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Commit 8e254c1d authored by Li Zefan's avatar Li Zefan Committed by Ingo Molnar
Browse files

tracing/filters: Defer pred allocation 



init_preds() allocates about 5392 bytes of memory (on x86_32) for
a TRACE_EVENT. With my config, at system boot total memory occupied
is:

	5392 * (642 + 15) == 3459KB

642 == cat available_events | wc -l
15 == number of dirs in events/ftrace

That's quite a lot, so we'd better defer memory allocation util
it's needed, that's when filter is used.

Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
LKML-Reference: <4A9B8EA5.6020700@cn.fujitsu.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 73222acf

include/linux/ftrace_event.h

+0 −1
Original line number Diff line number Diff line
@@ -133,7 +133,6 @@ struct ftrace_event_call { 
#define MAX_FILTER_PRED		32

#define MAX_FILTER_STR_VAL	128



extern int init_preds(struct ftrace_event_call *call);

extern void destroy_preds(struct ftrace_event_call *call);

extern int filter_match_preds(struct ftrace_event_call *call, void *rec);

extern int filter_current_check_discard(struct ftrace_event_call *call,

include/linux/syscalls.h

+0 −2
Original line number Diff line number Diff line
@@ -177,7 +177,6 @@ static void prof_sysexit_disable_##sname(struct ftrace_event_call *event_call) \ 
		event_enter_##sname.id = id;				\

		set_syscall_enter_id(num, id);				\

		INIT_LIST_HEAD(&event_enter_##sname.fields);		\

		init_preds(&event_enter_##sname);			\

		return 0;						\

	}								\

	TRACE_SYS_ENTER_PROFILE(sname);					\
@@ -214,7 +213,6 @@ static void prof_sysexit_disable_##sname(struct ftrace_event_call *event_call) \ 
		event_exit_##sname.id = id;				\

		set_syscall_exit_id(num, id);				\

		INIT_LIST_HEAD(&event_exit_##sname.fields);		\

		init_preds(&event_exit_##sname);			\

		return 0;						\

	}								\

	TRACE_SYS_EXIT_PROFILE(sname);					\

include/trace/ftrace.h

+0 −1
Original line number Diff line number Diff line
@@ -622,7 +622,6 @@ static int ftrace_raw_init_event_##call(void) \ 
		return -ENODEV;						\

	event_##call.id = id;						\

	INIT_LIST_HEAD(&event_##call.fields);				\

	init_preds(&event_##call);					\

	return 0;							\

}									\

									\

kernel/trace/trace_events_filter.c

+41 −9
Original line number Diff line number Diff line
@@ -309,7 +309,7 @@ void print_event_filter(struct ftrace_event_call *call, struct trace_seq *s) 
	struct event_filter *filter = call->filter;



	mutex_lock(&event_mutex);

	if (filter->filter_string)

	if (filter && filter->filter_string)

		trace_seq_printf(s, "%s\n", filter->filter_string);

	else

		trace_seq_printf(s, "none\n");
@@ -322,7 +322,7 @@ void print_subsystem_event_filter(struct event_subsystem *system, 
	struct event_filter *filter = system->filter;



	mutex_lock(&event_mutex);

	if (filter->filter_string)

	if (filter && filter->filter_string)

		trace_seq_printf(s, "%s\n", filter->filter_string);

	else

		trace_seq_printf(s, "none\n");
@@ -390,6 +390,9 @@ void destroy_preds(struct ftrace_event_call *call) 
	struct event_filter *filter = call->filter;

	int i;



	if (!filter)

		return;



	for (i = 0; i < MAX_FILTER_PRED; i++) {

		if (filter->preds[i])

			filter_free_pred(filter->preds[i]);
@@ -400,7 +403,7 @@ void destroy_preds(struct ftrace_event_call *call) 
	call->filter = NULL;

}



int init_preds(struct ftrace_event_call *call)

static int init_preds(struct ftrace_event_call *call)

{

	struct event_filter *filter;

	struct filter_pred *pred;
@@ -410,7 +413,6 @@ int init_preds(struct ftrace_event_call *call) 
	if (!call->filter)

		return -ENOMEM;



	call->filter_active = 0;

	filter->n_preds = 0;



	filter->preds = kzalloc(MAX_FILTER_PRED * sizeof(pred), GFP_KERNEL);
@@ -432,7 +434,28 @@ oom: 


	return -ENOMEM;

}

EXPORT_SYMBOL_GPL(init_preds);



static int init_subsystem_preds(struct event_subsystem *system)

{

	struct ftrace_event_call *call;

	int err;



	list_for_each_entry(call, &ftrace_events, list) {

		if (!call->define_fields)

			continue;



		if (strcmp(call->system, system->name) != 0)

			continue;



		if (!call->filter) {

			err = init_preds(call);

			if (err)

				return err;

		}

	}



	return 0;

}



enum {

	FILTER_DISABLE_ALL,
@@ -449,6 +472,9 @@ static void filter_free_subsystem_preds(struct event_subsystem *system, 
		if (!call->define_fields)

			continue;



		if (strcmp(call->system, system->name) != 0)

			continue;



		if (flag == FILTER_INIT_NO_RESET) {

			call->filter->no_reset = false;

			continue;
@@ -457,12 +483,10 @@ static void filter_free_subsystem_preds(struct event_subsystem *system, 
		if (flag == FILTER_SKIP_NO_RESET && call->filter->no_reset)

			continue;



		if (!strcmp(call->system, system->name)) {

		filter_disable_preds(call);

		remove_filter_string(call->filter);

	}

}

}



static int filter_add_pred_fn(struct filter_parse_state *ps,

			      struct ftrace_event_call *call,
@@ -1094,6 +1118,10 @@ int apply_event_filter(struct ftrace_event_call *call, char *filter_string) 


	mutex_lock(&event_mutex);



	err = init_preds(call);

	if (err)

		goto out_unlock;



	if (!strcmp(strstrip(filter_string), "0")) {

		filter_disable_preds(call);

		remove_filter_string(call->filter);
@@ -1139,6 +1167,10 @@ int apply_subsystem_event_filter(struct event_subsystem *system, 


	mutex_lock(&event_mutex);



	err = init_subsystem_preds(system);

	if (err)

		goto out_unlock;



	if (!strcmp(strstrip(filter_string), "0")) {

		filter_free_subsystem_preds(system, FILTER_DISABLE_ALL);

		remove_filter_string(system->filter);

kernel/trace/trace_export.c

+0 −1
Original line number Diff line number Diff line
@@ -135,7 +135,6 @@ __attribute__((section("_ftrace_events"))) event_##call = { \ 
static int ftrace_raw_init_event_##call(void)				\

{									\

	INIT_LIST_HEAD(&event_##call.fields);				\

	init_preds(&event_##call);					\

	return 0;							\

}									\