Fix: consumerd: slow metadata push slows down application registration

[lttng-tools.git] / src / common / waiter.h

diff --git a/src/common/waiter.h b/src/common/waiter.h
index 30eb38f835398288e0ec42a18d001021f27720da..ed84ac3c2894f6353a661e86164452cf84ef9e11 100644 (file)
--- a/src/common/waiter.h
+++ b/src/common/waiter.h
@@ -1,19 +1,8 @@
 /*
- * Copyright (C) 2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *               2017 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ * Copyright (C) 2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright (C) 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com>
  *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU Lesser General Public License, version 2.1 only,
- * as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
- * for more details.
- *
- * You should have received a copy of the GNU Lesser General Public License
- * along with this program; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ * SPDX-License-Identifier: LGPL-2.1-only
  *
  * This code is originally adapted from userspace-rcu's urcu-wait.h
  */
@@ -33,6 +22,10 @@ struct lttng_waiter {
        int32_t state;
 };
 
+struct lttng_wait_queue {
+       struct cds_wfs_stack stack;
+};
+
 LTTNG_HIDDEN
 void lttng_waiter_init(struct lttng_waiter *waiter);
 
@@ -40,11 +33,29 @@ LTTNG_HIDDEN
 void lttng_waiter_wait(struct lttng_waiter *waiter);
 
 /*
- * lttng_waiter_wake_up must only be called by a single waker.
+ * lttng_waiter_wake must only be called by a single waker.
  * It is invalid for multiple "wake" operations to be invoked
  * on a single waiter without re-initializing it before.
  */
 LTTNG_HIDDEN
-void lttng_waiter_wake_up(struct lttng_waiter *waiter);
+void lttng_waiter_wake(struct lttng_waiter *waiter);
+
+LTTNG_HIDDEN
+void lttng_wait_queue_init(struct lttng_wait_queue *queue);
+
+/*
+ * Atomically add a waiter to a wait queue.
+ * A full memory barrier is issued before being added to the wait queue.
+ */
+LTTNG_HIDDEN
+void lttng_wait_queue_add(struct lttng_wait_queue *queue,
+               struct lttng_waiter *waiter);
+
+/*
+ * Wake every waiter present in the wait queue and remove them from
+ * the queue.
+ */
+LTTNG_HIDDEN
+void lttng_wait_queue_wake_all(struct lttng_wait_queue *queue);
 
 #endif /* LTTNG_WAITER_H */