HRTIMER_RESTART, /* Timer must be restarted */
};
-/*
- * hrtimer callback modes:
- *
- * HRTIMER_CB_SOFTIRQ: Callback must run in softirq context
- * HRTIMER_CB_IRQSAFE_PERCPU: Callback must run in hardirq context
- * Special mode for tick emulation and
- * scheduler timer. Such timers are per
- * cpu and not allowed to be migrated on
- * cpu unplug.
- * HRTIMER_CB_IRQSAFE_UNLOCKED: Callback should run in hardirq context
- * with timer->base lock unlocked
- * used for timers which call wakeup to
- * avoid lock order problems with rq->lock
- */
-enum hrtimer_cb_mode {
- HRTIMER_CB_SOFTIRQ,
- HRTIMER_CB_IRQSAFE_PERCPU,
- HRTIMER_CB_IRQSAFE_UNLOCKED,
-};
-
/*
* Values to track state of the timer
*
* 0x00 inactive
* 0x01 enqueued into rbtree
* 0x02 callback function running
- * 0x04 callback pending (high resolution mode)
*
* Special cases:
* 0x03 callback function running and enqueued
#define HRTIMER_STATE_INACTIVE 0x00
#define HRTIMER_STATE_ENQUEUED 0x01
#define HRTIMER_STATE_CALLBACK 0x02
-#define HRTIMER_STATE_PENDING 0x04
-#define HRTIMER_STATE_MIGRATE 0x08
+#define HRTIMER_STATE_MIGRATE 0x04
/**
* struct hrtimer - the basic hrtimer structure
* @function: timer expiry callback function
* @base: pointer to the timer base (per cpu and per clock)
* @state: state information (See bit values above)
- * @cb_mode: high resolution timer feature to select the callback execution
- * mode
* @cb_entry: list head to enqueue an expired timer into the callback list
* @start_site: timer statistics field to store the site where the timer
* was started
struct hrtimer_clock_base *base;
unsigned long state;
struct list_head cb_entry;
- enum hrtimer_cb_mode cb_mode;
#ifdef CONFIG_TIMER_STATS
int start_pid;
void *start_site;
* @check_clocks: Indictator, when set evaluate time source and clock
* event devices whether high resolution mode can be
* activated.
- * @cb_pending: Expired timers are moved from the rbtree to this
- * list in the timer interrupt. The list is processed
- * in the softirq.
* @nr_events: Total number of timer interrupt events
*/
struct hrtimer_cpu_base {
spinlock_t lock;
struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES];
- struct list_head cb_pending;
#ifdef CONFIG_HIGH_RES_TIMERS
ktime_t expires_next;
int hres_active;
*/
static inline int hrtimer_is_queued(struct hrtimer *timer)
{
- return timer->state &
- (HRTIMER_STATE_ENQUEUED | HRTIMER_STATE_PENDING);
+ return timer->state & HRTIMER_STATE_ENQUEUED;
}
/*
static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { }
#endif
-/*
- * Check, whether the timer is on the callback pending list
- */
-static inline int hrtimer_cb_pending(const struct hrtimer *timer)
-{
- return timer->state & HRTIMER_STATE_PENDING;
-}
-
-/*
- * Remove a timer from the callback pending list
- */
-static inline void hrtimer_remove_cb_pending(struct hrtimer *timer)
-{
- list_del_init(&timer->cb_entry);
-}
-
/* High resolution timer related functions */
#ifdef CONFIG_HIGH_RES_TIMERS
{
}
+static void __run_hrtimer(struct hrtimer *timer);
+
/*
* When High resolution timers are active, try to reprogram. Note, that in case
* the state has HRTIMER_STATE_CALLBACK set, no reprogramming and no expiry
struct hrtimer_clock_base *base)
{
if (base->cpu_base->hres_active && hrtimer_reprogram(timer, base)) {
-
- /* Timer is expired, act upon the callback mode */
- switch(timer->cb_mode) {
- case HRTIMER_CB_IRQSAFE_PERCPU:
- case HRTIMER_CB_IRQSAFE_UNLOCKED:
- /*
- * This is solely for the sched tick emulation with
- * dynamic tick support to ensure that we do not
- * restart the tick right on the edge and end up with
- * the tick timer in the softirq ! The calling site
- * takes care of this. Also used for hrtimer sleeper !
