8 files changed, 163 insertions, 50 deletions

diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig
index 8d53106a0a92..95ed42951e0a 100644
--- a/kernel/time/Kconfig
+++ b/kernel/time/Kconfig
@@ -3,7 +3,6 @@
 #
 config TICK_ONESHOT
         bool
-        default n
 
 config NO_HZ
         bool "Tickless System (Dynamic Ticks)"
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 3d1e3e1a1971..f8d968063cea 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -72,6 +72,16 @@ void clockevents_set_mode(struct clock_event_device *dev,
 }
 
 /**
+ * clockevents_shutdown - shutdown the device and clear next_event
+ * @dev:        device to shutdown
+ */
+void clockevents_shutdown(struct clock_event_device *dev)
+{
+        clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
+        dev->next_event.tv64 = KTIME_MAX;
+}
+
+/**
  * clockevents_program_event - Reprogram the clock event device.
  * @expires:    absolute expiry time (monotonic clock)
  *
@@ -177,7 +187,7 @@ void clockevents_register_device(struct clock_event_device *dev)
 /*
  * Noop handler when we shut down an event device
  */
-static void clockevents_handle_noop(struct clock_event_device *dev)
+void clockevents_handle_noop(struct clock_event_device *dev)
 {
 }
 
@@ -199,7 +209,6 @@ void clockevents_exchange_device(struct clock_event_device *old,
          * released list and do a notify add later.
          */
         if (old) {
-                old->event_handler = clockevents_handle_noop;
                 clockevents_set_mode(old, CLOCK_EVT_MODE_UNUSED);
                 list_del(&old->list);
                 list_add(&old->list, &clockevents_released);
@@ -207,7 +216,7 @@ void clockevents_exchange_device(struct clock_event_device *old,
 
         if (new) {
                 BUG_ON(new->mode != CLOCK_EVT_MODE_UNUSED);
-                clockevents_set_mode(new, CLOCK_EVT_MODE_SHUTDOWN);
+                clockevents_shutdown(new);
         }
         local_irq_restore(flags);
 }
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 4c8d85421d24..9c114b726ab3 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -244,7 +244,7 @@ static void sync_cmos_clock(unsigned long dummy)
         if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2)
                 fail = update_persistent_clock(now);
 
-        next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec;
+        next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec - (TICK_NSEC / 2);
         if (next.tv_nsec <= 0)
                 next.tv_nsec += NSEC_PER_SEC;
 
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 31463d370b94..cb01cd8f919b 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -175,6 +175,8 @@ static void tick_do_periodic_broadcast(void)
  */
 static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
 {
+        ktime_t next;
+
         tick_do_periodic_broadcast();
 
         /*
@@ -185,10 +187,13 @@ static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
 
         /*
          * Setup the next period for devices, which do not have
-         * periodic mode:
+         * periodic mode. We read dev->next_event first and add to it
+         * when the event alrady expired. clockevents_program_event()
+         * sets dev->next_event only when the event is really
+         * programmed to the device.
          */
-        for (;;) {
-                ktime_t next = ktime_add(dev->next_event, tick_period);
+        for (next = dev->next_event; ;) {
+                next = ktime_add(next, tick_period);
 
                 if (!clockevents_program_event(dev, next, ktime_get()))
                         return;
@@ -205,7 +210,7 @@ static void tick_do_broadcast_on_off(void *why)
         struct clock_event_device *bc, *dev;
         struct tick_device *td;
         unsigned long flags, *reason = why;
-        int cpu;
+        int cpu, bc_stopped;
 
         spin_lock_irqsave(&tick_broadcast_lock, flags);
 
@@ -223,14 +228,16 @@ static void tick_do_broadcast_on_off(void *why)
         if (!tick_device_is_functional(dev))
                 goto out;
 
