Implement event notifier error counter

[lttng-modules.git] / src / lttng-event-notifier-notification.c

diff --git a/src/lttng-event-notifier-notification.c b/src/lttng-event-notifier-notification.c
index f675de4b1dbddbf6522928d79e810fe2323172dc..82424e8f0e91ea63849d00e8d538921de4d210a7 100644 (file)
--- a/src/lttng-event-notifier-notification.c
+++ b/src/lttng-event-notifier-notification.c
@@ -13,8 +13,12 @@
 #include <lttng/event-notifier-notification.h>
 
 /*
- * FIXME: this probably too low but it needs to be below 1024 bytes to avoid
- * the frame to be larger than the 1024 limit enforced by the kernel.
+ * The capture buffer size needs to be below 1024 bytes to avoid the
+ * frame to be larger than the 1024 limit enforced by the kernel. If we
+ * ever need to increase it, we will need to use a memory allocation
+ * scheme which allows allocating temporary memory chunks from the
+ * instrumentation sites. This could be done by adapting lttng
+ * tp-mempool to become nmi-safe and lock-free.
  */
 #define CAPTURE_BUFFER_SIZE 512
 
@@ -343,6 +347,23 @@ end:
        return ret;
 }
 
+static
+void record_error(struct lttng_event_notifier *event_notifier)
+{
+
+       struct lttng_event_notifier_group *event_notifier_group = event_notifier->group;
+       size_t dimension_index[1];
+       int ret;
+
+       dimension_index[0] = event_notifier->error_counter_index;
+
+       ret = event_notifier_group->error_counter->ops->counter_add(
+                       event_notifier_group->error_counter->counter,
+                       dimension_index, 1);
+       if (ret)
+               WARN_ON_ONCE(1);
+}
+
 static
 void notification_send(struct lttng_event_notifier_notification *notif,
                struct lttng_event_notifier *event_notifier)
@@ -371,9 +392,7 @@ void notification_send(struct lttng_event_notifier_notification *notif,
                        lttng_alignof(kernel_notif), -1);
        ret = event_notifier_group->ops->event_reserve(&ctx, 0);
        if (ret < 0) {
-               //TODO: error handling with counter maps
-               //silently drop for now.
-               WARN_ON_ONCE(1);
+               record_error(event_notifier);
                return;
        }