diff options
| author | Linux Build Service Account <lnxbuild@localhost> | 2017-04-24 06:48:04 -0700 |
|---|---|---|
| committer | Gerrit - the friendly Code Review server <code-review@localhost> | 2017-04-24 06:47:54 -0700 |
| commit | 048c70075fecb8f92d923fc5595efa00f2a00082 (patch) | |
| tree | 411ca7250cf154e90ae499613b56151be91fa637 | |
| parent | f9849a4c579ba09648b94c5212e2af87e015b263 (diff) | |
| parent | 883e3ea07e3b725c90e57bbf1200856d07b389ff (diff) | |
Merge "sched: Add a check for cpu unbound deferrable timers"
| -rw-r--r-- | include/linux/timer.h | 3 | ||||
| -rw-r--r-- | kernel/time/tick-sched.c | 6 | ||||
| -rw-r--r-- | kernel/time/timer.c | 34 |
3 files changed, 40 insertions, 3 deletions
diff --git a/include/linux/timer.h b/include/linux/timer.h index b1617e8932b2..1239c6ef949e 100644 --- a/include/linux/timer.h +++ b/include/linux/timer.h @@ -173,6 +173,9 @@ extern int mod_timer_pending(struct timer_list *timer, unsigned long expires); extern int mod_timer_pinned(struct timer_list *timer, unsigned long expires); extern void set_timer_slack(struct timer_list *time, int slack_hz); +#ifdef CONFIG_SMP +extern bool check_pending_deferrable_timers(int cpu); +#endif #define TIMER_NOT_PINNED 0 #define TIMER_PINNED 1 diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 651ff1a3a306..ec2102104cb8 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -19,6 +19,7 @@ #include <linux/percpu.h> #include <linux/profile.h> #include <linux/sched.h> +#include <linux/timer.h> #include <linux/module.h> #include <linux/irq_work.h> #include <linux/posix-timers.h> @@ -809,6 +810,11 @@ static void __tick_nohz_idle_enter(struct tick_sched *ts) now = tick_nohz_start_idle(ts); +#ifdef CONFIG_SMP + if (check_pending_deferrable_timers(cpu)) + raise_softirq_irqoff(TIMER_SOFTIRQ); +#endif + if (can_stop_idle_tick(cpu, ts)) { int was_stopped = ts->tick_stopped; diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 2bde2c2b1cb3..8315d4d72cc3 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -102,6 +102,7 @@ static DEFINE_PER_CPU(struct tvec_base, tvec_bases); unsigned int sysctl_timer_migration = 1; struct tvec_base tvec_base_deferrable; +static atomic_t deferrable_pending; void timers_update_migration(bool update_nohz) { @@ -150,9 +151,12 @@ static inline struct tvec_base *get_target_base(struct tvec_base *base, static inline void __run_deferrable_timers(void) { - if (smp_processor_id() == tick_do_timer_cpu && - time_after_eq(jiffies, tvec_base_deferrable.timer_jiffies)) - __run_timers(&tvec_base_deferrable); + if (time_after_eq(jiffies, tvec_base_deferrable.timer_jiffies)) { + if ((atomic_cmpxchg(&deferrable_pending, 1, 0) && + tick_do_timer_cpu == TICK_DO_TIMER_NONE) || + tick_do_timer_cpu == smp_processor_id()) + __run_timers(&tvec_base_deferrable); + } } static inline void init_timer_deferrable_global(void) @@ -1428,6 +1432,30 @@ static u64 cmp_next_hrtimer_event(u64 basem, u64 expires) return DIV_ROUND_UP_ULL(nextevt, TICK_NSEC) * TICK_NSEC; } +#ifdef CONFIG_SMP +/* + * check_pending_deferrable_timers - Check for unbound deferrable timer expiry. + * @cpu - Current CPU + * + * The function checks whether any global deferrable pending timers + * are exipired or not. This function does not check cpu bounded + * diferrable pending timers expiry. + * + * The function returns true when a cpu unbounded deferrable timer is expired. + */ +bool check_pending_deferrable_timers(int cpu) +{ + if (cpu == tick_do_timer_cpu || + tick_do_timer_cpu == TICK_DO_TIMER_NONE) { + if (time_after_eq(jiffies, tvec_base_deferrable.timer_jiffies) + && !atomic_cmpxchg(&deferrable_pending, 0, 1)) { + return true; + } + } + return false; +} +#endif + /** * get_next_timer_interrupt - return the time (clock mono) of the next timer * @basej: base time jiffies |