Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
  time, s390: Get rid of compile warning
  dw_apb_timer: constify clocksource name
  time: Cleanup old CONFIG_GENERIC_TIME references that snuck in
  time: Change jiffies_to_clock_t() argument type to unsigned long
  alarmtimers: Fix error handling
  clocksource: Make watchdog reset lockless
  posix-cpu-timers: Cure SMP accounting oddities
  s390: Use direct ktime path for s390 clockevent device
  clockevents: Add direct ktime programming function
  clockevents: Make minimum delay adjustments configurable
  nohz: Remove "Switched to NOHz mode" debugging messages
  proc: Consider NO_HZ when printing idle and iowait times
  nohz: Make idle/iowait counter update conditional
  nohz: Fix update_ts_time_stat idle accounting
  cputime: Clean up cputime_to_usecs and usecs_to_cputime macros
  alarmtimers: Rework RTC device selection using class interface
  alarmtimers: Add try_to_cancel functionality
  alarmtimers: Add more refined alarm state tracking
  alarmtimers: Remove period from alarm structure
  alarmtimers: Remove interval cap limit hack
  ...

9 files changed, 364 insertions, 213 deletions

diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig
index f06a8a365648..b26c2228fe92 100644
--- a/kernel/time/Kconfig
+++ b/kernel/time/Kconfig
@@ -27,3 +27,5 @@ config GENERIC_CLOCKEVENTS_BUILD
         default y
         depends on GENERIC_CLOCKEVENTS || GENERIC_CLOCKEVENTS_MIGR
 
+config GENERIC_CLOCKEVENTS_MIN_ADJUST
+        bool
diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index ea5e1a928d5b..c436e790b21b 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -53,27 +53,6 @@ static struct rtc_device	*rtcdev;
 static DEFINE_SPINLOCK(rtcdev_lock);
 
 /**
- * has_wakealarm - check rtc device has wakealarm ability
- * @dev: current device
- * @name_ptr: name to be returned
- *
- * This helper function checks to see if the rtc device can wake
- * from suspend.
- */
-static int has_wakealarm(struct device *dev, void *name_ptr)
-{
-        struct rtc_device *candidate = to_rtc_device(dev);
-
-        if (!candidate->ops->set_alarm)
-                return 0;
-        if (!device_may_wakeup(candidate->dev.parent))
-                return 0;
-
-        *(const char **)name_ptr = dev_name(dev);
-        return 1;
-}
-
-/**
  * alarmtimer_get_rtcdev - Return selected rtcdevice
  *
  * This function returns the rtc device to use for wakealarms.
@@ -82,37 +61,64 @@ static int has_wakealarm(struct device *dev, void *name_ptr)
  */
 static struct rtc_device *alarmtimer_get_rtcdev(void)
 {
-        struct device *dev;
-        char *str;
         unsigned long flags;
         struct rtc_device *ret;
 
         spin_lock_irqsave(&rtcdev_lock, flags);
-        if (!rtcdev) {
-                /* Find an rtc device and init the rtc_timer */
-                dev = class_find_device(rtc_class, NULL, &str, has_wakealarm);
-                /* If we have a device then str is valid. See has_wakealarm() */
-                if (dev) {
-                        rtcdev = rtc_class_open(str);
-                        /*
-                         * Drop the reference we got in class_find_device,
-                         * rtc_open takes its own.
-                         */
-                        put_device(dev);
-                        rtc_timer_init(&rtctimer, NULL, NULL);
-                }
-        }
         ret = rtcdev;
         spin_unlock_irqrestore(&rtcdev_lock, flags);
 
         return ret;
 }
+
+
+static int alarmtimer_rtc_add_device(struct device *dev,
+                                struct class_interface *class_intf)
+{
+        unsigned long flags;
+        struct rtc_device *rtc = to_rtc_device(dev);
+
+        if (rtcdev)
+                return -EBUSY;
+
+        if (!rtc->ops->set_alarm)
+                return -1;
+        if (!device_may_wakeup(rtc->dev.parent))
+                return -1;
+
+        spin_lock_irqsave(&rtcdev_lock, flags);
+        if (!rtcdev) {
+                rtcdev = rtc;
+                /* hold a reference so it doesn't go away */
+                get_device(dev);
+        }
+        spin_unlock_irqrestore(&rtcdev_lock, flags);
+        return 0;
+}
+
+static struct class_interface alarmtimer_rtc_interface = {
+        .add_dev = &alarmtimer_rtc_add_device,
+};
+
+static int alarmtimer_rtc_interface_setup(void)
+{
+        alarmtimer_rtc_interface.class = rtc_class;
+        return class_interface_register(&alarmtimer_rtc_interface);
+}
+static void alarmtimer_rtc_interface_remove(void)
+{
+        class_interface_unregister(&alarmtimer_rtc_interface);
+}
 #else
-#define alarmtimer_get_rtcdev() (0)
-#define rtcdev (0)
+static inline struct rtc_device *alarmtimer_get_rtcdev(void)
+{
+        return NULL;
+}
+#define rtcdev (NULL)
+static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
+static inline void alarmtimer_rtc_interface_remove(void) { }
 #endif
 
