clocksource: Refactor clocksource watchdog
[safe/jmp/linux-2.6] / kernel / time / tick-broadcast.c
index 75e7185..877dbed 100644 (file)
  * timer stops in C3 state.
  */
 
-struct tick_device tick_broadcast_device;
-static cpumask_t tick_broadcast_mask;
+static struct tick_device tick_broadcast_device;
+/* FIXME: Use cpumask_var_t. */
+static DECLARE_BITMAP(tick_broadcast_mask, NR_CPUS);
+static DECLARE_BITMAP(tmpmask, NR_CPUS);
 static DEFINE_SPINLOCK(tick_broadcast_lock);
+static int tick_broadcast_force;
 
 #ifdef CONFIG_TICK_ONESHOT
 static void tick_broadcast_clear_oneshot(int cpu);
@@ -45,9 +48,9 @@ struct tick_device *tick_get_broadcast_device(void)
        return &tick_broadcast_device;
 }
 
-cpumask_t *tick_get_broadcast_mask(void)
+struct cpumask *tick_get_broadcast_mask(void)
 {
-       return &tick_broadcast_mask;
+       return to_cpumask(tick_broadcast_mask);
 }
 
 /*
@@ -71,7 +74,7 @@ int tick_check_broadcast_device(struct clock_event_device *dev)
 
        clockevents_exchange_device(NULL, dev);
        tick_broadcast_device.evtdev = dev;
-       if (!cpus_empty(tick_broadcast_mask))
+       if (!cpumask_empty(tick_get_broadcast_mask()))
                tick_broadcast_start_periodic(dev);
        return 1;
 }
@@ -103,7 +106,7 @@ int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu)
         */
        if (!tick_device_is_functional(dev)) {
                dev->event_handler = tick_handle_periodic;
-               cpu_set(cpu, tick_broadcast_mask);
+               cpumask_set_cpu(cpu, tick_get_broadcast_mask());
                tick_broadcast_start_periodic(tick_broadcast_device.evtdev);
                ret = 1;
        } else {
@@ -115,7 +118,7 @@ int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu)
                if (!(dev->features & CLOCK_EVT_FEAT_C3STOP)) {
                        int cpu = smp_processor_id();
 
-                       cpu_clear(cpu, tick_broadcast_mask);
+                       cpumask_clear_cpu(cpu, tick_get_broadcast_mask());
                        tick_broadcast_clear_oneshot(cpu);
                }
        }
@@ -124,9 +127,9 @@ int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu)
 }
 
 /*
- * Broadcast the event to the cpus, which are set in the mask
+ * Broadcast the event to the cpus, which are set in the mask (mangled).
  */
-static void tick_do_broadcast(cpumask_t mask)
+static void tick_do_broadcast(struct cpumask *mask)
 {
        int cpu = smp_processor_id();
        struct tick_device *td;
@@ -134,21 +137,20 @@ static void tick_do_broadcast(cpumask_t mask)
        /*
         * Check, if the current cpu is in the mask
         */
-       if (cpu_isset(cpu, mask)) {
-               cpu_clear(cpu, mask);
+       if (cpumask_test_cpu(cpu, mask)) {
+               cpumask_clear_cpu(cpu, mask);
                td = &per_cpu(tick_cpu_device, cpu);
                td->evtdev->event_handler(td->evtdev);
        }
 
-       if (!cpus_empty(mask)) {
+       if (!cpumask_empty(mask)) {
                /*
                 * It might be necessary to actually check whether the devices
                 * have different broadcast functions. For now, just use the
                 * one of the first device. This works as long as we have this
                 * misfeature only on x86 (lapic)
                 */
-               cpu = first_cpu(mask);
-               td = &per_cpu(tick_cpu_device, cpu);
+               td = &per_cpu(tick_cpu_device, cpumask_first(mask));
                td->evtdev->broadcast(mask);
        }
 }
@@ -159,12 +161,11 @@ static void tick_do_broadcast(cpumask_t mask)
  */
 static void tick_do_periodic_broadcast(void)
 {
-       cpumask_t mask;
-
        spin_lock(&tick_broadcast_lock);
 
-       cpus_and(mask, cpu_online_map, tick_broadcast_mask);
-       tick_do_broadcast(mask);
+       cpumask_and(to_cpumask(tmpmask),
+                   cpu_online_mask, tick_get_broadcast_mask());
+       tick_do_broadcast(to_cpumask(tmpmask));
 
        spin_unlock(&tick_broadcast_lock);
 }
@@ -174,6 +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();
 
        /*
@@ -184,10 +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;
@@ -204,7 +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);
 
