/*
* linux/kernel/hrtimer.c
*
- * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
- * Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
+ * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
+ * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
+ * Copyright(C) 2006-2007 Timesys Corp., Thomas Gleixner
*
* High-resolution kernel timers
*
*/
#include <linux/cpu.h>
+#include <linux/irq.h>
#include <linux/module.h>
#include <linux/percpu.h>
#include <linux/hrtimer.h>
#include <linux/notifier.h>
#include <linux/syscalls.h>
+#include <linux/kallsyms.h>
#include <linux/interrupt.h>
+#include <linux/tick.h>
+#include <linux/seq_file.h>
+#include <linux/err.h>
#include <asm/uaccess.h>
*
* returns the time in ktime_t format
*/
-static ktime_t ktime_get(void)
+ktime_t ktime_get(void)
{
struct timespec now;
*
* returns the time in ktime_t format
*/
-static ktime_t ktime_get_real(void)
+ktime_t ktime_get_real(void)
{
struct timespec now;
* This ensures that we capture erroneous accesses to these clock ids
* rather than moving them into the range of valid clock id's.
*/
-
-#define MAX_HRTIMER_BASES 2
-
-static DEFINE_PER_CPU(struct hrtimer_base, hrtimer_bases[MAX_HRTIMER_BASES]) =
+DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
{
+
+ .clock_base =
{
- .index = CLOCK_REALTIME,
- .get_time = &ktime_get_real,
- .resolution = KTIME_REALTIME_RES,
- },
- {
- .index = CLOCK_MONOTONIC,
- .get_time = &ktime_get,
- .resolution = KTIME_MONOTONIC_RES,
- },
+ {
+ .index = CLOCK_REALTIME,
+ .get_time = &ktime_get_real,
+ .resolution = KTIME_LOW_RES,
+ },
+ {
+ .index = CLOCK_MONOTONIC,
+ .get_time = &ktime_get,
+ .resolution = KTIME_LOW_RES,
+ },
+ }
};
/**
*
* The function calculates the monotonic clock from the realtime
* clock and the wall_to_monotonic offset and stores the result
- * in normalized timespec format in the variable pointed to by ts.
+ * in normalized timespec format in the variable pointed to by @ts.
*/
void ktime_get_ts(struct timespec *ts)
{
* Get the coarse grained time at the softirq based on xtime and
* wall_to_monotonic.
*/
-static void hrtimer_get_softirq_time(struct hrtimer_base *base)
+static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
{
ktime_t xtim, tomono;
+ struct timespec xts;
unsigned long seq;
do {
seq = read_seqbegin(&xtime_lock);
- xtim = timespec_to_ktime(xtime);
- tomono = timespec_to_ktime(wall_to_monotonic);
-
+#ifdef CONFIG_NO_HZ
+ getnstimeofday(&xts);
+#else
+ xts = xtime;
+#endif
} while (read_seqretry(&xtime_lock, seq));
- base[CLOCK_REALTIME].softirq_time = xtim;
- base[CLOCK_MONOTONIC].softirq_time = ktime_add(xtim, tomono);
+ xtim = timespec_to_ktime(xts);
+ tomono = timespec_to_ktime(wall_to_monotonic);
+ base->clock_base[CLOCK_REALTIME].softirq_time = xtim;
+ base->clock_base[CLOCK_MONOTONIC].softirq_time =
+ ktime_add(xtim, tomono);
+}
+
+/*
+ * 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;
}
/*
*/
#ifdef CONFIG_SMP
-#define set_curr_timer(b, t) do { (b)->curr_timer = (t); } while (0)
-
/*
* We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock
* means that all timers which are tied to this base via timer->base are
* possible to set timer->base = NULL and drop the lock: the timer remains
* locked.
*/
-static struct hrtimer_base *lock_hrtimer_base(const struct hrtimer *timer,
- unsigned long *flags)
+static
+struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
+ unsigned long *flags)
{
- struct hrtimer_base *base;
+ struct hrtimer_clock_base *base;
for (;;) {
base = timer->base;
if (likely(base != NULL)) {
- spin_lock_irqsave(&base->lock, *flags);
+ spin_lock_irqsave(&base->cpu_base->lock, *flags);
if (likely(base == timer->base))
return base;
/* The timer has migrated to another CPU: */
- spin_unlock_irqrestore(&base->lock, *flags);
+ spin_unlock_irqrestore(&base->cpu_base->lock, *flags);
}
cpu_relax();
}
/*
* Switch the timer base to the current CPU when possible.
