tracing: create automated trace defines

This patch lowers the number of places a developer must modify to add
new tracepoints. The current method to add a new tracepoint
into an existing system is to write the trace point macro in the
trace header with one of the macros TRACE_EVENT, TRACE_FORMAT or
DECLARE_TRACE, then they must add the same named item into the C file
with the macro DEFINE_TRACE(name) and then add the trace point.

This change cuts out the needing to add the DEFINE_TRACE(name).
Every file that uses the tracepoint must still include the trace/<type>.h
file, but the one C file must also add a define before the including
of that file.

 #define CREATE_TRACE_POINTS
 #include <trace/mytrace.h>

This will cause the trace/mytrace.h file to also produce the C code
necessary to implement the trace point.

Note, if more than one trace/<type>.h is used to create the C code
it is best to list them all together.

 #define CREATE_TRACE_POINTS
 #include <trace/foo.h>
 #include <trace/bar.h>
 #include <trace/fido.h>

Thanks to Mathieu Desnoyers and Christoph Hellwig for coming up with
the cleaner solution of the define above the includes over my first
design to have the C code include a "special" header.

This patch converts sched, irq and lockdep and skb to use this new
method.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Zhao Lei <zhaolei@cn.fujitsu.com>
Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 3 insertions, 4 deletions

diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index d82142be8dd2..983d8be8dff7 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -17,9 +17,11 @@
 #include <linux/kernel_stat.h>
 #include <linux/rculist.h>
 #include <linux/hash.h>
-#include <trace/irq.h>
 #include <linux/bootmem.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/irq.h>
+
 #include "internals.h"
 
 /*
@@ -348,9 +350,6 @@ static void warn_no_thread(unsigned int irq, struct irqaction *action)
                "but no thread function available.", irq, action->name);
 }
 
-DEFINE_TRACE(irq_handler_entry);
-DEFINE_TRACE(irq_handler_exit);
-
 /**
  * handle_IRQ_event - irq action chain handler
  * @irq:        the interrupt number