perf/core: Add ::write_backward attribute to perf event

[cascardo/linux.git] / kernel / events / ring_buffer.c

diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index 60be55a..c49bab4 100644 (file)
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -230,10 +230,24 @@ out:
        return -ENOSPC;
 }
 
+int perf_output_begin_forward(struct perf_output_handle *handle,
+                            struct perf_event *event, unsigned int size)
+{
+       return __perf_output_begin(handle, event, size, false);
+}
+
+int perf_output_begin_backward(struct perf_output_handle *handle,
+                              struct perf_event *event, unsigned int size)
+{
+       return __perf_output_begin(handle, event, size, true);
+}
+
 int perf_output_begin(struct perf_output_handle *handle,
                      struct perf_event *event, unsigned int size)
 {
-       return __perf_output_begin(handle, event, size, false);
+
+       return __perf_output_begin(handle, event, size,
+                                  unlikely(is_write_backward(event)));
 }
 
 unsigned int perf_output_copy(struct perf_output_handle *handle,