/*
* 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
*
* Credits:
* based on kernel/timer.c
*
+ * Help, testing, suggestions, bugfixes, improvements were
+ * provided by:
+ *
+ * George Anzinger, Andrew Morton, Steven Rostedt, Roman Zippel
+ * et. al.
+ *
* For licencing details see kernel-base/COPYING
*/
#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 <linux/debugobjects.h>
+#include <linux/sched.h>
+#include <linux/timer.h>
#include <asm/uaccess.h>
-/**
- * ktime_get - get the monotonic time in ktime_t format
- *
- * returns the time in ktime_t format
- */
-static ktime_t ktime_get(void)
-{
- struct timespec now;
-
- ktime_get_ts(&now);
-
- return timespec_to_ktime(now);
-}
-
-/**
- * ktime_get_real - get the real (wall-) time in ktime_t format
- *
- * returns the time in ktime_t format
- */
-static ktime_t ktime_get_real(void)
-{
- struct timespec now;
-
- getnstimeofday(&now);
-
- return timespec_to_ktime(now);
-}
-
-EXPORT_SYMBOL_GPL(ktime_get_real);
+#include <trace/events/timer.h>
/*
* The timer bases:
+ *
+ * Note: If we want to add new timer bases, we have to skip the two
+ * clock ids captured by the cpu-timers. We do this by holding empty
+ * entries rather than doing math adjustment of the clock ids.
+ * 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,
+ },
+ }
};
-/**
- * ktime_get_ts - get the monotonic clock in timespec format
- *
- * @ts: pointer to timespec variable
- *
- * 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.
+/*
+ * Get the coarse grained time at the softirq based on xtime and
+ * wall_to_monotonic.
*/
-void ktime_get_ts(struct timespec *ts)
+static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
{
- struct timespec tomono;
+ ktime_t xtim, tomono;
+ struct timespec xts, tom;
unsigned long seq;
do {
seq = read_seqbegin(&xtime_lock);
- getnstimeofday(ts);
- tomono = wall_to_monotonic;
-
+ xts = current_kernel_time();
+ tom = wall_to_monotonic;
} while (read_seqretry(&xtime_lock, seq));
- set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec,
- ts->tv_nsec + tomono.tv_nsec);
+ xtim = timespec_to_ktime(xts);
+ tomono = timespec_to_ktime(tom);
+ base->clock_base[CLOCK_REALTIME].softirq_time = xtim;
+ base->clock_base[CLOCK_MONOTONIC].softirq_time =
+ ktime_add(xtim, tomono);
}
-EXPORT_SYMBOL_GPL(ktime_get_ts);
/*
* Functions and macros which are different for UP/SMP systems are kept in a
*/
#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();
}
}
+
+/*
+ * Get the preferred target CPU for NOHZ
+ */
+static int hrtimer_get_target(int this_cpu, int pinned)
+{
+#ifdef CONFIG_NO_HZ
+ if (!pinned && get_sysctl_timer_migration() && idle_cpu(this_cpu)) {
+ int preferred_cpu = get_nohz_load_balancer();
+
+ if (preferred_cpu >= 0)
+ return preferred_cpu;
+ }
+#endif
+ return this_cpu;
+}
+
+/*
+ * With HIGHRES=y we do not migrate the timer when it is expiring
+ * before the next event on the target cpu because we cannot reprogram
+ * the target cpu hardware and we would cause it to fire late.
+ *
+ * Called with cpu_base->lock of target cpu held.
+ */
+static int
+hrtimer_check_target(struct hrtimer *timer, struct hrtimer_clock_base *new_base)
+{
+#ifdef CONFIG_HIGH_RES_TIMERS
+ ktime_t expires;
+
+ if (!new_base->cpu_base->hres_active)
+ return 0;
+
+ expires = ktime_sub(hrtimer_get_expires(timer), new_base->offset);
+ return expires.tv64 <= new_base->cpu_base->expires_next.tv64;
+#else
+ return 0;
+#endif
+}
+
/*
* 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,
+ int pinned)
{
- struct hrtimer_base *new_base;
+ struct hrtimer_clock_base *new_base;
+ struct hrtimer_cpu_base *new_cpu_base;
+ int this_cpu = smp_processor_id();
+ int cpu = hrtimer_get_target(this_cpu, pinned);
- new_base = &__get_cpu_var(hrtimer_bases[base->index]);
+again:
+ new_cpu_base = &per_cpu(hrtimer_bases, cpu);
+ new_base = &new_cpu_base->clock_base[base->index];
if (base != new_base) {
/*
- * We are trying to schedule the timer on the local CPU.
+ * We are trying to move timer to new_base.
