ring-buffer: Froce rb_update_write_stamp() to be inlined

The function rb_update_write_stamp() is in the hotpath of the ring buffer
recording. Make sure that it is inlined as well. There's not many places
that call it.

Link: http://lkml.kernel.org/r/20161121183700.GW26852@two.firstfloor.org

Reported-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

kernel/trace/ring_buffer.c

@@ -2486,7 +2486,7 @@ static inline void rb_event_discard(struct ring_buffer_event *event)
 		event->time_delta = 1;
 }
 
-static inline bool
+static __always_inline bool
 rb_event_is_commit(struct ring_buffer_per_cpu *cpu_buffer,
 		   struct ring_buffer_event *event)
 {
@@ -2500,7 +2500,7 @@ rb_event_is_commit(struct ring_buffer_per_cpu *cpu_buffer,
 		rb_commit_index(cpu_buffer) == index;
 }
 
-static void
+static __always_inline void
 rb_update_write_stamp(struct ring_buffer_per_cpu *cpu_buffer,
 		      struct ring_buffer_event *event)
 {