lockup_detector: Separate touch_nmi_watchdog code path from touch_watchdog

When I combined the nmi_watchdog (hardlockup) and softlockup code, I
also combined the paths the touch_watchdog and touch_nmi_watchdog took.
This may not be the best idea as pointed out by Frederic W., that the
touch_watchdog case probably should not reset the hardlockup count.

Therefore the patch below falls back to the previous idea of keeping
the touch_nmi_watchdog a superset of the touch_watchdog case.
Signed-off-by: Don Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
LKML-Reference: <1273266711-18706-9-git-send-email-dzickus@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

kernel/watchdog.c

@@ -31,6 +31,7 @@ int watchdog_enabled;
 int __read_mostly softlockup_thresh = 60;
 
 static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts);
+static DEFINE_PER_CPU(bool, watchdog_nmi_touch);
 static DEFINE_PER_CPU(struct task_struct *, softlockup_watchdog);
 static DEFINE_PER_CPU(struct hrtimer, watchdog_hrtimer);
 static DEFINE_PER_CPU(bool, softlockup_touch_sync);
@@ -139,6 +140,7 @@ void touch_all_softlockup_watchdogs(void)
 
 void touch_nmi_watchdog(void)
 {
+	__get_cpu_var(watchdog_nmi_touch) = true;
 	touch_softlockup_watchdog();
 }
 EXPORT_SYMBOL(touch_nmi_watchdog);
@@ -201,10 +203,9 @@ void watchdog_overflow_callback(struct perf_event *event, int nmi,
 		 struct pt_regs *regs)
 {
 	int this_cpu = smp_processor_id();
-	unsigned long touch_ts = per_cpu(watchdog_touch_ts, this_cpu);
 
-	if (touch_ts == 0) {
-		__touch_watchdog();
+	if (__get_cpu_var(watchdog_nmi_touch) == true) {
+		__get_cpu_var(watchdog_nmi_touch) = false;
 		return;
 	}