Cleanup: lttng_abi_create_event{,_notifier}: use switch/case rather than if

[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..b39bfaad58545429beaf217badc56b81df7da3dc 100644 (file)
--- a/src/lttng-event-notifier-notification.c
+++ b/src/lttng-event-notifier-notification.c
@@ -11,10 +11,15 @@
 #include <lttng/events.h>
 #include <lttng/msgpack.h>
 #include <lttng/event-notifier-notification.h>
+#include <wrapper/barrier.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 +348,33 @@ end:
        return ret;
 }
 
+static
+void record_error(struct lttng_event_notifier *event_notifier)
+{
+
+       struct lttng_event_notifier_group *event_notifier_group = event_notifier->group;
+       struct lttng_counter *error_counter;
+       size_t dimension_index[1];
+       int ret;
+
+       /*
+        * lttng_smp_load_acquire paired with lttng_smp_store_release orders
+        * creation of the error counter and setting error_counter_len
+        * before the error_counter is used.
+        */
+       error_counter = lttng_smp_load_acquire(&event_notifier_group->error_counter);
+       /* This group may not have an error counter attached to it. */
+       if (!error_counter)
+               return;
+
+       dimension_index[0] = event_notifier->error_counter_index;
+
+       ret = error_counter->ops->counter_add(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 +403,7 @@ 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;
        }
 
@@ -396,7 +426,8 @@ void notification_send(struct lttng_event_notifier_notification *notif,
 
 void lttng_event_notifier_notification_send(struct lttng_event_notifier *event_notifier,
                struct lttng_probe_ctx *lttng_probe_ctx,
-               const char *stack_data)
+               const char *stack_data,
+               struct lttng_kernel_notifier_ctx *notif_ctx)
 {
        struct lttng_event_notifier_notification notif = { 0 };
        int ret;
@@ -410,7 +441,7 @@ void lttng_event_notifier_notification_send(struct lttng_event_notifier *event_n
                goto end;
        }
 
-       if (unlikely(!list_empty(&event_notifier->capture_bytecode_runtime_head))) {
+       if (unlikely(notif_ctx->eval_capture)) {
                struct lttng_bytecode_runtime *capture_bc_runtime;
 
                /*
@@ -419,7 +450,7 @@ void lttng_event_notifier_notification_send(struct lttng_event_notifier *event_n
                 * `output` parameter to the capture buffer. If the interpreter
                 * fails, append an empty capture to the buffer.
                 */
-               list_for_each_entry(capture_bc_runtime,
+               list_for_each_entry_rcu(capture_bc_runtime,
                                &event_notifier->capture_bytecode_runtime_head, node) {
                        struct lttng_interpreter_output output;