*/
-static inline struct hrtimer_base *
-switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_base *base)
+static inline struct hrtimer_clock_base *
+switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base)
{
- struct hrtimer_base *new_base;
+ struct hrtimer_clock_base *new_base;
+ struct hrtimer_cpu_base *new_cpu_base;
- new_base = &__get_cpu_var(hrtimer_bases)[base->index];
+ new_cpu_base = &__get_cpu_var(hrtimer_bases);
+ new_base = &new_cpu_base->clock_base[base->index];
if (base != new_base) {
/*
* completed. There is no conflict as we hold the lock until
* the timer is enqueued.
*/
- if (unlikely(base->curr_timer == timer))
+ if (unlikely(hrtimer_callback_running(timer)))
return base;
/* See the comment in lock_timer_base() */
timer->base = NULL;
- spin_unlock(&base->lock);
- spin_lock(&new_base->lock);
+ spin_unlock(&base->cpu_base->lock);
+ spin_lock(&new_base->cpu_base->lock);
timer->base = new_base;
}
return new_base;
#else /* CONFIG_SMP */
-#define set_curr_timer(b, t) do { } while (0)
-
-static inline struct hrtimer_base *
+static inline struct hrtimer_clock_base *
lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
{
- struct hrtimer_base *base = timer->base;
+ struct hrtimer_clock_base *base = timer->base;
- spin_lock_irqsave(&base->lock, *flags);
+ spin_lock_irqsave(&base->cpu_base->lock, *flags);
return base;
}
-#define switch_hrtimer_base(t, b) (b)
+# define switch_hrtimer_base(t, b) (b)
#endif /* !CONFIG_SMP */
return ktime_add(kt, tmp);
}
-
-#else /* CONFIG_KTIME_SCALAR */
-
# endif /* !CONFIG_KTIME_SCALAR */
/*
* Divide a ktime value by a nanosecond value
*/
-static unsigned long ktime_divns(const ktime_t kt, s64 div)
+unsigned long ktime_divns(const ktime_t kt, s64 div)
{
u64 dclc, inc, dns;
int sft = 0;
return (unsigned long) dclc;
}
-
-#else /* BITS_PER_LONG < 64 */
-# define ktime_divns(kt, div) (unsigned long)((kt).tv64 / (div))
#endif /* BITS_PER_LONG >= 64 */
+/* High resolution timer related functions */
+#ifdef CONFIG_HIGH_RES_TIMERS
+
+/*
+ * High resolution timer enabled ?
+ */
+static int hrtimer_hres_enabled __read_mostly = 1;
+
+/*
+ * Enable / Disable high resolution mode
+ */
+static int __init setup_hrtimer_hres(char *str)
+{
+ if (!strcmp(str, "off"))
+ hrtimer_hres_enabled = 0;
+ else if (!strcmp(str, "on"))
+ hrtimer_hres_enabled = 1;
+ else
+ return 0;
+ return 1;
+}
+
+__setup("highres=", setup_hrtimer_hres);
+
+/*
+ * hrtimer_high_res_enabled - query, if the highres mode is enabled
+ */
+static inline int hrtimer_is_hres_enabled(void)
+{
+ return hrtimer_hres_enabled;
+}
+
+/*
+ * Is the high resolution mode active ?
+ */
+static inline int hrtimer_hres_active(void)
+{
+ return __get_cpu_var(hrtimer_bases).hres_active;
+}
+
+/*
+ * Reprogram the event source with checking both queues for the
+ * next event
+ * Called with interrupts disabled and base->lock held
+ */
+static void hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base)
+{
+ int i;
+ struct hrtimer_clock_base *base = cpu_base->clock_base;
+ ktime_t expires;
+
+ cpu_base->expires_next.tv64 = KTIME_MAX;
+
+ for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
+ struct hrtimer *timer;
+
+ if (!base->first)
+ continue;
+ timer = rb_entry(base->first, struct hrtimer, node);
+ expires = ktime_sub(timer->expires, base->offset);
+ if (expires.tv64 < cpu_base->expires_next.tv64)
+ cpu_base->expires_next = expires;
+ }
+
+ if (cpu_base->expires_next.tv64 != KTIME_MAX)
+ tick_program_event(cpu_base->expires_next, 1);
+}
+
+/*
+ * Shared reprogramming for clock_realtime and clock_monotonic
+ *
+ * When a timer is enqueued and expires earlier than the already enqueued
+ * timers, we have to check, whether it expires earlier than the timer for
+ * which the clock event device was armed.