- */
- debug_hrtimer_deactivate(timer);
- return 1;
- case HRTIMER_CB_SOFTIRQ:
- /*
- * Move everything else into the softirq pending list !
- */
- list_add_tail(&timer->cb_entry,
- &base->cpu_base->cb_pending);
- timer->state = HRTIMER_STATE_PENDING;
- return 1;
- default:
- BUG();
- }
+ /*
+ * XXX: recursion check?
+ * hrtimer_forward() should round up with timer granularity
+ * so that we never get into inf recursion here,
+ * it doesn't do that though
+ */
+ __run_hrtimer(timer);
+ return 1;
}
return 0;
}
return 1;
}
-static inline void hrtimer_raise_softirq(void)
-{
- raise_softirq(HRTIMER_SOFTIRQ);
-}
-
#else
static inline int hrtimer_hres_active(void) { return 0; }
{
return 0;
}
-static inline void hrtimer_raise_softirq(void) { }
#endif /* CONFIG_HIGH_RES_TIMERS */
struct hrtimer_clock_base *base,
unsigned long newstate, int reprogram)
{
- /* High res. callback list. NOP for !HIGHRES */
- if (hrtimer_cb_pending(timer))
- hrtimer_remove_cb_pending(timer);
- else {
+ if (timer->state & HRTIMER_STATE_ENQUEUED) {
/*
* Remove the timer from the rbtree and replace the
* first entry pointer if necessary.
{
struct hrtimer_clock_base *base, *new_base;
unsigned long flags;
- int ret, raise;
+ int ret;
base = lock_hrtimer_base(timer, &flags);
enqueue_hrtimer(timer, new_base,
new_base->cpu_base == &__get_cpu_var(hrtimer_bases));
- /*
- * The timer may be expired and moved to the cb_pending
- * list. We can not raise the softirq with base lock held due
- * to a possible deadlock with runqueue lock.
- */
- raise = timer->state == HRTIMER_STATE_PENDING;
-
- /*
- * We use preempt_disable to prevent this task from migrating after
- * setting up the softirq and raising it. Otherwise, if me migrate
- * we will raise the softirq on the wrong CPU.
- */
- preempt_disable();
-
unlock_hrtimer_base(timer, &flags);
- if (raise)
- hrtimer_raise_softirq();
- preempt_enable();
-
return ret;
}
EXPORT_SYMBOL_GPL(hrtimer_start_range_ns);
}
EXPORT_SYMBOL_GPL(hrtimer_get_res);
-static void run_hrtimer_pending(struct hrtimer_cpu_base *cpu_base)
-{
- spin_lock_irq(&cpu_base->lock);
-
- while (!list_empty(&cpu_base->cb_pending)) {
- enum hrtimer_restart (*fn)(struct hrtimer *);
- struct hrtimer *timer;
- int restart;
- int emulate_hardirq_ctx = 0;
-
- timer = list_entry(cpu_base->cb_pending.next,
- struct hrtimer, cb_entry);
-
- debug_hrtimer_deactivate(timer);
- timer_stats_account_hrtimer(timer);
-
- fn = timer->function;
- /*
- * A timer might have been added to the cb_pending list
- * when it was migrated during a cpu-offline operation.
- * Emulate hardirq context for such timers.
- */
- if (timer->cb_mode == HRTIMER_CB_IRQSAFE_PERCPU ||
- timer->cb_mode == HRTIMER_CB_IRQSAFE_UNLOCKED)
- emulate_hardirq_ctx = 1;
-
- __remove_hrtimer(timer, timer->base, HRTIMER_STATE_CALLBACK, 0);
- spin_unlock_irq(&cpu_base->lock);
-
- if (unlikely(emulate_hardirq_ctx)) {
- local_irq_disable();
- restart = fn(timer);
- local_irq_enable();
- } else
- restart = fn(timer);
-
- spin_lock_irq(&cpu_base->lock);
-
- timer->state &= ~HRTIMER_STATE_CALLBACK;
- if (restart == HRTIMER_RESTART) {
- BUG_ON(hrtimer_active(timer));
- /*
- * Enqueue the timer, allow reprogramming of the event
- * device
- */
- enqueue_hrtimer(timer, timer->base, 1);
- } else if (hrtimer_active(timer)) {
- /*
- * If the timer was rearmed on another CPU, reprogram
- * the event device.
