---

yaml
---
r: 100420
b: refs/heads/master
c: 1b29b01
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: bc0c38d139ec7fcd5c030aea16b008f3732e42ac
+refs/heads/master: 1b29b01887e6032dcaf818c14999c7a39593b4e7

trunk/kernel/trace/Kconfig

@@ -8,3 +8,16 @@ config TRACING
 	bool
 	select DEBUG_FS
 
+config FTRACE
+	bool "Kernel Function Tracer"
+	depends on DEBUG_KERNEL && HAVE_FTRACE
+	select FRAME_POINTER
+	select TRACING
+	help
+	  Enable the kernel to trace every kernel function. This is done
+	  by using a compiler feature to insert a small, 5-byte No-Operation
+	  instruction to the beginning of every kernel function, which NOP
+	  sequence is then dynamically patched into a tracer call when
+	  tracing is enabled by the administrator. If it's runtime disabled
+	  (the bootup default), then the overhead of the instructions is very
+	  small and not measurable even in micro-benchmarks.

trunk/kernel/trace/Makefile

@@ -1,5 +1,6 @@
 obj-$(CONFIG_FTRACE) += libftrace.o
 
 obj-$(CONFIG_TRACING) += trace.o
+obj-$(CONFIG_FTRACE) += trace_functions.o
 
 libftrace-y := ftrace.o

trunk/kernel/trace/trace_functions.c

@@ -0,0 +1,73 @@
+/*
+ * ring buffer based function tracer
+ *
+ * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
+ * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
+ *
+ * Based on code from the latency_tracer, that is:
+ *
+ *  Copyright (C) 2004-2006 Ingo Molnar
+ *  Copyright (C) 2004 William Lee Irwin III
+ */
+#include <linux/fs.h>
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+#include <linux/ftrace.h>
+
+#include "trace.h"
+
+static notrace void function_reset(struct trace_array *tr)
+{
+	int cpu;
+
+	tr->time_start = now(tr->cpu);
+
+	for_each_online_cpu(cpu)
+		tracing_reset(tr->data[cpu]);
+}
+
+static notrace void start_function_trace(struct trace_array *tr)
+{
+	function_reset(tr);
+	tracing_start_function_trace();
+}
+
+static notrace void stop_function_trace(struct trace_array *tr)
+{
+	tracing_stop_function_trace();
+}
+
+static notrace void function_trace_init(struct trace_array *tr)
+{
+	if (tr->ctrl)
+		start_function_trace(tr);
+}
+
+static notrace void function_trace_reset(struct trace_array *tr)
+{
+	if (tr->ctrl)
+		stop_function_trace(tr);
+}
+
+static notrace void function_trace_ctrl_update(struct trace_array *tr)
+{
+	if (tr->ctrl)
+		start_function_trace(tr);
+	else
+		stop_function_trace(tr);
+}
+
+static struct tracer function_trace __read_mostly =
+{
+	.name	     = "ftrace",
+	.init	     = function_trace_init,
+	.reset	     = function_trace_reset,
+	.ctrl_update = function_trace_ctrl_update,
+};
+
+static __init int init_function_trace(void)
+{
+	return register_tracer(&function_trace);
+}
+
+device_initcall(init_function_trace);