-
 /**
  * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
  * @base: pointer to the base where the timer is being run
@@ -126,6 +132,8 @@ static struct rtc_device *alarmtimer_get_rtcdev(void)
 static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
 {
         timerqueue_add(&base->timerqueue, &alarm->node);
+        alarm->state |= ALARMTIMER_STATE_ENQUEUED;
+
         if (&alarm->node == timerqueue_getnext(&base->timerqueue)) {
                 hrtimer_try_to_cancel(&base->timer);
                 hrtimer_start(&base->timer, alarm->node.expires,
@@ -147,7 +155,12 @@ static void alarmtimer_remove(struct alarm_base *base, struct alarm *alarm)
 {
         struct timerqueue_node *next = timerqueue_getnext(&base->timerqueue);
 
+        if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
+                return;
+
         timerqueue_del(&base->timerqueue, &alarm->node);
+        alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
+
         if (next == &alarm->node) {
                 hrtimer_try_to_cancel(&base->timer);
                 next = timerqueue_getnext(&base->timerqueue);
@@ -174,6 +187,7 @@ static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
         unsigned long flags;
         ktime_t now;
         int ret = HRTIMER_NORESTART;
+        int restart = ALARMTIMER_NORESTART;
 
         spin_lock_irqsave(&base->lock, flags);
         now = base->gettime();
@@ -187,17 +201,19 @@ static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
                 alarm = container_of(next, struct alarm, node);
 
                 timerqueue_del(&base->timerqueue, &alarm->node);
-                alarm->enabled = 0;
-                /* Re-add periodic timers */
-                if (alarm->period.tv64) {
-                        alarm->node.expires = ktime_add(expired, alarm->period);
-                        timerqueue_add(&base->timerqueue, &alarm->node);
-                        alarm->enabled = 1;
-                }
+                alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
+
+                alarm->state |= ALARMTIMER_STATE_CALLBACK;
                 spin_unlock_irqrestore(&base->lock, flags);
                 if (alarm->function)
-                        alarm->function(alarm);
+                        restart = alarm->function(alarm, now);
                 spin_lock_irqsave(&base->lock, flags);
+                alarm->state &= ~ALARMTIMER_STATE_CALLBACK;
+
+                if (restart != ALARMTIMER_NORESTART) {
+                        timerqueue_add(&base->timerqueue, &alarm->node);
+                        alarm->state |= ALARMTIMER_STATE_ENQUEUED;
+                }
         }
 
         if (next) {
@@ -234,7 +250,7 @@ static int alarmtimer_suspend(struct device *dev)
         freezer_delta = ktime_set(0, 0);
         spin_unlock_irqrestore(&freezer_delta_lock, flags);
 
-        rtc = rtcdev;
+        rtc = alarmtimer_get_rtcdev();
         /* If we have no rtcdev, just return */
         if (!rtc)
                 return 0;
@@ -299,53 +315,111 @@ static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
  * @function: callback that is run when the alarm fires
  */
 void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
-                void (*function)(struct alarm *))
+                enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
 {
         timerqueue_init(&alarm->node);
-        alarm->period = ktime_set(0, 0);
         alarm->function = function;
         alarm->type = type;
-        alarm->enabled = 0;
+        alarm->state = ALARMTIMER_STATE_INACTIVE;
 }
 
 /**
  * alarm_start - Sets an alarm to fire
  * @alarm: ptr to alarm to set
  * @start: time to run the alarm
- * @period: period at which the alarm will recur
  */
-void alarm_start(struct alarm *alarm, ktime_t start, ktime_t period)
+void alarm_start(struct alarm *alarm, ktime_t start)
 {
         struct alarm_base *base = &alarm_bases[alarm->type];
         unsigned long flags;
 
         spin_lock_irqsave(&base->lock, flags);
-        if (alarm->enabled)
+        if (alarmtimer_active(alarm))
                 alarmtimer_remove(base, alarm);
         alarm->node.expires = start;
-        alarm->period = period;
         alarmtimer_enqueue(base, alarm);
-        alarm->enabled = 1;
         spin_unlock_irqrestore(&base->lock, flags);
 }
 