+        bc_stopped = cpus_empty(tick_broadcast_mask);
+
         switch (*reason) {
         case CLOCK_EVT_NOTIFY_BROADCAST_ON:
         case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
                 if (!cpu_isset(cpu, tick_broadcast_mask)) {
                         cpu_set(cpu, tick_broadcast_mask);
-                        if (td->mode == TICKDEV_MODE_PERIODIC)
-                                clockevents_set_mode(dev,
-                                                     CLOCK_EVT_MODE_SHUTDOWN);
+                        if (tick_broadcast_device.mode ==
+                            TICKDEV_MODE_PERIODIC)
+                                clockevents_shutdown(dev);
                 }
                 if (*reason == CLOCK_EVT_NOTIFY_BROADCAST_FORCE)
                         tick_broadcast_force = 1;
@@ -239,15 +246,17 @@ static void tick_do_broadcast_on_off(void *why)
                 if (!tick_broadcast_force &&
                     cpu_isset(cpu, tick_broadcast_mask)) {
                         cpu_clear(cpu, tick_broadcast_mask);
-                        if (td->mode == TICKDEV_MODE_PERIODIC)
+                        if (tick_broadcast_device.mode ==
+                            TICKDEV_MODE_PERIODIC)
                                 tick_setup_periodic(dev, 0);
                 }
                 break;
         }
 
-        if (cpus_empty(tick_broadcast_mask))
-                clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
-        else {
+        if (cpus_empty(tick_broadcast_mask)) {
+                if (!bc_stopped)
+                        clockevents_shutdown(bc);
+        } else if (bc_stopped) {
                 if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
                         tick_broadcast_start_periodic(bc);
                 else
@@ -298,7 +307,7 @@ void tick_shutdown_broadcast(unsigned int *cpup)
 
         if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) {
                 if (bc && cpus_empty(tick_broadcast_mask))
-                        clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
+                        clockevents_shutdown(bc);
         }
 
         spin_unlock_irqrestore(&tick_broadcast_lock, flags);
@@ -313,7 +322,7 @@ void tick_suspend_broadcast(void)
 
         bc = tick_broadcast_device.evtdev;
         if (bc)
-                clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
+                clockevents_shutdown(bc);
 
         spin_unlock_irqrestore(&tick_broadcast_lock, flags);
 }
@@ -364,16 +373,8 @@ cpumask_t *tick_get_broadcast_oneshot_mask(void)
 static int tick_broadcast_set_event(ktime_t expires, int force)
 {
         struct clock_event_device *bc = tick_broadcast_device.evtdev;
-        ktime_t now = ktime_get();
-        int res;
-
-        for(;;) {
-                res = clockevents_program_event(bc, expires, now);
-                if (!res || !force)
-                        return res;
-                now = ktime_get();
-                expires = ktime_add(now, ktime_set(0, bc->min_delta_ns));
-        }
+
+        return tick_dev_program_event(bc, expires, force);
 }
 
 int tick_resume_broadcast_oneshot(struct clock_event_device *bc)
@@ -491,14 +492,52 @@ static void tick_broadcast_clear_oneshot(int cpu)
         cpu_clear(cpu, tick_broadcast_oneshot_mask);
 }
 
+static void tick_broadcast_init_next_event(cpumask_t *mask, ktime_t expires)
+{
+        struct tick_device *td;
+        int cpu;
+
+        for_each_cpu_mask_nr(cpu, *mask) {
+                td = &per_cpu(tick_cpu_device, cpu);
+                if (td->evtdev)
+                        td->evtdev->next_event = expires;
+        }
+}
+
 /**
  * tick_broadcast_setup_oneshot - setup the broadcast device
  */
 void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
 {
-        bc->event_handler = tick_handle_oneshot_broadcast;
-        clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
-        bc->next_event.tv64 = KTIME_MAX;
+        /* Set it up only once ! */
+        if (bc->event_handler != tick_handle_oneshot_broadcast) {
+                int was_periodic = bc->mode == CLOCK_EVT_MODE_PERIODIC;
+                int cpu = smp_processor_id();
+                cpumask_t mask;
+
+                bc->event_handler = tick_handle_oneshot_broadcast;
+                clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
+
+                /* Take the do_timer update */
+                tick_do_timer_cpu = cpu;
+
+                /*
+                 * We must be careful here. There might be other CPUs
+                 * waiting for periodic broadcast. We need to set the
+                 * oneshot_mask bits for those and program the
+                 * broadcast device to fire.
+                 */
+                mask = tick_broadcast_mask;
+                cpu_clear(cpu, mask);
+                cpus_or(tick_broadcast_oneshot_mask,
+                        tick_broadcast_oneshot_mask, mask);
+
+                if (was_periodic && !cpus_empty(mask)) {
+                        tick_broadcast_init_next_event(&mask, tick_next_period);
+                        tick_broadcast_set_event(tick_next_period, 1);
+                } else
+                        bc->next_event.tv64 = KTIME_MAX;
+        }
 }
 
