| From: Ingo Molnar <mingo@elte.hu> |
| Date: Fri, 3 Jul 2009 08:30:20 -0500 |
| Subject: timers: preempt-rt support |
| |
| Signed-off-by: Ingo Molnar <mingo@elte.hu> |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| --- |
| kernel/timer.c | 15 ++++++++++++--- |
| 1 file changed, 12 insertions(+), 3 deletions(-) |
| |
| --- a/kernel/timer.c |
| +++ b/kernel/timer.c |
| @@ -1352,7 +1352,17 @@ unsigned long get_next_timer_interrupt(u |
| if (cpu_is_offline(smp_processor_id())) |
| return expires; |
| |
| +#ifdef CONFIG_PREEMPT_RT_FULL |
| + /* |
| + * On PREEMPT_RT we cannot sleep here. If the trylock does not |
| + * succeed then we return the worst-case 'expires in 1 tick' |
| + * value: |
| + */ |
| + if (!spin_trylock(&base->lock)) |
| + return now + 1; |
| +#else |
| spin_lock(&base->lock); |
| +#endif |
| if (base->active_timers) { |
| if (time_before_eq(base->next_timer, base->timer_jiffies)) |
| base->next_timer = __next_timer_interrupt(base); |
| @@ -1362,7 +1372,6 @@ unsigned long get_next_timer_interrupt(u |
| |
| if (time_before_eq(expires, now)) |
| return now; |
| - |
| return cmp_next_hrtimer_event(now, expires); |
| } |
| #endif |
| @@ -1752,7 +1761,7 @@ static void __cpuinit migrate_timers(int |
| |
| BUG_ON(cpu_online(cpu)); |
| old_base = per_cpu(tvec_bases, cpu); |
| - new_base = get_cpu_var(tvec_bases); |
| + new_base = get_local_var(tvec_bases); |
| /* |
| * The caller is globally serialized and nobody else |
| * takes two locks at once, deadlock is not possible. |
| @@ -1773,7 +1782,7 @@ static void __cpuinit migrate_timers(int |
| |
| spin_unlock(&old_base->lock); |
| spin_unlock_irq(&new_base->lock); |
| - put_cpu_var(tvec_bases); |
| + put_local_var(tvec_bases); |
| } |
| #endif /* CONFIG_HOTPLUG_CPU */ |
| |