* However we can't change timer's base while it is running,
* so we keep it on the same CPU. No hassle vs. reprogramming
* the event source in the high resolution case. The softirq
* 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);
+
+ if (cpu != this_cpu && hrtimer_check_target(timer, new_base)) {
+ cpu = this_cpu;
+ spin_unlock(&new_base->cpu_base->lock);
+ spin_lock(&base->cpu_base->lock);
+ timer->base = base;
+ goto again;
+ }
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, p) (b)
#endif /* !CONFIG_SMP */
# ifndef CONFIG_KTIME_SCALAR
/**
* ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable
- *
* @kt: addend
* @nsec: the scalar nsec value to add
*
return ktime_add(kt, tmp);
}
-#else /* CONFIG_KTIME_SCALAR */
+EXPORT_SYMBOL_GPL(ktime_add_ns);
+
+/**
+ * ktime_sub_ns - Subtract a scalar nanoseconds value from a ktime_t variable
+ * @kt: minuend
+ * @nsec: the scalar nsec value to subtract
+ *
+ * Returns the subtraction of @nsec from @kt in ktime_t format
+ */
+ktime_t ktime_sub_ns(const ktime_t kt, u64 nsec)
+{
+ ktime_t tmp;
+ if (likely(nsec < NSEC_PER_SEC)) {
+ tmp.tv64 = nsec;
+ } else {
+ unsigned long rem = do_div(nsec, NSEC_PER_SEC);
+
+ tmp = ktime_set((long)nsec, rem);
+ }
+
+ return ktime_sub(kt, tmp);
+}
+
+EXPORT_SYMBOL_GPL(ktime_sub_ns);
# endif /* !CONFIG_KTIME_SCALAR */
/*
* Divide a ktime value by a nanosecond value
*/
-static unsigned long ktime_divns(const ktime_t kt, nsec_t div)
+u64 ktime_divns(const ktime_t kt, s64 div)
{
- u64 dclc, inc, dns;
+ u64 dclc;
int sft = 0;
- dclc = dns = ktime_to_ns(kt);
- inc = div;
+ dclc = ktime_to_ns(kt);
/* Make sure the divisor is less than 2^32: */
while (div >> 32) {
sft++;
dclc >>= sft;
do_div(dclc, (unsigned long) div);
- return (unsigned long) dclc;
+ return dclc;
}
-
-#else /* BITS_PER_LONG < 64 */
-# define ktime_divns(kt, div) (unsigned long)((kt).tv64 / (div))
#endif /* BITS_PER_LONG >= 64 */
/*
- * Counterpart to lock_timer_base above:
+ * Add two ktime values and do a safety check for overflow:
+ */
+ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs)
+{
+ ktime_t res = ktime_add(lhs, rhs);
+
+ /*
+ * We use KTIME_SEC_MAX here, the maximum timeout which we can
+ * return to user space in a timespec:
+ */
+ if (res.tv64 < 0 || res.tv64 < lhs.tv64 || res.tv64 < rhs.tv64)
+ res = ktime_set(KTIME_SEC_MAX, 0);
+
+ return res;
+}
+
+EXPORT_SYMBOL_GPL(ktime_add_safe);
+
+#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
+
+static struct debug_obj_descr hrtimer_debug_descr;
+
+/*
+ * fixup_init is called when:
+ * - an active object is initialized
+ */
+static int hrtimer_fixup_init(void *addr, enum debug_obj_state state)
+{
+ struct hrtimer *timer = addr;
+
+ switch (state) {
+ case ODEBUG_STATE_ACTIVE:
+ hrtimer_cancel(timer);
+ debug_object_init(timer, &hrtimer_debug_descr);
+ return 1;
+ default:
+ return 0;
+ }
+}
+
+/*
+ * fixup_activate is called when:
+ * - an active object is activated
+ * - an unknown object is activated (might be a statically initialized object)
+ */
+static int hrtimer_fixup_activate(void *addr, enum debug_obj_state state)
+{
+ switch (state) {
+
+ case ODEBUG_STATE_NOTAVAILABLE:
+ WARN_ON_ONCE(1);
+ return 0;
+
+ case ODEBUG_STATE_ACTIVE:
+ WARN_ON(1);
+
+ default:
+ return 0;
+ }
+}
+
+/*
+ * fixup_free is called when:
+ * - an active object is freed
+ */
+static int hrtimer_fixup_free(void *addr, enum debug_obj_state state)
+{
+ struct hrtimer *timer = addr;
+
+ switch (state) {
+ case ODEBUG_STATE_ACTIVE:
+ hrtimer_cancel(timer);
+ debug_object_free(timer, &hrtimer_debug_descr);
+ return 1;
+ default:
+ return 0;
+ }
+}
+
+static struct debug_obj_descr hrtimer_debug_descr = {
+ .name = "hrtimer",
+ .fixup_init = hrtimer_fixup_init,
+ .fixup_activate = hrtimer_fixup_activate,
+ .fixup_free = hrtimer_fixup_free,
+};
+
+static inline void debug_hrtimer_init(struct hrtimer *timer)
+{
+ debug_object_init(timer, &hrtimer_debug_descr);
+}
+
+static inline void debug_hrtimer_activate(struct hrtimer *timer)
+{
+ debug_object_activate(timer, &hrtimer_debug_descr);
+}
+
+static inline void debug_hrtimer_deactivate(struct hrtimer *timer)
+{
+ debug_object_deactivate(timer, &hrtimer_debug_descr);
+}
+
+static inline void debug_hrtimer_free(struct hrtimer *timer)
+{
+ debug_object_free(timer, &hrtimer_debug_descr);
+}
+
+static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
+ enum hrtimer_mode mode);
+
+void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t clock_id,
+ enum hrtimer_mode mode)
+{
+ debug_object_init_on_stack(timer, &hrtimer_debug_descr);
+ __hrtimer_init(timer, clock_id, mode);
+}
+EXPORT_SYMBOL_GPL(hrtimer_init_on_stack);
+
+void destroy_hrtimer_on_stack(struct hrtimer *timer)
+{
+ debug_object_free(timer, &hrtimer_debug_descr);
+}
+
+#else
+static inline void debug_hrtimer_init(struct hrtimer *timer) { }
+static inline void debug_hrtimer_activate(struct hrtimer *timer) { }
+static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { }
+#endif
+
+static inline void
+debug_init(struct hrtimer *timer, clockid_t clockid,
+ enum hrtimer_mode mode)
+{
+ debug_hrtimer_init(timer);
+ trace_hrtimer_init(timer, clockid, mode);
+}
+
+static inline void debug_activate(struct hrtimer *timer)
+{
+ debug_hrtimer_activate(timer);
+ trace_hrtimer_start(timer);
+}
+
+static inline void debug_deactivate(struct hrtimer *timer)
+{
+ debug_hrtimer_deactivate(timer);
+ trace_hrtimer_cancel(timer);
+}
+
+/* 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 skip_equal)
+{
+ int i;
+ struct hrtimer_clock_base *base = cpu_base->clock_base;
+ ktime_t expires, expires_next;
+
+ 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(hrtimer_get_expires(timer), base->offset);
+ /*
+ * clock_was_set() has changed base->offset so the
+ * result might be negative. Fix it up to prevent a
+ * false positive in clockevents_program_event()
+ */
+ if (expires.tv64 < 0)
+ expires.tv64 = 0;
+ if (expires.tv64 < expires_next.tv64)
+ expires_next = expires;
+ }
+
+ if (skip_equal && expires_next.tv64 == cpu_base->expires_next.tv64)
+ return;
+
+ cpu_base->expires_next.tv64 = expires_next.tv64;
+
+ 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)
+{
+ struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
+ ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
+ int res;
+
+ WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0);
+
+ /*
+ * 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_interrupt 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;
+
+ /*
+ * CLOCK_REALTIME timer might be requested with an absolute
+ * expiry time which is less than base->offset. Nothing wrong
+ * about that, just avoid to call into the tick code, which
+ * has now objections against negative expiry values.