+ *
+ * Called with interrupts disabled and base->cpu_base.lock held
+ */
+static int hrtimer_reprogram(struct hrtimer *timer,
+ struct hrtimer_clock_base *base)
+{
+ ktime_t *expires_next = &__get_cpu_var(hrtimer_bases).expires_next;
+ ktime_t expires = ktime_sub(timer->expires, base->offset);
+ int res;
+
+ /*
+ * When the callback is running, we do not reprogram the clock event
+ * device. The timer callback is either running on a different CPU or
+ * the callback is executed in the hrtimer_interupt context. The
+ * reprogramming is handled either by the softirq, which called the
+ * callback or at the end of the hrtimer_interrupt.
+ */
+ if (hrtimer_callback_running(timer))
+ return 0;
+
+ if (expires.tv64 >= expires_next->tv64)
+ return 0;
+
+ /*
+ * Clockevents returns -ETIME, when the event was in the past.
+ */
+ res = tick_program_event(expires, 0);
+ if (!IS_ERR_VALUE(res))
+ *expires_next = expires;
+ return res;
+}
+
+
+/*
+ * Retrigger next event is called after clock was set
+ *
+ * Called with interrupts disabled via on_each_cpu()
+ */
+static void retrigger_next_event(void *arg)
+{
+ struct hrtimer_cpu_base *base;
+ struct timespec realtime_offset;
+ unsigned long seq;
+
+ if (!hrtimer_hres_active())
+ return;
+
+ do {
+ seq = read_seqbegin(&xtime_lock);
+ set_normalized_timespec(&realtime_offset,
+ -wall_to_monotonic.tv_sec,
+ -wall_to_monotonic.tv_nsec);
+ } while (read_seqretry(&xtime_lock, seq));
+
+ base = &__get_cpu_var(hrtimer_bases);
+
+ /* Adjust CLOCK_REALTIME offset */
+ spin_lock(&base->lock);
+ base->clock_base[CLOCK_REALTIME].offset =
+ timespec_to_ktime(realtime_offset);
+
+ hrtimer_force_reprogram(base);
+ spin_unlock(&base->lock);
+}
+
+/*
+ * Clock realtime was set
+ *
+ * Change the offset of the realtime clock vs. the monotonic
+ * clock.
+ *
+ * We might have to reprogram the high resolution timer interrupt. On
+ * SMP we call the architecture specific code to retrigger _all_ high
+ * resolution timer interrupts. On UP we just disable interrupts and
+ * call the high resolution interrupt code.
+ */
+void clock_was_set(void)
+{
+ /* Retrigger the CPU local events everywhere */
+ on_each_cpu(retrigger_next_event, NULL, 0, 1);
+}
+
+/*
+ * 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);
+}
+
+/*
+ * Initialize the high resolution related parts of cpu_base
+ */
+static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base)
+{
+ base->expires_next.tv64 = KTIME_MAX;
+ base->hres_active = 0;
+ INIT_LIST_HEAD(&base->cb_pending);
+}
+
+/*
+ * Initialize the high resolution related parts of a hrtimer
+ */
+static inline void hrtimer_init_timer_hres(struct hrtimer *timer)
+{
+ INIT_LIST_HEAD(&timer->cb_entry);
+}
+
+/*
+ * 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
+ * check happens. The timer gets enqueued into the rbtree. The reprogramming
+ * and expiry check is done in the hrtimer_interrupt or in the softirq.
+ */
+static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
+ 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_NO_RESTART:
+ /*
+ * We can call the callback from here. No restart
+ * happens, so no danger of recursion
+ */
+ BUG_ON(timer->function(timer) != HRTIMER_NORESTART);
+ return 1;
+ case HRTIMER_CB_IRQSAFE_NO_SOFTIRQ:
+ /*
+ * 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.
