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authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>2015-04-01 18:57:27 (GMT)
committerSteven Rostedt <rostedt@goodmis.org>2015-04-08 13:39:55 (GMT)
commit889204278ccf98c5c097b1d1ae69babc6a3222fd (patch)
tree53778b4af3b5ca401c57bc707f9f5ba838c394e7 /samples
parentacd388fd3af350ab24c6ab6f19b83fc4a4f3aa60 (diff)
tracing: Update trace-event-sample with TRACE_SYSTEM_VAR documentation
Add documentation about TRACE_SYSTEM needing to be alpha-numeric or with underscores, and that if it is not, then the use of TRACE_SYSTEM_VAR is required to make something that is. An example of this is shown in samples/trace_events/trace-events-sample.h Link: http://lkml.kernel.org/r/20150403013802.220157513@goodmis.org Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'samples')
-rw-r--r--samples/trace_events/trace-events-sample.h20
1 files changed, 19 insertions, 1 deletions
diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h
index a2c8b02..19405f1 100644
--- a/samples/trace_events/trace-events-sample.h
+++ b/samples/trace_events/trace-events-sample.h
@@ -22,7 +22,25 @@
* protection, just like TRACE_INCLUDE_FILE.
*/
#undef TRACE_SYSTEM
-#define TRACE_SYSTEM sample
+#define TRACE_SYSTEM sample-trace
+
+/*
+ * TRACE_SYSTEM is expected to be a C valid variable (alpha-numeric
+ * and underscore), although it may start with numbers. If for some
+ * reason it is not, you need to add the following lines:
+ */
+#undef TRACE_SYSTEM_VAR
+#define TRACE_SYSTEM_VAR sample_trace
+/*
+ * But the above is only needed if TRACE_SYSTEM is not alpha-numeric
+ * and underscored. By default, TRACE_SYSTEM_VAR will be equal to
+ * TRACE_SYSTEM. As TRACE_SYSTEM_VAR must be alpha-numeric, if
+ * TRACE_SYSTEM is not, then TRACE_SYSTEM_VAR must be defined with
+ * only alpha-numeric and underscores.
+ *
+ * The TRACE_SYSTEM_VAR is only used internally and not visible to
+ * user space.
+ */
/*
* Notice that this file is not protected like a normal header.

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