 /*
@@ -538,4 +577,12 @@ void tick_shutdown_broadcast_oneshot(unsigned int *cpup)
         spin_unlock_irqrestore(&tick_broadcast_lock, flags);
 }
 
+/*
+ * Check, whether the broadcast device is in one shot mode
+ */
+int tick_broadcast_oneshot_active(void)
+{
+        return tick_broadcast_device.mode == TICKDEV_MODE_ONESHOT;
+}
+
 #endif
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index 80c4336f4188..df12434b43ca 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -33,7 +33,7 @@ DEFINE_PER_CPU(struct tick_device, tick_cpu_device);
  */
 ktime_t tick_next_period;
 ktime_t tick_period;
-int tick_do_timer_cpu __read_mostly = -1;
+int tick_do_timer_cpu __read_mostly = TICK_DO_TIMER_BOOT;
 DEFINE_SPINLOCK(tick_device_lock);
 
 /*
@@ -109,7 +109,8 @@ void tick_setup_periodic(struct clock_event_device *dev, int broadcast)
         if (!tick_device_is_functional(dev))
                 return;
 
-        if (dev->features & CLOCK_EVT_FEAT_PERIODIC) {
+        if ((dev->features & CLOCK_EVT_FEAT_PERIODIC) &&
+            !tick_broadcast_oneshot_active()) {
                 clockevents_set_mode(dev, CLOCK_EVT_MODE_PERIODIC);
         } else {
                 unsigned long seq;
@@ -148,7 +149,7 @@ static void tick_setup_device(struct tick_device *td,
                  * If no cpu took the do_timer update, assign it to
                  * this cpu:
                  */
-                if (tick_do_timer_cpu == -1) {
+                if (tick_do_timer_cpu == TICK_DO_TIMER_BOOT) {
                         tick_do_timer_cpu = cpu;
                         tick_next_period = ktime_get();
                         tick_period = ktime_set(0, NSEC_PER_SEC / HZ);
@@ -161,6 +162,7 @@ static void tick_setup_device(struct tick_device *td,
         } else {
                 handler = td->evtdev->event_handler;
                 next_event = td->evtdev->next_event;
+                td->evtdev->event_handler = clockevents_handle_noop;
         }
 
         td->evtdev = newdev;
@@ -248,7 +250,7 @@ static int tick_check_new_device(struct clock_event_device *newdev)
          * not give it back to the clockevents layer !
          */
         if (tick_is_broadcast_device(curdev)) {
-                clockevents_set_mode(curdev, CLOCK_EVT_MODE_SHUTDOWN);
+                clockevents_shutdown(curdev);
                 curdev = NULL;
         }
         clockevents_exchange_device(curdev, newdev);
@@ -299,7 +301,8 @@ static void tick_shutdown(unsigned int *cpup)
         if (*cpup == tick_do_timer_cpu) {
                 int cpu = first_cpu(cpu_online_map);
 
-                tick_do_timer_cpu = (cpu != NR_CPUS) ? cpu : -1;
+                tick_do_timer_cpu = (cpu != NR_CPUS) ? cpu :
+                        TICK_DO_TIMER_NONE;
         }
         spin_unlock_irqrestore(&tick_device_lock, flags);
 }
@@ -310,7 +313,7 @@ static void tick_suspend(void)
         unsigned long flags;
 
         spin_lock_irqsave(&tick_device_lock, flags);
-        clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_SHUTDOWN);
+        clockevents_shutdown(td->evtdev);
         spin_unlock_irqrestore(&tick_device_lock, flags);
 }
 
diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index f13f2b7f4fd4..469248782c23 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -1,6 +1,10 @@
 /*
  * tick internal variable and functions used by low/high res code
  */
+
+#define TICK_DO_TIMER_NONE      -1
+#define TICK_DO_TIMER_BOOT      -2
+
 DECLARE_PER_CPU(struct tick_device, tick_cpu_device);
 extern spinlock_t tick_device_lock;
 extern ktime_t tick_next_period;
@@ -10,6 +14,8 @@ extern int tick_do_timer_cpu __read_mostly;
 extern void tick_setup_periodic(struct clock_event_device *dev, int broadcast);
 extern void tick_handle_periodic(struct clock_event_device *dev);
 
+extern void clockevents_shutdown(struct clock_event_device *dev);
+
 /*
  * NO_HZ / high resolution timer shared code
  */
@@ -17,6 +23,8 @@ extern void tick_handle_periodic(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 *));
@@ -27,6 +35,7 @@ extern void tick_broadcast_oneshot_control(unsigned long reason);
 extern void tick_broadcast_switch_to_oneshot(void);
 extern void tick_shutdown_broadcast_oneshot(unsigned int *cpup);
 extern int tick_resume_broadcast_oneshot(struct clock_event_device *bc);
+extern int tick_broadcast_oneshot_active(void);
 # else /* BROADCAST */
 static inline void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
 {
@@ -35,6 +44,7 @@ static inline void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
 static inline void tick_broadcast_oneshot_control(unsigned long reason) { }
 static inline void tick_broadcast_switch_to_oneshot(void) { }
 static inline void tick_shutdown_broadcast_oneshot(unsigned int *cpup) { }
+static inline int tick_broadcast_oneshot_active(void) { return 0; }
 # endif /* !BROADCAST */
 
 #else /* !ONESHOT */
@@ -64,6 +74,7 @@ static inline int tick_resume_broadcast_oneshot(struct clock_event_device *bc)
 {
         return 0;
 }
+static inline int tick_broadcast_oneshot_active(void) { return 0; }
 #endif /* !TICK_ONESHOT */
 
 /*
diff --git a/kernel/time/tick-oneshot.c b/kernel/time/tick-oneshot.c
index 450c04935b66..2e8de678e767 100644
--- a/kernel/time/tick-oneshot.c
+++ b/kernel/time/tick-oneshot.c
@@ -23,24 +23,56 @@
 #include "tick-internal.h"
 
 /**
- * tick_program_event
+ * tick_program_event internal worker function
  */
-int tick_program_event(ktime_t expires, int force)
+int tick_dev_program_event(struct clock_event_device *dev, ktime_t expires,
+                           int force)
 {
-        struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev;
         ktime_t now = ktime_get();
+        int i;
 
-        while (1) {
+        for (i = 0;;) {
                 int ret = clockevents_program_event(dev, expires, now);
 
                 if (!ret || !force)
                         return ret;
+
+                /*
+                 * We tried 2 times to program the device with the given
+                 * min_delta_ns. If that's not working then we double it
+                 * and emit a warning.
+                 */
+                if (++i > 2) {
+                        /* Increase the min. delta and try again */
+                        if (!dev->min_delta_ns)
+                                dev->min_delta_ns = 5000;
+                        else
+                                dev->min_delta_ns += dev->min_delta_ns >> 1;
+
+                        printk(KERN_WARNING
+                               "CE: %s increasing min_delta_ns to %lu nsec\n",
+                               dev->name ? dev->name : "?",
+                               dev->min_delta_ns << 1);
+
+                        i = 0;
+                }
+
                 now = ktime_get();
-                expires = ktime_add(now, ktime_set(0, dev->min_delta_ns));
+                expires = ktime_add_ns(now, dev->min_delta_ns);
         }
 }
 