+ */
+ return 1;
+ case HRTIMER_CB_IRQSAFE:
+ 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;
+ raise_softirq(HRTIMER_SOFTIRQ);
+ return 1;
+ default:
+ BUG();
+ }
+ }
+ return 0;
+}
+
+/*
+ * Switch to high resolution mode
+ */
+static void hrtimer_switch_to_hres(void)
+{
+ struct hrtimer_cpu_base *base = &__get_cpu_var(hrtimer_bases);
+ unsigned long flags;
+
+ if (base->hres_active)
+ return;
+
+ local_irq_save(flags);
+
+ if (tick_init_highres()) {
+ local_irq_restore(flags);
+ return;
+ }
+ base->hres_active = 1;
+ base->clock_base[CLOCK_REALTIME].resolution = KTIME_HIGH_RES;
+ base->clock_base[CLOCK_MONOTONIC].resolution = KTIME_HIGH_RES;
+
+ tick_setup_sched_timer();
+
+ /* "Retrigger" the interrupt to get things going */
+ retrigger_next_event(NULL);
+ local_irq_restore(flags);
+ printk(KERN_INFO "Switched to high resolution mode on CPU %d\n",
+ smp_processor_id());
+}
+
+#else
+
+static inline int hrtimer_hres_active(void) { return 0; }
+static inline int hrtimer_is_hres_enabled(void) { return 0; }
+static inline void hrtimer_switch_to_hres(void) { }
+static inline void hrtimer_force_reprogram(struct hrtimer_cpu_base *base) { }
+static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
+ struct hrtimer_clock_base *base)
+{
+ return 0;
+}
+static inline int hrtimer_cb_pending(struct hrtimer *timer) { return 0; }
+static inline void hrtimer_remove_cb_pending(struct hrtimer *timer) { }
+static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) { }
+static inline void hrtimer_init_timer_hres(struct hrtimer *timer) { }
+
+#endif /* CONFIG_HIGH_RES_TIMERS */
+
+#ifdef CONFIG_TIMER_STATS
+void __timer_stats_hrtimer_set_start_info(struct hrtimer *timer, void *addr)
+{
+ if (timer->start_site)
+ return;
+
+ timer->start_site = addr;
+ memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
+ timer->start_pid = current->pid;
+}
+#endif
+
/*
* Counterpart to lock_timer_base above:
*/
static inline
void unlock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
{
- spin_unlock_irqrestore(&timer->base->lock, *flags);
+ spin_unlock_irqrestore(&timer->base->cpu_base->lock, *flags);
}
/**
* The timer is inserted in expiry order. Insertion into the
* red black tree is O(log(n)). Must hold the base lock.
*/
-static void enqueue_hrtimer(struct hrtimer *timer, struct hrtimer_base *base)
+static void enqueue_hrtimer(struct hrtimer *timer,
+ struct hrtimer_clock_base *base, int reprogram)
{
struct rb_node **link = &base->active.rb_node;
struct rb_node *parent = NULL;
* Insert the timer to the rbtree and check whether it
* replaces the first pending timer
*/
- rb_link_node(&timer->node, parent, link);
- rb_insert_color(&timer->node, &base->active);
-
if (!base->first || timer->expires.tv64 <
- rb_entry(base->first, struct hrtimer, node)->expires.tv64)
+ rb_entry(base->first, struct hrtimer, node)->expires.tv64) {
+ /*
+ * Reprogram the clock event device. When the timer is already
+ * expired hrtimer_enqueue_reprogram has either called the
+ * callback or added it to the pending list and raised the
+ * softirq.
+ *
+ * This is a NOP for !HIGHRES
+ */
+ if (reprogram && hrtimer_enqueue_reprogram(timer, base))
+ return;
+
base->first = &timer->node;
+ }
+
+ 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;
}
/*
* __remove_hrtimer - internal function to remove a timer
*
* Caller must hold the base lock.
+ *
+ * High resolution timer mode reprograms the clock event device when the
+ * timer is the one which expires next. The caller can disable this by setting
+ * reprogram to zero. This is useful, when the context does a reprogramming
+ * anyway (e.g. timer interrupt)
*/
-static void __remove_hrtimer(struct hrtimer *timer, struct hrtimer_base *base)
+static void __remove_hrtimer(struct hrtimer *timer,
+ struct hrtimer_clock_base *base,
+ unsigned long newstate, int reprogram)
{
- /*
- * Remove the timer from the rbtree and replace the
- * first entry pointer if necessary.
- */
- if (base->first == &timer->node)
- base->first = rb_next(&timer->node);
- rb_erase(&timer->node, &base->active);
- rb_set_parent(&timer->node, &timer->node);
+ /* High res. callback list. NOP for !HIGHRES */
+ if (hrtimer_cb_pending(timer))
+ hrtimer_remove_cb_pending(timer);
+ else {
+ /*
+ * Remove the timer from the rbtree and replace the
+ * first entry pointer if necessary.
+ */
+ if (base->first == &timer->node) {
+ base->first = rb_next(&timer->node);
+ /* Reprogram the clock event device. if enabled */
+ if (reprogram && hrtimer_hres_active())
+ hrtimer_force_reprogram(base->cpu_base);
+ }
+ rb_erase(&timer->node, &base->active);
+ }
+ timer->state = newstate;
}
/*
* remove hrtimer, called with base lock held
*/
static inline int
-remove_hrtimer(struct hrtimer *timer, struct hrtimer_base *base)
+remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base)
{
- if (hrtimer_active(timer)) {
- __remove_hrtimer(timer, base);
+ if (hrtimer_is_queued(timer)) {
+ int reprogram;
+
+ /*
+ * Remove the timer and force reprogramming when high
+ * resolution mode is active and the timer is on the current
+ * CPU. If we remove a timer on another CPU, reprogramming is
+ * skipped. The interrupt event on this CPU is fired and
+ * reprogramming happens in the interrupt handler. This is a
+ * rare case and less expensive than a smp call.
