From: Thomas Gleixner 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 ] [ made new helper static, Adrian Bunk ] Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar Signed-off-by: Andrew Morton --- include/linux/timer.h | 10 ++++++++++ kernel/hrtimer.c | 2 +- kernel/timer.c | 14 +++++++++++--- 3 files changed, 22 insertions(+), 4 deletions(-) Index: linux-2.6.20-rc4-mm1-bo/include/linux/timer.h =================================================================== --- linux-2.6.20-rc4-mm1-bo.orig/include/linux/timer.h +++ linux-2.6.20-rc4-mm1-bo/include/linux/timer.h @@ -61,7 +61,17 @@ extern int del_timer(struct timer_list * 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 Index: linux-2.6.20-rc4-mm1-bo/kernel/hrtimer.c =================================================================== --- linux-2.6.20-rc4-mm1-bo.orig/kernel/hrtimer.c +++ linux-2.6.20-rc4-mm1-bo/kernel/hrtimer.c @@ -533,7 +533,7 @@ ktime_t hrtimer_get_remaining(const stru } 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 * Index: linux-2.6.20-rc4-mm1-bo/kernel/timer.c =================================================================== --- linux-2.6.20-rc4-mm1-bo.orig/kernel/timer.c +++ linux-2.6.20-rc4-mm1-bo/kernel/timer.c @@ -591,7 +591,7 @@ static inline void __run_timers(tvec_bas 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_ev /** * 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 /******************************************************************/ -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/