Commit 8781915a authored by Ezequiel Garcia's avatar Ezequiel Garcia Committed by Steven Rostedt
Browse files

trace: Move trace event enable from fs_initcall to core_initcall 

This patch splits trace event initialization in two stages:
 * ftrace enable
 * sysfs event entry creation

This allows to capture trace events from an earlier point
by using 'trace_event' kernel parameter and is important
to trace boot-up allocations.

Note that, in order to enable events at core_initcall,
it's necessary to move init_ftrace_syscalls() from
core_initcall to early_initcall.

Link: http://lkml.kernel.org/r/1347461277-25302-1-git-send-email-elezegarcia@gmail.com



Signed-off-by: default avatarEzequiel Garcia <elezegarcia@gmail.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 5224c3a3

kernel/trace/trace_events.c

+72 −36
Original line number Diff line number Diff line
@@ -1199,6 +1199,31 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events, 
	return 0;

}



static void event_remove(struct ftrace_event_call *call)

{

	ftrace_event_enable_disable(call, 0);

	if (call->event.funcs)

		__unregister_ftrace_event(&call->event);

	list_del(&call->list);

}



static int event_init(struct ftrace_event_call *call)

{

	int ret = 0;



	if (WARN_ON(!call->name))

		return -EINVAL;



	if (call->class->raw_init) {

		ret = call->class->raw_init(call);

		if (ret < 0 && ret != -ENOSYS)

			pr_warn("Could not initialize trace events/%s\n",

				call->name);

	}



	return ret;

}



static int

__trace_add_event_call(struct ftrace_event_call *call, struct module *mod,

		       const struct file_operations *id,
@@ -1209,19 +1234,9 @@ __trace_add_event_call(struct ftrace_event_call *call, struct module *mod, 
	struct dentry *d_events;

	int ret;



	/* The linker may leave blanks */

	if (!call->name)

		return -EINVAL;



	if (call->class->raw_init) {

		ret = call->class->raw_init(call);

		if (ret < 0) {

			if (ret != -ENOSYS)

				pr_warning("Could not initialize trace events/%s\n",

					   call->name);

	ret = event_init(call);

	if (ret < 0)

		return ret;

		}

	}



	d_events = event_trace_events_dir();

	if (!d_events)
@@ -1272,13 +1287,10 @@ static void remove_subsystem_dir(const char *name) 
 */

static void __trace_remove_event_call(struct ftrace_event_call *call)

{

	ftrace_event_enable_disable(call, 0);

	if (call->event.funcs)

		__unregister_ftrace_event(&call->event);

	debugfs_remove_recursive(call->dir);

	list_del(&call->list);

	event_remove(call);

	trace_destroy_fields(call);

	destroy_preds(call);

	debugfs_remove_recursive(call->dir);

	remove_subsystem_dir(call->class->system);

}
@@ -1450,15 +1462,43 @@ static __init int setup_trace_event(char *str) 
}

__setup("trace_event=", setup_trace_event);



static __init int event_trace_enable(void)

{

	struct ftrace_event_call **iter, *call;

	char *buf = bootup_event_buf;

	char *token;

	int ret;



	for_each_event(iter, __start_ftrace_events, __stop_ftrace_events) {



		call = *iter;

		ret = event_init(call);

		if (!ret)

			list_add(&call->list, &ftrace_events);

	}



	while (true) {

		token = strsep(&buf, ",");



		if (!token)

			break;

		if (!*token)

			continue;



		ret = ftrace_set_clr_event(token, 1);

		if (ret)

			pr_warn("Failed to enable trace event: %s\n", token);

	}

	return 0;

}



static __init int event_trace_init(void)

{

	struct ftrace_event_call **call;

	struct ftrace_event_call *call;

	struct dentry *d_tracer;

	struct dentry *entry;

	struct dentry *d_events;

	int ret;

	char *buf = bootup_event_buf;

	char *token;



	d_tracer = tracing_init_dentry();

	if (!d_tracer)
@@ -1497,24 +1537,19 @@ static __init int event_trace_init(void) 
	if (trace_define_common_fields())

		pr_warning("tracing: Failed to allocate common fields");



	for_each_event(call, __start_ftrace_events, __stop_ftrace_events) {

		__trace_add_event_call(*call, NULL, &ftrace_event_id_fops,

	/*

	 * Early initialization already enabled ftrace event.

	 * Now it's only necessary to create the event directory.

	 */

	list_for_each_entry(call, &ftrace_events, list) {



		ret = event_create_dir(call, d_events,

				       &ftrace_event_id_fops,

				       &ftrace_enable_fops,

				       &ftrace_event_filter_fops,

				       &ftrace_event_format_fops);

	}



	while (true) {

		token = strsep(&buf, ",");



		if (!token)

			break;

		if (!*token)

			continue;



		ret = ftrace_set_clr_event(token, 1);

		if (ret)

			pr_warning("Failed to enable trace event: %s\n", token);

		if (ret < 0)

			event_remove(call);

	}



	ret = register_module_notifier(&trace_module_nb);
@@ -1523,6 +1558,7 @@ static __init int event_trace_init(void) 


	return 0;

}

core_initcall(event_trace_enable);

fs_initcall(event_trace_init);



#ifdef CONFIG_FTRACE_STARTUP_TEST

kernel/trace/trace_syscalls.c

+1 −1
Original line number Diff line number Diff line
@@ -487,7 +487,7 @@ int __init init_ftrace_syscalls(void) 


	return 0;

}

core_initcall(init_ftrace_syscalls);

early_initcall(init_ftrace_syscalls);



#ifdef CONFIG_PERF_EVENTS

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