nohz: Use enum code for tick stop failure tracing message

It makes nohz tracing more lightweight, standard and easier to parse.

Examples:

       user_loop-2904  [007] d..1   517.701126: tick_stop: success=1 dependency=NONE
       user_loop-2904  [007] dn.1   518.021181: tick_stop: success=0 dependency=SCHED
    posix_timers-6142  [007] d..1  1739.027400: tick_stop: success=0 dependency=POSIX_TIMER
       user_loop-5463  [007] dN.1  1185.931939: tick_stop: success=0 dependency=PERF_EVENTS

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
diff --git a/include/trace/events/timer.h b/include/trace/events/timer.h
index 073b9ac..5144013 100644
--- a/include/trace/events/timer.h
+++ b/include/trace/events/timer.h
@@ -328,23 +328,49 @@
 );
 
 #ifdef CONFIG_NO_HZ_COMMON
+
+#define TICK_DEP_NAMES					\
+		tick_dep_name(NONE)			\
+		tick_dep_name(POSIX_TIMER)		\
+		tick_dep_name(PERF_EVENTS)		\
+		tick_dep_name(SCHED)			\
+		tick_dep_name_end(CLOCK_UNSTABLE)
+
+#undef tick_dep_name
+#undef tick_dep_name_end
+
+#define tick_dep_name(sdep) TRACE_DEFINE_ENUM(TICK_DEP_MASK_##sdep);
+#define tick_dep_name_end(sdep)  TRACE_DEFINE_ENUM(TICK_DEP_MASK_##sdep);
+
+TICK_DEP_NAMES
+
+#undef tick_dep_name
+#undef tick_dep_name_end
+
+#define tick_dep_name(sdep) { TICK_DEP_MASK_##sdep, #sdep },
+#define tick_dep_name_end(sdep) { TICK_DEP_MASK_##sdep, #sdep }
+
+#define show_tick_dep_name(val)				\
+	__print_symbolic(val, TICK_DEP_NAMES)
+
 TRACE_EVENT(tick_stop,
 
-	TP_PROTO(int success, char *error_msg),
+	TP_PROTO(int success, int dependency),
 
-	TP_ARGS(success, error_msg),
+	TP_ARGS(success, dependency),
 
 	TP_STRUCT__entry(
 		__field( int ,		success	)
-		__string( msg, 		error_msg )
+		__field( int ,		dependency )
 	),
 
 	TP_fast_assign(
 		__entry->success	= success;
-		__assign_str(msg, error_msg);
+		__entry->dependency	= dependency;
 	),
 
-	TP_printk("success=%s msg=%s",  __entry->success ? "yes" : "no", __get_str(msg))
+	TP_printk("success=%d dependency=%s",  __entry->success, \
+			show_tick_dep_name(__entry->dependency))
 );
 #endif