_cpu_base *base = this_cpu_ptr(&hrtimer_bases); if (tick_init_highres()) { printk(KERN_WARNING "Could not switch to high resolution " "mode on CPU %d\n", base->cpu); - return 0; + return; } base->hres_active = 1; hrtimer_resolution = HIGH_RES_NSEC; @@ -694,7 +703,6 @@ static int hrtimer_switch_to_hres(void) tick_setup_sched_timer(); /* "Retrigger" the interrupt to get things going */ retrigger_next_event(NULL); - return 1; } static void clock_was_set_work(struct work_struct *work) @@ -718,7 +726,7 @@ void clock_was_set_delayed(void) static inline int __hrtimer_hres_active(struct hrtimer_cpu_base *b) { return 0; } static inline int hrtimer_hres_active(void) { return 0; } static inline int hrtimer_is_hres_enabled(void) { return 0; } -static inline int hrtimer_switch_to_hres(void) { return 0; } +static inline void hrtimer_switch_to_hres(void) { } static inline void hrtimer_force_reprogram(struct hrtimer_cpu_base *base, int skip_equal) { } static inline int hrtimer_reprogram(struct hrtimer *timer, |