 /**
- * alarm_cancel - Tries to cancel an alarm timer
+ * alarm_try_to_cancel - Tries to cancel an alarm timer
  * @alarm: ptr to alarm to be canceled
+ *
+ * Returns 1 if the timer was canceled, 0 if it was not running,
+ * and -1 if the callback was running
  */
-void alarm_cancel(struct alarm *alarm)
+int alarm_try_to_cancel(struct alarm *alarm)
 {
         struct alarm_base *base = &alarm_bases[alarm->type];
         unsigned long flags;
-
+        int ret = -1;
         spin_lock_irqsave(&base->lock, flags);
-        if (alarm->enabled)
+
+        if (alarmtimer_callback_running(alarm))
+                goto out;
+
+        if (alarmtimer_is_queued(alarm)) {
                 alarmtimer_remove(base, alarm);
-        alarm->enabled = 0;
+                ret = 1;
+        } else
+                ret = 0;
+out:
         spin_unlock_irqrestore(&base->lock, flags);
+        return ret;
+}
+
+
+/**
+ * alarm_cancel - Spins trying to cancel an alarm timer until it is done
+ * @alarm: ptr to alarm to be canceled
+ *
+ * Returns 1 if the timer was canceled, 0 if it was not active.
+ */
+int alarm_cancel(struct alarm *alarm)
+{
+        for (;;) {
+                int ret = alarm_try_to_cancel(alarm);
+                if (ret >= 0)
+                        return ret;
+                cpu_relax();
+        }
+}
+
+
+u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
+{
+        u64 overrun = 1;
+        ktime_t delta;
+
+        delta = ktime_sub(now, alarm->node.expires);
+
+        if (delta.tv64 < 0)
+                return 0;
+
+        if (unlikely(delta.tv64 >= interval.tv64)) {
+                s64 incr = ktime_to_ns(interval);
+
+                overrun = ktime_divns(delta, incr);
+
+                alarm->node.expires = ktime_add_ns(alarm->node.expires,
+                                                        incr*overrun);
+
+                if (alarm->node.expires.tv64 > now.tv64)
+                        return overrun;
+                /*
+                 * This (and the ktime_add() below) is the
+                 * correction for exact:
+                 */
+                overrun++;
+        }
+
+        alarm->node.expires = ktime_add(alarm->node.expires, interval);
+        return overrun;
 }
 
 
+
+
 /**
  * clock2alarm - helper that converts from clockid to alarmtypes
  * @clockid: clockid.
@@ -365,12 +439,21 @@ static enum alarmtimer_type clock2alarm(clockid_t clockid)
  *
  * Posix timer callback for expired alarm timers.
  */
-static void alarm_handle_timer(struct alarm *alarm)
+static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
+                                                        ktime_t now)
 {
         struct k_itimer *ptr = container_of(alarm, struct k_itimer,
-                                                it.alarmtimer);
+                                                it.alarm.alarmtimer);
         if (posix_timer_event(ptr, 0) != 0)
                 ptr->it_overrun++;
+
+        /* Re-add periodic timers */
+        if (ptr->it.alarm.interval.tv64) {
+                ptr->it_overrun += alarm_forward(alarm, now,
+                                                ptr->it.alarm.interval);
+                return ALARMTIMER_RESTART;
+        }
+        return ALARMTIMER_NORESTART;
 }
 
 /**
@@ -427,7 +510,7 @@ static int alarm_timer_create(struct k_itimer *new_timer)
 
         type = clock2alarm(new_timer->it_clock);
         base = &alarm_bases[type];
-        alarm_init(&new_timer->it.alarmtimer, type, alarm_handle_timer);
+        alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
         return 0;
 }
 
@@ -444,9 +527,9 @@ static void alarm_timer_get(struct k_itimer *timr,
         memset(cur_setting, 0, sizeof(struct itimerspec));
 
         cur_setting->it_interval =
-                        ktime_to_timespec(timr->it.alarmtimer.period);
+                        ktime_to_timespec(timr->it.alarm.interval);
         cur_setting->it_value =
-                        ktime_to_timespec(timr->it.alarmtimer.node.expires);
+                ktime_to_timespec(timr->it.alarm.alarmtimer.node.expires);
         return;
 }
 
@@ -461,7 +544,9 @@ static int alarm_timer_del(struct k_itimer *timr)
         if (!rtcdev)
                 return -ENOTSUPP;
 
-        alarm_cancel(&timr->it.alarmtimer);
+        if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
+                return TIMER_RETRY;
+
         return 0;
 }
 
