Commit 4114fbfd authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Steven Rostedt (VMware)
Browse files

tracing: Enable creating new instance early boot 

Enable creating new trace_array instance in early boot stage.
If the instances directory is not created, postpone it until
the tracefs is initialized.

Link: https://lkml.kernel.org/r/159974154763.478751.6289753509587233103.stgit@devnote2



Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent a838deab

kernel/trace/trace.c

+42 −11
Original line number Diff line number Diff line
@@ -8636,6 +8636,24 @@ struct trace_array *trace_array_find_get(const char *instance) 
	return tr;

}



static int trace_array_create_dir(struct trace_array *tr)

{

	int ret;



	tr->dir = tracefs_create_dir(tr->name, trace_instance_dir);

	if (!tr->dir)

		return -EINVAL;



	ret = event_trace_add_tracer(tr->dir, tr);

	if (ret)

		tracefs_remove(tr->dir);



	init_tracer_tracefs(tr, tr->dir);

	__update_tracer_options(tr);



	return ret;

}



static struct trace_array *trace_array_create(const char *name)

{

	struct trace_array *tr;
@@ -8671,30 +8689,27 @@ static struct trace_array *trace_array_create(const char *name) 
	if (allocate_trace_buffers(tr, trace_buf_size) < 0)

		goto out_free_tr;



	tr->dir = tracefs_create_dir(name, trace_instance_dir);

	if (!tr->dir)

		goto out_free_tr;



	ret = event_trace_add_tracer(tr->dir, tr);

	if (ret) {

		tracefs_remove(tr->dir);

	if (ftrace_allocate_ftrace_ops(tr) < 0)

		goto out_free_tr;

	}



	ftrace_init_trace_array(tr);



	init_tracer_tracefs(tr, tr->dir);

	init_trace_flags_index(tr);

	__update_tracer_options(tr);



	if (trace_instance_dir) {

		ret = trace_array_create_dir(tr);

		if (ret)

			goto out_free_tr;

	}



	list_add(&tr->list, &ftrace_trace_arrays);



	tr->ref++;





	return tr;



 out_free_tr:

	ftrace_free_ftrace_ops(tr);

	free_trace_buffers(tr);

	free_cpumask_var(tr->tracing_cpumask);

	kfree(tr->name);
@@ -8852,11 +8867,27 @@ static int instance_rmdir(const char *name) 


static __init void create_trace_instances(struct dentry *d_tracer)

{

	struct trace_array *tr;



	trace_instance_dir = tracefs_create_instance_dir("instances", d_tracer,

							 instance_mkdir,

							 instance_rmdir);

	if (MEM_FAIL(!trace_instance_dir, "Failed to create instances directory\n"))

		return;



	mutex_lock(&event_mutex);

	mutex_lock(&trace_types_lock);



	list_for_each_entry(tr, &ftrace_trace_arrays, list) {

		if (!tr->name)

			continue;

		if (MEM_FAIL(trace_array_create_dir(tr) < 0,

			     "Failed to create instance directory\n"))

			break;

	}



	mutex_unlock(&trace_types_lock);

	mutex_unlock(&event_mutex);

}



static void

kernel/trace/trace.h

+7 −0
Original line number Diff line number Diff line
@@ -1125,6 +1125,8 @@ extern int ftrace_is_dead(void); 
int ftrace_create_function_files(struct trace_array *tr,

				 struct dentry *parent);

void ftrace_destroy_function_files(struct trace_array *tr);

int ftrace_allocate_ftrace_ops(struct trace_array *tr);

void ftrace_free_ftrace_ops(struct trace_array *tr);

void ftrace_init_global_array_ops(struct trace_array *tr);

void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func);

void ftrace_reset_array_ops(struct trace_array *tr);
@@ -1146,6 +1148,11 @@ ftrace_create_function_files(struct trace_array *tr, 
{

	return 0;

}

static inline int ftrace_allocate_ftrace_ops(struct trace_array *tr)

{

	return 0;

}

static inline void ftrace_free_ftrace_ops(struct trace_array *tr) { }

static inline void ftrace_destroy_function_files(struct trace_array *tr) { }

static inline __init void

ftrace_init_global_array_ops(struct trace_array *tr) { }

kernel/trace/trace_functions.c

+14 −8
Original line number Diff line number Diff line
@@ -34,10 +34,14 @@ enum { 
	TRACE_FUNC_OPT_STACK	= 0x1,

};



static int allocate_ftrace_ops(struct trace_array *tr)

int ftrace_allocate_ftrace_ops(struct trace_array *tr)

{

	struct ftrace_ops *ops;



	/* The top level array uses the "global_ops" */

	if (tr->flags & TRACE_ARRAY_FL_GLOBAL)

		return 0;



	ops = kzalloc(sizeof(*ops), GFP_KERNEL);

	if (!ops)

		return -ENOMEM;
@@ -48,15 +52,19 @@ static int allocate_ftrace_ops(struct trace_array *tr) 


	tr->ops = ops;

	ops->private = tr;



	return 0;

}



void ftrace_free_ftrace_ops(struct trace_array *tr)

{

	kfree(tr->ops);

	tr->ops = NULL;

}



int ftrace_create_function_files(struct trace_array *tr,

				 struct dentry *parent)

{

	int ret;



	/*

	 * The top level array uses the "global_ops", and the files are

	 * created on boot up.
@@ -64,9 +72,8 @@ int ftrace_create_function_files(struct trace_array *tr, 
	if (tr->flags & TRACE_ARRAY_FL_GLOBAL)

		return 0;



	ret = allocate_ftrace_ops(tr);

	if (ret)

		return ret;

	if (!tr->ops)

		return -EINVAL;



	ftrace_create_filter_files(tr->ops, parent);
@@ -76,8 +83,7 @@ int ftrace_create_function_files(struct trace_array *tr, 
void ftrace_destroy_function_files(struct trace_array *tr)

{

	ftrace_destroy_filter_files(tr->ops);

	kfree(tr->ops);

	tr->ops = NULL;

	ftrace_free_ftrace_ops(tr);

}



static int function_trace_init(struct trace_array *tr)