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nohz: fix wrong event handler after online an offlined cpu

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On the tickless system(CONFIG_NO_HZ=y and CONFIG_HIGH_RES_TIMERS=n), after
I made an offlined cpu online, I found this cpu's event handler was
tick_handle_periodic, not tick_nohz_handler.

After debuging, I found this bug was caused by the wrong tick mode.  the
tick mode is not changed to NOHZ_MODE_INACTIVE when the cpu is offline.

This patch fixes this bug.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Miao Xie 2008-08-20 16:37:38 -07:00 committed by Ingo Molnar
parent 6a55617ed5
commit 3c4fbe5e01
2 changed files with 9 additions and 2 deletions
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5
include/linux/tick.h
View file

@ -74,10 +74,13 @@ extern struct tick_device *tick_get_device(int cpu);
extern int tick_init_highres(void);
extern int tick_program_event(ktime_t expires, int force);
extern void tick_setup_sched_timer(void);
# endif
# if defined CONFIG_NO_HZ || defined CONFIG_HIGH_RES_TIMERS
extern void tick_cancel_sched_timer(int cpu);
# else
static inline void tick_cancel_sched_timer(int cpu) { }
# endif /* HIGHRES */
# endif
# ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
extern struct tick_device *tick_get_broadcast_device(void);

6
kernel/time/tick-sched.c
View file

@ -643,17 +643,21 @@ void tick_setup_sched_timer(void)
ts->nohz_mode = NOHZ_MODE_HIGHRES;
#endif
}
#endif /* HIGH_RES_TIMERS */
#if defined CONFIG_NO_HZ || defined CONFIG_HIGH_RES_TIMERS
void tick_cancel_sched_timer(int cpu)
{
struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
# ifdef CONFIG_HIGH_RES_TIMERS
if (ts->sched_timer.base)
hrtimer_cancel(&ts->sched_timer);
# endif
ts->nohz_mode = NOHZ_MODE_INACTIVE;
}
#endif /* HIGH_RES_TIMERS */
#endif
/**
* Async notification about clocksource changes