@@ -481,25 +566,17 @@ static int alarm_timer_set(struct k_itimer *timr, int flags,
         if (!rtcdev)
                 return -ENOTSUPP;
 
-        /*
-         * XXX HACK! Currently we can DOS a system if the interval
-         * period on alarmtimers is too small. Cap the interval here
-         * to 100us and solve this properly in a future patch! -jstultz
-         */
-        if ((new_setting->it_interval.tv_sec == 0) &&
-                        (new_setting->it_interval.tv_nsec < 100000))
-                new_setting->it_interval.tv_nsec = 100000;
-
         if (old_setting)
                 alarm_timer_get(timr, old_setting);
 
         /* If the timer was already set, cancel it */
-        alarm_cancel(&timr->it.alarmtimer);
+        if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
+                return TIMER_RETRY;
 
         /* start the timer */
-        alarm_start(&timr->it.alarmtimer,
-                        timespec_to_ktime(new_setting->it_value),
-                        timespec_to_ktime(new_setting->it_interval));
+        timr->it.alarm.interval = timespec_to_ktime(new_setting->it_interval);
+        alarm_start(&timr->it.alarm.alarmtimer,
+                        timespec_to_ktime(new_setting->it_value));
         return 0;
 }
 
@@ -509,13 +586,15 @@ static int alarm_timer_set(struct k_itimer *timr, int flags,
  *
  * Wakes up the task that set the alarmtimer
  */
-static void alarmtimer_nsleep_wakeup(struct alarm *alarm)
+static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
+                                                                ktime_t now)
 {
         struct task_struct *task = (struct task_struct *)alarm->data;
 
         alarm->data = NULL;
         if (task)
                 wake_up_process(task);
+        return ALARMTIMER_NORESTART;
 }
 
 /**
@@ -530,7 +609,7 @@ static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp)
         alarm->data = (void *)current;
         do {
                 set_current_state(TASK_INTERRUPTIBLE);
-                alarm_start(alarm, absexp, ktime_set(0, 0));
+                alarm_start(alarm, absexp);
                 if (likely(alarm->data))
                         schedule();
 
@@ -691,6 +770,7 @@ static struct platform_driver alarmtimer_driver = {
  */
 static int __init alarmtimer_init(void)
 {
+        struct platform_device *pdev;
         int error = 0;
         int i;
         struct k_clock alarm_clock = {
@@ -719,10 +799,26 @@ static int __init alarmtimer_init(void)
                                 HRTIMER_MODE_ABS);
                 alarm_bases[i].timer.function = alarmtimer_fired;
         }
+
+        error = alarmtimer_rtc_interface_setup();
+        if (error)
+                return error;
+
         error = platform_driver_register(&alarmtimer_driver);
-        platform_device_register_simple("alarmtimer", -1, NULL, 0);
+        if (error)
+                goto out_if;
 
+        pdev = platform_device_register_simple("alarmtimer", -1, NULL, 0);
+        if (IS_ERR(pdev)) {
+                error = PTR_ERR(pdev);
+                goto out_drv;
+        }
+        return 0;
+
+out_drv:
+        platform_driver_unregister(&alarmtimer_driver);
+out_if:
+        alarmtimer_rtc_interface_remove();
         return error;
 }
 device_initcall(alarmtimer_init);
-
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index e4c699dfa4e8..1ecd6ba36d6c 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -94,42 +94,143 @@ void clockevents_shutdown(struct clock_event_device *dev)
         dev->next_event.tv64 = KTIME_MAX;
 }
 
