Commit 81a59555 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Steven Rostedt (VMware)
Browse files

tracing/boot: Add per-event settings 

Add per-event settings for boottime tracing. User can set filter,
actions and enable on each event on boot. The event entries are
under ftrace.event.GROUP.EVENT node (note that the option key
includes event's group name and event name.) This supports below
configs.

 - ftrace.event.GROUP.EVENT.enable
   Enables GROUP:EVENT tracing.

 - ftrace.event.GROUP.EVENT.filter = FILTER
   Set FILTER rule to the GROUP:EVENT.

 - ftrace.event.GROUP.EVENT.actions = ACTION[, ACTION2...]
   Set ACTIONs to the GROUP:EVENT.

For example,

  ftrace.event.sched.sched_process_exec {
                filter = "pid < 128"
		enable
  }

this will enable tracing "sched:sched_process_exec" event
with "pid < 128" filter.

Link: http://lkml.kernel.org/r/157867238942.17873.11177628789184546198.stgit@devnote2



Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 9c5b9d3d

kernel/trace/trace_boot.c

+60 −0
Original line number Diff line number Diff line
@@ -56,6 +56,7 @@ trace_boot_set_ftrace_options(struct trace_array *tr, struct xbc_node *node) 


#ifdef CONFIG_EVENT_TRACING

extern int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set);

extern int trigger_process_regex(struct trace_event_file *file, char *buff);



static void __init

trace_boot_enable_events(struct trace_array *tr, struct xbc_node *node)
@@ -74,8 +75,66 @@ trace_boot_enable_events(struct trace_array *tr, struct xbc_node *node) 
			pr_err("Failed to enable event: %s\n", p);

	}

}



static void __init

trace_boot_init_one_event(struct trace_array *tr, struct xbc_node *gnode,

			  struct xbc_node *enode)

{

	struct trace_event_file *file;

	struct xbc_node *anode;

	char buf[MAX_BUF_LEN];

	const char *p, *group, *event;



	group = xbc_node_get_data(gnode);

	event = xbc_node_get_data(enode);



	mutex_lock(&event_mutex);

	file = find_event_file(tr, group, event);

	if (!file) {

		pr_err("Failed to find event: %s:%s\n", group, event);

		goto out;

	}



	p = xbc_node_find_value(enode, "filter", NULL);

	if (p && *p != '\0') {

		if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))

			pr_err("filter string is too long: %s\n", p);

		else if (apply_event_filter(file, buf) < 0)

			pr_err("Failed to apply filter: %s\n", buf);

	}



	xbc_node_for_each_array_value(enode, "actions", anode, p) {

		if (strlcpy(buf, p, ARRAY_SIZE(buf)) >= ARRAY_SIZE(buf))

			pr_err("action string is too long: %s\n", p);

		else if (trigger_process_regex(file, buf) < 0)

			pr_err("Failed to apply an action: %s\n", buf);

	}



	if (xbc_node_find_value(enode, "enable", NULL)) {

		if (trace_event_enable_disable(file, 1, 0) < 0)

			pr_err("Failed to enable event node: %s:%s\n",

				group, event);

	}

out:

	mutex_unlock(&event_mutex);

}



static void __init

trace_boot_init_events(struct trace_array *tr, struct xbc_node *node)

{

	struct xbc_node *gnode, *enode;



	node = xbc_node_find_child(node, "event");

	if (!node)

		return;

	/* per-event key starts with "event.GROUP.EVENT" */

	xbc_node_for_each_child(node, gnode)

		xbc_node_for_each_child(gnode, enode)

			trace_boot_init_one_event(tr, gnode, enode);

}

#else

#define trace_boot_enable_events(tr, node) do {} while (0)

#define trace_boot_init_events(tr, node) do {} while (0)

#endif



static void __init
@@ -104,6 +163,7 @@ static int __init trace_boot_init(void) 
		return 0;



	trace_boot_set_ftrace_options(tr, trace_node);

	trace_boot_init_events(tr, trace_node);

	trace_boot_enable_events(tr, trace_node);

	trace_boot_enable_tracer(tr, trace_node);

kernel/trace/trace_events_trigger.c

+1 −1
Original line number Diff line number Diff line
@@ -213,7 +213,7 @@ static int event_trigger_regex_open(struct inode *inode, struct file *file) 
	return ret;

}



static int trigger_process_regex(struct trace_event_file *file, char *buff)

int trigger_process_regex(struct trace_event_file *file, char *buff)

{

	char *command, *next = buff;

	struct event_command *p;

CRA Git | Maintained and supported by SUSTech CRA and CCSE