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authorThomas Gleixner <tglx@linutronix.de>2007-02-16 01:27:47 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-02-16 08:13:58 -0800
commitfd064b9b7770d5c7705bf9542950c7bd81c30f98 (patch)
tree8b14c81f983e49b5553fd6764139bffb1d4f1648
parent1cfd68496e53f7be09a3c1358d1d389004217541 (diff)
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op-kernel-dev-fd064b9b7770d5c7705bf9542950c7bd81c30f98.tar.gz
[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: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/timer.h10
-rw-r--r--kernel/hrtimer.c2
-rw-r--r--kernel/timer.c14
3 files changed, 22 insertions, 4 deletions
diff --git a/include/linux/timer.h b/include/linux/timer.h
index fb5edaa..bd0af32 100644
--- a/include/linux/timer.h
+++ b/include/linux/timer.h
@@ -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
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index c0fdb9b..bd57ef4 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -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
*
diff --git a/kernel/timer.c b/kernel/timer.c
index 201bee0..6d843e1 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -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
/******************************************************************/
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