diff options
| -rw-r--r-- | arch/x86/xen/smp_pv.c | 1 | ||||
| -rw-r--r-- | include/linux/tick.h | 12 | ||||
| -rw-r--r-- | kernel/sched/idle.c | 1 | ||||
| -rw-r--r-- | kernel/time/tick-sched.c | 46 |
4 files changed, 39 insertions, 21 deletions
diff --git a/arch/x86/xen/smp_pv.c b/arch/x86/xen/smp_pv.c index c0c756c76afe..2e20ae2fa2d6 100644 --- a/arch/x86/xen/smp_pv.c +++ b/arch/x86/xen/smp_pv.c @@ -425,6 +425,7 @@ static void xen_pv_play_dead(void) /* used only with HOTPLUG_CPU */ * data back is to call: */ tick_nohz_idle_enter(); + tick_nohz_idle_stop_tick_protected(); cpuhp_online_idle(CPUHP_AP_ONLINE_IDLE); } diff --git a/include/linux/tick.h b/include/linux/tick.h index 7f8c9a127f5a..1d253df9ea3c 100644 --- a/include/linux/tick.h +++ b/include/linux/tick.h @@ -115,6 +115,7 @@ enum tick_dep_bits { extern bool tick_nohz_enabled; extern bool tick_nohz_tick_stopped(void); extern bool tick_nohz_tick_stopped_cpu(int cpu); +extern void tick_nohz_idle_stop_tick(void); extern void tick_nohz_idle_enter(void); extern void tick_nohz_idle_exit(void); extern void tick_nohz_irq_exit(void); @@ -123,10 +124,19 @@ extern unsigned long tick_nohz_get_idle_calls(void); extern unsigned long tick_nohz_get_idle_calls_cpu(int cpu); extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time); extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time); + +static inline void tick_nohz_idle_stop_tick_protected(void) +{ + local_irq_disable(); + tick_nohz_idle_stop_tick(); + local_irq_enable(); +} + #else /* !CONFIG_NO_HZ_COMMON */ #define tick_nohz_enabled (0) static inline int tick_nohz_tick_stopped(void) { return 0; } static inline int tick_nohz_tick_stopped_cpu(int cpu) { return 0; } +static inline void tick_nohz_idle_stop_tick(void) { } static inline void tick_nohz_idle_enter(void) { } static inline void tick_nohz_idle_exit(void) { } @@ -136,6 +146,8 @@ static inline ktime_t tick_nohz_get_sleep_length(void) } static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; } static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; } + +static inline void tick_nohz_idle_stop_tick_protected(void) { } #endif /* !CONFIG_NO_HZ_COMMON */ #ifdef CONFIG_NO_HZ_FULL diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index 2975f195e1c4..c0bc111878e6 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -216,6 +216,7 @@ static void do_idle(void) __current_set_polling(); tick_nohz_idle_enter(); + tick_nohz_idle_stop_tick_protected(); while (!need_resched()) { check_pgt_cache(); diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 5d4a0342f934..678349aec483 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -528,14 +528,11 @@ static void tick_nohz_stop_idle(struct tick_sched *ts, ktime_t now) sched_clock_idle_wakeup_event(); } -static ktime_t tick_nohz_start_idle(struct tick_sched *ts) +static void tick_nohz_start_idle(struct tick_sched *ts) { - ktime_t now = ktime_get(); - - ts->idle_entrytime = now; + ts->idle_entrytime = ktime_get(); ts->idle_active = 1; sched_clock_idle_sleep_event(); - return now; } /** @@ -894,19 +891,21 @@ static bool can_stop_idle_tick(int cpu, struct tick_sched *ts) return true; } -static void __tick_nohz_idle_enter(struct tick_sched *ts) +static void __tick_nohz_idle_stop_tick(struct tick_sched *ts) { - ktime_t now, expires; + ktime_t expires; int cpu = smp_processor_id(); - now = tick_nohz_start_idle(ts); - if (can_stop_idle_tick(cpu, ts)) { int was_stopped = ts->tick_stopped; ts->idle_calls++; - expires = tick_nohz_stop_sched_tick(ts, now, cpu); + /* + * The idle entry time should be a sufficient approximation of + * the current time at this point. + */ + expires = tick_nohz_stop_sched_tick(ts, ts->idle_entrytime, cpu); if (expires > 0LL) { ts->idle_sleeps++; ts->idle_expires = expires; @@ -920,16 +919,19 @@ static void __tick_nohz_idle_enter(struct tick_sched *ts) } /** - * tick_nohz_idle_enter - stop the idle tick from the idle task + * tick_nohz_idle_stop_tick - stop the idle tick from the idle task * * When the next event is more than a tick into the future, stop the idle tick - * Called when we start the idle loop. - * - * The arch is responsible of calling: + */ +void tick_nohz_idle_stop_tick(void) +{ + __tick_nohz_idle_stop_tick(this_cpu_ptr(&tick_cpu_sched)); +} + +/** + * tick_nohz_idle_enter - prepare for entering idle on the current CPU * - * - rcu_idle_enter() after its last use of RCU before the CPU is put - * to sleep. - * - rcu_idle_exit() before the first use of RCU after the CPU is woken up. + * Called when we start the idle loop. */ void tick_nohz_idle_enter(void) { @@ -941,7 +943,7 @@ void tick_nohz_idle_enter(void) ts = this_cpu_ptr(&tick_cpu_sched); ts->inidle = 1; - __tick_nohz_idle_enter(ts); + tick_nohz_start_idle(ts); local_irq_enable(); } @@ -958,10 +960,12 @@ void tick_nohz_irq_exit(void) { struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched); - if (ts->inidle) - __tick_nohz_idle_enter(ts); - else + if (ts->inidle) { + tick_nohz_start_idle(ts); + __tick_nohz_idle_stop_tick(ts); + } else { tick_nohz_full_update_tick(ts); + } } /** |