+#ifdef CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST
+
+/* Limit min_delta to a jiffie */
+#define MIN_DELTA_LIMIT         (NSEC_PER_SEC / HZ)
+
+/**
+ * clockevents_increase_min_delta - raise minimum delta of a clock event device
+ * @dev:       device to increase the minimum delta
+ *
+ * Returns 0 on success, -ETIME when the minimum delta reached the limit.
+ */
+static int clockevents_increase_min_delta(struct clock_event_device *dev)
+{
+        /* Nothing to do if we already reached the limit */
+        if (dev->min_delta_ns >= MIN_DELTA_LIMIT) {
+                printk(KERN_WARNING "CE: Reprogramming failure. Giving up\n");
+                dev->next_event.tv64 = KTIME_MAX;
+                return -ETIME;
+        }
+
+        if (dev->min_delta_ns < 5000)
+                dev->min_delta_ns = 5000;
+        else
+                dev->min_delta_ns += dev->min_delta_ns >> 1;
+
+        if (dev->min_delta_ns > MIN_DELTA_LIMIT)
+                dev->min_delta_ns = MIN_DELTA_LIMIT;
+
+        printk(KERN_WARNING "CE: %s increased min_delta_ns to %llu nsec\n",
+               dev->name ? dev->name : "?",
+               (unsigned long long) dev->min_delta_ns);
+        return 0;
+}
+
+/**
+ * clockevents_program_min_delta - Set clock event device to the minimum delay.
+ * @dev:        device to program
+ *
+ * Returns 0 on success, -ETIME when the retry loop failed.
+ */
+static int clockevents_program_min_delta(struct clock_event_device *dev)
+{
+        unsigned long long clc;
+        int64_t delta;
+        int i;
+
+        for (i = 0;;) {
+                delta = dev->min_delta_ns;
+                dev->next_event = ktime_add_ns(ktime_get(), delta);
+
+                if (dev->mode == CLOCK_EVT_MODE_SHUTDOWN)
+                        return 0;
+
+                dev->retries++;
+                clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
+                if (dev->set_next_event((unsigned long) clc, dev) == 0)
+                        return 0;
+
+                if (++i > 2) {
+                        /*
+                         * We tried 3 times to program the device with the
+                         * given min_delta_ns. Try to increase the minimum
+                         * delta, if that fails as well get out of here.
+                         */
+                        if (clockevents_increase_min_delta(dev))
+                                return -ETIME;
+                        i = 0;
+                }
+        }
+}
+
+#else  /* CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST */
+
+/**
+ * clockevents_program_min_delta - Set clock event device to the minimum delay.
+ * @dev:        device to program
+ *
+ * Returns 0 on success, -ETIME when the retry loop failed.
+ */
+static int clockevents_program_min_delta(struct clock_event_device *dev)
+{
+        unsigned long long clc;
+        int64_t delta;
+
+        delta = dev->min_delta_ns;
+        dev->next_event = ktime_add_ns(ktime_get(), delta);
+
+        if (dev->mode == CLOCK_EVT_MODE_SHUTDOWN)
+                return 0;
+
+        dev->retries++;
+        clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
+        return dev->set_next_event((unsigned long) clc, dev);
+}
+
+#endif /* CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST */
+
 /**
  * clockevents_program_event - Reprogram the clock event device.
+ * @dev:        device to program
  * @expires:    absolute expiry time (monotonic clock)
+ * @force:      program minimum delay if expires can not be set
  *
  * Returns 0 on success, -ETIME when the event is in the past.
  */
 int clockevents_program_event(struct clock_event_device *dev, ktime_t expires,
-                              ktime_t now)
+                              bool force)
 {
         unsigned long long clc;
         int64_t delta;
+        int rc;
 
         if (unlikely(expires.tv64 < 0)) {
                 WARN_ON_ONCE(1);
                 return -ETIME;
         }
 
-        delta = ktime_to_ns(ktime_sub(expires, now));
-
-        if (delta <= 0)
-                return -ETIME;
-
         dev->next_event = expires;
 
         if (dev->mode == CLOCK_EVT_MODE_SHUTDOWN)
                 return 0;
 
-        if (delta > dev->max_delta_ns)
-                delta = dev->max_delta_ns;
-        if (delta < dev->min_delta_ns)
-                delta = dev->min_delta_ns;
+        /* Shortcut for clockevent devices that can deal with ktime. */
+        if (dev->features & CLOCK_EVT_FEAT_KTIME)
+                return dev->set_next_ktime(expires, dev);
+
+        delta = ktime_to_ns(ktime_sub(expires, ktime_get()));
+        if (delta <= 0)
+                return force ? clockevents_program_min_delta(dev) : -ETIME;
 
-        clc = delta * dev->mult;
-        clc >>= dev->shift;
+        delta = min(delta, (int64_t) dev->max_delta_ns);
+        delta = max(delta, (int64_t) dev->min_delta_ns);
 
-        return dev->set_next_event((unsigned long) clc, dev);
+        clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
+        rc = dev->set_next_event((unsigned long) clc, dev);
+
+        return (rc && force) ? clockevents_program_min_delta(dev) : rc;
 }
 
 /**
@@ -258,7 +359,7 @@ int clockevents_update_freq(struct clock_event_device *dev, u32 freq)
         if (dev->mode != CLOCK_EVT_MODE_ONESHOT)
                 return 0;
 
-        return clockevents_program_event(dev, dev->next_event, ktime_get());
+        return clockevents_program_event(dev, dev->next_event, false);
 }
 
