tracing: Move event storage for array from macro to standalone function

The code that shows array fields for events is defined for all events.
This can add up quite a bit when you have over 500 events.

By making helper functions in the core kernel to do the work
instead, we can shrink the size of the kernel down a bit.

With a kernel configured with 502 events, the change in size was:

   text    data     bss     dec     hex filename
12990946        1913568 9785344 24689858        178bcc2 /tmp/vmlinux
12987390        1913504 9785344 24686238        178ae9e /tmp/vmlinux.patched

That's a total of 3556 bytes, which comes down to 7 bytes per event.
Although it's not much, this code is just called at initialization of
the events.

Link: http://lkml.kernel.org/r/20120810034708.084036335@goodmis.org

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

2 files changed, 8 insertions, 12 deletions

diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index a91ab93d7250..ffe642eb84fa 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -202,6 +202,10 @@ extern int ftrace_event_reg(struct ftrace_event_call *event,
 int ftrace_output_event(struct trace_iterator *iter, struct ftrace_event_call *event,
                         char *fmt, ...);
 
+int ftrace_event_define_field(struct ftrace_event_call *call,
+                              char *type, int len, char *item, int offset,
+                              int field_size, int sign, int filter);
+
 enum {
         TRACE_EVENT_FL_FILTERED_BIT,
         TRACE_EVENT_FL_CAP_ANY_BIT,
@@ -500,10 +504,6 @@ enum {
         FILTER_TRACE_FN,
 };
 
-#define EVENT_STORAGE_SIZE 128
-extern struct mutex event_storage_mutex;
-extern char event_storage[EVENT_STORAGE_SIZE];
-
 extern int trace_event_raw_init(struct ftrace_event_call *call);
 extern int trace_define_field(struct ftrace_event_call *call, const char *type,
                               const char *name, int offset, int size,
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 3873d6e4697f..54928faf2119 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -302,15 +302,11 @@ static struct trace_event_functions ftrace_event_type_funcs_##call = {	\
 #undef __array
 #define __array(type, item, len)                                        \
         do {                                                            \
-                mutex_lock(&event_storage_mutex);                       \
                 BUILD_BUG_ON(len > MAX_FILTER_STR_VAL);                 \
-                snprintf(event_storage, sizeof(event_storage),          \
-                         "%s[%d]", #type, len);                         \
-                ret = trace_define_field(event_call, event_storage, #item, \
-                                 offsetof(typeof(field), item),         \
-                                 sizeof(field.item),                    \
-                                 is_signed_type(type), FILTER_OTHER);   \
-                mutex_unlock(&event_storage_mutex);                     \
+                ret = ftrace_event_define_field(event_call, #type, len, \
+                                #item, offsetof(typeof(field), item),   \
+                                sizeof(field.item),                     \
+                                is_signed_type(type), FILTER_OTHER); \
                 if (ret)                                                \
                         return ret;                                     \
         } while (0);