tracing: Add per_cpu directory into tracing instances

Add the per_cpu directory to the created tracing instances:

  cd /sys/kernel/debug/tracing/instances
  mkdir foo
  ls foo/per_cpu/cpu0
buffer_size_kb	snapshot_raw  trace	  trace_pipe_raw
snapshot	stats	      trace_pipe
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

kernel/trace/trace.c

@@ -5506,6 +5506,7 @@ static __init void create_trace_instances(struct dentry *d_tracer)
 static void
 init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer)
 {
+	int cpu;
 
 	trace_create_file("trace_options", 0644, d_tracer,
 			  tr, &tracing_iter_fops);
@@ -5538,12 +5539,15 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer)
 	trace_create_file("snapshot", 0644, d_tracer,
 			  (void *)&tr->trace_cpu, &snapshot_fops);
 #endif
+
+	for_each_tracing_cpu(cpu)
+		tracing_init_debugfs_percpu(tr, cpu);
+
 }
 
 static __init int tracer_init_debugfs(void)
 {
 	struct dentry *d_tracer;
-	int cpu;
 
 	trace_access_lock_init();
 
@@ -5583,9 +5587,6 @@ static __init int tracer_init_debugfs(void)
 
 	create_trace_options_dir(&global_trace);
 
-	for_each_tracing_cpu(cpu)
-		tracing_init_debugfs_percpu(&global_trace, cpu);
-
 	return 0;
 }