tracing: timer: Add deferrable flag to timer_start

The timer_start event now shows whether the timer is
deferrable in case of a low-res timer. The debug_activate
function now includes a deferrable flag while calling
the trace_timer_start event.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Badhri Jagan Sridharan <Badhri@google.com>
[jstultz: Fixed minor whitespace and grammer tweaks
 pointed out by Ingo]
Signed-off-by: John Stultz <john.stultz@linaro.org>

include/trace/events/timer.h

@@ -43,27 +43,32 @@ DEFINE_EVENT(timer_class, timer_init,
  */
 TRACE_EVENT(timer_start,
 
-	TP_PROTO(struct timer_list *timer, unsigned long expires),
+	TP_PROTO(struct timer_list *timer,
+		unsigned long expires,
+		unsigned int deferrable),
 
-	TP_ARGS(timer, expires),
+	TP_ARGS(timer, expires, deferrable),
 
 	TP_STRUCT__entry(
 		__field( void *,	timer		)
 		__field( void *,	function	)
 		__field( unsigned long,	expires		)
 		__field( unsigned long,	now		)
+		__field( unsigned int,	deferrable	)
 	),
 
 	TP_fast_assign(
 		__entry->timer		= timer;
 		__entry->function	= timer->function;
 		__entry->expires	= expires;
 		__entry->now		= jiffies;
+		__entry->deferrable     = deferrable;
 	),
 
-	TP_printk("timer=%p function=%pf expires=%lu [timeout=%ld]",
+	TP_printk("timer=%p function=%pf expires=%lu [timeout=%ld] defer=%c",
 		  __entry->timer, __entry->function, __entry->expires,
-		  (long)__entry->expires - __entry->now)
+		  (long)__entry->expires - __entry->now,
+		  __entry->deferrable > 0 ? 'y':'n')
 );
 
 /**

kernel/time/timer.c

@@ -650,7 +650,7 @@ static inline void
 debug_activate(struct timer_list *timer, unsigned long expires)
 {
 	debug_timer_activate(timer);
-	trace_timer_start(timer, expires);
+	trace_timer_start(timer, expires, tbase_get_deferrable(timer->base));
 }
 
 static inline void debug_deactivate(struct timer_list *timer)