ftrace: inject markers via trace_marker file

Allow a user to inject a marker (TRACE_PRINT entry) into the trace ring
buffer. The related file operations are derived from code by Frédéric
Weisbecker <fweisbec@gmail.com>.

Signed-off-by: Pekka Paalanen <pq@iki.fi>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 4 insertions, 0 deletions

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 648433d18ccb..42f65d0097f0 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -124,6 +124,10 @@ struct trace_entry {
 };
 
 #define TRACE_ENTRY_SIZE        sizeof(struct trace_entry)
+#define TRACE_BUF_SIZE          1024
+#define TRACE_PRINT_BUF_SIZE \
+        (sizeof(struct trace_field) - offsetof(struct trace_field, print.buf))
+#define TRACE_CONT_BUF_SIZE     sizeof(struct trace_field)
 
 /*
  * The CPU trace array - it consists of thousands of trace entries