highres: improve debug output

Add some more debug information to the hrtimer and clock events code.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/i386/kernel/apic.c

@@ -524,6 +524,9 @@ void __init setup_boot_APIC_clock(void)
 		 */
 		if (nmi_watchdog != NMI_IO_APIC)
 			lapic_clockevent.features &= ~CLOCK_EVT_FEAT_DUMMY;
+		else
+			printk(KERN_WARNING "APIC timer registered as dummy,"
+			       " due to nmi_watchdog=1!\n");
 	}
 
 	/* Setup the lapic or request the broadcast */

kernel/hrtimer.c

@@ -558,7 +558,8 @@ static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
  */
 static int hrtimer_switch_to_hres(void)
 {
-	struct hrtimer_cpu_base *base = &__get_cpu_var(hrtimer_bases);
+	int cpu = smp_processor_id();
+	struct hrtimer_cpu_base *base = &per_cpu(hrtimer_bases, cpu);
 	unsigned long flags;
 
 	if (base->hres_active)
@@ -568,6 +569,8 @@ static int hrtimer_switch_to_hres(void)
 
 	if (tick_init_highres()) {
 		local_irq_restore(flags);
+		printk(KERN_WARNING "Could not switch to high resolution "
+				    "mode on CPU %d\n", cpu);
 		return 0;
 	}
 	base->hres_active = 1;

kernel/time/tick-oneshot.c

@@ -73,8 +73,21 @@ int tick_switch_to_oneshot(void (*handler)(struct clock_event_device *))
 	struct clock_event_device *dev = td->evtdev;
 
 	if (!dev || !(dev->features & CLOCK_EVT_FEAT_ONESHOT) ||
-	    !tick_device_is_functional(dev))
+		    !tick_device_is_functional(dev)) {
+
+		printk(KERN_INFO "Clockevents: "
+		       "could not switch to one-shot mode:");
+		if (!dev) {
+			printk(" no tick device\n");
+		} else {
+			if (!tick_device_is_functional(dev))
+				printk(" %s is not functional.\n", dev->name);
+			else
+				printk(" %s does not support one-shot mode.\n",
+				       dev->name);
+		}
 		return -EINVAL;
+	}
 
 	td->mode = TICKDEV_MODE_ONESHOT;
 	dev->event_handler = handler;