diff options
| -rw-r--r-- | kernel/time/tick-broadcast.c | 13 | ||||
| -rw-r--r-- | kernel/time/tick-internal.h | 2 | ||||
| -rw-r--r-- | kernel/time/tick-sched.c | 31 |
3 files changed, 38 insertions, 8 deletions
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index cb01cd8..f98a1b7 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -384,6 +384,19 @@ int tick_resume_broadcast_oneshot(struct clock_event_device *bc) } /* + * Called from irq_enter() when idle was interrupted to reenable the + * per cpu device. + */ +void tick_check_oneshot_broadcast(int cpu) +{ + if (cpu_isset(cpu, tick_broadcast_oneshot_mask)) { + struct tick_device *td = &per_cpu(tick_cpu_device, cpu); + + clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_ONESHOT); + } +} + +/* * Handle oneshot mode broadcasting */ static void tick_handle_oneshot_broadcast(struct clock_event_device *dev) diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h index 4692487..b1c05bf 100644 --- a/kernel/time/tick-internal.h +++ b/kernel/time/tick-internal.h @@ -36,6 +36,7 @@ extern void tick_broadcast_switch_to_oneshot(void); extern void tick_shutdown_broadcast_oneshot(unsigned int *cpup); extern int tick_resume_broadcast_oneshot(struct clock_event_device *bc); extern int tick_broadcast_oneshot_active(void); +extern void tick_check_oneshot_broadcast(int cpu); # else /* BROADCAST */ static inline void tick_broadcast_setup_oneshot(struct clock_event_device *bc) { @@ -45,6 +46,7 @@ static inline void tick_broadcast_oneshot_control(unsigned long reason) { } static inline void tick_broadcast_switch_to_oneshot(void) { } static inline void tick_shutdown_broadcast_oneshot(unsigned int *cpup) { } static inline int tick_broadcast_oneshot_active(void) { return 0; } +static inline void tick_check_oneshot_broadcast(int cpu) { } # endif /* !BROADCAST */ #else /* !ONESHOT */ diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 7aedf43..0581c11 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -508,10 +508,6 @@ static void tick_nohz_handler(struct clock_event_device *dev) update_process_times(user_mode(regs)); profile_tick(CPU_PROFILING); - /* Do not restart, when we are in the idle loop */ - if (ts->tick_stopped) - return; - while (tick_nohz_reprogram(ts, now)) { now = ktime_get(); tick_do_update_jiffies64(now); @@ -557,6 +553,27 @@ static void tick_nohz_switch_to_nohz(void) smp_processor_id()); } +/* + * When NOHZ is enabled and the tick is stopped, we need to kick the + * tick timer from irq_enter() so that the jiffies update is kept + * alive during long running softirqs. That's ugly as hell, but + * correctness is key even if we need to fix the offending softirq in + * the first place. + * + * Note, this is different to tick_nohz_restart. We just kick the + * timer and do not touch the other magic bits which need to be done + * when idle is left. + */ +static void tick_nohz_kick_tick(int cpu) +{ + struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu); + + if (!ts->tick_stopped) + return; + + tick_nohz_restart(ts, ktime_get()); +} + #else static inline void tick_nohz_switch_to_nohz(void) { } @@ -568,9 +585,11 @@ static inline void tick_nohz_switch_to_nohz(void) { } */ void tick_check_idle(int cpu) { + tick_check_oneshot_broadcast(cpu); #ifdef CONFIG_NO_HZ tick_nohz_stop_idle(cpu); tick_nohz_update_jiffies(); + tick_nohz_kick_tick(cpu); #endif } @@ -627,10 +646,6 @@ static enum hrtimer_restart tick_sched_timer(struct hrtimer *timer) profile_tick(CPU_PROFILING); } - /* Do not restart, when we are in the idle loop */ - if (ts->tick_stopped) - return HRTIMER_NORESTART; - hrtimer_forward(timer, now, tick_period); return HRTIMER_RESTART; |
