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Commit 0fc3ca9a authored by Steven Rostedt's avatar Steven Rostedt Committed by Steven Rostedt
Browse files

tracing/filter: Call synchronize_sched() just once for system filters 



By separating out the reseting of the filter->n_preds to zero from
the reallocation of preds for the filter, we can reset groups of
filters first, call synchronize_sched() just once, and then reallocate
each of the filters in the system group.

Cc: Tom Zanussi <tzanussi@gmail.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent c9c53ca0

kernel/trace/trace_events_filter.c

+63 −17
Original line number Diff line number Diff line
@@ -570,17 +570,28 @@ static void __free_preds(struct event_filter *filter) 
	filter->n_preds = 0;

}



static void reset_preds(struct event_filter *filter)

{

	struct filter_pred *pred;

	int n_preds = filter->n_preds;

	int i;



	filter->n_preds = 0;

	if (!filter->preds)

		return;



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

		pred = filter->preds[i];

		pred->fn = filter_pred_none;

	}

}



static void filter_disable_preds(struct ftrace_event_call *call)

{

	struct event_filter *filter = call->filter;

	int i;



	call->flags &= ~TRACE_EVENT_FL_FILTERED;

	if (filter->preds) {

		for (i = 0; i < filter->n_preds; i++)

			filter->preds[i]->fn = filter_pred_none;

	}

	filter->n_preds = 0;

	reset_preds(filter);

}



static void __free_filter(struct event_filter *filter)
@@ -620,15 +631,17 @@ static int __alloc_preds(struct event_filter *filter, int n_preds) 


	if (filter->preds) {

		if (filter->a_preds < n_preds) {

			/* We need to reallocate */

			filter->n_preds = 0;

			/*

			 * It is possible that the filter is currently

			 * being used. We need to zero out the number

			 * of preds, wait on preemption and then free

			 * the preds.

			 * We need to reallocate.

			 * We should have already have zeroed out

			 * the pred count and called synchronized_sched()

			 * to make sure no one is using the preds.

			 */

			if (WARN_ON_ONCE(filter->n_preds)) {

				/* We need to reset it now */

				filter->n_preds = 0;

				synchronize_sched();

			}

			__free_preds(filter);

		}

	}
@@ -1328,6 +1341,30 @@ static int replace_system_preds(struct event_subsystem *system, 
		/* try to see if the filter can be applied */

		err = replace_preds(call, filter, ps, filter_string, true);

		if (err)

			goto fail;

	}



	/* set all filter pred counts to zero */

	list_for_each_entry(call, &ftrace_events, list) {

		struct event_filter *filter = call->filter;



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

			continue;



		reset_preds(filter);

	}



	/*

	 * Since some of the preds may be used under preemption

	 * we need to wait for them to finish before we may

	 * reallocate them.

	 */

	synchronize_sched();



	list_for_each_entry(call, &ftrace_events, list) {

		struct event_filter *filter = call->filter;



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

			continue;



		/* really apply the filter */
@@ -1342,12 +1379,14 @@ static int replace_system_preds(struct event_subsystem *system, 
		fail = false;

	}



	if (fail) {

	if (fail)

		goto fail;



	return 0;

 fail:

	parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);

	return -EINVAL;

}

	return 0;

}



int apply_event_filter(struct ftrace_event_call *call, char *filter_string)

{
@@ -1381,6 +1420,13 @@ int apply_event_filter(struct ftrace_event_call *call, char *filter_string) 
		goto out;

	}



	/*

	 * Make sure all the pred counts are zero so that

	 * no task is using it when we reallocate the preds array.

	 */

	reset_preds(call->filter);

	synchronize_sched();



	err = replace_preds(call, call->filter, ps, filter_string, false);

	if (err)

		append_filter_err(ps, call->filter);