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authorThomas Gleixner <tglx@linutronix.de>2007-02-16 12:27:51 +0300
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-02-16 19:13:58 +0300
commit303e967ff90a9d19ad3f8c9028ccbfa7f408fbb3 (patch)
treecd8c057e98b57896ffbbe4d98a4264393a652204 /kernel
parent3c8aa39d7c445ae2612b6b626f76f077e7a7ab0d (diff)
downloadlinux-303e967ff90a9d19ad3f8c9028ccbfa7f408fbb3.tar.xz
[PATCH] hrtimers; add state tracking
Reintroduce ktimers feature "optimized away" by the ktimers review process: multiple hrtimer states to enable the running of hrtimers without holding the cpu-base-lock. (The "optimized" rbtree hack carried only 2 states worth of information and we need 4 for high resolution timers and dynamic ticks.) No functional changes. Build-fixes-from: Andrew Morton <akpm@osdl.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: john stultz <johnstul@us.ibm.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/hrtimer.c40
1 files changed, 32 insertions, 8 deletions
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 89a9f535b4ce..fee18b27252f 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -150,6 +150,23 @@ static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
}
/*
+ * Helper function to check, whether the timer is on one of the queues
+ */
+static inline int hrtimer_is_queued(struct hrtimer *timer)
+{
+ return timer->state & HRTIMER_STATE_ENQUEUED;
+}
+
+/*
+ * Helper function to check, whether the timer is running the callback
+ * function
+ */
+static inline int hrtimer_callback_running(struct hrtimer *timer)
+{
+ return timer->state & HRTIMER_STATE_CALLBACK;
+}
+
+/*
* Functions and macros which are different for UP/SMP systems are kept in a
* single place
*/
@@ -390,6 +407,11 @@ static void enqueue_hrtimer(struct hrtimer *timer,
*/
rb_link_node(&timer->node, parent, link);
rb_insert_color(&timer->node, &base->active);
+ /*
+ * HRTIMER_STATE_ENQUEUED is or'ed to the current state to preserve the
+ * state of a possibly running callback.
+ */
+ timer->state |= HRTIMER_STATE_ENQUEUED;
if (!base->first || timer->expires.tv64 <
rb_entry(base->first, struct hrtimer, node)->expires.tv64)
@@ -402,7 +424,8 @@ static void enqueue_hrtimer(struct hrtimer *timer,
* Caller must hold the base lock.
*/
static void __remove_hrtimer(struct hrtimer *timer,
- struct hrtimer_clock_base *base)
+ struct hrtimer_clock_base *base,
+ unsigned long newstate)
{
/*
* Remove the timer from the rbtree and replace the
@@ -411,7 +434,7 @@ static void __remove_hrtimer(struct hrtimer *timer,
if (base->first == &timer->node)
base->first = rb_next(&timer->node);
rb_erase(&timer->node, &base->active);
- rb_set_parent(&timer->node, &timer->node);
+ timer->state = newstate;
}
/*
@@ -420,8 +443,8 @@ static void __remove_hrtimer(struct hrtimer *timer,
static inline int
remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base)
{
- if (hrtimer_active(timer)) {
- __remove_hrtimer(timer, base);
+ if (hrtimer_is_queued(timer)) {
+ __remove_hrtimer(timer, base, HRTIMER_STATE_INACTIVE);
return 1;
}
return 0;
@@ -493,7 +516,7 @@ int hrtimer_try_to_cancel(struct hrtimer *timer)
base = lock_hrtimer_base(timer, &flags);
- if (base->cpu_base->curr_timer != timer)
+ if (!hrtimer_callback_running(timer))
ret = remove_hrtimer(timer, base);
unlock_hrtimer_base(timer, &flags);
@@ -598,7 +621,6 @@ void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
clock_id = CLOCK_MONOTONIC;
timer->base = &cpu_base->clock_base[clock_id];
- rb_set_parent(&timer->node, &timer->node);
}
EXPORT_SYMBOL_GPL(hrtimer_init);
@@ -649,13 +671,14 @@ static inline void run_hrtimer_queue(struct hrtimer_cpu_base *cpu_base,
fn = timer->function;
set_curr_timer(cpu_base, timer);
- __remove_hrtimer(timer, base);
+ __remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK);
spin_unlock_irq(&cpu_base->lock);
restart = fn(timer);
spin_lock_irq(&cpu_base->lock);
+ timer->state &= ~HRTIMER_STATE_CALLBACK;
if (restart != HRTIMER_NORESTART) {
BUG_ON(hrtimer_active(timer));
enqueue_hrtimer(timer, base);
@@ -826,7 +849,8 @@ static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
while ((node = rb_first(&old_base->active))) {
timer = rb_entry(node, struct hrtimer, node);
- __remove_hrtimer(timer, old_base);
+ BUG_ON(timer->state & HRTIMER_STATE_CALLBACK);
+ __remove_hrtimer(timer, old_base, HRTIMER_STATE_INACTIVE);
timer->base = new_base;
enqueue_hrtimer(timer, new_base);
}