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>

3 files changed, 11 insertions, 5 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index c209d214169c..d880ab2772ce 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -884,13 +884,18 @@ trace_current_buffer_lock_reserve(unsigned char type, unsigned long len,
 void trace_current_buffer_unlock_commit(struct ring_buffer_event *event,
                                         unsigned long flags, int pc)
 {
-        return __trace_buffer_unlock_commit(&global_trace, event, flags, pc, 1);
+        __trace_buffer_unlock_commit(&global_trace, event, flags, pc, 1);
 }
 
 void trace_nowake_buffer_unlock_commit(struct ring_buffer_event *event,
                                         unsigned long flags, int pc)
 {
-        return __trace_buffer_unlock_commit(&global_trace, event, flags, pc, 0);
+        __trace_buffer_unlock_commit(&global_trace, event, flags, pc, 0);
+}
+
+void trace_current_buffer_discard_commit(struct ring_buffer_event *event)
+{
+        ring_buffer_discard_commit(global_trace.buffer, event);
 }
 
 void
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 3cf856fa597b..dfefffd7ae39 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -497,6 +497,7 @@ void trace_current_buffer_unlock_commit(struct ring_buffer_event *event,
                                         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);
diff --git a/kernel/trace/trace_events_stage_3.h b/kernel/trace/trace_events_stage_3.h
index 9d2fa78cecca..d2f34bf30e59 100644
--- a/kernel/trace/trace_events_stage_3.h
+++ b/kernel/trace/trace_events_stage_3.h
@@ -223,9 +223,9 @@ static void ftrace_raw_event_##call(proto)				\
         assign;                                                         \
                                                                         \
         if (call->preds && !filter_match_preds(call, entry))            \
-                ring_buffer_event_discard(event);                       \
-                                                                        \
-        trace_nowake_buffer_unlock_commit(event, irq_flags, pc);        \
+                trace_current_buffer_discard_commit(event);             \
+        else                                                            \
+                trace_nowake_buffer_unlock_commit(event, irq_flags, pc); \
                                                                         \
 }                                                                       \
                                                                         \