+ */
+ timer_stats_hrtimer_clear_start_info(timer);
+ reprogram = base->cpu_base == &__get_cpu_var(hrtimer_bases);
+ __remove_hrtimer(timer, base, HRTIMER_STATE_INACTIVE,
+ reprogram);
return 1;
}
return 0;
int
hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
{
- struct hrtimer_base *base, *new_base;
+ struct hrtimer_clock_base *base, *new_base;
unsigned long flags;
int ret;
/* Switch the timer base, if necessary: */
new_base = switch_hrtimer_base(timer, base);
- if (mode == HRTIMER_REL) {
+ if (mode == HRTIMER_MODE_REL) {
tim = ktime_add(tim, new_base->get_time());
/*
* CONFIG_TIME_LOW_RES is a temporary way for architectures
}
timer->expires = tim;
- enqueue_hrtimer(timer, new_base);
+ timer_stats_hrtimer_set_start_info(timer);
+
+ enqueue_hrtimer(timer, new_base, base == new_base);
unlock_hrtimer_base(timer, &flags);
*/
int hrtimer_try_to_cancel(struct hrtimer *timer)
{
- struct hrtimer_base *base;
+ struct hrtimer_clock_base *base;
unsigned long flags;
int ret = -1;
base = lock_hrtimer_base(timer, &flags);
- if (base->curr_timer != timer)
+ if (!hrtimer_callback_running(timer))
ret = remove_hrtimer(timer, base);
unlock_hrtimer_base(timer, &flags);
*/
ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
{
- struct hrtimer_base *base;
+ struct hrtimer_clock_base *base;
unsigned long flags;
ktime_t rem;
base = lock_hrtimer_base(timer, &flags);
- rem = ktime_sub(timer->expires, timer->base->get_time());
+ rem = ktime_sub(timer->expires, base->get_time());
unlock_hrtimer_base(timer, &flags);
return rem;
}
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
*
*/
ktime_t hrtimer_get_next_event(void)
{
- struct hrtimer_base *base = __get_cpu_var(hrtimer_bases);
+ struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
+ struct hrtimer_clock_base *base = cpu_base->clock_base;
ktime_t delta, mindelta = { .tv64 = KTIME_MAX };
unsigned long flags;
int i;
- for (i = 0; i < MAX_HRTIMER_BASES; i++, base++) {
- struct hrtimer *timer;
+ spin_lock_irqsave(&cpu_base->lock, flags);
- spin_lock_irqsave(&base->lock, flags);
- if (!base->first) {
- spin_unlock_irqrestore(&base->lock, flags);
- continue;
+ if (!hrtimer_hres_active()) {
+ for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++, base++) {
+ struct hrtimer *timer;
+
+ if (!base->first)
+ continue;
+
+ timer = rb_entry(base->first, struct hrtimer, node);
+ delta.tv64 = timer->expires.tv64;
+ delta = ktime_sub(delta, base->get_time());
+ if (delta.tv64 < mindelta.tv64)
+ mindelta.tv64 = delta.tv64;
}
- timer = rb_entry(base->first, struct hrtimer, node);
- delta.tv64 = timer->expires.tv64;
- spin_unlock_irqrestore(&base->lock, flags);
- delta = ktime_sub(delta, base->get_time());
- if (delta.tv64 < mindelta.tv64)
- mindelta.tv64 = delta.tv64;
}
+
+ spin_unlock_irqrestore(&cpu_base->lock, flags);
+
if (mindelta.tv64 < 0)
mindelta.tv64 = 0;
return mindelta;
void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
enum hrtimer_mode mode)
{
- struct hrtimer_base *bases;
+ struct hrtimer_cpu_base *cpu_base;
memset(timer, 0, sizeof(struct hrtimer));
- bases = __raw_get_cpu_var(hrtimer_bases);
+ cpu_base = &__raw_get_cpu_var(hrtimer_bases);
- if (clock_id == CLOCK_REALTIME && mode != HRTIMER_ABS)
+ if (clock_id == CLOCK_REALTIME && mode != HRTIMER_MODE_ABS)
clock_id = CLOCK_MONOTONIC;
- timer->base = &bases[clock_id];
- rb_set_parent(&timer->node, &timer->node);
+ timer->base = &cpu_base->clock_base[clock_id];
+ hrtimer_init_timer_hres(timer);
+
+#ifdef CONFIG_TIMER_STATS
+ timer->start_site = NULL;
+ timer->start_pid = -1;
+ memset(timer->start_comm, 0, TASK_COMM_LEN);
+#endif
}
EXPORT_SYMBOL_GPL(hrtimer_init);
* @which_clock: which clock to query
* @tp: pointer to timespec variable to store the resolution
*
- * Store the resolution of the clock selected by which_clock in the
- * variable pointed to by tp.