 /*
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index e0980f0d9a0a..cf52fda2e096 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -186,6 +186,7 @@ static struct timer_list watchdog_timer;
 static DECLARE_WORK(watchdog_work, clocksource_watchdog_work);
 static DEFINE_SPINLOCK(watchdog_lock);
 static int watchdog_running;
+static atomic_t watchdog_reset_pending;
 
 static int clocksource_watchdog_kthread(void *data);
 static void __clocksource_change_rating(struct clocksource *cs, int rating);
@@ -247,12 +248,14 @@ static void clocksource_watchdog(unsigned long data)
         struct clocksource *cs;
         cycle_t csnow, wdnow;
         int64_t wd_nsec, cs_nsec;
-        int next_cpu;
+        int next_cpu, reset_pending;
 
         spin_lock(&watchdog_lock);
         if (!watchdog_running)
                 goto out;
 
+        reset_pending = atomic_read(&watchdog_reset_pending);
+
         list_for_each_entry(cs, &watchdog_list, wd_list) {
 
                 /* Clocksource already marked unstable? */
@@ -268,7 +271,8 @@ static void clocksource_watchdog(unsigned long data)
                 local_irq_enable();
 
                 /* Clocksource initialized ? */
-                if (!(cs->flags & CLOCK_SOURCE_WATCHDOG)) {
+                if (!(cs->flags & CLOCK_SOURCE_WATCHDOG) ||
+                    atomic_read(&watchdog_reset_pending)) {
                         cs->flags |= CLOCK_SOURCE_WATCHDOG;
                         cs->wd_last = wdnow;
                         cs->cs_last = csnow;
@@ -283,8 +287,11 @@ static void clocksource_watchdog(unsigned long data)
                 cs->cs_last = csnow;
                 cs->wd_last = wdnow;
 
+                if (atomic_read(&watchdog_reset_pending))
+                        continue;
+
                 /* Check the deviation from the watchdog clocksource. */
-                if (abs(cs_nsec - wd_nsec) > WATCHDOG_THRESHOLD) {
+                if ((abs(cs_nsec - wd_nsec) > WATCHDOG_THRESHOLD)) {
                         clocksource_unstable(cs, cs_nsec - wd_nsec);
                         continue;
                 }
@@ -303,6 +310,13 @@ static void clocksource_watchdog(unsigned long data)
         }
 
         /*
+         * We only clear the watchdog_reset_pending, when we did a
+         * full cycle through all clocksources.
+         */
+        if (reset_pending)
+                atomic_dec(&watchdog_reset_pending);
+
+        /*
          * Cycle through CPUs to check if the CPUs stay synchronized
          * to each other.
          */
@@ -344,23 +358,7 @@ static inline void clocksource_reset_watchdog(void)
 
 static void clocksource_resume_watchdog(void)
 {
-        unsigned long flags;
-
-        /*
-         * We use trylock here to avoid a potential dead lock when
-         * kgdb calls this code after the kernel has been stopped with
-         * watchdog_lock held. When watchdog_lock is held we just
-         * return and accept, that the watchdog might trigger and mark
-         * the monitored clock source (usually TSC) unstable.
-         *
-         * This does not affect the other caller clocksource_resume()
-         * because at this point the kernel is UP, interrupts are
-         * disabled and nothing can hold watchdog_lock.
-         */
-        if (!spin_trylock_irqsave(&watchdog_lock, flags))
-                return;
-        clocksource_reset_watchdog();
-        spin_unlock_irqrestore(&watchdog_lock, flags);
+        atomic_inc(&watchdog_reset_pending);
 }
 
 static void clocksource_enqueue_watchdog(struct clocksource *cs)
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index c7218d132738..f954282d9a82 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -194,7 +194,7 @@ static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
         for (next = dev->next_event; ;) {
                 next = ktime_add(next, tick_period);
 
-                if (!clockevents_program_event(dev, next, ktime_get()))
+                if (!clockevents_program_event(dev, next, false))
                         return;
                 tick_do_periodic_broadcast();
         }
@@ -373,7 +373,7 @@ static int tick_broadcast_set_event(ktime_t expires, int force)
 {
         struct clock_event_device *bc = tick_broadcast_device.evtdev;
 
