From 303e967ff90a9d19ad3f8c9028ccbfa7f408fbb3 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 16 Feb 2007 01:27:51 -0800 Subject: [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 Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar Cc: Roman Zippel Cc: john stultz Cc: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/hrtimer.c | 40 ++++++++++++++++++++++++++++++++-------- 1 file changed, 32 insertions(+), 8 deletions(-) (limited to 'kernel') diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index 89a9f535b4ce..fee18b27252f 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -149,6 +149,23 @@ static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base) ktime_add(xtim, tomono); } +/* + * 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); } -- cgit v1.2.3