2012/5/4 Frederic Weisbecker <fweisbec@xxxxxxxxx>:
> On Thu, May 03, 2012 at 05:55:57PM +0300, Gilad Ben-Yossef wrote:
>> @@ -1317,9 +1322,15 @@ unsigned long get_next_timer_interrupt(unsigned long now)
>> if (cpu_is_offline(smp_processor_id()))
>> return now + NEXT_TIMER_MAX_DELTA;
>> spin_lock(&base->lock);
>> - if (time_before_eq(base->next_timer, base->timer_jiffies))
>> - base->next_timer = __next_timer_interrupt(base);
>> - expires = base->next_timer;
>> + if (time_before_eq(base->next_timer, base->timer_jiffies)) {
>> +
>> + if (__next_timer_interrupt(base, &expires))
>> + base->next_timer = expires;
>> + else
>> + expires = now + NEXT_TIMER_MAX_DELTA;
>
> I believe you can update base->next_timer to now + NEXT_TIMER_MAX_DELTA,
> so on any further idle interrupt exit that call tick_nohz_stop_sched_tick(),
> we won't get again the overhead of __next_timer_interrupt().
Ah forget that, I was confused. If we do that we actually get the useless timer
at now + NEXT_TIMER_MAX_DELTA.
So I think the patch is fine.
Acked-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
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