-        return tick_dev_program_event(bc, expires, force);
+        return clockevents_program_event(bc, expires, force);
 }
 
 int tick_resume_broadcast_oneshot(struct clock_event_device *bc)
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index 119528de8235..da6c9ecad4e4 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -94,7 +94,7 @@ void tick_handle_periodic(struct clock_event_device *dev)
          */
         next = ktime_add(dev->next_event, tick_period);
         for (;;) {
-                if (!clockevents_program_event(dev, next, ktime_get()))
+                if (!clockevents_program_event(dev, next, false))
                         return;
                 /*
                  * Have to be careful here. If we're in oneshot mode,
@@ -137,7 +137,7 @@ void tick_setup_periodic(struct clock_event_device *dev, int broadcast)
                 clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT);
 
                 for (;;) {
-                        if (!clockevents_program_event(dev, next, ktime_get()))
+                        if (!clockevents_program_event(dev, next, false))
                                 return;
                         next = ktime_add(next, tick_period);
                 }
diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index 1009b06d6f89..4e265b901fed 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -26,8 +26,6 @@ extern void clockevents_shutdown(struct clock_event_device *dev);
 extern void tick_setup_oneshot(struct clock_event_device *newdev,
                                void (*handler)(struct clock_event_device *),
                                ktime_t nextevt);
-extern int tick_dev_program_event(struct clock_event_device *dev,
-                                  ktime_t expires, int force);
 extern int tick_program_event(ktime_t expires, int force);
 extern void tick_oneshot_notify(void);
 extern int tick_switch_to_oneshot(void (*handler)(struct clock_event_device *));
diff --git a/kernel/time/tick-oneshot.c b/kernel/time/tick-oneshot.c
index 2d04411a5f05..824109060a33 100644
--- a/kernel/time/tick-oneshot.c
+++ b/kernel/time/tick-oneshot.c
@@ -21,74 +21,6 @@
 
 #include "tick-internal.h"
 
-/* Limit min_delta to a jiffie */
-#define MIN_DELTA_LIMIT         (NSEC_PER_SEC / HZ)
-
-static int tick_increase_min_delta(struct clock_event_device *dev)
-{
-        /* Nothing to do if we already reached the limit */
-        if (dev->min_delta_ns >= MIN_DELTA_LIMIT)
-                return -ETIME;
-
-        if (dev->min_delta_ns < 5000)
-                dev->min_delta_ns = 5000;
-        else
-                dev->min_delta_ns += dev->min_delta_ns >> 1;
-
-        if (dev->min_delta_ns > MIN_DELTA_LIMIT)
-                dev->min_delta_ns = MIN_DELTA_LIMIT;
-
-        printk(KERN_WARNING "CE: %s increased min_delta_ns to %llu nsec\n",
-               dev->name ? dev->name : "?",
-               (unsigned long long) dev->min_delta_ns);
-        return 0;
-}
-
-/**
- * tick_program_event internal worker function
- */
-int tick_dev_program_event(struct clock_event_device *dev, ktime_t expires,
-                           int force)
-{
-        ktime_t now = ktime_get();
-        int i;
-
-        for (i = 0;;) {
-                int ret = clockevents_program_event(dev, expires, now);
-
-                if (!ret || !force)
-                        return ret;
-
-                dev->retries++;
-                /*
-                 * We tried 3 times to program the device with the given
-                 * min_delta_ns. If that's not working then we increase it
-                 * and emit a warning.
-                 */
-                if (++i > 2) {
-                        /* Increase the min. delta and try again */
-                        if (tick_increase_min_delta(dev)) {
-                                /*
-                                 * Get out of the loop if min_delta_ns
-                                 * hit the limit already. That's
-                                 * better than staying here forever.
-                                 *
-                                 * We clear next_event so we have a
-                                 * chance that the box survives.
-                                 */
-                                printk(KERN_WARNING
-                                       "CE: Reprogramming failure. Giving up\n");
-                                dev->next_event.tv64 = KTIME_MAX;
-                                return -ETIME;
-                        }
-                        i = 0;
-                }
-
-                now = ktime_get();
-                expires = ktime_add_ns(now, dev->min_delta_ns);
-        }
-}
-
 /**
  * tick_program_event
  */
@@ -96,7 +28,7 @@ int tick_program_event(ktime_t expires, int force)
 {
         struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev);
 
-        return tick_dev_program_event(dev, expires, force);
+        return clockevents_program_event(dev, expires, force);
 }
 
 /**
@@ -104,11 +36,10 @@ int tick_program_event(ktime_t expires, int force)
  */
 void tick_resume_oneshot(void)
 {
-        struct tick_device *td = &__get_cpu_var(tick_cpu_device);
-        struct clock_event_device *dev = td->evtdev;
+        struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev);
 
         clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT);
-        tick_program_event(ktime_get(), 1);
+        clockevents_program_event(dev, ktime_get(), true);
 }
 
 /**
@@ -120,7 +51,7 @@ void tick_setup_oneshot(struct clock_event_device *newdev,
 {
         newdev->event_handler = handler;
         clockevents_set_mode(newdev, CLOCK_EVT_MODE_ONESHOT);
-        tick_dev_program_event(newdev, next_event, 1);
+        clockevents_program_event(newdev, next_event, true);
 }
 
