Linux-2.6.33.2/kernel/hrtimer.c
/*
* linux/kernel/hrtimer.c
*
* 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
*
* In contrast to the low-resolution timeout API implemented in
* kernel/timer.c, hrtimers provide finer resolution and accuracy
* depending on system configuration and capabilities.
*
* These timers are currently used for:
* - itimers
* - POSIX timers
* - nanosleep
* - precise in-kernel timing
*
* Started by: Thomas Gleixner and Ingo Molnar
*
* 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/cpu.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 <linux/debugobjects.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <asm/uaccess.h>
#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_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
{
.clock_base =
{
{
.index = CLOCK_REALTIME,
.get_time = &ktime_get_real,
.resolution = KTIME_LOW_RES,
},
{
.index = CLOCK_MONOTONIC,
.get_time = &ktime_get,
.resolution = KTIME_LOW_RES,
},
}
};
/*
* Get the coarse grained time at the softirq based on xtime and
* wall_to_monotonic.
*/
static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
{
ktime_t xtim, tomono;
struct timespec xts, tom;
unsigned long seq;
do {
seq = read_seqbegin(&xtime_lock);
xts = current_kernel_time();
tom = wall_to_monotonic;
} while (read_seqretry(&xtime_lock, seq));
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);
}
/*
* Functions and macros which are different for UP/SMP systems are kept in a
* single place
*/
#ifdef CONFIG_SMP
/*
* 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
* locked, and the base itself is locked too.
*
* So __run_timers/migrate_timers can safely modify all timers which could
* be found on the lists/queues.
*
* When the timer's base is locked, and the timer removed from list, it is
* possible to set timer->base = NULL and drop the lock: the timer remains
* locked.
*/
static
struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
unsigned long *flags)
{
struct hrtimer_clock_base *base;
for (;;) {
base = timer->base;
if (likely(base != NULL)) {
raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
if (likely(base == timer->base))
return base;
/* The timer has migrated to another CPU: */
raw_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_clock_base *
switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
int pinned)
{
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);
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 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
* code will take care of this when the timer function has
* completed. There is no conflict as we hold the lock until
* the timer is enqueued.
*/
if (unlikely(hrtimer_callback_running(timer)))
return base;
/* See the comment in lock_timer_base() */
timer->base = NULL;
raw_spin_unlock(&base->cpu_base->lock);
raw_spin_lock(&new_base->cpu_base->lock);
if (cpu != this_cpu && hrtimer_check_target(timer, new_base)) {
cpu = this_cpu;
raw_spin_unlock(&new_base->cpu_base->lock);
raw_spin_lock(&base->cpu_base->lock);
timer->base = base;
goto again;
}
timer->base = new_base;
}
return new_base;
}
#else /* CONFIG_SMP */
static inline struct hrtimer_clock_base *
lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
{
struct hrtimer_clock_base *base = timer->base;
raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
return base;
}
# define switch_hrtimer_base(t, b, p) (b)
#endif /* !CONFIG_SMP */
/*
* Functions for the union type storage format of ktime_t which are
* too large for inlining:
*/
#if BITS_PER_LONG < 64
# 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
*
* Returns the sum of kt and nsec in ktime_t format
*/
ktime_t ktime_add_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_add(kt, tmp);
}
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
*/
u64 ktime_divns(const ktime_t kt, s64 div)
{
u64 dclc;
int sft = 0;
dclc = ktime_to_ns(kt);
/* Make sure the divisor is less than 2^32: */
while (div >> 32) {
sft++;
div >>= 1;
}
dclc >>= sft;
do_div(dclc, (unsigned long) div);
return dclc;
}
#endif /* BITS_PER_LONG >= 64 */
/*
* 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 */
raw_spin_lock(&base->lock);
base->clock_base[CLOCK_REALTIME].offset =
timespec_to_ktime(realtime_offset);
hrtimer_force_reprogram(base, 0);
raw_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) {
raw_spin_unlock(&base->cpu_base->lock);
raise_softirq_irqoff(HRTIMER_SOFTIRQ);
raw_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)
{
raw_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.
* Returns the number of overruns.
*/
u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
{
u64 orun = 1;
ktime_t delta;
delta = ktime_sub(now, hrtimer_get_expires(timer));
if (delta.tv64 < 0)
return 0;
if (interval.tv64 < timer->base->resolution.tv64)
interval.tv64 = timer->base->resolution.tv64;
if (unlikely(delta.tv64 >= interval.tv64)) {
s64 incr = ktime_to_ns(interval);
orun = ktime_divns(delta, incr);
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
* correction for exact:
*/
orun++;
}
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 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:
*/
while (*link) {
parent = *link;
entry = rb_entry(parent, struct hrtimer, node);
/*
* We dont care about collisions. Nodes with
* the same expiry time stay together.
*/
if (hrtimer_get_expires_tv64(timer) <
hrtimer_get_expires_tv64(entry)) {
link = &(*link)->rb_left;
} 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;
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_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);
/*
* 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 (leftmost && new_base->cpu_base == &__get_cpu_var(hrtimer_bases))
hrtimer_enqueue_reprogram(timer, new_base, wakeup);
unlock_hrtimer_base(timer, &flags);
return ret;
}
/**
* 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
*/
int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
unsigned long delta_ns, const enum hrtimer_mode mode)
{
return __hrtimer_start_range_ns(timer, tim, delta_ns, mode, 1);
}
EXPORT_SYMBOL_GPL(hrtimer_start_range_ns);
/**
* 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)
*
* Returns:
* 0 on success
* 1 when the timer was active
*/
int
hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
{
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
* cannot be stopped
*/
int hrtimer_try_to_cancel(struct hrtimer *timer)
{
struct hrtimer_clock_base *base;
unsigned long flags;
int ret = -1;
base = lock_hrtimer_base(timer, &flags);
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:
* 0 when the timer was not active
* 1 when the timer was active
*/
int hrtimer_cancel(struct hrtimer *timer)
{
for (;;) {
int ret = hrtimer_try_to_cancel(timer);
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_clock_base *base;
unsigned long flags;
ktime_t rem;
base = lock_hrtimer_base(timer, &flags);
rem = hrtimer_expires_remaining(timer);
unlock_hrtimer_base(timer, &flags);
return rem;
}
EXPORT_SYMBOL_GPL(hrtimer_get_remaining);
#ifdef CONFIG_NO_HZ
/**
* hrtimer_get_next_event - get the time until next expiry event
*
* Returns the delta to the next expiry event or KTIME_MAX if no timer
* is pending.