- */
- struct hrtimer_clock_base *base = timer->base;
-
- if (base->first == &timer->node &&
- hrtimer_reprogram(timer, base)) {
- /*
- * Timer is expired. Thus move it from tree to
- * pending list again.
- */
- __remove_hrtimer(timer, base,
- HRTIMER_STATE_PENDING, 0);
- list_add_tail(&timer->cb_entry,
- &base->cpu_base->cb_pending);
- }
- }
- }
- spin_unlock_irq(&cpu_base->lock);
-}
-
static void __run_hrtimer(struct hrtimer *timer)
{
struct hrtimer_clock_base *base = timer->base;
enum hrtimer_restart (*fn)(struct hrtimer *);
int restart;
+ WARN_ON(!irqs_disabled());
+
debug_hrtimer_deactivate(timer);
__remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
timer_stats_account_hrtimer(timer);
-
fn = timer->function;
- if (timer->cb_mode == HRTIMER_CB_IRQSAFE_PERCPU ||
- timer->cb_mode == HRTIMER_CB_IRQSAFE_UNLOCKED) {
- /*
- * Used for scheduler timers, avoid lock inversion with
- * rq->lock and tasklist_lock.
- *
- * These timers are required to deal with enqueue expiry
- * themselves and are not allowed to migrate.
- */
- spin_unlock(&cpu_base->lock);
- restart = fn(timer);
- spin_lock(&cpu_base->lock);
- } else
- restart = fn(timer);
+
+ /*
+ * Because we run timers from hardirq context, there is no chance
+ * they get migrated to another cpu, therefore its safe to unlock
+ * the timer base.
+ */
+ spin_unlock(&cpu_base->lock);
+ restart = fn(timer);
+ spin_lock(&cpu_base->lock);
/*
* Note: We clear the CALLBACK bit after enqueue_hrtimer to avoid
struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
struct hrtimer_clock_base *base;
ktime_t expires_next, now;
- int i, raise = 0;
+ int i;
BUG_ON(!cpu_base->hres_active);
cpu_base->nr_events++;
break;
}
- /* Move softirq callbacks to the pending list */
- if (timer->cb_mode == HRTIMER_CB_SOFTIRQ) {
- __remove_hrtimer(timer, base,
- HRTIMER_STATE_PENDING, 0);
- list_add_tail(&timer->cb_entry,
- &base->cpu_base->cb_pending);
- raise = 1;
- continue;
- }
-
__run_hrtimer(timer);
}
spin_unlock(&cpu_base->lock);
if (tick_program_event(expires_next, 0))
goto retry;
}
-
- /* Raise softirq ? */
- if (raise)
- raise_softirq(HRTIMER_SOFTIRQ);
}
/**
local_irq_restore(flags);
}
-static void run_hrtimer_softirq(struct softirq_action *h)
-{
- run_hrtimer_pending(&__get_cpu_var(hrtimer_bases));
-}
-
#endif /* CONFIG_HIGH_RES_TIMERS */
/*
*/
void hrtimer_run_pending(void)
{
- struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
-
if (hrtimer_hres_active())
return;
*/
if (tick_check_oneshot_change(!hrtimer_is_hres_enabled()))
hrtimer_switch_to_hres();
-
- run_hrtimer_pending(cpu_base);
}
/*
hrtimer_get_expires_tv64(timer))
break;
- if (timer->cb_mode == HRTIMER_CB_SOFTIRQ) {
- __remove_hrtimer(timer, base,
- HRTIMER_STATE_PENDING, 0);
- list_add_tail(&timer->cb_entry,
- &base->cpu_base->cb_pending);
- continue;
- }
-
__run_hrtimer(timer);
}
spin_unlock(&cpu_base->lock);
{
sl->timer.function = hrtimer_wakeup;
sl->task = task;
-#ifdef CONFIG_HIGH_RES_TIMERS
- sl->timer.cb_mode = HRTIMER_CB_IRQSAFE_UNLOCKED;
-#endif
}
static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++)
