rtla: Check for trace off also in the trace instance

With the addition of --trigger option, it is also possible to stop
the trace from the -t tracing instance using the traceoff trigger.

Make rtla tools to check if the trace is stopped also in the trace
instance, stopping the execution of the tool.

Link: https://lkml.kernel.org/r/59fc7c6f23dddd5c8b7ef1782cf3da51ea2ce0f5.1646247211.git.bristot@kernel.org

Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

tools/tracing/rtla/src/osnoise_hist.c

@@ -848,7 +848,7 @@ int osnoise_hist_main(int argc, char *argv[])
 			goto out_hist;
 		}
 
-		if (!tracefs_trace_is_on(trace->inst))
+		if (trace_is_off(&tool->trace, &record->trace))
 			break;
 	};
 
@@ -858,7 +858,7 @@ int osnoise_hist_main(int argc, char *argv[])
 
 	return_value = 0;
 
-	if (!tracefs_trace_is_on(trace->inst)) {
+	if (trace_is_off(&tool->trace, &record->trace)) {
 		printf("rtla timelat hit stop tracing\n");
 		if (params->trace_output) {
 			printf("  Saving trace to %s\n", params->trace_output);

tools/tracing/rtla/src/osnoise_top.c

@@ -629,7 +629,7 @@ int osnoise_top_main(int argc, char **argv)
 		if (!params->quiet)
 			osnoise_print_stats(params, tool);
 
-		if (!tracefs_trace_is_on(trace->inst))
+		if (trace_is_off(&tool->trace, &record->trace))
 			break;
 
 	} while (!stop_tracing);
@@ -638,7 +638,7 @@ int osnoise_top_main(int argc, char **argv)
 
 	return_value = 0;
 
-	if (!tracefs_trace_is_on(trace->inst)) {
+	if (trace_is_off(&tool->trace, &record->trace)) {
 		printf("osnoise hit stop tracing\n");
 		if (params->trace_output) {
 			printf("  Saving trace to %s\n", params->trace_output);

tools/tracing/rtla/src/timerlat_hist.c

@@ -861,15 +861,15 @@ int timerlat_hist_main(int argc, char *argv[])
 			goto out_hist;
 		}
 
-		if (!tracefs_trace_is_on(trace->inst))
+		if (trace_is_off(&tool->trace, &record->trace))
 			break;
 	};
 
 	timerlat_print_stats(params, tool);
 
 	return_value = 0;
 
-	if (!tracefs_trace_is_on(trace->inst)) {
+	if (trace_is_off(&tool->trace, &record->trace)) {
 		printf("rtla timelat hit stop tracing\n");
 		if (params->trace_output) {
 			printf("  Saving trace to %s\n", params->trace_output);

tools/tracing/rtla/src/timerlat_top.c

@@ -655,7 +655,7 @@ int timerlat_top_main(int argc, char *argv[])
 		if (!params->quiet)
 			timerlat_print_stats(params, top);
 
-		if (!tracefs_trace_is_on(trace->inst))
+		if (trace_is_off(&top->trace, &record->trace))
 			break;
 
 	};
@@ -664,7 +664,7 @@ int timerlat_top_main(int argc, char *argv[])
 
 	return_value = 0;
 
-	if (!tracefs_trace_is_on(trace->inst)) {
+	if (trace_is_off(&top->trace, &record->trace)) {
 		printf("rtla timelat hit stop tracing\n");
 		if (params->trace_output) {
 			printf("  Saving trace to %s\n", params->trace_output);

tools/tracing/rtla/src/trace.c

@@ -516,3 +516,22 @@ void trace_events_destroy(struct trace_instance *instance,
 	trace_events_disable(instance, events);
 	trace_events_free(events);
 }
+
+int trace_is_off(struct trace_instance *tool, struct trace_instance *trace)
+{
+	/*
+	 * The tool instance is always present, it is the one used to collect
+	 * data.
+	 */
+	if (!tracefs_trace_is_on(tool->inst))
+		return 1;
+
+	/*
+	 * The trace instance is only enabled when -t is set. IOW, when the system
+	 * is tracing.
+	 */
+	if (trace && !tracefs_trace_is_on(trace->inst))
+		return 1;
+
+	return 0;
+}

tools/tracing/rtla/src/trace.h

@@ -47,3 +47,4 @@ int trace_events_enable(struct trace_instance *instance,
 
 int trace_event_add_filter(struct trace_events *event, char *filter);
 int trace_event_add_trigger(struct trace_events *event, char *trigger);
+int trace_is_off(struct trace_instance *tool, struct trace_instance *trace);