Remove the sessiond "ready" counter mechanism

[lttng-tools.git] / src / bin / lttng-sessiond / ready.c

diff --git a/src/bin/lttng-sessiond/ready.c b/src/bin/lttng-sessiond/ready.c
deleted file mode 100644 (file)
index 3a268b0..0000000
--- a/src/bin/lttng-sessiond/ready.c
+++ /dev/null
@@ -1,80 +0,0 @@
-/*
- * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
- *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *               2013 - 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 General Public License, version 2 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 General Public License for more details.
- *
- * You should have received a copy of the GNU 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.
- */
-
-#include <common/macros.h>
-#include <urcu.h>
-#include "lttng-sessiond.h"
-
-/*
- * The initialization of the session daemon is done in multiple phases.
- *
- * While all threads are launched near-simultaneously, only some of them
- * are needed to ensure the session daemon can start to respond to client
- * requests.
- *
- * There are two important guarantees that we wish to offer with respect
- * to the initialisation of the session daemon:
- *   - When the daemonize/background launcher process exits, the sessiond
- *     is fully able to respond to client requests,
- *   - Auto-loaded sessions are visible to clients.
- *
- * In order to achieve this, a number of support threads have to be launched
- * to allow the "client" thread to function properly. Moreover, since the
- * "load session" thread needs the client thread, we must provide a way
- * for the "load session" thread to know that the "client" thread is up
- * and running.
- *
- * Hence, the support threads decrement the lttng_sessiond_ready counter
- * while the "client" threads waits for it to reach 0. Once the "client" thread
- * unblocks, it posts the message_thread_ready semaphore which allows the
- * "load session" thread to progress.
- *
- * This implies that the "load session" thread is the last to be initialized
- * and will explicitly call sessiond_signal_parents(), which signals the parents
- * that the session daemon is fully initialized.
- *
- * The four (4) support threads are:
- *  - agent_thread
- *  - notification_thread
- *  - rotation_thread
- *  - health_thread
- */
-#define NR_LTTNG_SESSIOND_SUPPORT_THREADS 4
-int lttng_sessiond_ready = NR_LTTNG_SESSIOND_SUPPORT_THREADS;
-
-LTTNG_HIDDEN
-void sessiond_notify_ready(void)
-{
-       /*
-        * This memory barrier is paired with the one performed by
-        * the client thread after it has seen that 'lttng_sessiond_ready' is 0.
-        *
-        * The purpose of these memory barriers is to ensure that all
-        * initialization operations of the various threads that call this
-        * function to signal that they are ready are commited/published
-        * before the client thread can see the 'lttng_sessiond_ready' counter
-        * reach 0.
-        *
-        * Note that this could be a 'write' memory barrier, but a full barrier
-        * is used in case the code using this utility changes. The performance
-        * implications of this choice are minimal since this is a slow path.
-        */
-       cmm_smp_mb();
-       uatomic_sub(&lttng_sessiond_ready, 1);
-}