[PATCH v3] tracing: timer: Add deferrable flag to timer_start

[Badhri Jagan Sridharan <badhri@google.com>]

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

Signed-off-by: Badhri Jagan Sridharan <Badhri@google.com>
---
Changelog since v2:
- fixed indentation

Changelog since v1:
- fixed indentation
- moved deferrable flag checking to tracing code

 include/trace/events/timer.h | 12 ++++++++----
 kernel/time/timer.c          |  3 ++-
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/include/trace/events/timer.h b/include/trace/events/timer.h
index 68c2c20..342d741 100644
--- a/include/trace/events/timer.h
+++ b/include/trace/events/timer.h
@@ -43,15 +43,17 @@ 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, char 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( char,		deferrable	)
 	),
 
 	TP_fast_assign(
@@ -59,11 +61,13 @@ TRACE_EVENT(timer_start,
 		__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')
 );
 
 /**
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 2ece3aa..e5588da 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -648,7 +648,8 @@ 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)
-- 
2.2.0.rc0.207.ga3a616c