nmi_watchdog fix for x86_64 to be more like i386

[David Bahi]

Thanks to tglx and ghaskins for all the help in tracking down a very
early nmi_watchdog crash on certain x86_64 machines.

This modifies nmi_watchdog_tick behavior for 
x86_64 arch to consider both timer and hpet IRQs
just as the i386 arch does.

Signed-off-by: David Bahi <dbahi@xxxxxxxxxx>

---
 arch/x86_64/kernel/nmi.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

Index: linux-2.6.22.8-rt9_1267/arch/x86_64/kernel/nmi.c
===================================================================
--- linux-2.6.22.8-rt9_1267.orig/arch/x86_64/kernel/nmi.c
+++ linux-2.6.22.8-rt9_1267/arch/x86_64/kernel/nmi.c
@@ -369,8 +369,6 @@ int notrace __kprobes nmi_watchdog_tick(
 		touched = 1;
 	}
 
-	sum = read_pda(apic_timer_irqs);
-
 	if (__get_cpu_var(nmi_touch)) {
 		__get_cpu_var(nmi_touch) = 0;
 		touched = 1;
@@ -386,6 +384,12 @@ int notrace __kprobes nmi_watchdog_tick(
 		cpu_clear(cpu, backtrace_mask);
 	}
 
+	/*
+	 * Take the local apic timer and PIT/HPET into account. We don't
+	 * know which one is active, when we have highres/dyntick on
+	 */
+	sum = read_pda(apic_timer_irqs) + kstat_cpu(cpu).irqs[0];
+
 #ifdef CONFIG_X86_MCE
 	/* Could check oops_in_progress here too, but it's safer
 	   not too */

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