 /**
+ * tick_program_event
+ */
+int tick_program_event(ktime_t expires, int force)
+{
+        struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev;
+
+        return tick_dev_program_event(dev, expires, force);
+}
+
+/**
  * tick_resume_onshot - resume oneshot mode
  */
 void tick_resume_oneshot(void)
@@ -61,7 +93,7 @@ void tick_setup_oneshot(struct clock_event_device *newdev,
 {
         newdev->event_handler = handler;
         clockevents_set_mode(newdev, CLOCK_EVT_MODE_ONESHOT);
-        clockevents_program_event(newdev, next_event, ktime_get());
+        tick_dev_program_event(newdev, next_event, 1);
 }
 
 /**
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index b33be61c0f6b..a547be11cf97 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -20,6 +20,7 @@
 #include <linux/profile.h>
 #include <linux/sched.h>
 #include <linux/tick.h>
+#include <linux/module.h>
 
 #include <asm/irq_regs.h>
 
@@ -75,6 +76,9 @@ static void tick_do_update_jiffies64(ktime_t now)
                                                            incr * ticks);
                 }
                 do_timer(++ticks);
+
+                /* Keep the tick_next_period variable up to date */
+                tick_next_period = ktime_add(last_jiffies_update, tick_period);
         }
         write_sequnlock(&xtime_lock);
 }
@@ -187,9 +191,17 @@ u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time)
 {
         struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
 
-        *last_update_time = ktime_to_us(ts->idle_lastupdate);
+        if (!tick_nohz_enabled)
+                return -1;
+
+        if (ts->idle_active)
+                *last_update_time = ktime_to_us(ts->idle_lastupdate);
+        else
+                *last_update_time = ktime_to_us(ktime_get());
+
         return ktime_to_us(ts->idle_sleeptime);
 }
+EXPORT_SYMBOL_GPL(get_cpu_idle_time_us);
 
 /**
  * tick_nohz_stop_sched_tick - stop the idle tick from the idle task
@@ -221,7 +233,7 @@ void tick_nohz_stop_sched_tick(int inidle)
          */
         if (unlikely(!cpu_online(cpu))) {
                 if (cpu == tick_do_timer_cpu)
-                        tick_do_timer_cpu = -1;
+                        tick_do_timer_cpu = TICK_DO_TIMER_NONE;
         }
 
         if (unlikely(ts->nohz_mode == NOHZ_MODE_INACTIVE))
@@ -258,7 +270,7 @@ void tick_nohz_stop_sched_tick(int inidle)
         next_jiffies = get_next_timer_interrupt(last_jiffies);
         delta_jiffies = next_jiffies - last_jiffies;
 
-        if (rcu_needs_cpu(cpu))
+        if (rcu_needs_cpu(cpu) || printk_needs_cpu(cpu))
                 delta_jiffies = 1;
         /*
          * Do not stop the tick, if we are only one off
@@ -303,7 +315,7 @@ void tick_nohz_stop_sched_tick(int inidle)
                  * invoked.
                  */
                 if (cpu == tick_do_timer_cpu)
-                        tick_do_timer_cpu = -1;
+                        tick_do_timer_cpu = TICK_DO_TIMER_NONE;
 
                 ts->idle_sleeps++;
 
@@ -468,7 +480,7 @@ static void tick_nohz_handler(struct clock_event_device *dev)
          * this duty, then the jiffies update is still serialized by
          * xtime_lock.
          */
-        if (unlikely(tick_do_timer_cpu == -1))
+        if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_NONE))
                 tick_do_timer_cpu = cpu;
 
         /* Check, if the jiffies need an update */
@@ -570,7 +582,7 @@ static enum hrtimer_restart tick_sched_timer(struct hrtimer *timer)
          * this duty, then the jiffies update is still serialized by
          * xtime_lock.
          */
-        if (unlikely(tick_do_timer_cpu == -1))
+        if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_NONE))
                 tick_do_timer_cpu = cpu;
 #endif
 
@@ -622,7 +634,7 @@ void tick_setup_sched_timer(void)
          */
         hrtimer_init(&ts->sched_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
         ts->sched_timer.function = tick_sched_timer;
-        ts->sched_timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
+        ts->sched_timer.cb_mode = HRTIMER_CB_IRQSAFE_PERCPU;
 
         /* Get the next period (per cpu) */
         hrtimer_set_expires(&ts->sched_timer, tick_init_jiffy_update());