trigger/action executor: move trigger registration state change to client thread

Set the unregistered state of the sessiond side trigger object in the
client thread since we want to minimize the possibility of the
notification thread being stalled due to a long execution of an action
in the action executor thread.

Stalling the client thread is, comparatively, less harmful.

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: I7de875996b430e49ec50896f8b26a75af7993c74

diff --git a/src/bin/lttng-sessiond/cmd.c b/src/bin/lttng-sessiond/cmd.c
index 73773bd137726c4f09cbd4508338f8b391ad8583..c7745abf1485d37f2e651ec8d37490adbb6b85a9 100644 (file)
--- a/src/bin/lttng-sessiond/cmd.c
+++ b/src/bin/lttng-sessiond/cmd.c
@@ -4549,6 +4549,7 @@ enum lttng_error_code cmd_unregister_trigger(const struct lttng_credentials *cmd
        const char *trigger_name;
        uid_t trigger_owner;
        enum lttng_trigger_status trigger_status;
+       struct lttng_trigger *sessiond_trigger = NULL;
 
        trigger_status = lttng_trigger_get_name(trigger, &trigger_name);
        trigger_name = trigger_status == LTTNG_TRIGGER_STATUS_OK ? trigger_name : "(unnamed)";
@@ -4576,6 +4577,28 @@ enum lttng_error_code cmd_unregister_trigger(const struct lttng_credentials *cmd
                }
        }
 
+       /* Fetch the sessiond side trigger object. */
+       ret_code = notification_thread_command_get_trigger(
+                       notification_thread, trigger, &sessiond_trigger);
+       if (ret_code != LTTNG_OK) {
+               DBG("Failed to get trigger from notification thread during unregister: trigger name = '%s', trigger owner uid = %d, error code = %d",
+                               trigger_name, (int) trigger_owner, ret_code);
+               goto end;
+       }
+
+       assert(sessiond_trigger);
+
+       /*
+        * From this point on, no matter what, consider the trigger
+        * unregistered.
+        *
+        * We set the unregistered state of the sessiond side trigger object in
+        * the client thread since we want to minimize the possibility of the
+        * notification thread being stalled due to a long execution of an
+        * action that required the trigger lock.
+        */
+       lttng_trigger_set_as_unregistered(sessiond_trigger);
+
        ret_code = notification_thread_command_unregister_trigger(notification_thread,
                                                                  trigger);
        if (ret_code != LTTNG_OK) {
@@ -4600,6 +4623,7 @@ enum lttng_error_code cmd_unregister_trigger(const struct lttng_credentials *cmd
        }
 
 end:
+       lttng_trigger_put(sessiond_trigger);
        return ret_code;
 }
 

diff --git a/src/bin/lttng-sessiond/notification-thread-events.c b/src/bin/lttng-sessiond/notification-thread-events.c
index 28e553f44875c59c74f28fc29d1dbd9adf102e54..90fdadd61280bc2452063931ad1c7ca1fc837f8b 100644 (file)
--- a/src/bin/lttng-sessiond/notification-thread-events.c
+++ b/src/bin/lttng-sessiond/notification-thread-events.c
@@ -3049,9 +3049,6 @@ int handle_notification_thread_command_unregister_trigger(
        trigger_ht_element = caa_container_of(triggers_ht_node,
                        struct lttng_trigger_ht_element, node);
 
-       /* From this point, consider the trigger unregistered no matter what. */
-       lttng_trigger_set_as_unregistered(trigger_ht_element->trigger);
-
        /* Remove trigger from channel_triggers_ht. */
        cds_lfht_for_each_entry(state->channel_triggers_ht, &iter, trigger_list,
                        channel_triggers_ht_node) {