sched: fix buddie group latency

[safe/jmp/linux-2.6] / kernel / time / clockevents.c

diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 5fb139f..ea2f48a 100644 (file)
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -41,6 +41,11 @@ unsigned long clockevent_delta2ns(unsigned long latch,
 {
        u64 clc = ((u64) latch << evt->shift);
 
+       if (unlikely(!evt->mult)) {
+               evt->mult = 1;
+               WARN_ON(1);
+       }
+
        do_div(clc, evt->mult);
        if (clc < 1000)
                clc = 1000;
@@ -67,6 +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)
  *
@@ -128,7 +143,7 @@ static void clockevents_do_notify(unsigned long reason, void *dev)
 }
 
 /*
- * Called after a notify add to make devices availble which were
+ * Called after a notify add to make devices available which were
  * released from the notifier call.
  */
 static void clockevents_notify_released(void)
@@ -151,6 +166,16 @@ static void clockevents_notify_released(void)
 void clockevents_register_device(struct clock_event_device *dev)
 {
        BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED);
+       BUG_ON(!dev->cpumask);
+
+       /*
+        * A nsec2cyc multiplicator of 0 is invalid and we'd crash
+        * on it, so fix it up and emit a warning:
+        */
+       if (unlikely(!dev->mult)) {
+               dev->mult = 1;
+               WARN_ON(1);
+       }
 
        spin_lock(&clockevents_lock);
 
@@ -164,7 +189,7 @@ 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)
 {
 }
 
@@ -186,7 +211,6 @@ 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);
@@ -194,7 +218,7 @@ 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);
 }
@@ -205,6 +229,8 @@ void clockevents_exchange_device(struct clock_event_device *old,
  */
 void clockevents_notify(unsigned long reason, void *arg)
 {
+       struct list_head *node, *tmp;
+
        spin_lock(&clockevents_lock);
        clockevents_do_notify(reason, arg);
 
@@ -214,13 +240,8 @@ void clockevents_notify(unsigned long reason, void *arg)
                 * Unregister the clock event devices which were
                 * released from the users in the notify chain.
                 */
-               while (!list_empty(&clockevents_released)) {
-                       struct clock_event_device *dev;
-
-                       dev = list_entry(clockevents_released.next,
-                                        struct clock_event_device, list);
-                       list_del(&dev->list);
-               }
+               list_for_each_safe(node, tmp, &clockevents_released)
+                       list_del(node);
                break;
        default:
                break;