+ * Store the resolution of the clock selected by @which_clock in the
+ * variable pointed to by @tp.
*/
int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp)
{
- struct hrtimer_base *bases;
+ struct hrtimer_cpu_base *cpu_base;
- bases = __raw_get_cpu_var(hrtimer_bases);
- *tp = ktime_to_timespec(bases[which_clock].resolution);
+ cpu_base = &__raw_get_cpu_var(hrtimer_bases);
+ *tp = ktime_to_timespec(cpu_base->clock_base[which_clock].resolution);
return 0;
}
EXPORT_SYMBOL_GPL(hrtimer_get_res);
+#ifdef CONFIG_HIGH_RES_TIMERS
+
+/*
+ * High resolution timer interrupt
+ * Called with interrupts disabled
+ */
+void hrtimer_interrupt(struct clock_event_device *dev)
+{
+ 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;
+
+ BUG_ON(!cpu_base->hres_active);
+ cpu_base->nr_events++;
+ dev->next_event.tv64 = KTIME_MAX;
+
+ retry:
+ now = ktime_get();
+
+ expires_next.tv64 = KTIME_MAX;
+
+ base = cpu_base->clock_base;
+
+ for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
+ ktime_t basenow;
+ struct rb_node *node;
+
+ spin_lock(&cpu_base->lock);
+
+ basenow = ktime_add(now, base->offset);
+
+ while ((node = base->first)) {
+ struct hrtimer *timer;
+
+ timer = rb_entry(node, struct hrtimer, node);
+
+ if (basenow.tv64 < timer->expires.tv64) {
+ ktime_t expires;
+
+ expires = ktime_sub(timer->expires,
+ base->offset);
+ if (expires.tv64 < expires_next.tv64)
+ expires_next = expires;
+ 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;
+ }
+
+ __remove_hrtimer(timer, base,
+ HRTIMER_STATE_CALLBACK, 0);
+ timer_stats_account_hrtimer(timer);
+
+ /*
+ * Note: We clear the CALLBACK bit after
+ * enqueue_hrtimer to avoid reprogramming of
+ * the event hardware. This happens at the end
+ * of this function anyway.
+ */
+ if (timer->function(timer) != HRTIMER_NORESTART) {
+ BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
+ enqueue_hrtimer(timer, base, 0);
+ }
+ timer->state &= ~HRTIMER_STATE_CALLBACK;
+ }
+ spin_unlock(&cpu_base->lock);
+ base++;
+ }
+
+ cpu_base->expires_next = expires_next;
+
+ /* Reprogramming necessary ? */
+ if (expires_next.tv64 != KTIME_MAX) {
+ if (tick_program_event(expires_next, 0))
+ goto retry;
+ }
+
+ /* Raise softirq ? */
+ if (raise)
+ raise_softirq(HRTIMER_SOFTIRQ);
+}
+
+static void run_hrtimer_softirq(struct softirq_action *h)
+{
+ struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
+
+ spin_lock_irq(&cpu_base->lock);
+
+ while (!list_empty(&cpu_base->cb_pending)) {
+ enum hrtimer_restart (*fn)(struct hrtimer *);
+ struct hrtimer *timer;
+ int restart;
+
+ timer = list_entry(cpu_base->cb_pending.next,
+ struct hrtimer, cb_entry);
+
+ timer_stats_account_hrtimer(timer);
+
+ fn = timer->function;
+ __remove_hrtimer(timer, timer->base, HRTIMER_STATE_CALLBACK, 0);
+ spin_unlock_irq(&cpu_base->lock);
+
+ 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.
