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-rw-r--r--include/linux/hrtimer.h1
-rw-r--r--include/linux/interrupt.h3
-rw-r--r--kernel/time/hrtimer.c163
-rw-r--r--kernel/time/tick-common.c10
-rw-r--r--kernel/time/timer.c2
5 files changed, 55 insertions, 124 deletions
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index d194c1d..048270a 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -459,7 +459,6 @@ extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode);
/* Soft interrupt function to run the hrtimer queues: */
extern void hrtimer_run_queues(void);
-extern void hrtimer_run_pending(void);
/* Bootup initialization: */
extern void __init hrtimers_init(void);
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 950ae45..6bf15a6 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -413,7 +413,8 @@ enum
BLOCK_IOPOLL_SOFTIRQ,
TASKLET_SOFTIRQ,
SCHED_SOFTIRQ,
- HRTIMER_SOFTIRQ,
+ HRTIMER_SOFTIRQ, /* Unused, but kept as tools rely on the
+ numbering. Sigh! */
RCU_SOFTIRQ, /* Preferable RCU should always be the last softirq */
NR_SOFTIRQS
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 30178d0..fc6b6d2 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -555,59 +555,48 @@ hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
}
/*
- * 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.
*
- * 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.
- *
* Called with interrupts disabled and base->cpu_base.lock held
*/
-static int hrtimer_reprogram(struct hrtimer *timer,
- struct hrtimer_clock_base *base)
+static void hrtimer_reprogram(struct hrtimer *timer,
+ struct hrtimer_clock_base *base)
{
struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&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 the timer is not on the current cpu, we cannot reprogram
+ * the other cpus clock event device.
*/
- if (hrtimer_callback_running(timer))
- return 0;
+ if (base->cpu_base != cpu_base)
+ return;
+
+ /*
+ * If the hrtimer interrupt is running, then it will
+ * reevaluate the clock bases and reprogram the clock event
+ * device. The callbacks are always executed in hard interrupt
+ * context so we don't need an extra check for a running
+ * callback.
+ */
+ if (cpu_base->in_hrtirq)
+ return;
/*
* 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.
+ * expiry time which is less than base->offset. Set it to 0.
*/
if (expires.tv64 < 0)
- return -ETIME;
+ expires.tv64 = 0;
if (expires.tv64 >= cpu_base->expires_next.tv64)
- return 0;
-
- /*
- * When the target cpu of the timer is currently executing
- * hrtimer_interrupt(), then we do not touch the clock event
- * device. hrtimer_interrupt() will reevaluate all clock bases
- * before reprogramming the device.
- */
- if (cpu_base->in_hrtirq)
- return 0;
+ return;
+ /* Update the pointer to the next expiring timer */
cpu_base->next_timer = timer;
/*
@@ -617,15 +606,14 @@ static int hrtimer_reprogram(struct hrtimer *timer,
* to make progress.
*/
if (cpu_base->hang_detected)
- return 0;
+ return;
/*
- * Clockevents returns -ETIME, when the event was in the past.
+ * Program the timer hardware. We enforce the expiry for
+ * events which are already in the past.
*/
- res = tick_program_event(expires, 0);
- if (!IS_ERR_VALUE(res))
- cpu_base->expires_next = expires;
- return res;
+ cpu_base->expires_next = expires;
+ tick_program_event(expires, 1);
}
/*
@@ -660,19 +648,11 @@ static void retrigger_next_event(void *arg)
*/
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);
+ struct hrtimer_cpu_base *base = this_cpu_ptr(&hrtimer_bases);
if (tick_init_highres()) {
- local_irq_restore(flags);
printk(KERN_WARNING "Could not switch to high resolution "
- "mode on CPU %d\n", cpu);
+ "mode on CPU %d\n", base->cpu);
return 0;
}
base->hres_active = 1;
@@ -681,7 +661,6 @@ static int hrtimer_switch_to_hres(void)
tick_setup_sched_timer();
/* "Retrigger" the interrupt to get things going */
retrigger_next_event(NULL);
- local_irq_restore(flags);
return 1;
}
@@ -984,26 +963,8 @@ int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
* on dynticks target.
*/
wake_up_nohz_cpu(new_base->cpu_base->cpu);
- } else if (new_base->cpu_base == this_cpu_ptr(&hrtimer_bases) &&
- hrtimer_reprogram(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 (wakeup) {
- /*
- * We need to drop cpu_base->lock to avoid a
- * lock ordering issue vs. rq->lock.
- */
- raw_spin_unlock(&new_base->cpu_base->lock);
- raise_softirq_irqoff(HRTIMER_SOFTIRQ);
- local_irq_restore(flags);
- return ret;
- } else {
- __raise_softirq_irqoff(HRTIMER_SOFTIRQ);
- }
+ } else {
+ hrtimer_reprogram(timer, new_base);
}
unlock_hrtimer_base(timer, &flags);
@@ -1354,7 +1315,7 @@ retry:
* local version of hrtimer_peek_ahead_timers() called with interrupts
* disabled.
*/
-static void __hrtimer_peek_ahead_timers(void)
+static inline void __hrtimer_peek_ahead_timers(void)
{
struct tick_device *td;
@@ -1366,29 +1327,6 @@ static void __hrtimer_peek_ahead_timers(void)
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) { }
@@ -1396,31 +1334,7 @@ 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
+ * Called from run_local_timers in hardirq context every jiffy
*/
void hrtimer_run_queues(void)
{
@@ -1430,6 +1344,18 @@ void hrtimer_run_queues(void)
if (__hrtimer_hres_active(cpu_base))
return;
+ /*
+ * This _is_ ugly: We have to check periodically, whether we
+ * can switch to highres and / or nohz mode. The clocksource
+ * switch happens 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();
+ return;
+ }
+
raw_spin_lock(&cpu_base->lock);
now = hrtimer_update_base(cpu_base);
__hrtimer_run_queues(cpu_base, now);
@@ -1700,9 +1626,6 @@ 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
}
/**
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index 3ae6afa..ea5f9ea 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -102,6 +102,16 @@ void tick_handle_periodic(struct clock_event_device *dev)
tick_periodic(cpu);
+#if defined(CONFIG_HIGH_RES_TIMERS) || defined(CONFIG_NO_HZ_COMMON)
+ /*
+ * The cpu might have transitioned to HIGHRES or NOHZ mode via
+ * update_process_times() -> run_local_timers() ->
+ * hrtimer_run_queues().
+ */
+ if (dev->event_handler != tick_handle_periodic)
+ return;
+#endif
+
if (dev->state != CLOCK_EVT_STATE_ONESHOT)
return;
for (;;) {
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 2ece3aa..b31f13f 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1409,8 +1409,6 @@ static void run_timer_softirq(struct softirq_action *h)
{
struct tvec_base *base = __this_cpu_read(tvec_bases);
- hrtimer_run_pending();
-
if (time_after_eq(jiffies, base->timer_jiffies))
__run_timers(base);
}
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