rtla: Introduce common_threshold_handler() helper

Several functions duplicate the logic for handling threshold actions.
When a threshold is reached, these functions stop the trace, perform
configured actions, and restart the trace if --on-threshold continue
is set.

Create common_threshold_handler() to centralize this shared logic and
avoid code duplication. The function executes the configured threshold
actions and restarts the necessary trace instances when appropriate.

Also add should_continue_tracing() helper to encapsulate the check
for whether tracing should continue after a threshold event, improving
code readability at call sites.

In timerlat_top_bpf_main_loop(), use common_params directly instead
of casting through timerlat_params when only common fields are needed.

Signed-off-by: Wander Lairson Costa <wander@redhat.com>
Link: https://lore.kernel.org/r/20260309195040.1019085-5-wander@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

Author: walac

tools/tracing/rtla/src/common.c

@@ -207,6 +207,38 @@ common_apply_config(struct osnoise_tool *tool, struct common_params *params)
 }
 
 
+/**
+ * common_threshold_handler - handle latency threshold overflow
+ * @tool: pointer to the osnoise_tool instance containing trace contexts
+ *
+ * Executes the configured threshold actions (e.g., saving trace, printing,
+ * sending signals). If the continue flag is set (--on-threshold continue),
+ * restarts the auxiliary trace instances to continue monitoring.
+ *
+ * Return: 0 for success, -1 for error.
+ */
+int
+common_threshold_handler(const struct osnoise_tool *tool)
+{
+	actions_perform(&tool->params->threshold_actions);
+
+	if (!should_continue_tracing(tool->params))
+		/* continue flag not set, break */
+		return 0;
+
+	/* continue action reached, re-enable tracing */
+	if (tool->record && trace_instance_start(&tool->record->trace))
+		goto err;
+	if (tool->aa && trace_instance_start(&tool->aa->trace))
+		goto err;
+
+	return 0;
+
+err:
+	err_msg("Error restarting trace\n");
+	return -1;
+}
+
 int run_tool(struct tool_ops *ops, int argc, char *argv[])
 {
 	struct common_params *params;
@@ -385,17 +417,14 @@ int top_main_loop(struct osnoise_tool *tool)
 				/* stop tracing requested, do not perform actions */
 				return 0;
 
-			actions_perform(&params->threshold_actions);
+			retval = common_threshold_handler(tool);
+			if (retval)
+				return retval;
+
 
-			if (!params->threshold_actions.continue_flag)
-				/* continue flag not set, break */
+			if (!should_continue_tracing(params))
 				return 0;
 
-			/* continue action reached, re-enable tracing */
-			if (record)
-				trace_instance_start(&record->trace);
-			if (tool->aa)
-				trace_instance_start(&tool->aa->trace);
 			trace_instance_start(trace);
 		}
 
@@ -436,18 +465,14 @@ int hist_main_loop(struct osnoise_tool *tool)
 				/* stop tracing requested, do not perform actions */
 				break;
 
-			actions_perform(&params->threshold_actions);
+			retval = common_threshold_handler(tool);
+			if (retval)
+				return retval;
 
-			if (!params->threshold_actions.continue_flag)
-				/* continue flag not set, break */
-				break;
+			if (!should_continue_tracing(params))
+				return 0;
 
-			/* continue action reached, re-enable tracing */
-			if (tool->record)
-				trace_instance_start(&tool->record->trace);
-			if (tool->aa)
-				trace_instance_start(&tool->aa->trace);
-			trace_instance_start(&tool->trace);
+			trace_instance_start(trace);
 		}
 
 		/* is there still any user-threads ? */

tools/tracing/rtla/src/common.h

@@ -146,6 +146,24 @@ struct tool_ops {
 	void (*free)(struct osnoise_tool *tool);
 };
 