+ */
+ if (timer->base->first == &timer->node)
+ hrtimer_reprogram(timer, timer->base);
+ }
+ }
+ spin_unlock_irq(&cpu_base->lock);
+}
+
+#endif /* CONFIG_HIGH_RES_TIMERS */
+
/*
* Expire the per base hrtimer-queue:
*/
-static inline void run_hrtimer_queue(struct hrtimer_base *base)
+static inline void run_hrtimer_queue(struct hrtimer_cpu_base *cpu_base,
+ int index)
{
struct rb_node *node;
+ struct hrtimer_clock_base *base = &cpu_base->clock_base[index];
if (!base->first)
return;
if (base->get_softirq_time)
base->softirq_time = base->get_softirq_time();
- spin_lock_irq(&base->lock);
+ spin_lock_irq(&cpu_base->lock);
while ((node = base->first)) {
struct hrtimer *timer;
- int (*fn)(struct hrtimer *);
+ enum hrtimer_restart (*fn)(struct hrtimer *);
int restart;
timer = rb_entry(node, struct hrtimer, node);
if (base->softirq_time.tv64 <= timer->expires.tv64)
break;
+ timer_stats_account_hrtimer(timer);
+
fn = timer->function;
- set_curr_timer(base, timer);
- __remove_hrtimer(timer, base);
- spin_unlock_irq(&base->lock);
+ __remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
+ spin_unlock_irq(&cpu_base->lock);
restart = fn(timer);
- spin_lock_irq(&base->lock);
+ spin_lock_irq(&cpu_base->lock);
+ timer->state &= ~HRTIMER_STATE_CALLBACK;
if (restart != HRTIMER_NORESTART) {
BUG_ON(hrtimer_active(timer));
- enqueue_hrtimer(timer, base);
+ enqueue_hrtimer(timer, base, 0);
}
}
- set_curr_timer(base, NULL);
- spin_unlock_irq(&base->lock);
+ spin_unlock_irq(&cpu_base->lock);
}
/*
* Called from timer softirq every jiffy, expire hrtimers:
+ *
+ * For HRT its the fall back code to run the softirq in the timer
+ * softirq context in case the hrtimer initialization failed or has
+ * not been done yet.
*/
void hrtimer_run_queues(void)
{
- struct hrtimer_base *base = __get_cpu_var(hrtimer_bases);
+ struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
int i;
- hrtimer_get_softirq_time(base);
+ if (hrtimer_hres_active())
+ return;
+
+ /*
+ * This _is_ ugly: We have to check in the softirq context,
+ * whether we can switch to highres and / or nohz mode. The
+ * clocksource switch happens in the timer interrupt with
+ * xtime_lock held. Notification from there only sets the
+ * check bit in the tick_oneshot code, otherwise we might
+ * deadlock vs. xtime_lock.
+ */
+ if (tick_check_oneshot_change(!hrtimer_is_hres_enabled()))
+ hrtimer_switch_to_hres();
- for (i = 0; i < MAX_HRTIMER_BASES; i++)
- run_hrtimer_queue(&base[i]);
+ hrtimer_get_softirq_time(cpu_base);
+
+ for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++)
+ run_hrtimer_queue(cpu_base, i);
}
/*
* Sleep related functions:
*/
-static int hrtimer_wakeup(struct hrtimer *timer)
+static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer)
{
struct hrtimer_sleeper *t =
container_of(timer, struct hrtimer_sleeper, timer);
{
sl->timer.function = hrtimer_wakeup;
sl->task = task;
+#ifdef CONFIG_HIGH_RES_TIMERS
+ sl->timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_RESTART;
+#endif
}
static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)
set_current_state(TASK_INTERRUPTIBLE);
hrtimer_start(&t->timer, t->timer.expires, mode);
- schedule();
+ if (likely(t->task))
+ schedule();
hrtimer_cancel(&t->timer);
- mode = HRTIMER_ABS;
+ mode = HRTIMER_MODE_ABS;
} while (t->task && !signal_pending(current));
return t->task == NULL;
}
-static long __sched nanosleep_restart(struct restart_block *restart)
+long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
{
struct hrtimer_sleeper t;
struct timespec __user *rmtp;
restart->fn = do_no_restart_syscall;
- hrtimer_init(&t.timer, restart->arg3, HRTIMER_ABS);
- t.timer.expires.tv64 = ((u64)restart->arg1 << 32) | (u64) restart->arg0;
+ hrtimer_init(&t.timer, restart->arg0, HRTIMER_MODE_ABS);
+ t.timer.expires.tv64 = ((u64)restart->arg3 << 32) | (u64) restart->arg2;
