X-Git-Url: http://git.efficios.com/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Fmain.c;h=5e644a72d9f821ec638d31e752542fa42cf2cffb;hp=f9b41d2707bd26aff4f95a72aa1885d2f2f09280;hb=a503e1ef71bfe98526469205fc2956cc65954019;hpb=bc4b3ff16b26d5430fe701fd0680a157c65e21f8

diff --git a/src/bin/lttng-sessiond/main.c b/src/bin/lttng-sessiond/main.c
index f9b41d270..5e644a72d 100644
--- a/src/bin/lttng-sessiond/main.c
+++ b/src/bin/lttng-sessiond/main.c
@@ -366,10 +366,21 @@ LTTNG_HIDDEN
 void sessiond_notify_ready(void)
 {
 	/*
-	 * The _return variant is used since the implied memory barriers are
-	 * required.
+	 * 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.
 	 */
-	(void) uatomic_sub_return(&lttng_sessiond_ready, 1);
+	cmm_smp_mb();
+	uatomic_sub(&lttng_sessiond_ready, 1);
 }
 
 static
@@ -847,7 +858,7 @@ error:
  *
  * Useful for CPU hotplug feature.
  */
-static int update_kernel_stream(struct consumer_data *consumer_data, int fd)
+static int update_kernel_stream(int fd)
 {
 	int ret = 0;
 	struct ltt_session *session;
@@ -1081,7 +1092,7 @@ static void *thread_manage_kernel(void *data)
 					 * New CPU detected by the kernel. Adding kernel stream to
 					 * kernel session and updating the kernel consumer
 					 */
-					ret = update_kernel_stream(&kconsumer_data, pollfd);
+					ret = update_kernel_stream(pollfd);
 					if (ret < 0) {
 						continue;
 					}
@@ -4563,8 +4574,17 @@ static void *thread_manage_clients(void *data)
 		if (ret > 0 || (ret < 0 && errno != EINTR)) {
 			goto exit;
 		}
-		cmm_smp_rmb();
 	}
+	/*
+	 * This barrier is paired with the one in sessiond_notify_ready() to
+	 * ensure that loads accessing data initialized by the other threads,
+	 * on which this thread was waiting, are not performed before this point.
+	 *
+	 * Note that this could be a 'read' memory barrier, but a full barrier
+	 * is used in case the code changes. The performance implications of
+	 * this choice are minimal since this is a slow path.
+	 */
+	cmm_smp_mb();
 
 	/* This testpoint is after we signal readiness to the parent. */
 	if (testpoint(sessiond_thread_manage_clients)) {
@@ -4578,6 +4598,8 @@ static void *thread_manage_clients(void *data)
 	health_code_update();
 
 	while (1) {
+		const struct cmd_completion_handler *cmd_completion_handler;
+
 		DBG("Accepting client command ...");
 
 		/* Inifinite blocking call, waiting for transmission */
@@ -4720,6 +4742,18 @@ static void *thread_manage_clients(void *data)
 			continue;
 		}
 
+		cmd_completion_handler = cmd_pop_completion_handler();
+		if (cmd_completion_handler) {
+			enum lttng_error_code completion_code;
+
+			completion_code = cmd_completion_handler->run(
+					cmd_completion_handler->data);
+			if (completion_code != LTTNG_OK) {
+				clean_command_ctx(&cmd_ctx);
+				continue;
+			}
+		}
+
 		health_code_update();
 
 		DBG("Sending response (size: %d, retcode: %s (%d))",
@@ -5810,6 +5844,12 @@ int main(int argc, char **argv)
 		goto exit_set_signal_handler;
 	}
 
+	/*
+	 * Init config from environment variables.
+	 * Command line option override env configuration per-doc. Do env first.
+	 */
+	sessiond_config_apply_env_config(&config);
+
 	/*
 	 * Parse arguments and load the daemon configuration file.
 	 *
@@ -5824,9 +5864,6 @@ int main(int argc, char **argv)
 		goto exit_options;
 	}
 
-	/* Init config from environment variables. */
-	sessiond_config_apply_env_config(&config);
-
 	/*
 	 * Resolve all paths received as arguments, configuration option, or
 	 * through environment variable as absolute paths. This is necessary