tracing: clean up tracing profiler

Ingo Molnar suggested clean ups for the profiling code. This patch
makes those updates.
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>

kernel/trace/ftrace.c

@@ -271,8 +271,10 @@ struct ftrace_profile_stat {
 #define PROFILES_PER_PAGE					\
 	(PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
 
-static int ftrace_profile_bits;
-static int ftrace_profile_enabled;
+static int ftrace_profile_bits __read_mostly;
+static int ftrace_profile_enabled __read_mostly;
+
+/* ftrace_profile_lock - synchronize the enable and disable of the profiler */
 static DEFINE_MUTEX(ftrace_profile_lock);
 
 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
@@ -670,7 +672,7 @@ ftrace_profile_write(struct file *filp, const char __user *ubuf,
 		     size_t cnt, loff_t *ppos)
 {
 	unsigned long val;
-	char buf[64];
+	char buf[64];		/* big enough to hold a number */
 	int ret;
 
 	if (cnt >= sizeof(buf))
@@ -719,7 +721,7 @@ static ssize_t
 ftrace_profile_read(struct file *filp, char __user *ubuf,
 		     size_t cnt, loff_t *ppos)
 {
-	char buf[64];
+	char buf[64];		/* big enough to hold a number */
 	int r;
 
 	r = sprintf(buf, "%u\n", ftrace_profile_enabled);