- if (do_nanosleep(&t, HRTIMER_ABS))
+ if (do_nanosleep(&t, HRTIMER_MODE_ABS))
return 0;
- rmtp = (struct timespec __user *) restart->arg2;
+ rmtp = (struct timespec __user *) restart->arg1;
if (rmtp) {
time = ktime_sub(t.timer.expires, t.timer.base->get_time());
if (time.tv64 <= 0)
return -EFAULT;
}
- restart->fn = nanosleep_restart;
+ restart->fn = hrtimer_nanosleep_restart;
/* The other values in restart are already filled in */
return -ERESTART_RESTARTBLOCK;
return 0;
/* Absolute timers do not update the rmtp value and restart: */
- if (mode == HRTIMER_ABS)
+ if (mode == HRTIMER_MODE_ABS)
return -ERESTARTNOHAND;
if (rmtp) {
}
restart = ¤t_thread_info()->restart_block;
- restart->fn = nanosleep_restart;
- restart->arg0 = t.timer.expires.tv64 & 0xFFFFFFFF;
- restart->arg1 = t.timer.expires.tv64 >> 32;
- restart->arg2 = (unsigned long) rmtp;
- restart->arg3 = (unsigned long) t.timer.base->index;
+ restart->fn = hrtimer_nanosleep_restart;
+ restart->arg0 = (unsigned long) t.timer.base->index;
+ restart->arg1 = (unsigned long) rmtp;
+ restart->arg2 = t.timer.expires.tv64 & 0xFFFFFFFF;
+ restart->arg3 = t.timer.expires.tv64 >> 32;
return -ERESTART_RESTARTBLOCK;
}
if (!timespec_valid(&tu))
return -EINVAL;
- return hrtimer_nanosleep(&tu, rmtp, HRTIMER_REL, CLOCK_MONOTONIC);
+ return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
}
/*
*/
static void __devinit init_hrtimers_cpu(int cpu)
{
- struct hrtimer_base *base = per_cpu(hrtimer_bases, cpu);
+ struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
int i;
- for (i = 0; i < MAX_HRTIMER_BASES; i++, base++) {
- spin_lock_init(&base->lock);
- lockdep_set_class(&base->lock, &base->lock_key);
- }
+ spin_lock_init(&cpu_base->lock);
+ lockdep_set_class(&cpu_base->lock, &cpu_base->lock_key);
+
+ for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++)
+ cpu_base->clock_base[i].cpu_base = cpu_base;
+
+ hrtimer_init_hres(cpu_base);
}
#ifdef CONFIG_HOTPLUG_CPU
-static void migrate_hrtimer_list(struct hrtimer_base *old_base,
- struct hrtimer_base *new_base)
+static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
+ struct hrtimer_clock_base *new_base)
{
struct hrtimer *timer;
struct rb_node *node;
while ((node = rb_first(&old_base->active))) {
timer = rb_entry(node, struct hrtimer, node);
- __remove_hrtimer(timer, old_base);
+ BUG_ON(hrtimer_callback_running(timer));
+ __remove_hrtimer(timer, old_base, HRTIMER_STATE_INACTIVE, 0);
timer->base = new_base;
- enqueue_hrtimer(timer, new_base);
+ /*
+ * Enqueue the timer. Allow reprogramming of the event device
+ */
+ enqueue_hrtimer(timer, new_base, 1);
}
}
static void migrate_hrtimers(int cpu)
{
- struct hrtimer_base *old_base, *new_base;
+ struct hrtimer_cpu_base *old_base, *new_base;
int i;
BUG_ON(cpu_online(cpu));
- old_base = per_cpu(hrtimer_bases, cpu);
- new_base = get_cpu_var(hrtimer_bases);
-
- local_irq_disable();
+ old_base = &per_cpu(hrtimer_bases, cpu);
+ new_base = &get_cpu_var(hrtimer_bases);
- for (i = 0; i < MAX_HRTIMER_BASES; i++) {
+ tick_cancel_sched_timer(cpu);
- spin_lock(&new_base->lock);
- spin_lock(&old_base->lock);
-
- BUG_ON(old_base->curr_timer);
+ local_irq_disable();
- migrate_hrtimer_list(old_base, new_base);
+ spin_lock(&new_base->lock);
+ spin_lock(&old_base->lock);
- spin_unlock(&old_base->lock);
- spin_unlock(&new_base->lock);
- old_base++;
- new_base++;
+ for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
+ migrate_hrtimer_list(&old_base->clock_base[i],
+ &new_base->clock_base[i]);
}
+ spin_unlock(&old_base->lock);
+ spin_unlock(&new_base->lock);
local_irq_enable();
put_cpu_var(hrtimer_bases);
#ifdef CONFIG_HOTPLUG_CPU
case CPU_DEAD:
+ clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DEAD, &cpu);
migrate_hrtimers(cpu);
break;
#endif
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, NULL);
+#endif
}
git.openpandora.org / pandora-kernel.git / blobdiff