*/
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;
raw_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;
}
}
raw_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_cpu_base *cpu_base;
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, clockid_t clock_id,
enum hrtimer_mode mode)
{
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.
*/
int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp)
{
struct hrtimer_cpu_base *cpu_base;
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.
*/
raw_spin_unlock(&cpu_base->lock);
trace_hrtimer_expire_entry(timer, now);
restart = fn(timer);
trace_hrtimer_expire_exit(timer);
raw_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
/*
* 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, entry_time, delta;
int i, retries = 0;
BUG_ON(!cpu_base->hres_active);
cpu_base->nr_events++;
dev->next_event.tv64 = KTIME_MAX;
entry_time = now = ktime_get();
retry:
expires_next.tv64 = KTIME_MAX;
raw_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;
base = cpu_base->clock_base;
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;
timer = rb_entry(node, struct hrtimer, node);
/*
* 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;
raw_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;
}
/*
* 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));
}
/*
* local version of hrtimer_peek_ahead_timers() called with interrupts
* disabled.
*/
static void __hrtimer_peek_ahead_timers(void)
{
struct tick_device *td;
if (!hrtimer_hres_active())
return;
td = &__get_cpu_var(tick_cpu_device);
if (td && td->evtdev)
hrtimer_interrupt(td->evtdev);
}
/**
* hrtimer_peek_ahead_timers -- run soft-expired timers now
*
* 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.
*
*/
void hrtimer_peek_ahead_timers(void)
{
unsigned long flags;
local_irq_save(flags);
__hrtimer_peek_ahead_timers();
local_irq_restore(flags);
}
static void run_hrtimer_softirq(struct softirq_action *h)
{
hrtimer_peek_ahead_timers();
}
#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)
{
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();
}
/*
* Called from hardirq context every jiffy
*/
void hrtimer_run_queues(void)
{
struct rb_node *node;
struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
struct hrtimer_clock_base *base;
int index, gettime = 1;
if (hrtimer_hres_active())
return;
for (index = 0; index < HRTIMER_MAX_CLOCK_BASES; index++) {
base = &cpu_base->clock_base[index];
if (!base->first)
continue;
if (gettime) {
hrtimer_get_softirq_time(cpu_base);
gettime = 0;
}
raw_spin_lock(&cpu_base->lock);
while ((node = base->first)) {
struct hrtimer *timer;
timer = rb_entry(node, struct hrtimer, node);
if (base->softirq_time.tv64 <=
hrtimer_get_expires_tv64(timer))
break;
__run_hrtimer(timer, &base->softirq_time);
}
raw_spin_unlock(&cpu_base->lock);
}
}
/*
* Sleep related functions:
*/
static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer)
{
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;
}
void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task)
{
sl->timer.function = hrtimer_wakeup;
sl->task = task;
}
EXPORT_SYMBOL_GPL(hrtimer_init_sleeper);
static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)
{
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;
if (likely(t->task))
schedule();
hrtimer_cancel(&t->timer);
mode = HRTIMER_MODE_ABS;
} 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);
if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
return -EFAULT;
return 1;
}
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;
}
/* The other values in restart are already filled in */
ret = -ERESTART_RESTARTBLOCK;
out:
destroy_hrtimer_on_stack(&t.timer);
return ret;
}
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;
}
SYSCALL_DEFINE2(nanosleep, struct timespec __user *, rqtp,
struct timespec __user *, rmtp)
{
struct timespec tu;
if (copy_from_user(&tu, rqtp, sizeof(tu)))
return -EFAULT;
if (!timespec_valid(&tu))
return -EINVAL;
return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
}
/*
* Functions related to boot-time initialization:
*/
static void __cpuinit init_hrtimers_cpu(int cpu)
{
struct hrtimer_cpu_base *cpu_base = &per_cpu(hrtimer_bases, cpu);
int i;
raw_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_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);
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 scpu)
{
struct hrtimer_cpu_base *old_base, *new_base;
int i;
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.
*/
raw_spin_lock(&new_base->lock);
raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
migrate_hrtimer_list(&old_base->clock_base[i],
&new_base->clock_base[i]);
}
raw_spin_unlock(&old_base->lock);
raw_spin_unlock(&new_base->lock);
/* Check, if we got expired work to do */
__hrtimer_peek_ahead_timers();
local_irq_enable();
}
#endif /* CONFIG_HOTPLUG_CPU */
static int __cpuinit hrtimer_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
int scpu = (long)hcpu;
switch (action) {
case CPU_UP_PREPARE:
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:
case CPU_DEAD_FROZEN:
{
clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DEAD, &scpu);
migrate_hrtimers(scpu);
break;
}
#endif
default:
break;
}
return NOTIFY_OK;
}
static struct notifier_block __cpuinitdata hrtimers_nb = {
.notifier_call = hrtimer_cpu_notify,
};
void __init hrtimers_init(void)
{
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);