+ */
+ if (expires.tv64 < 0)
+ return -ETIME;
+
+ if (expires.tv64 >= cpu_base->expires_next.tv64)
+ return 0;
+
+ /*
+ * If a hang was detected in the last timer interrupt then we
+ * do not schedule a timer which is earlier than the expiry
+ * which we enforced in the hang detection. We want the system
+ * to make progress.
+ */
+ if (cpu_base->hang_detected)
+ return 0;
+
+ /*
+ * Clockevents returns -ETIME, when the event was in the past.
+ */
+ res = tick_program_event(expires, 0);
+ if (!IS_ERR_VALUE(res))
+ cpu_base->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, 0);
+ 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, 1);
+}
+
+/*
+ * During resume we might have to reprogram the high resolution timer
+ * interrupt (on the local CPU):
+ */
+void hres_timers_resume(void)
+{
+ WARN_ONCE(!irqs_disabled(),
+ KERN_INFO "hres_timers_resume() called with IRQs enabled!");
+
+ retrigger_next_event(NULL);
+}
+
+/*
+ * 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;
+}
+
+/*
+ * Initialize the high resolution related parts of a hrtimer
+ */
+static inline void hrtimer_init_timer_hres(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
+ * 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,
+ int wakeup)
+{
+ if (base->cpu_base->hres_active && hrtimer_reprogram(timer, base)) {
+ if (wakeup) {
+ spin_unlock(&base->cpu_base->lock);
+ raise_softirq_irqoff(HRTIMER_SOFTIRQ);
+ spin_lock(&base->cpu_base->lock);
+ } else
+ __raise_softirq_irqoff(HRTIMER_SOFTIRQ);
+
+ return 1;
+ }
+
+ return 0;
+}
+
+/*
+ * Switch to high resolution mode
+ */
+static int hrtimer_switch_to_hres(void)
+{
+ int cpu = smp_processor_id();
+ struct hrtimer_cpu_base *base = &per_cpu(hrtimer_bases, cpu);
+ unsigned long flags;
+
+ if (base->hres_active)
+ return 1;
+
+ local_irq_save(flags);
+
+ if (tick_init_highres()) {
+ local_irq_restore(flags);
+ printk(KERN_WARNING "Could not switch to high resolution "
+ "mode on CPU %d\n", cpu);
+ return 0;
+ }
+ 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);
+ return 1;
+}
+
+#else
+
+static inline int hrtimer_hres_active(void) { return 0; }
+static inline int hrtimer_is_hres_enabled(void) { return 0; }
+static inline int hrtimer_switch_to_hres(void) { return 0; }
+static inline void
+hrtimer_force_reprogram(struct hrtimer_cpu_base *base, int skip_equal) { }
+static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
+ struct hrtimer_clock_base *base,
+ int wakeup)
+{
+ return 0;
+}
+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 */
+
+static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
+{
+#ifdef CONFIG_TIMER_STATS
+ if (timer->start_site)
+ return;
+ timer->start_site = __builtin_return_address(0);
+ memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
+ timer->start_pid = current->pid;
+#endif
+}
+
+static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
+{
+#ifdef CONFIG_TIMER_STATS
+ timer->start_site = NULL;
+#endif
+}
+
+static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
+{
+#ifdef CONFIG_TIMER_STATS
+ if (likely(!timer_stats_active))
+ return;
+ timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
+ timer->function, timer->start_comm, 0);
+#endif
+}
+
+/*
+ * Counterpart to lock_hrtimer_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);
}
/**
* hrtimer_forward - forward the timer expiry
- *
* @timer: hrtimer to forward
+ * @now: forward past this time
* @interval: the interval to forward
*
* Forward the timer expiry so it will expire in the future.
- * The number of overruns is added to the overrun field.
+ * Returns the number of overruns.
*/
-unsigned long
-hrtimer_forward(struct hrtimer *timer, ktime_t interval)
+u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
{
- unsigned long orun = 1;
- ktime_t delta, now;
-
- now = timer->base->get_time();
+ u64 orun = 1;
+ ktime_t delta;
- delta = ktime_sub(now, timer->expires);
+ delta = ktime_sub(now, hrtimer_get_expires(timer));
if (delta.tv64 < 0)
return 0;
interval.tv64 = timer->base->resolution.tv64;
if (unlikely(delta.tv64 >= interval.tv64)) {
- nsec_t incr = ktime_to_ns(interval);
+ s64 incr = ktime_to_ns(interval);
orun = ktime_divns(delta, incr);
- timer->expires = ktime_add_ns(timer->expires, incr * orun);
- if (timer->expires.tv64 > now.tv64)
+ hrtimer_add_expires_ns(timer, incr * orun);
+ if (hrtimer_get_expires_tv64(timer) > now.tv64)
return orun;
/*
* This (and the ktime_add() below) is the
*/
orun++;
}
- timer->expires = ktime_add(timer->expires, interval);
+ hrtimer_add_expires(timer, interval);
return orun;
}
+EXPORT_SYMBOL_GPL(hrtimer_forward);
/*
* enqueue_hrtimer - internal function to (re)start a timer
*
* The timer is inserted in expiry order. Insertion into the
* red black tree is O(log(n)). Must hold the base lock.
+ *
+ * Returns 1 when the new timer is the leftmost timer in the tree.
*/
-static void enqueue_hrtimer(struct hrtimer *timer, struct hrtimer_base *base)
+static int enqueue_hrtimer(struct hrtimer *timer,
+ struct hrtimer_clock_base *base)
{
struct rb_node **link = &base->active.rb_node;
struct rb_node *parent = NULL;
struct hrtimer *entry;
+ int leftmost = 1;
+
+ debug_activate(timer);
/*
* Find the right place in the rbtree:
* We dont care about collisions. Nodes with
* the same expiry time stay together.