@@ -222,30 +228,35 @@ static void tick_do_broadcast_on_off(void *why)
        if (!tick_device_is_functional(dev))
                goto out;
 
+       bc_stopped = cpumask_empty(tick_get_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 (!cpumask_test_cpu(cpu, tick_get_broadcast_mask())) {
+                       cpumask_set_cpu(cpu, tick_get_broadcast_mask());
+                       if (tick_broadcast_device.mode ==
+                           TICKDEV_MODE_PERIODIC)
+                               clockevents_shutdown(dev);
                }
                if (*reason == CLOCK_EVT_NOTIFY_BROADCAST_FORCE)
-                       dev->features |= CLOCK_EVT_FEAT_DUMMY;
+                       tick_broadcast_force = 1;
                break;
        case CLOCK_EVT_NOTIFY_BROADCAST_OFF:
-               if (cpu_isset(cpu, tick_broadcast_mask)) {
-                       cpu_clear(cpu, tick_broadcast_mask);
-                       if (td->mode == TICKDEV_MODE_PERIODIC)
+               if (!tick_broadcast_force &&
+                   cpumask_test_cpu(cpu, tick_get_broadcast_mask())) {
+                       cpumask_clear_cpu(cpu, tick_get_broadcast_mask());
+                       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 (cpumask_empty(tick_get_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
@@ -261,7 +272,7 @@ out:
  */
 void tick_broadcast_on_off(unsigned long reason, int *oncpu)
 {
-       if (!cpu_isset(*oncpu, cpu_online_map))
+       if (!cpumask_test_cpu(*oncpu, cpu_online_mask))
                printk(KERN_ERR "tick-broadcast: ignoring broadcast for "
                       "offline CPU #%d\n", *oncpu);
        else
@@ -292,11 +303,11 @@ void tick_shutdown_broadcast(unsigned int *cpup)
        spin_lock_irqsave(&tick_broadcast_lock, flags);
 
        bc = tick_broadcast_device.evtdev;
-       cpu_clear(cpu, tick_broadcast_mask);
+       cpumask_clear_cpu(cpu, tick_get_broadcast_mask());
 
        if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) {
-               if (bc && cpus_empty(tick_broadcast_mask))
-                       clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
+               if (bc && cpumask_empty(tick_get_broadcast_mask()))
+                       clockevents_shutdown(bc);
        }
 
        spin_unlock_irqrestore(&tick_broadcast_lock, flags);
@@ -311,7 +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);
 }
@@ -331,10 +342,10 @@ int tick_resume_broadcast(void)
 
                switch (tick_broadcast_device.mode) {
                case TICKDEV_MODE_PERIODIC:
-                       if(!cpus_empty(tick_broadcast_mask))
+                       if (!cpumask_empty(tick_get_broadcast_mask()))
                                tick_broadcast_start_periodic(bc);
-                       broadcast = cpu_isset(smp_processor_id(),
-                                             tick_broadcast_mask);
+                       broadcast = cpumask_test_cpu(smp_processor_id(),
+                                                    tick_get_broadcast_mask());
                        break;
                case TICKDEV_MODE_ONESHOT:
                        broadcast = tick_resume_broadcast_oneshot(bc);
@@ -349,29 +360,22 @@ int tick_resume_broadcast(void)
 
 #ifdef CONFIG_TICK_ONESHOT
 
-static cpumask_t tick_broadcast_oneshot_mask;
+/* FIXME: use cpumask_var_t. */
+static DECLARE_BITMAP(tick_broadcast_oneshot_mask, NR_CPUS);
 
 /*
- * Debugging: see timer_list.c
+ * Exposed for debugging: see timer_list.c
  */
-cpumask_t *tick_get_broadcast_oneshot_mask(void)
+struct cpumask *tick_get_broadcast_oneshot_mask(void)
 {
-       return &tick_broadcast_oneshot_mask;
+       return to_cpumask(tick_broadcast_oneshot_mask);
 }
 
 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)
@@ -381,12 +385,24 @@ int tick_resume_broadcast_oneshot(struct clock_event_device *bc)
 }
 
 /*
+ * Called from irq_enter() when idle was interrupted to reenable the
+ * per cpu device.
+ */
+void tick_check_oneshot_broadcast(int cpu)
+{
+       if (cpumask_test_cpu(cpu, to_cpumask(tick_broadcast_oneshot_mask))) {
+               struct tick_device *td = &per_cpu(tick_cpu_device, cpu);
+
+               clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_ONESHOT);
+       }
+}
+
+/*
  * Handle oneshot mode broadcasting
  */
 static void tick_handle_oneshot_broadcast(struct clock_event_device *dev)
 {
        struct tick_device *td;
-       cpumask_t mask;
        ktime_t now, next_event;
        int cpu;
 