cpu_base->clock_base[i].cpu_base = cpu_base;
- INIT_LIST_HEAD(&cpu_base->cb_pending);
hrtimer_init_hres(cpu_base);
}
#ifdef CONFIG_HOTPLUG_CPU
-static int migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
- struct hrtimer_clock_base *new_base, int dcpu)
+static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
+ struct hrtimer_clock_base *new_base, int dcpu)
{
struct hrtimer *timer;
struct rb_node *node;
- int raise = 0;
while ((node = rb_first(&old_base->active))) {
timer = rb_entry(node, struct hrtimer, node);
BUG_ON(hrtimer_callback_running(timer));
debug_hrtimer_deactivate(timer);
- /*
- * Should not happen. Per CPU timers should be
- * canceled _before_ the migration code is called
- */
- if (timer->cb_mode == HRTIMER_CB_IRQSAFE_PERCPU) {
- __remove_hrtimer(timer, old_base,
- HRTIMER_STATE_INACTIVE, 0);
- WARN(1, "hrtimer (%p %p)active but cpu %d dead\n",
- timer, timer->function, dcpu);
- continue;
- }
-
/*
* Mark it as STATE_MIGRATE not INACTIVE otherwise the
* timer could be seen as !active and just vanish away
* otherwise we end up with a stale timer.
*/
if (timer->state == HRTIMER_STATE_MIGRATE) {
- timer->state = HRTIMER_STATE_PENDING;
- list_add_tail(&timer->cb_entry,
- &new_base->cpu_base->cb_pending);
- raise = 1;
+ /* XXX: running on offline cpu */
+ __run_hrtimer(timer);
}
#endif
/* Clear the migration state bit */
timer->state &= ~HRTIMER_STATE_MIGRATE;
}
- return raise;
}
-#ifdef CONFIG_HIGH_RES_TIMERS
-static int migrate_hrtimer_pending(struct hrtimer_cpu_base *old_base,
- struct hrtimer_cpu_base *new_base)
-{
- struct hrtimer *timer;
- int raise = 0;
-
- while (!list_empty(&old_base->cb_pending)) {
- timer = list_entry(old_base->cb_pending.next,
- struct hrtimer, cb_entry);
-
- __remove_hrtimer(timer, timer->base, HRTIMER_STATE_PENDING, 0);
- timer->base = &new_base->clock_base[timer->base->index];
- list_add_tail(&timer->cb_entry, &new_base->cb_pending);
- raise = 1;
- }
- return raise;
-}
-#else
-static int migrate_hrtimer_pending(struct hrtimer_cpu_base *old_base,
- struct hrtimer_cpu_base *new_base)
-{
- return 0;
-}
-#endif
-
static void migrate_hrtimers(int cpu)
{
struct hrtimer_cpu_base *old_base, *new_base;
- int i, raise = 0;
+ int i;
BUG_ON(cpu_online(cpu));
old_base = &per_cpu(hrtimer_bases, cpu);
spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
- if (migrate_hrtimer_list(&old_base->clock_base[i],
- &new_base->clock_base[i], cpu))
- raise = 1;
+ migrate_hrtimer_list(&old_base->clock_base[i],
+ &new_base->clock_base[i], cpu);
}
- if (migrate_hrtimer_pending(old_base, new_base))
- raise = 1;
-
spin_unlock(&old_base->lock);
spin_unlock_irq(&new_base->lock);
put_cpu_var(hrtimer_bases);
-
- if (raise)
- hrtimer_raise_softirq();
}
#endif /* CONFIG_HOTPLUG_CPU */
hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE,
(void *)(long)smp_processor_id());
register_cpu_notifier(&hrtimers_nb);
-#ifdef CONFIG_HIGH_RES_TIMERS
- open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq);
-#endif
}
/**
projects / linux-platform-drivers-x86.git / commitdiff