tracing: Create class struct for events

This patch creates a ftrace_event_class struct that event structs point to.
This class struct will be made to hold information to modify the
events. Currently the class struct only holds the events system name.

This patch slightly increases the size, but this change lays the ground work
of other changes to make the footprint of tracepoints smaller.

With 82 standard tracepoints, and 618 system call tracepoints
(two tracepoints per syscall: enter and exit):

   text	   data	    bss	    dec	    hex	filename
4913961	1088356	 861512	6863829	 68bbd5	vmlinux.orig
4914025	1088868	 861512	6864405	 68be15	vmlinux.class

This patch also cleans up some stale comments in ftrace.h.

v2: Fixed missing semi-colon in macro.

Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 19 insertions, 25 deletions

diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 75dd7787fb37..7dcdfd824aab 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -62,7 +62,10 @@
                 struct trace_entry      ent;                            \
                 tstruct                                                 \
                 char                    __data[0];                      \
-        };
+        };                                                              \
+                                                                        \
+        static struct ftrace_event_class event_class_##name;
+
 #undef DEFINE_EVENT
 #define DEFINE_EVENT(template, name, proto, args)       \
         static struct ftrace_event_call                 \
@@ -430,22 +433,6 @@ perf_trace_disable_##name(struct ftrace_event_call *unused)		\
  *
  * Override the macros in <trace/trace_events.h> to include the following:
  *
- * static void ftrace_event_<call>(proto)
- * {
- *      event_trace_printk(_RET_IP_, "<call>: " <fmt>);
- * }
- *
- * static int ftrace_reg_event_<call>(struct ftrace_event_call *unused)
- * {
- *      return register_trace_<call>(ftrace_event_<call>);
- * }
- *
- * static void ftrace_unreg_event_<call>(struct ftrace_event_call *unused)
- * {
- *      unregister_trace_<call>(ftrace_event_<call>);
- * }
- *
- *
  * For those macros defined with TRACE_EVENT:
  *
  * static struct ftrace_event_call event_<call>;
@@ -497,17 +484,21 @@ perf_trace_disable_##name(struct ftrace_event_call *unused)		\
  *
  * static const char print_fmt_<call>[] = <TP_printk>;
  *
+ * static struct ftrace_event_class __used event_class_<template> = {
+ *      .system                 = "<system>",
+ * };
+ *
  * static struct ftrace_event_call __used
  * __attribute__((__aligned__(4)))
  * __attribute__((section("_ftrace_events"))) event_<call> = {
  *      .name                   = "<call>",
- *      .system                 = "<system>",
+ *      .class                  = event_class_<template>,
  *      .raw_init               = trace_event_raw_init,
- *      .regfunc                = ftrace_reg_event_<call>,
- *      .unregfunc              = ftrace_unreg_event_<call>,
+ *      .regfunc                = ftrace_raw_reg_event_<call>,
+ *      .unregfunc              = ftrace_raw_unreg_event_<call>,
  *      .print_fmt              = print_fmt_<call>,
  *      .define_fields          = ftrace_define_fields_<call>,
- * }
+ * };
  *
  */
 
@@ -627,7 +618,10 @@ static struct trace_event ftrace_event_type_##call = {			\
 
 #undef DECLARE_EVENT_CLASS
 #define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print)  \
-static const char print_fmt_##call[] = print;
+static const char print_fmt_##call[] = print;                           \
+static struct ftrace_event_class __used event_class_##call = {          \
+        .system                 = __stringify(TRACE_SYSTEM)             \
+};
 
 #undef DEFINE_EVENT
 #define DEFINE_EVENT(template, call, proto, args)                       \
@@ -636,7 +630,7 @@ static struct ftrace_event_call __used					\
 __attribute__((__aligned__(4)))                                         \
 __attribute__((section("_ftrace_events"))) event_##call = {             \
         .name                   = #call,                                \
-        .system                 = __stringify(TRACE_SYSTEM),            \
+        .class                  = &event_class_##template,              \
         .event                  = &ftrace_event_type_##call,            \
         .raw_init               = trace_event_raw_init,                 \
         .regfunc                = ftrace_raw_reg_event_##call,          \
@@ -644,7 +638,7 @@ __attribute__((section("_ftrace_events"))) event_##call = {		\
         .print_fmt              = print_fmt_##template,                 \
         .define_fields          = ftrace_define_fields_##template,      \
         _TRACE_PERF_INIT(call)                                  \
-}
+};
 
 #undef DEFINE_EVENT_PRINT
 #define DEFINE_EVENT_PRINT(template, call, proto, args, print)          \
@@ -655,7 +649,7 @@ static struct ftrace_event_call __used					\
 __attribute__((__aligned__(4)))                                         \
 __attribute__((section("_ftrace_events"))) event_##call = {             \
         .name                   = #call,                                \
-        .system                 = __stringify(TRACE_SYSTEM),            \
+        .class                  = &event_class_##template,              \
         .event                  = &ftrace_event_type_##call,            \
         .raw_init               = trace_event_raw_init,                 \
         .regfunc                = ftrace_raw_reg_event_##call,          \