@@ -394,14 +410,13 @@ static void tick_handle_oneshot_broadcast(struct clock_event_device *dev)
 again:
        dev->next_event.tv64 = KTIME_MAX;
        next_event.tv64 = KTIME_MAX;
-       mask = CPU_MASK_NONE;
+       cpumask_clear(to_cpumask(tmpmask));
        now = ktime_get();
        /* Find all expired events */
-       for (cpu = first_cpu(tick_broadcast_oneshot_mask); cpu != NR_CPUS;
-            cpu = next_cpu(cpu, tick_broadcast_oneshot_mask)) {
+       for_each_cpu(cpu, tick_get_broadcast_oneshot_mask()) {
                td = &per_cpu(tick_cpu_device, cpu);
                if (td->evtdev->next_event.tv64 <= now.tv64)
-                       cpu_set(cpu, mask);
+                       cpumask_set_cpu(cpu, to_cpumask(tmpmask));
                else if (td->evtdev->next_event.tv64 < next_event.tv64)
                        next_event.tv64 = td->evtdev->next_event.tv64;
        }
@@ -409,7 +424,7 @@ again:
        /*
         * Wakeup the cpus which have an expired event.
         */
-       tick_do_broadcast(mask);
+       tick_do_broadcast(to_cpumask(tmpmask));
 
        /*
         * Two reasons for reprogram:
@@ -461,15 +476,16 @@ void tick_broadcast_oneshot_control(unsigned long reason)
                goto out;
 
        if (reason == CLOCK_EVT_NOTIFY_BROADCAST_ENTER) {
-               if (!cpu_isset(cpu, tick_broadcast_oneshot_mask)) {
-                       cpu_set(cpu, tick_broadcast_oneshot_mask);
+               if (!cpumask_test_cpu(cpu, tick_get_broadcast_oneshot_mask())) {
+                       cpumask_set_cpu(cpu, tick_get_broadcast_oneshot_mask());
                        clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
                        if (dev->next_event.tv64 < bc->next_event.tv64)
                                tick_broadcast_set_event(dev->next_event, 1);
                }
        } else {
-               if (cpu_isset(cpu, tick_broadcast_oneshot_mask)) {
-                       cpu_clear(cpu, tick_broadcast_oneshot_mask);
+               if (cpumask_test_cpu(cpu, tick_get_broadcast_oneshot_mask())) {
+                       cpumask_clear_cpu(cpu,
+                                         tick_get_broadcast_oneshot_mask());
                        clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT);
                        if (dev->next_event.tv64 != KTIME_MAX)
                                tick_program_event(dev->next_event, 1);
@@ -487,7 +503,20 @@ out:
  */
 static void tick_broadcast_clear_oneshot(int cpu)
 {
-       cpu_clear(cpu, tick_broadcast_oneshot_mask);
+       cpumask_clear_cpu(cpu, tick_get_broadcast_oneshot_mask());
+}
+
+static void tick_broadcast_init_next_event(struct cpumask *mask,
+                                          ktime_t expires)
+{
+       struct tick_device *td;
+       int cpu;
+
+       for_each_cpu(cpu, mask) {
+               td = &per_cpu(tick_cpu_device, cpu);
+               if (td->evtdev)
+                       td->evtdev->next_event = expires;
+       }
 }
 
 /**
@@ -495,9 +524,36 @@ static void tick_broadcast_clear_oneshot(int cpu)
  */
 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();
+
+               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.
+                */
+               cpumask_copy(to_cpumask(tmpmask), tick_get_broadcast_mask());
+               cpumask_clear_cpu(cpu, to_cpumask(tmpmask));
+               cpumask_or(tick_get_broadcast_oneshot_mask(),
+                          tick_get_broadcast_oneshot_mask(),
+                          to_cpumask(tmpmask));
+
+               if (was_periodic && !cpumask_empty(to_cpumask(tmpmask))) {
+                       tick_broadcast_init_next_event(to_cpumask(tmpmask),
+                                                      tick_next_period);
+                       tick_broadcast_set_event(tick_next_period, 1);
+               } else
+                       bc->next_event.tv64 = KTIME_MAX;
+       }
 }
 
 /*
@@ -532,9 +588,17 @@ void tick_shutdown_broadcast_oneshot(unsigned int *cpup)
         * Clear the broadcast mask flag for the dead cpu, but do not
         * stop the broadcast device!
         */
-       cpu_clear(cpu, tick_broadcast_oneshot_mask);
+       cpumask_clear_cpu(cpu, tick_get_broadcast_oneshot_mask());
 
        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