[PATCH -tip] Tracing/fastboot: Only trace non-module initcalls

[Frederic Weisbecker]

At this time, only built-in initcalls interest us.
We can't really produce a relevant graph if we include
the modules initcall too.

I had good results after this patch (see svg in attachment).

Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
---
 include/linux/ftrace.h    |    2 ++
 init/main.c               |    1 +
 kernel/trace/trace_boot.c |   11 ++++++++---
 3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index ed53265..5812dba 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -225,9 +225,11 @@ struct boot_trace {
 #ifdef CONFIG_BOOT_TRACER
 extern void trace_boot(struct boot_trace *it, initcall_t fn);
 extern void start_boot_trace(void);
+extern void stop_boot_trace(void);
 #else
 static inline void trace_boot(struct boot_trace *it, initcall_t fn) { }
 static inline void start_boot_trace(void) { }
+static inline void stop_boot_trace(void) { }
 #endif
 
 
diff --git a/init/main.c b/init/main.c
index 47d621a..2e5c37e 100644
--- a/init/main.c
+++ b/init/main.c
@@ -976,6 +976,7 @@ static int __init kernel_init(void * unused)
 	 * we're essentially up and running. Get rid of the
 	 * initmem segments and start the user-mode stuff..
 	 */
+	stop_boot_trace();
 	init_post();
 	return 0;
 }
diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
index b9dc2c0..a7efe35 100644
--- a/kernel/trace/trace_boot.c
+++ b/kernel/trace/trace_boot.c
@@ -22,11 +22,16 @@ void start_boot_trace(void)
 	trace_boot_enabled = 1;
 }
 
-void stop_boot_trace(struct trace_array *tr)
+void stop_boot_trace(void)
 {
 	trace_boot_enabled = 0;
 }
 
+void reset_boot_trace(struct trace_array *tr)
+{
+	stop_boot_trace();
+}
+
 static void boot_trace_init(struct trace_array *tr)
 {
 	int cpu;
@@ -43,7 +48,7 @@ static void boot_trace_ctrl_update(struct trace_array *tr)
 	if (tr->ctrl)
 		start_boot_trace();
 	else
-		stop_boot_trace(tr);
+		stop_boot_trace();
 }
 
 static enum print_line_t initcall_print_line(struct trace_iterator *iter)
@@ -81,7 +86,7 @@ struct tracer boot_tracer __read_mostly =
 {
 	.name		= "initcall",
 	.init		= boot_trace_init,
-	.reset		= stop_boot_trace,
+	.reset		= reset_boot_trace,
 	.ctrl_update	= boot_trace_ctrl_update,
 	.print_line	= initcall_print_line,
 };