*/
- if (timer->expires.tv64 < entry->expires.tv64)
+ if (hrtimer_get_expires_tv64(timer) <
+ hrtimer_get_expires_tv64(entry)) {
link = &(*link)->rb_left;
- else
+ } else {
link = &(*link)->rb_right;
+ leftmost = 0;
+ }
}
/*
* Insert the timer to the rbtree and check whether it
* replaces the first pending timer
*/
+ if (leftmost)
+ 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;
- timer->state = HRTIMER_PENDING;
-
- if (!base->first || timer->expires.tv64 <
- rb_entry(base->first, struct hrtimer, node)->expires.tv64)
- base->first = &timer->node;
+ return leftmost;
}
/*
* __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)
+{
+ if (!(timer->state & HRTIMER_STATE_ENQUEUED))
+ goto out;
+
+ /*
+ * 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);
+#ifdef CONFIG_HIGH_RES_TIMERS
+ /* Reprogram the clock event device. if enabled */
+ if (reprogram && hrtimer_hres_active()) {
+ ktime_t expires;
+
+ expires = ktime_sub(hrtimer_get_expires(timer),
+ base->offset);
+ if (base->cpu_base->expires_next.tv64 == expires.tv64)
+ hrtimer_force_reprogram(base->cpu_base, 1);
+ }
+#endif
+ }
+ rb_erase(&timer->node, &base->active);
+out:
+ timer->state = newstate;
+}
+
+/*
+ * remove hrtimer, called with base lock held
+ */
+static inline int
+remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *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.
+ */
+ debug_deactivate(timer);
+ 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_range_ns(struct hrtimer *timer, ktime_t tim,
+ unsigned long delta_ns, const enum hrtimer_mode mode,
+ int wakeup)
{
+ struct hrtimer_clock_base *base, *new_base;
+ unsigned long flags;
+ int ret, leftmost;
+
+ base = lock_hrtimer_base(timer, &flags);
+
+ /* Remove an active timer from the queue: */
+ ret = remove_hrtimer(timer, base);
+
+ /* Switch the timer base, if necessary: */
+ new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
+
+ if (mode & HRTIMER_MODE_REL) {
+ tim = ktime_add_safe(tim, new_base->get_time());
+ /*
+ * CONFIG_TIME_LOW_RES is a temporary way for architectures
+ * to signal that they simply return xtime in
+ * do_gettimeoffset(). In this case we want to round up by
+ * resolution when starting a relative timer, to avoid short
+ * timeouts. This will go away with the GTOD framework.
+ */
+#ifdef CONFIG_TIME_LOW_RES
+ tim = ktime_add_safe(tim, base->resolution);
+#endif
+ }
+
+ hrtimer_set_expires_range_ns(timer, tim, delta_ns);
+
+ timer_stats_hrtimer_set_start_info(timer);
+
+ leftmost = enqueue_hrtimer(timer, new_base);
+
/*
- * Remove the timer from the rbtree and replace the
- * first entry pointer if necessary.
+ * Only allow reprogramming if the new base is on this CPU.
+ * (it might still be on another CPU if the timer was pending)
+ *
+ * XXX send_remote_softirq() ?
*/
- if (base->first == &timer->node)
- base->first = rb_next(&timer->node);
- rb_erase(&timer->node, &base->active);
+ if (leftmost && new_base->cpu_base == &__get_cpu_var(hrtimer_bases))
+ hrtimer_enqueue_reprogram(timer, new_base, wakeup);
+
+ unlock_hrtimer_base(timer, &flags);
+
+ return ret;
}
-/*
- * remove hrtimer, called with base lock held
+/**
+ * hrtimer_start_range_ns - (re)start an hrtimer on the current CPU
+ * @timer: the timer to be added
+ * @tim: expiry time
+ * @delta_ns: "slack" range for the timer
+ * @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
+ *
+ * Returns:
+ * 0 on success
+ * 1 when the timer was active
*/
-static inline int
-remove_hrtimer(struct hrtimer *timer, struct hrtimer_base *base)
+int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
+ unsigned long delta_ns, const enum hrtimer_mode mode)
{
- if (hrtimer_active(timer)) {
- __remove_hrtimer(timer, base);
- timer->state = HRTIMER_INACTIVE;
- return 1;
- }
- return 0;
+ return __hrtimer_start_range_ns(timer, tim, delta_ns, mode, 1);
}
+EXPORT_SYMBOL_GPL(hrtimer_start_range_ns);
/**
- * hrtimer_start - (re)start an relative timer on the current CPU
- *
+ * hrtimer_start - (re)start an hrtimer on the current CPU
* @timer: the timer to be added
* @tim: expiry time
* @mode: expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
int
hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
{
- struct hrtimer_base *base, *new_base;
- unsigned long flags;
- int ret;
-
- base = lock_hrtimer_base(timer, &flags);
-
- /* Remove an active timer from the queue: */
- ret = remove_hrtimer(timer, base);
-
- /* Switch the timer base, if necessary: */
- new_base = switch_hrtimer_base(timer, base);
-
- if (mode == HRTIMER_REL)
- tim = ktime_add(tim, new_base->get_time());
- timer->expires = tim;
-
- enqueue_hrtimer(timer, new_base);
-
- unlock_hrtimer_base(timer, &flags);
-
- return ret;
+ return __hrtimer_start_range_ns(timer, tim, 0, mode, 1);
}
+EXPORT_SYMBOL_GPL(hrtimer_start);
+
/**
* hrtimer_try_to_cancel - try to deactivate a timer
- *
* @timer: hrtimer to stop
*
* Returns:
* 0 when the timer was not active
* 1 when the timer was active
* -1 when the timer is currently excuting the callback function and
- * can not be stopped
+ * cannot be stopped
*/
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);
return ret;
}
+EXPORT_SYMBOL_GPL(hrtimer_try_to_cancel);
/**
* hrtimer_cancel - cancel a timer and wait for the handler to finish.
- *
* @timer: the timer to be cancelled
*
* Returns:
if (ret >= 0)
return ret;
+ cpu_relax();
}
}
+EXPORT_SYMBOL_GPL(hrtimer_cancel);
/**
* hrtimer_get_remaining - get remaining time for the timer
- *
* @timer: the timer to read
*/
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 = hrtimer_expires_remaining(timer);
unlock_hrtimer_base(timer, &flags);
return rem;
}
+EXPORT_SYMBOL_GPL(hrtimer_get_remaining);
+#ifdef CONFIG_NO_HZ
/**
- * hrtimer_rebase - rebase an initialized hrtimer to a different base
+ * hrtimer_get_next_event - get the time until next expiry event
*
- * @timer: the timer to be rebased
- * @clock_id: the clock to be used
+ * Returns the delta to the next expiry event or KTIME_MAX if no timer
+ * is pending.
