diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2008-03-26 18:35:10 +0000 |
|---|---|---|
| committer | Chris Wright <chrisw@sous-sol.org> | 2008-04-18 18:53:20 -0700 |
| commit | e8f696e9daa00e52b9c7ad1822fcda354d0baabd (patch) | |
| tree | 3145dbc9d024491af257121fc5b810b268e1f788 /include | |
| parent | 3d6fec02c6a996f658bdaa6a1da381f9b72da032 (diff) | |
NOHZ: reevaluate idle sleep length after add_timer_on()
upstream commit: 06d8308c61e54346585b2691c13ee3f90cb6fb2f
add_timer_on() can add a timer on a CPU which is currently in a long
idle sleep, but the timer wheel is not reevaluated by the nohz code on
that CPU. So a timer can be delayed for quite a long time. This
triggered a false positive in the clocksource watchdog code.
To avoid this we need to wake up the idle CPU and enforce the
reevaluation of the timer wheel for the next timer event.
Add a function, which checks a given CPU for idle state, marks the
idle task with NEED_RESCHED and sends a reschedule IPI to notify the
other CPU of the change in the timer wheel.
Call this function from add_timer_on().
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
--
include/linux/sched.h | 6 ++++++
kernel/sched.c | 43 +++++++++++++++++++++++++++++++++++++++++++
kernel/timer.c | 10 +++++++++-
3 files changed, 58 insertions(+), 1 deletion(-)
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/sched.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index cc14656f8682..59e00dff7c10 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1449,6 +1449,12 @@ static inline void idle_task_exit(void) {} extern void sched_idle_next(void); +#if defined(CONFIG_NO_HZ) && defined(CONFIG_SMP) +extern void wake_up_idle_cpu(int cpu); +#else +static inline void wake_up_idle_cpu(int cpu) { } +#endif + #ifdef CONFIG_SCHED_DEBUG extern unsigned int sysctl_sched_latency; extern unsigned int sysctl_sched_min_granularity; |