rtla/trace: Add trace event trigger helpers

Add a set of helper functions to allow rtla tools to trigger event
actions in the trace instance.

Link: https://lkml.kernel.org/r/e0d31abe879a78a5600b64f904d0dfa8f76e4fbb.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>

diff --git a/tools/tracing/rtla/src/trace.c b/tools/tracing/rtla/src/trace.c
index 9ad3d8890ec5cb852fd5170146b95193d135f1bf..7f8661b2724dea96486db87a1cdc67ad293ff83b 100644 (file)
--- a/tools/tracing/rtla/src/trace.c
+++ b/tools/tracing/rtla/src/trace.c
@@ -204,6 +204,8 @@ static void trace_events_free(struct trace_events *events)
 
                tevent = tevent->next;
 
+               if (free_event->trigger)
+                       free(free_event->trigger);
                free(free_event->system);
                free(free_event);
        }
@@ -235,6 +237,48 @@ struct trace_events *trace_event_alloc(const char *event_string)
        return tevent;
 }
 
+/*
+ * trace_event_add_trigger - record an event trigger action
+ */
+int trace_event_add_trigger(struct trace_events *event, char *trigger)
+{
+       if (event->trigger)
+               free(event->trigger);
+
+       event->trigger = strdup(trigger);
+       if (!event->trigger)
+               return 1;
+
+       return 0;
+}
+
+/*
+ * trace_event_disable_trigger - disable an event trigger
+ */
+static void trace_event_disable_trigger(struct trace_instance *instance,
+                                       struct trace_events *tevent)
+{
+       char trigger[1024];
+       int retval;
+
+       if (!tevent->trigger)
+               return;
+
+       if (!tevent->trigger_enabled)
+               return;
+
+       debug_msg("Disabling %s:%s trigger %s\n", tevent->system,
+                 tevent->event ? : "*", tevent->trigger);
+
+       snprintf(trigger, 1024, "!%s\n", tevent->trigger);
+
+       retval = tracefs_event_file_write(instance->inst, tevent->system,
+                                         tevent->event, "trigger", trigger);
+       if (retval < 0)
+               err_msg("Error disabling %s:%s trigger %s\n", tevent->system,
+                       tevent->event ? : "*", tevent->trigger);
+}
+
 /*
  * trace_events_disable - disable all trace events
  */
@@ -248,14 +292,52 @@ void trace_events_disable(struct trace_instance *instance,
 
        while (tevent) {
                debug_msg("Disabling event %s:%s\n", tevent->system, tevent->event ? : "*");
-               if (tevent->enabled)
+               if (tevent->enabled) {
+                       trace_event_disable_trigger(instance, tevent);
                        tracefs_event_disable(instance->inst, tevent->system, tevent->event);
+               }
 
                tevent->enabled = 0;
                tevent = tevent->next;
        }
 }
 
+/*
+ * trace_event_enable_trigger - enable an event trigger associated with an event
+ */
+static int trace_event_enable_trigger(struct trace_instance *instance,
+                                     struct trace_events *tevent)
+{
+       char trigger[1024];
+       int retval;
+
+       if (!tevent->trigger)
+               return 0;
+
+       if (!tevent->event) {
+               err_msg("Trigger %s applies only for single events, not for all %s:* events\n",
+                       tevent->trigger, tevent->system);
+               return 1;
+       }
+
+       snprintf(trigger, 1024, "%s\n", tevent->trigger);
+
+       debug_msg("Enabling %s:%s trigger %s\n", tevent->system,
+                 tevent->event ? : "*", tevent->trigger);
+
+       retval = tracefs_event_file_write(instance->inst, tevent->system,
+                                         tevent->event, "trigger", trigger);
+       if (retval < 0) {
+               err_msg("Error enabling %s:%s trigger %s\n", tevent->system,
+                       tevent->event ? : "*", tevent->trigger);
+               return 1;
+       }
+
+       tevent->trigger_enabled = 1;
+
+       return 0;
+}
+
 /*
  * trace_events_enable - enable all events
  */
@@ -275,6 +357,10 @@ int trace_events_enable(struct trace_instance *instance,
                }
 
 
+               retval = trace_event_enable_trigger(instance, tevent);
+               if (retval)
+                       return 1;
+
                tevent->enabled = 1;
                tevent = tevent->next;
        }

diff --git a/tools/tracing/rtla/src/trace.h b/tools/tracing/rtla/src/trace.h
index 9f9751f7ee36f4920ea3073559b0a137edf37d3d..856b26d9306413788e04341f823ab336dd3f1e0d 100644 (file)
--- a/tools/tracing/rtla/src/trace.h
+++ b/tools/tracing/rtla/src/trace.h
@@ -6,7 +6,9 @@ struct trace_events {
        struct trace_events *next;
        char *system;
        char *event;
+       char *trigger;
        char enabled;
+       char trigger_enabled;
 };
 
 struct trace_instance {
@@ -40,3 +42,5 @@ void trace_events_destroy(struct trace_instance *instance,
                          struct trace_events *events);
 int trace_events_enable(struct trace_instance *instance,
                          struct trace_events *events);
+
+int trace_event_add_trigger(struct trace_events *event, char *trigger);