*/
-void hrtimer_rebase(struct hrtimer *timer, const clockid_t clock_id)
+ktime_t hrtimer_get_next_event(void)
+{
+ 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;
+
+ spin_lock_irqsave(&cpu_base->lock, flags);
+
+ 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 = hrtimer_get_expires_tv64(timer);
+ 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;
+}
+#endif
+
+static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
+ enum hrtimer_mode mode)
{
- struct hrtimer_base *bases;
+ struct hrtimer_cpu_base *cpu_base;
- bases = per_cpu(hrtimer_bases, raw_smp_processor_id());
- timer->base = &bases[clock_id];
+ memset(timer, 0, sizeof(struct hrtimer));
+
+ cpu_base = &__raw_get_cpu_var(hrtimer_bases);
+
+ if (clock_id == CLOCK_REALTIME && mode != HRTIMER_MODE_ABS)
+ clock_id = CLOCK_MONOTONIC;
+
+ 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
}
/**
* hrtimer_init - initialize a timer to the given clock
- *
* @timer: the timer to be initialized
* @clock_id: the clock to be used
+ * @mode: timer mode abs/rel
*/
-void hrtimer_init(struct hrtimer *timer, const clockid_t clock_id)
+void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
+ enum hrtimer_mode mode)
{
- memset(timer, 0, sizeof(struct hrtimer));
- hrtimer_rebase(timer, clock_id);
+ debug_init(timer, clock_id, mode);
+ __hrtimer_init(timer, clock_id, mode);
}
+EXPORT_SYMBOL_GPL(hrtimer_init);
/**
* hrtimer_get_res - get the timer resolution for a clock
- *
* @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 = per_cpu(hrtimer_bases, raw_smp_processor_id());
- *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);
+
+static void __run_hrtimer(struct hrtimer *timer, ktime_t *now)
+{
+ struct hrtimer_clock_base *base = timer->base;
+ struct hrtimer_cpu_base *cpu_base = base->cpu_base;
+ enum hrtimer_restart (*fn)(struct hrtimer *);
+ int restart;
+
+ WARN_ON(!irqs_disabled());
+
+ debug_deactivate(timer);
+ __remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
+ timer_stats_account_hrtimer(timer);
+ fn = timer->function;
+
+ /*
+ * 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);
+ trace_hrtimer_expire_entry(timer, now);
+ restart = fn(timer);
+ trace_hrtimer_expire_exit(timer);
+ spin_lock(&cpu_base->lock);
+
+ /*
+ * Note: We clear the CALLBACK bit after enqueue_hrtimer and
+ * we do not reprogramm the event hardware. Happens either in
+ * hrtimer_start_range_ns() or in hrtimer_interrupt()
+ */
+ if (restart != HRTIMER_NORESTART) {
+ BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
+ enqueue_hrtimer(timer, base);
+ }
+ timer->state &= ~HRTIMER_STATE_CALLBACK;
+}
+
+#ifdef CONFIG_HIGH_RES_TIMERS
/*
- * Expire the per base hrtimer-queue:
+ * High resolution timer interrupt
+ * Called with interrupts disabled
*/
-static inline void run_hrtimer_queue(struct hrtimer_base *base)
+void hrtimer_interrupt(struct clock_event_device *dev)
{
- ktime_t now = base->get_time();
- struct rb_node *node;
+ struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
+ struct hrtimer_clock_base *base;
+ ktime_t expires_next, now, entry_time, delta;
+ int i, retries = 0;
- spin_lock_irq(&base->lock);
+ BUG_ON(!cpu_base->hres_active);
+ cpu_base->nr_events++;
+ dev->next_event.tv64 = KTIME_MAX;
- while ((node = base->first)) {
- struct hrtimer *timer;
- int (*fn)(void *);
- int restart;
- void *data;
+ entry_time = now = ktime_get();
+retry:
+ expires_next.tv64 = KTIME_MAX;
- timer = rb_entry(node, struct hrtimer, node);
- if (now.tv64 <= timer->expires.tv64)
- break;
+ spin_lock(&cpu_base->lock);
+ /*
+ * We set expires_next to KTIME_MAX here with cpu_base->lock
+ * held to prevent that a timer is enqueued in our queue via
+ * the migration code. This does not affect enqueueing of
+ * timers which run their callback and need to be requeued on
+ * this CPU.
+ */
+ cpu_base->expires_next.tv64 = KTIME_MAX;
- fn = timer->function;
- data = timer->data;
- set_curr_timer(base, timer);
- __remove_hrtimer(timer, base);
- spin_unlock_irq(&base->lock);
+ base = cpu_base->clock_base;
- /*
- * fn == NULL is special case for the simplest timer
- * variant - wake up process and do not restart:
- */
- if (!fn) {
- wake_up_process(data);
- restart = HRTIMER_NORESTART;
- } else
- restart = fn(data);
+ for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
+ ktime_t basenow;
+ struct rb_node *node;
+
+ basenow = ktime_add(now, base->offset);
+
+ while ((node = base->first)) {
+ struct hrtimer *timer;
- spin_lock_irq(&base->lock);
+ timer = rb_entry(node, struct hrtimer, node);
- if (restart == HRTIMER_RESTART)
- enqueue_hrtimer(timer, base);
- else
- timer->state = HRTIMER_EXPIRED;
+ /*
+ * The immediate goal for using the softexpires is
+ * minimizing wakeups, not running timers at the
+ * earliest interrupt after their soft expiration.
+ * This allows us to avoid using a Priority Search
+ * Tree, which can answer a stabbing querry for
+ * overlapping intervals and instead use the simple
+ * BST we already have.
+ * We don't add extra wakeups by delaying timers that
+ * are right-of a not yet expired timer, because that
+ * timer will have to trigger a wakeup anyway.
+ */
+
+ if (basenow.tv64 < hrtimer_get_softexpires_tv64(timer)) {
+ ktime_t expires;
+
+ expires = ktime_sub(hrtimer_get_expires(timer),
+ base->offset);
+ if (expires.tv64 < expires_next.tv64)
+ expires_next = expires;
+ break;
+ }
+
+ __run_hrtimer(timer, &basenow);
+ }
+ base++;
+ }
+
+ /*
+ * Store the new expiry value so the migration code can verify
+ * against it.