+/**
+ * should_continue_tracing - check if tracing should continue after threshold
+ * @params: pointer to the common parameters structure
+ *
+ * Returns true if the continue action was configured (--on-threshold continue),
+ * indicating that tracing should be restarted after handling the threshold event.
+ *
+ * Return: 1 if tracing should continue, 0 otherwise.
+ */
+static inline int
+should_continue_tracing(const struct common_params *params)
+{
+	return params->threshold_actions.continue_flag;
+}
+
+int
+common_threshold_handler(const struct osnoise_tool *tool);
+
 int osnoise_set_cpus(struct osnoise_context *context, char *cpus);
 void osnoise_restore_cpus(struct osnoise_context *context);
 

tools/tracing/rtla/src/timerlat_hist.c

@@ -17,6 +17,7 @@
 #include "timerlat.h"
 #include "timerlat_aa.h"
 #include "timerlat_bpf.h"
+#include "common.h"
 
 struct timerlat_hist_cpu {
 	int			*irq;
@@ -1047,26 +1048,24 @@ static struct osnoise_tool
 
 static int timerlat_hist_bpf_main_loop(struct osnoise_tool *tool)
 {
-	struct timerlat_params *params = to_timerlat_params(tool->params);
 	int retval;
 
 	while (!stop_tracing) {
 		timerlat_bpf_wait(-1);
 
 		if (!stop_tracing) {
 			/* Threshold overflow, perform actions on threshold */
-			actions_perform(&params->common.threshold_actions);
+			retval = common_threshold_handler(tool);
+			if (retval)
+				return retval;
 
-			if (!params->common.threshold_actions.continue_flag)
-				/* continue flag not set, break */
+			if (!should_continue_tracing(tool->params))
 				break;
 
-			/* continue action reached, re-enable tracing */
-			if (tool->record)
-				trace_instance_start(&tool->record->trace);
-			if (tool->aa)
-				trace_instance_start(&tool->aa->trace);
-			timerlat_bpf_restart_tracing();
+			if (timerlat_bpf_restart_tracing()) {
+				err_msg("Error restarting BPF trace\n");
+				return -1;
+			}
 		}
 	}
 	timerlat_bpf_detach();

tools/tracing/rtla/src/timerlat_top.c

@@ -17,6 +17,7 @@
 #include "timerlat.h"
 #include "timerlat_aa.h"
 #include "timerlat_bpf.h"
+#include "common.h"
 
 struct timerlat_top_cpu {
 	unsigned long long	irq_count;
@@ -795,48 +796,47 @@ static struct osnoise_tool
 static int
 timerlat_top_bpf_main_loop(struct osnoise_tool *tool)
 {
-	struct timerlat_params *params = to_timerlat_params(tool->params);
+	const struct common_params *params = tool->params;
 	int retval, wait_retval;
 
-	if (params->common.aa_only) {
+	if (params->aa_only) {
 		/* Auto-analysis only, just wait for stop tracing */
 		timerlat_bpf_wait(-1);
 		return 0;
 	}
 
 	/* Pull and display data in a loop */
 	while (!stop_tracing) {
-		wait_retval = timerlat_bpf_wait(params->common.quiet ? -1 :
-						params->common.sleep_time);
+		wait_retval = timerlat_bpf_wait(params->quiet ? -1 :
+						params->sleep_time);
 
 		retval = timerlat_top_bpf_pull_data(tool);
 		if (retval) {
 			err_msg("Error pulling BPF data\n");
 			return retval;
 		}
 
-		if (!params->common.quiet)
+		if (!params->quiet)
 			timerlat_print_stats(tool);
 
 		if (wait_retval != 0) {
 			/* Stopping requested by tracer */
-			actions_perform(&params->common.threshold_actions);
+			retval = common_threshold_handler(tool);
+			if (retval)
+				return retval;
 
-			if (!params->common.threshold_actions.continue_flag)
-				/* continue flag not set, break */
+			if (!should_continue_tracing(tool->params))
 				break;
 
-			/* continue action reached, re-enable tracing */
-			if (tool->record)
-				trace_instance_start(&tool->record->trace);
-			if (tool->aa)
-				trace_instance_start(&tool->aa->trace);
-			timerlat_bpf_restart_tracing();
+			if (timerlat_bpf_restart_tracing()) {
+				err_msg("Error restarting BPF trace\n");
+				return -1;
+			}
 		}
 
 		/* is there still any user-threads ? */
-		if (params->common.user_workload) {
-			if (params->common.user.stopped_running) {
+		if (params->user_workload) {
+			if (params->user.stopped_running) {
 				debug_msg("timerlat user space threads stopped!\n");
 				break;
 			}