diff options
Diffstat (limited to 'kernel/time/tick-sched.c')
| -rw-r--r-- | kernel/time/tick-sched.c | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 52db9e3c526e..8c3fef1db09c 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -160,6 +160,18 @@ void tick_nohz_stop_sched_tick(void) cpu = smp_processor_id(); ts = &per_cpu(tick_cpu_sched, cpu); + /* + * If this cpu is offline and it is the one which updates + * jiffies, then give up the assignment and let it be taken by + * the cpu which runs the tick timer next. If we don't drop + * this here the jiffies might be stale and do_timer() never + * invoked. + */ + if (unlikely(!cpu_online(cpu))) { + if (cpu == tick_do_timer_cpu) + tick_do_timer_cpu = -1; + } + if (unlikely(ts->nohz_mode == NOHZ_MODE_INACTIVE)) goto end; @@ -546,6 +558,7 @@ void tick_setup_sched_timer(void) { struct tick_sched *ts = &__get_cpu_var(tick_cpu_sched); ktime_t now = ktime_get(); + u64 offset; /* * Emulate tick processing via per-CPU hrtimers: @@ -554,8 +567,12 @@ void tick_setup_sched_timer(void) ts->sched_timer.function = tick_sched_timer; ts->sched_timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ; - /* Get the next period */ + /* Get the next period (per cpu) */ ts->sched_timer.expires = tick_init_jiffy_update(); + offset = ktime_to_ns(tick_period) >> 1; + do_div(offset, NR_CPUS); + offset *= smp_processor_id(); + ts->sched_timer.expires = ktime_add_ns(ts->sched_timer.expires, offset); for (;;) { hrtimer_forward(&ts->sched_timer, now, tick_period); |