+ */
+ cpu_base->expires_next = expires_next;
+ spin_unlock(&cpu_base->lock);
+
+ /* Reprogramming necessary ? */
+ if (expires_next.tv64 == KTIME_MAX ||
+ !tick_program_event(expires_next, 0)) {
+ cpu_base->hang_detected = 0;
+ return;
}
- set_curr_timer(base, NULL);
- spin_unlock_irq(&base->lock);
+
+ /*
+ * The next timer was already expired due to:
+ * - tracing
+ * - long lasting callbacks
+ * - being scheduled away when running in a VM
+ *
+ * We need to prevent that we loop forever in the hrtimer
+ * interrupt routine. We give it 3 attempts to avoid
+ * overreacting on some spurious event.
+ */
+ now = ktime_get();
+ cpu_base->nr_retries++;
+ if (++retries < 3)
+ goto retry;
+ /*
+ * Give the system a chance to do something else than looping
+ * here. We stored the entry time, so we know exactly how long
+ * we spent here. We schedule the next event this amount of
+ * time away.
+ */
+ cpu_base->nr_hangs++;
+ cpu_base->hang_detected = 1;
+ delta = ktime_sub(now, entry_time);
+ if (delta.tv64 > cpu_base->max_hang_time.tv64)
+ cpu_base->max_hang_time = delta;
+ /*
+ * Limit it to a sensible value as we enforce a longer
+ * delay. Give the CPU at least 100ms to catch up.
+ */
+ if (delta.tv64 > 100 * NSEC_PER_MSEC)
+ expires_next = ktime_add_ns(now, 100 * NSEC_PER_MSEC);
+ else
+ expires_next = ktime_add(now, delta);
+ tick_program_event(expires_next, 1);
+ printk_once(KERN_WARNING "hrtimer: interrupt took %llu ns\n",
+ ktime_to_ns(delta));
}
/*
- * Called from timer softirq every jiffy, expire hrtimers:
+ * local version of hrtimer_peek_ahead_timers() called with interrupts
+ * disabled.
*/
-void hrtimer_run_queues(void)
+static void __hrtimer_peek_ahead_timers(void)
{
- struct hrtimer_base *base = __get_cpu_var(hrtimer_bases);
- int i;
+ struct tick_device *td;
- for (i = 0; i < MAX_HRTIMER_BASES; i++)
- run_hrtimer_queue(&base[i]);
-}
+ if (!hrtimer_hres_active())
+ return;
-/*
- * Sleep related functions:
- */
+ td = &__get_cpu_var(tick_cpu_device);
+ if (td && td->evtdev)
+ hrtimer_interrupt(td->evtdev);
+}
/**
- * schedule_hrtimer - sleep until timeout
- *
- * @timer: hrtimer variable initialized with the correct clock base
- * @mode: timeout value is abs/rel
- *
- * Make the current task sleep until @timeout is
- * elapsed.
- *
- * You can set the task state as follows -
- *
- * %TASK_UNINTERRUPTIBLE - at least @timeout is guaranteed to
- * pass before the routine returns. The routine will return 0
+ * hrtimer_peek_ahead_timers -- run soft-expired timers now
*
- * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
- * delivered to the current task. In this case the remaining time
- * will be returned
+ * hrtimer_peek_ahead_timers will peek at the timer queue of
+ * the current cpu and check if there are any timers for which
+ * the soft expires time has passed. If any such timers exist,
+ * they are run immediately and then removed from the timer queue.
*
- * The current task state is guaranteed to be TASK_RUNNING when this
- * routine returns.
*/
-static ktime_t __sched
-schedule_hrtimer(struct hrtimer *timer, const enum hrtimer_mode mode)
+void hrtimer_peek_ahead_timers(void)
{
- /* fn stays NULL, meaning single-shot wakeup: */
- timer->data = current;
-
- hrtimer_start(timer, timer->expires, mode);
+ unsigned long flags;
- schedule();
- hrtimer_cancel(timer);
+ local_irq_save(flags);
+ __hrtimer_peek_ahead_timers();
+ local_irq_restore(flags);
+}
- /* Return the remaining time: */
- if (timer->state != HRTIMER_EXPIRED)
- return ktime_sub(timer->expires, timer->base->get_time());
- else
- return (ktime_t) {.tv64 = 0 };
+static void run_hrtimer_softirq(struct softirq_action *h)
+{
+ hrtimer_peek_ahead_timers();
}
-static inline ktime_t __sched
-schedule_hrtimer_interruptible(struct hrtimer *timer,
- const enum hrtimer_mode mode)
+#else /* CONFIG_HIGH_RES_TIMERS */
+
+static inline void __hrtimer_peek_ahead_timers(void) { }
+
+#endif /* !CONFIG_HIGH_RES_TIMERS */
+
+/*
+ * 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_pending(void)
{
- set_current_state(TASK_INTERRUPTIBLE);
+ if (hrtimer_hres_active())
+ return;
- return schedule_hrtimer(timer, mode);
+ /*
+ * 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();
}
-static long __sched
-nanosleep_restart(struct restart_block *restart, clockid_t clockid)
+/*
+ * Called from hardirq context every jiffy
+ */
+void hrtimer_run_queues(void)
{
- struct timespec __user *rmtp, tu;
- void *rfn_save = restart->fn;
- struct hrtimer timer;
- ktime_t rem;
+ struct rb_node *node;
+ struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
+ struct hrtimer_clock_base *base;
+ int index, gettime = 1;
- restart->fn = do_no_restart_syscall;
+ if (hrtimer_hres_active())
+ return;
- hrtimer_init(&timer, clockid);
+ for (index = 0; index < HRTIMER_MAX_CLOCK_BASES; index++) {
+ base = &cpu_base->clock_base[index];
- timer.expires.tv64 = ((u64)restart->arg1 << 32) | (u64) restart->arg0;
+ if (!base->first)
+ continue;
- rem = schedule_hrtimer_interruptible(&timer, HRTIMER_ABS);
+ if (gettime) {
+ hrtimer_get_softirq_time(cpu_base);
+ gettime = 0;
+ }
- if (rem.tv64 <= 0)
- return 0;
+ spin_lock(&cpu_base->lock);
- rmtp = (struct timespec __user *) restart->arg2;
- tu = ktime_to_timespec(rem);
- if (rmtp && copy_to_user(rmtp, &tu, sizeof(tu)))
- return -EFAULT;
+ while ((node = base->first)) {
+ struct hrtimer *timer;
- restart->fn = rfn_save;
