X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=kernel%2Ftimer.c;h=13e2b513be019bf0b8b6b9218e4f268fff95f58a;hb=5acd57936c3224fd86e838201e528e0169373e9b;hp=8aadc62efd65379dff44fcc08cc57e3c0fd90bbf;hpb=55c888d6d09a0df236adfaf8ccf06ff5d0646775;p=linux-2.6

diff --git a/kernel/timer.c b/kernel/timer.c
index 8aadc62efd..13e2b513be 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -365,6 +365,34 @@ int del_timer(struct timer_list *timer)
 EXPORT_SYMBOL(del_timer);
 
 #ifdef CONFIG_SMP
+/*
+ * This function tries to deactivate a timer. Upon successful (ret >= 0)
+ * exit the timer is not queued and the handler is not running on any CPU.
+ *
+ * It must not be called from interrupt contexts.
+ */
+int try_to_del_timer_sync(struct timer_list *timer)
+{
+	timer_base_t *base;
+	unsigned long flags;
+	int ret = -1;
+
+	base = lock_timer_base(timer, &flags);
+
+	if (base->running_timer == timer)
+		goto out;
+
+	ret = 0;
+	if (timer_pending(timer)) {
+		detach_timer(timer, 1);
+		ret = 1;
+	}
+out:
+	spin_unlock_irqrestore(&base->lock, flags);
+
+	return ret;
+}
+
 /***
  * del_timer_sync - deactivate a timer and wait for the handler to finish.
  * @timer: the timer to be deactivated
@@ -384,28 +412,13 @@ EXPORT_SYMBOL(del_timer);
  */
 int del_timer_sync(struct timer_list *timer)
 {
-	timer_base_t *base;
-	unsigned long flags;
-	int ret = -1;
-
 	check_timer(timer);
 
-	do {
-		base = lock_timer_base(timer, &flags);
-
-		if (base->running_timer == timer)
-			goto unlock;
-
-		ret = 0;
-		if (timer_pending(timer)) {
-			detach_timer(timer, 1);
-			ret = 1;
-		}
-unlock:
-		spin_unlock_irqrestore(&base->lock, flags);
-	} while (ret < 0);
-
-	return ret;
+	for (;;) {
+		int ret = try_to_del_timer_sync(timer);
+		if (ret >= 0)
+			return ret;
+	}
 }
 
 EXPORT_SYMBOL(del_timer_sync);
@@ -476,10 +489,14 @@ static inline void __run_timers(tvec_base_t *base)
 			detach_timer(timer, 1);
 			spin_unlock_irq(&base->t_base.lock);
 			{
-				u32 preempt_count = preempt_count();
+				int preempt_count = preempt_count();
 				fn(data);
 				if (preempt_count != preempt_count()) {
-					printk("huh, entered %p with %08x, exited with %08x?\n", fn, preempt_count, preempt_count());
+					printk(KERN_WARNING "huh, entered %p "
+					       "with preempt_count %08x, exited"
+					       " with %08x?\n",
+					       fn, preempt_count,
+					       preempt_count());
 					BUG();
 				}
 			}
@@ -933,6 +950,7 @@ void do_timer(struct pt_regs *regs)
 {
 	jiffies_64++;
 	update_times();
+	softlockup_tick(regs);
 }
 
 #ifdef __ARCH_WANT_SYS_ALARM
@@ -1006,7 +1024,7 @@ asmlinkage long sys_getppid(void)
 	parent = me->group_leader->real_parent;
 	for (;;) {
 		pid = parent->tgid;
-#ifdef CONFIG_SMP
+#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
 {
 		struct task_struct *old = parent;
 
@@ -1411,7 +1429,7 @@ static inline u64 time_interpolator_get_cycles(unsigned int src)
 	}
 }
 
-static inline u64 time_interpolator_get_counter(void)
+static inline u64 time_interpolator_get_counter(int writelock)
 {
 	unsigned int src = time_interpolator->source;
 
@@ -1425,6 +1443,15 @@ static inline u64 time_interpolator_get_counter(void)
 			now = time_interpolator_get_cycles(src);
 			if (lcycle && time_after(lcycle, now))
 				return lcycle;
+
+			/* When holding the xtime write lock, there's no need
+			 * to add the overhead of the cmpxchg.  Readers are
+			 * force to retry until the write lock is released.
+			 */
+			if (writelock) {
+				time_interpolator->last_cycle = now;
+				return now;
+			}
 			/* Keep track of the last timer value returned. The use of cmpxchg here
 			 * will cause contention in an SMP environment.
 			 */
@@ -1438,7 +1465,7 @@ static inline u64 time_interpolator_get_counter(void)
 void time_interpolator_reset(void)
 {
 	time_interpolator->offset = 0;
-	time_interpolator->last_counter = time_interpolator_get_counter();
+	time_interpolator->last_counter = time_interpolator_get_counter(1);
 }
 
 #define GET_TI_NSECS(count,i) (((((count) - i->last_counter) & (i)->mask) * (i)->nsec_per_cyc) >> (i)->shift)
@@ -1450,7 +1477,7 @@ unsigned long time_interpolator_get_offset(void)
 		return 0;
 
 	return time_interpolator->offset +
-		GET_TI_NSECS(time_interpolator_get_counter(), time_interpolator);
+		GET_TI_NSECS(time_interpolator_get_counter(0), time_interpolator);
 }
 
 #define INTERPOLATOR_ADJUST 65536
@@ -1473,7 +1500,7 @@ static void time_interpolator_update(long delta_nsec)
 	 * and the tuning logic insures that.
          */
 
-	counter = time_interpolator_get_counter();
+	counter = time_interpolator_get_counter(1);
 	offset = time_interpolator->offset + GET_TI_NSECS(counter, time_interpolator);
 
 	if (delta_nsec < 0 || (unsigned long) delta_nsec < offset)
@@ -1580,7 +1607,7 @@ void msleep(unsigned int msecs)
 EXPORT_SYMBOL(msleep);
 
 /**
- * msleep_interruptible - sleep waiting for waitqueue interruptions
+ * msleep_interruptible - sleep waiting for signals
  * @msecs: Time in milliseconds to sleep for
  */
 unsigned long msleep_interruptible(unsigned int msecs)