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-rw-r--r--kernel/hrtimer.c106
1 files changed, 76 insertions, 30 deletions
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index f1c4155b49a..14bc9cfa639 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -21,6 +21,12 @@
* 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
*/
@@ -66,6 +72,12 @@ EXPORT_SYMBOL_GPL(ktime_get_real);
/*
* 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
@@ -406,8 +418,19 @@ hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
/* Switch the timer base, if necessary: */
new_base = switch_hrtimer_base(timer, base);
- if (mode == HRTIMER_REL)
+ if (mode == HRTIMER_REL) {
tim = ktime_add(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(tim, base->resolution);
+#endif
+ }
timer->expires = tim;
enqueue_hrtimer(timer, new_base);
@@ -482,30 +505,61 @@ ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
return rem;
}
+#ifdef CONFIG_NO_IDLE_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_base *bases;
+ struct hrtimer_base *base = __get_cpu_var(hrtimer_bases);
+ ktime_t delta, mindelta = { .tv64 = KTIME_MAX };
+ unsigned long flags;
+ int i;
- bases = per_cpu(hrtimer_bases, raw_smp_processor_id());
- timer->base = &bases[clock_id];
+ for (i = 0; i < MAX_HRTIMER_BASES; i++, base++) {
+ struct hrtimer *timer;
+
+ spin_lock_irqsave(&base->lock, flags);
+ if (!base->first) {
+ spin_unlock_irqrestore(&base->lock, flags);
+ continue;
+ }
+ timer = rb_entry(base->first, struct hrtimer, node);
+ delta.tv64 = timer->expires.tv64;
+ spin_unlock_irqrestore(&base->lock, flags);
+ delta = ktime_sub(delta, base->get_time());
+ if (delta.tv64 < mindelta.tv64)
+ mindelta.tv64 = delta.tv64;
+ }
+ if (mindelta.tv64 < 0)
+ mindelta.tv64 = 0;
+ return mindelta;
}
+#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)
{
+ struct hrtimer_base *bases;
+
memset(timer, 0, sizeof(struct hrtimer));
- hrtimer_rebase(timer, clock_id);
+
+ bases = per_cpu(hrtimer_bases, raw_smp_processor_id());
+
+ if (clock_id == CLOCK_REALTIME && mode != HRTIMER_ABS)
+ clock_id = CLOCK_MONOTONIC;
+
+ timer->base = &bases[clock_id];
}
/**
@@ -550,6 +604,7 @@ static inline void run_hrtimer_queue(struct hrtimer_base *base)
fn = timer->function;
data = timer->data;
set_curr_timer(base, timer);
+ timer->state = HRTIMER_RUNNING;
__remove_hrtimer(timer, base);
spin_unlock_irq(&base->lock);
@@ -565,6 +620,10 @@ static inline void run_hrtimer_queue(struct hrtimer_base *base)
spin_lock_irq(&base->lock);
+ /* Another CPU has added back the timer */
+ if (timer->state != HRTIMER_RUNNING)
+ continue;
+
if (restart == HRTIMER_RESTART)
enqueue_hrtimer(timer, base);
else
@@ -638,8 +697,7 @@ schedule_hrtimer_interruptible(struct hrtimer *timer,
return schedule_hrtimer(timer, mode);
}
-static long __sched
-nanosleep_restart(struct restart_block *restart, clockid_t clockid)
+static long __sched nanosleep_restart(struct restart_block *restart)
{
struct timespec __user *rmtp;
struct timespec tu;
@@ -649,7 +707,7 @@ nanosleep_restart(struct restart_block *restart, clockid_t clockid)
restart->fn = do_no_restart_syscall;
- hrtimer_init(&timer, clockid);
+ hrtimer_init(&timer, (clockid_t) restart->arg3, HRTIMER_ABS);
timer.expires.tv64 = ((u64)restart->arg1 << 32) | (u64) restart->arg0;
@@ -669,16 +727,6 @@ nanosleep_restart(struct restart_block *restart, clockid_t clockid)
return -ERESTART_RESTARTBLOCK;
}
-static long __sched nanosleep_restart_mono(struct restart_block *restart)
-{
- return nanosleep_restart(restart, CLOCK_MONOTONIC);
-}
-
-static long __sched nanosleep_restart_real(struct restart_block *restart)
-{
- return nanosleep_restart(restart, CLOCK_REALTIME);
-}
-
long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
const enum hrtimer_mode mode, const clockid_t clockid)
{
@@ -687,7 +735,7 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
struct timespec tu;
ktime_t rem;
- hrtimer_init(&timer, clockid);
+ hrtimer_init(&timer, clockid, mode);
timer.expires = timespec_to_ktime(*rqtp);
@@ -695,7 +743,7 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
if (rem.tv64 <= 0)
return 0;
- /* Absolute timers do not update the rmtp value: */
+ /* Absolute timers do not update the rmtp value and restart: */
if (mode == HRTIMER_ABS)
return -ERESTARTNOHAND;
@@ -705,11 +753,11 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
return -EFAULT;
restart = &current_thread_info()->restart_block;
- restart->fn = (clockid == CLOCK_MONOTONIC) ?
- nanosleep_restart_mono : nanosleep_restart_real;
+ restart->fn = nanosleep_restart;
restart->arg0 = timer.expires.tv64 & 0xFFFFFFFF;
restart->arg1 = timer.expires.tv64 >> 32;
restart->arg2 = (unsigned long) rmtp;
+ restart->arg3 = (unsigned long) timer.base->index;
return -ERESTART_RESTARTBLOCK;
}
@@ -736,10 +784,8 @@ static void __devinit init_hrtimers_cpu(int cpu)
struct hrtimer_base *base = per_cpu(hrtimer_bases, cpu);
int i;
- for (i = 0; i < MAX_HRTIMER_BASES; i++) {
+ for (i = 0; i < MAX_HRTIMER_BASES; i++, base++)
spin_lock_init(&base->lock);
- base++;
- }
}
#ifdef CONFIG_HOTPLUG_CPU
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-20 06:36:44 +0000