+ timer = rb_entry(node, struct hrtimer, node);
+ if (base->softirq_time.tv64 <=
+ hrtimer_get_expires_tv64(timer))
+ break;
- /* The other values in restart are already filled in */
- return -ERESTART_RESTARTBLOCK;
+ __run_hrtimer(timer, &base->softirq_time);
+ }
+ spin_unlock(&cpu_base->lock);
+ }
}
-static long __sched nanosleep_restart_mono(struct restart_block *restart)
+/*
+ * Sleep related functions:
+ */
+static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer)
{
- return nanosleep_restart(restart, CLOCK_MONOTONIC);
+ struct hrtimer_sleeper *t =
+ container_of(timer, struct hrtimer_sleeper, timer);
+ struct task_struct *task = t->task;
+
+ t->task = NULL;
+ if (task)
+ wake_up_process(task);
+
+ return HRTIMER_NORESTART;
}
-static long __sched nanosleep_restart_real(struct restart_block *restart)
+void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task)
{
- return nanosleep_restart(restart, CLOCK_REALTIME);
+ sl->timer.function = hrtimer_wakeup;
+ sl->task = task;
}
+EXPORT_SYMBOL_GPL(hrtimer_init_sleeper);
-long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
- const enum hrtimer_mode mode, const clockid_t clockid)
+static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)
{
- struct restart_block *restart;
- struct hrtimer timer;
- struct timespec tu;
- ktime_t rem;
+ hrtimer_init_sleeper(t, current);
+
+ do {
+ set_current_state(TASK_INTERRUPTIBLE);
+ hrtimer_start_expires(&t->timer, mode);
+ if (!hrtimer_active(&t->timer))
+ t->task = NULL;
- hrtimer_init(&timer, clockid);
+ if (likely(t->task))
+ schedule();
- timer.expires = timespec_to_ktime(*rqtp);
+ hrtimer_cancel(&t->timer);
+ mode = HRTIMER_MODE_ABS;
- rem = schedule_hrtimer_interruptible(&timer, mode);
+ } while (t->task && !signal_pending(current));
+
+ __set_current_state(TASK_RUNNING);
+
+ return t->task == NULL;
+}
+
+static int update_rmtp(struct hrtimer *timer, struct timespec __user *rmtp)
+{
+ struct timespec rmt;
+ ktime_t rem;
+
+ rem = hrtimer_expires_remaining(timer);
if (rem.tv64 <= 0)
return 0;
+ rmt = ktime_to_timespec(rem);
- /* Absolute timers do not update the rmtp value: */
- if (mode == HRTIMER_ABS)
- return -ERESTARTNOHAND;
+ if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
+ return -EFAULT;
- tu = ktime_to_timespec(rem);
+ return 1;
+}
- if (rmtp && copy_to_user(rmtp, &tu, sizeof(tu)))
- return -EFAULT;
+long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
+{
+ struct hrtimer_sleeper t;
+ struct timespec __user *rmtp;
+ int ret = 0;
+
+ hrtimer_init_on_stack(&t.timer, restart->nanosleep.index,
+ HRTIMER_MODE_ABS);
+ hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires);
+
+ if (do_nanosleep(&t, HRTIMER_MODE_ABS))
+ goto out;
+
+ rmtp = restart->nanosleep.rmtp;
+ if (rmtp) {
+ ret = update_rmtp(&t.timer, rmtp);
+ if (ret <= 0)
+ goto out;
+ }
- restart = ¤t_thread_info()->restart_block;
- restart->fn = (clockid == CLOCK_MONOTONIC) ?
- nanosleep_restart_mono : nanosleep_restart_real;
- restart->arg0 = timer.expires.tv64 & 0xFFFFFFFF;
- restart->arg1 = timer.expires.tv64 >> 32;
- restart->arg2 = (unsigned long) rmtp;
+ /* The other values in restart are already filled in */
+ ret = -ERESTART_RESTARTBLOCK;
+out:
+ destroy_hrtimer_on_stack(&t.timer);
+ return ret;
+}
- return -ERESTART_RESTARTBLOCK;
+long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
+ const enum hrtimer_mode mode, const clockid_t clockid)
+{
+ struct restart_block *restart;
+ struct hrtimer_sleeper t;
+ int ret = 0;
+ unsigned long slack;
+
+ slack = current->timer_slack_ns;
+ if (rt_task(current))
+ slack = 0;
+
+ hrtimer_init_on_stack(&t.timer, clockid, mode);
+ hrtimer_set_expires_range_ns(&t.timer, timespec_to_ktime(*rqtp), slack);
+ if (do_nanosleep(&t, mode))
+ goto out;
+
+ /* Absolute timers do not update the rmtp value and restart: */
+ if (mode == HRTIMER_MODE_ABS) {
+ ret = -ERESTARTNOHAND;
+ goto out;
+ }
+
+ if (rmtp) {
+ ret = update_rmtp(&t.timer, rmtp);
+ if (ret <= 0)
+ goto out;
+ }
+
+ restart = ¤t_thread_info()->restart_block;
+ restart->fn = hrtimer_nanosleep_restart;
+ restart->nanosleep.index = t.timer.base->index;
+ restart->nanosleep.rmtp = rmtp;
+ restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer);
+
+ ret = -ERESTART_RESTARTBLOCK;
+out:
+ destroy_hrtimer_on_stack(&t.timer);
+ return ret;
}
-asmlinkage long
-sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp)
+SYSCALL_DEFINE2(nanosleep, struct timespec __user *, rqtp,
+ struct timespec __user *, rmtp)
{
struct timespec tu;
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);
}
/*
* Functions related to boot-time initialization:
*/
-static void __devinit init_hrtimers_cpu(int cpu)
+static void __cpuinit 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++) {
- spin_lock_init(&base->lock);
- base++;
- }
+ spin_lock_init(&cpu_base->lock);
+
+ 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));
+ debug_deactivate(timer);
+
+ /*
+ * Mark it as STATE_MIGRATE not INACTIVE otherwise the
+ * timer could be seen as !active and just vanish away
+ * under us on another CPU
+ */
+ __remove_hrtimer(timer, old_base, HRTIMER_STATE_MIGRATE, 0);
timer->base = new_base;
+ /*
+ * Enqueue the timers on the new cpu. This does not
+ * reprogram the event device in case the timer
+ * expires before the earliest on this CPU, but we run
+ * hrtimer_interrupt after we migrated everything to
+ * sort out already expired timers and reprogram the
+ * event device.