 /**
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index eb98e55196b9..40420644d0ba 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -158,9 +158,10 @@ update_ts_time_stats(int cpu, struct tick_sched *ts, ktime_t now, u64 *last_upda
 
         if (ts->idle_active) {
                 delta = ktime_sub(now, ts->idle_entrytime);
-                ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
                 if (nr_iowait_cpu(cpu) > 0)
                         ts->iowait_sleeptime = ktime_add(ts->iowait_sleeptime, delta);
+                else
+                        ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
                 ts->idle_entrytime = now;
         }
 
@@ -196,11 +197,11 @@ static ktime_t tick_nohz_start_idle(int cpu, struct tick_sched *ts)
 /**
  * get_cpu_idle_time_us - get the total idle time of a cpu
  * @cpu: CPU number to query
- * @last_update_time: variable to store update time in
+ * @last_update_time: variable to store update time in. Do not update
+ * counters if NULL.
  *
  * Return the cummulative idle time (since boot) for a given
- * CPU, in microseconds. The idle time returned includes
- * the iowait time (unlike what "top" and co report).
+ * CPU, in microseconds.
  *
  * This time is measured via accounting rather than sampling,
  * and is as accurate as ktime_get() is.
@@ -210,20 +211,35 @@ static ktime_t tick_nohz_start_idle(int cpu, struct tick_sched *ts)
 u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time)
 {
         struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
+        ktime_t now, idle;
 
         if (!tick_nohz_enabled)
                 return -1;
 
-        update_ts_time_stats(cpu, ts, ktime_get(), last_update_time);
+        now = ktime_get();
+        if (last_update_time) {
+                update_ts_time_stats(cpu, ts, now, last_update_time);
+                idle = ts->idle_sleeptime;
+        } else {
+                if (ts->idle_active && !nr_iowait_cpu(cpu)) {
+                        ktime_t delta = ktime_sub(now, ts->idle_entrytime);
+
+                        idle = ktime_add(ts->idle_sleeptime, delta);
+                } else {
+                        idle = ts->idle_sleeptime;
+                }
+        }
+
+        return ktime_to_us(idle);
 
-        return ktime_to_us(ts->idle_sleeptime);
 }
 EXPORT_SYMBOL_GPL(get_cpu_idle_time_us);
 
-/*
+/**
  * get_cpu_iowait_time_us - get the total iowait time of a cpu
  * @cpu: CPU number to query
- * @last_update_time: variable to store update time in
+ * @last_update_time: variable to store update time in. Do not update
+ * counters if NULL.
  *
  * Return the cummulative iowait time (since boot) for a given
  * CPU, in microseconds.
@@ -236,13 +252,26 @@ EXPORT_SYMBOL_GPL(get_cpu_idle_time_us);
 u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time)
 {
         struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
+        ktime_t now, iowait;
 
         if (!tick_nohz_enabled)
                 return -1;
 
-        update_ts_time_stats(cpu, ts, ktime_get(), last_update_time);
+        now = ktime_get();
+        if (last_update_time) {
+                update_ts_time_stats(cpu, ts, now, last_update_time);
+                iowait = ts->iowait_sleeptime;
+        } else {
+                if (ts->idle_active && nr_iowait_cpu(cpu) > 0) {
+                        ktime_t delta = ktime_sub(now, ts->idle_entrytime);
 
-        return ktime_to_us(ts->iowait_sleeptime);
+                        iowait = ktime_add(ts->iowait_sleeptime, delta);
+                } else {
+                        iowait = ts->iowait_sleeptime;
+                }
+        }
+
+        return ktime_to_us(iowait);
 }
 EXPORT_SYMBOL_GPL(get_cpu_iowait_time_us);
 
@@ -634,8 +663,6 @@ static void tick_nohz_switch_to_nohz(void)
                 next = ktime_add(next, tick_period);
         }
         local_irq_enable();
-
-        printk(KERN_INFO "Switched to NOHz mode on CPU #%d\n", smp_processor_id());
 }
 
 /*
@@ -787,10 +814,8 @@ void tick_setup_sched_timer(void)
         }
 
 #ifdef CONFIG_NO_HZ
-        if (tick_nohz_enabled) {
+        if (tick_nohz_enabled)
                 ts->nohz_mode = NOHZ_MODE_HIGHRES;
-                printk(KERN_INFO "Switched to NOHz mode on CPU #%d\n", smp_processor_id());
-        }
 #endif
 }
 #endif /* HIGH_RES_TIMERS */