Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit fd064b9b authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Linus Torvalds
Browse files

[PATCH] Extend next_timer_interrupt() to use a reference jiffie 



For CONFIG_NO_HZ we need to calculate the next timer wheel event based on a
given jiffie value.  Extend the existing code to allow the extra 'now'
argument.  Provide a compability function for the existing implementations to
call the function with now == jiffies.  (This also solves the racyness of the
original code vs.  jiffies changing during the iteration.)

No functional changes to existing users of this infrastructure.

[ remove WARN_ON() that triggered on s390, by Carsten Otte <cotte@de.ibm.com> ]
[ made new helper static, Adrian Bunk <bunk@stusta.de> ]
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 1cfd6849

include/linux/timer.h

+10 −0
Original line number Diff line number Diff line
@@ -61,7 +61,17 @@ extern int del_timer(struct timer_list * timer); 
extern int __mod_timer(struct timer_list *timer, unsigned long expires);

extern int mod_timer(struct timer_list *timer, unsigned long expires);



/*

 * Return when the next timer-wheel timeout occurs (in absolute jiffies),

 * locks the timer base:

 */

extern unsigned long next_timer_interrupt(void);

/*

 * Return when the next timer-wheel timeout occurs (in absolute jiffies),

 * locks the timer base and does the comparison against the given

 * jiffie.

 */

extern unsigned long get_next_timer_interrupt(unsigned long now);



/**

 * add_timer - start a timer

kernel/hrtimer.c

+1 −1
Original line number Diff line number Diff line
@@ -533,7 +533,7 @@ ktime_t hrtimer_get_remaining(const struct hrtimer *timer) 
}

EXPORT_SYMBOL_GPL(hrtimer_get_remaining);



#ifdef CONFIG_NO_IDLE_HZ

#if defined(CONFIG_NO_IDLE_HZ) || defined(CONFIG_NO_HZ)

/**

 * hrtimer_get_next_event - get the time until next expiry event

 *

kernel/timer.c

+11 −3
Original line number Diff line number Diff line
@@ -591,7 +591,7 @@ static inline void __run_timers(tvec_base_t *base) 
	spin_unlock_irq(&base->lock);

}



#ifdef CONFIG_NO_IDLE_HZ

#if defined(CONFIG_NO_IDLE_HZ) || defined(CONFIG_NO_HZ)

/*

 * Find out when the next timer event is due to happen. This

 * is used on S/390 to stop all activity when a cpus is idle.
@@ -687,10 +687,10 @@ static unsigned long cmp_next_hrtimer_event(unsigned long now, 
/**

 * next_timer_interrupt - return the jiffy of the next pending timer

 */

unsigned long next_timer_interrupt(void)

unsigned long get_next_timer_interrupt(unsigned long now)

{

	tvec_base_t *base = __get_cpu_var(tvec_bases);

	unsigned long expires, now = jiffies;

	unsigned long expires;



	spin_lock(&base->lock);

	expires = __next_timer_interrupt(base);
@@ -701,6 +701,14 @@ unsigned long next_timer_interrupt(void) 


	return cmp_next_hrtimer_event(now, expires);

}



#ifdef CONFIG_NO_IDLE_HZ

unsigned long next_timer_interrupt(void)

{

	return get_next_timer_interrupt(jiffies);

}

#endif



#endif



/******************************************************************/