+ */
enqueue_hrtimer(timer, new_base);
+
+ /* Clear the migration state bit */
+ timer->state &= ~HRTIMER_STATE_MIGRATE;
}
}
-static void migrate_hrtimers(int cpu)
+static void migrate_hrtimers(int scpu)
{
- 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);
+ BUG_ON(cpu_online(scpu));
+ tick_cancel_sched_timer(scpu);
local_irq_disable();
+ old_base = &per_cpu(hrtimer_bases, scpu);
+ new_base = &__get_cpu_var(hrtimer_bases);
+ /*
+ * The caller is globally serialized and nobody else
+ * takes two locks at once, deadlock is not possible.
+ */
+ spin_lock(&new_base->lock);
+ spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
- for (i = 0; i < MAX_HRTIMER_BASES; i++) {
-
- spin_lock(&new_base->lock);
- spin_lock(&old_base->lock);
-
- BUG_ON(old_base->curr_timer);
-
- migrate_hrtimer_list(old_base, new_base);
-
- 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);
+
+ /* Check, if we got expired work to do */
+ __hrtimer_peek_ahead_timers();
local_irq_enable();
- put_cpu_var(hrtimer_bases);
}
+
#endif /* CONFIG_HOTPLUG_CPU */
-static int __devinit hrtimer_cpu_notify(struct notifier_block *self,
+static int __cpuinit hrtimer_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
- long cpu = (long)hcpu;
+ int scpu = (long)hcpu;
switch (action) {
case CPU_UP_PREPARE:
- init_hrtimers_cpu(cpu);
+ case CPU_UP_PREPARE_FROZEN:
+ init_hrtimers_cpu(scpu);
break;
#ifdef CONFIG_HOTPLUG_CPU
+ case CPU_DYING:
+ case CPU_DYING_FROZEN:
+ clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DYING, &scpu);
+ break;
case CPU_DEAD:
- migrate_hrtimers(cpu);
+ case CPU_DEAD_FROZEN:
+ {
+ clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DEAD, &scpu);
+ migrate_hrtimers(scpu);
break;
+ }
#endif
default:
return NOTIFY_OK;
}
-static struct notifier_block __devinitdata hrtimers_nb = {
+static struct notifier_block __cpuinitdata hrtimers_nb = {
.notifier_call = hrtimer_cpu_notify,
};
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
+}
+
+/**
+ * schedule_hrtimeout_range - sleep until timeout
+ * @expires: timeout value (ktime_t)
+ * @delta: slack in expires timeout (ktime_t)
+ * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
+ *
+ * Make the current task sleep until the given expiry time has
+ * elapsed. The routine will return immediately unless
+ * the current task state has been set (see set_current_state()).
+ *
+ * The @delta argument gives the kernel the freedom to schedule the
+ * actual wakeup to a time that is both power and performance friendly.
+ * The kernel give the normal best effort behavior for "@expires+@delta",
+ * but may decide to fire the timer earlier, but no earlier than @expires.
+ *
+ * You can set the task state as follows -
+ *
+ * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
+ * pass before the routine returns.
+ *
+ * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
+ * delivered to the current task.
+ *
+ * The current task state is guaranteed to be TASK_RUNNING when this
+ * routine returns.
+ *
+ * Returns 0 when the timer has expired otherwise -EINTR
+ */
+int __sched schedule_hrtimeout_range(ktime_t *expires, unsigned long delta,
+ const enum hrtimer_mode mode)
+{
+ struct hrtimer_sleeper t;
+
+ /*
+ * Optimize when a zero timeout value is given. It does not
+ * matter whether this is an absolute or a relative time.
+ */
+ if (expires && !expires->tv64) {
+ __set_current_state(TASK_RUNNING);
+ return 0;
+ }
+
+ /*
+ * A NULL parameter means "inifinte"
+ */
+ if (!expires) {
+ schedule();
+ __set_current_state(TASK_RUNNING);
+ return -EINTR;
+ }
+
+ hrtimer_init_on_stack(&t.timer, CLOCK_MONOTONIC, mode);
+ hrtimer_set_expires_range_ns(&t.timer, *expires, delta);
+
+ hrtimer_init_sleeper(&t, current);
+
+ hrtimer_start_expires(&t.timer, mode);
+ if (!hrtimer_active(&t.timer))
+ t.task = NULL;
+
+ if (likely(t.task))
+ schedule();
+
+ hrtimer_cancel(&t.timer);
+ destroy_hrtimer_on_stack(&t.timer);
+
+ __set_current_state(TASK_RUNNING);
+
+ return !t.task ? 0 : -EINTR;
}
+EXPORT_SYMBOL_GPL(schedule_hrtimeout_range);
+/**
+ * schedule_hrtimeout - sleep until timeout
+ * @expires: timeout value (ktime_t)
+ * @mode: timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
+ *
+ * Make the current task sleep until the given expiry time has
+ * elapsed. The routine will return immediately unless
+ * the current task state has been set (see set_current_state()).
+ *
+ * You can set the task state as follows -
+ *
+ * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
+ * pass before the routine returns.
+ *
+ * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
+ * delivered to the current task.
+ *
+ * The current task state is guaranteed to be TASK_RUNNING when this
+ * routine returns.
+ *
+ * Returns 0 when the timer has expired otherwise -EINTR
+ */
+int __sched schedule_hrtimeout(ktime_t *expires,
+ const enum hrtimer_mode mode)
+{
+ return schedule_hrtimeout_range(expires, 0, mode);
+}
+EXPORT_SYMBOL_GPL(schedule_hrtimeout);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff