tracing/filters: use ring_buffer_discard_commit for discarded events

The ring_buffer_discard_commit makes better usage of the ring_buffer
when an event has been discarded. It tries to remove it completely if
possible.

This patch converts the trace event filtering to use
ring_buffer_discard_commit instead of the ring_buffer_event_discard.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 3cf856f..dfefffd 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -497,6 +497,7 @@
 					unsigned long flags, int pc);
 void trace_nowake_buffer_unlock_commit(struct ring_buffer_event *event,
 					unsigned long flags, int pc);
+void trace_current_buffer_discard_commit(struct ring_buffer_event *event);
 
 struct trace_entry *tracing_get_trace_entry(struct trace_array *tr,
 						struct trace_array_cpu *data);