tracepoints: add DECLARE_TRACE() and DEFINE_TRACE()

[linux-3.10.git] / Documentation / tracepoints.txt

diff --git a/Documentation/tracepoints.txt b/Documentation/tracepoints.txt
index 5d354e1..e8ad47b 100644 (file)
--- a/Documentation/tracepoints.txt
+++ b/Documentation/tracepoints.txt
@@ -42,7 +42,7 @@ In include/trace/subsys.h :
 
 #include <linux/tracepoint.h>
 
-DEFINE_TRACE(subsys_eventname,
+DECLARE_TRACE(subsys_eventname,
        TPPTOTO(int firstarg, struct task_struct *p),
        TPARGS(firstarg, p));
 
@@ -50,6 +50,8 @@ In subsys/file.c (where the tracing statement must be added) :
 
 #include <trace/subsys.h>
 
+DEFINE_TRACE(subsys_eventname);
+
 void somefct(void)
 {
        ...
@@ -86,6 +88,9 @@ to limit collisions. Tracepoint names are global to the kernel: they are
 considered as being the same whether they are in the core kernel image or in
 modules.
 
+If the tracepoint has to be used in kernel modules, an
+EXPORT_TRACEPOINT_SYMBOL_GPL() or EXPORT_TRACEPOINT_SYMBOL() can be used to
+export the defined tracepoints.
 
 * Probe / tracepoint example