Launch the notification thread using lttng_thread
authorJérémie Galarneau <jeremie.galarneau@efficios.com>
Tue, 27 Nov 2018 21:37:05 +0000 (16:37 -0500)
committerJérémie Galarneau <jeremie.galarneau@efficios.com>
Wed, 5 Dec 2018 17:25:11 +0000 (12:25 -0500)
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
src/bin/lttng-sessiond/main.c
src/bin/lttng-sessiond/notification-thread.c
src/bin/lttng-sessiond/notification-thread.h
src/bin/lttng-sessiond/rotation-thread.c
src/bin/lttng-sessiond/rotation-thread.h

index 8820fdbddca9ee8e177063c290be0f917e92ea72..4749f8621b62d1b0512304dcbac6677fd1e79124 100644 (file)
@@ -194,7 +194,6 @@ static pthread_t kernel_thread;
 static pthread_t dispatch_thread;
 static pthread_t agent_reg_thread;
 static pthread_t load_session_thread;
-static pthread_t notification_thread;
 static pthread_t rotation_thread;
 static pthread_t timer_thread;
 
@@ -5497,14 +5496,12 @@ int main(int argc, char **argv)
        struct lttng_pipe *ust32_channel_monitor_pipe = NULL,
                        *ust64_channel_monitor_pipe = NULL,
                        *kernel_channel_monitor_pipe = NULL;
-       bool notification_thread_launched = false;
        bool rotation_thread_launched = false;
        bool timer_thread_launched = false;
        struct lttng_thread *ht_cleanup_thread = NULL;
        struct timer_thread_parameters timer_thread_ctx;
        /* Queue of rotation jobs populated by the sessiond-timer. */
        struct rotation_thread_timer_queue *rotation_timer_queue = NULL;
-       sem_t notification_thread_ready;
 
        init_kernel_workarounds();
 
@@ -5853,37 +5850,23 @@ int main(int argc, char **argv)
                goto exit_health;
        }
 
-       /*
-        * The rotation thread needs the notification thread to be ready before
-        * creating the rotate_notification_channel, so we use this semaphore as
-        * a rendez-vous point.
-        */
-       sem_init(&notification_thread_ready, 0, 0);
-
        /* notification_thread_data acquires the pipes' read side. */
        notification_thread_handle = notification_thread_handle_create(
                        ust32_channel_monitor_pipe,
                        ust64_channel_monitor_pipe,
-                       kernel_channel_monitor_pipe,
-                       &notification_thread_ready);
+                       kernel_channel_monitor_pipe);
        if (!notification_thread_handle) {
                retval = -1;
                ERR("Failed to create notification thread shared data");
-               stop_threads();
                goto exit_notification;
        }
 
        /* Create notification thread. */
-       ret = pthread_create(&notification_thread, default_pthread_attr(),
-                       thread_notification, notification_thread_handle);
-       if (ret) {
-               errno = ret;
-               PERROR("pthread_create notification");
+       if (!launch_notification_thread(notification_thread_handle)) {
                retval = -1;
-               stop_threads();
                goto exit_notification;
+
        }
-       notification_thread_launched = true;
 
        /* Create timer thread. */
        ret = pthread_create(&timer_thread, default_pthread_attr(),
@@ -5900,8 +5883,7 @@ int main(int argc, char **argv)
        /* rotation_thread_data acquires the pipes' read side. */
        rotation_thread_handle = rotation_thread_handle_create(
                        rotation_timer_queue,
-                       notification_thread_handle,
-                       &notification_thread_ready);
+                       notification_thread_handle);
        if (!rotation_thread_handle) {
                retval = -1;
                ERR("Failed to create rotation thread shared data");
@@ -6093,7 +6075,6 @@ exit_dispatch:
 exit_client:
 exit_rotation:
 exit_notification:
-       sem_destroy(&notification_thread_ready);
        lttng_thread_list_shutdown_orphans();
 exit_health:
 exit_init_data:
@@ -6117,25 +6098,6 @@ exit_init_data:
         */
        rcu_barrier();
 
-       /*
-        * The teardown of the notification system is performed after the
-        * session daemon's teardown in order to allow it to be notified
-        * of the active session and channels at the moment of the teardown.
-        */
-       if (notification_thread_handle) {
-               if (notification_thread_launched) {
-                       notification_thread_command_quit(
-                                       notification_thread_handle);
-                       ret = pthread_join(notification_thread, &status);
-                       if (ret) {
-                               errno = ret;
-                               PERROR("pthread_join notification thread");
-                               retval = -1;
-                       }
-               }
-               notification_thread_handle_destroy(notification_thread_handle);
-       }
-
        if (rotation_thread_handle) {
                if (rotation_thread_launched) {
                        ret = pthread_join(rotation_thread, &status);
@@ -6172,6 +6134,14 @@ exit_init_data:
        rcu_thread_offline();
        rcu_unregister_thread();
 
+       /*
+        * The teardown of the notification system is performed after the
+        * session daemon's teardown in order to allow it to be notified
+        * of the active session and channels at the moment of the teardown.
+        */
+       if (notification_thread_handle) {
+               notification_thread_handle_destroy(notification_thread_handle);
+       }
        lttng_pipe_destroy(ust32_channel_monitor_pipe);
        lttng_pipe_destroy(ust64_channel_monitor_pipe);
        lttng_pipe_destroy(kernel_channel_monitor_pipe);
index 4ce38e180e106986ae630a0c85483e93568405a3..9809e6190cd60cbb453cea62b704a62e6da84cc5 100644 (file)
@@ -37,6 +37,7 @@
 #include "notification-thread-commands.h"
 #include "lttng-sessiond.h"
 #include "health-sessiond.h"
+#include "thread.h"
 
 #include <urcu.h>
 #include <urcu/list.h>
@@ -56,6 +57,7 @@ void notification_thread_handle_destroy(
 
        assert(cds_list_empty(&handle->cmd_queue.list));
        pthread_mutex_destroy(&handle->cmd_queue.lock);
+       sem_destroy(&handle->ready);
 
        if (handle->cmd_queue.event_pipe) {
                lttng_pipe_destroy(handle->cmd_queue.event_pipe);
@@ -85,8 +87,7 @@ end:
 struct notification_thread_handle *notification_thread_handle_create(
                struct lttng_pipe *ust32_channel_monitor_pipe,
                struct lttng_pipe *ust64_channel_monitor_pipe,
-               struct lttng_pipe *kernel_channel_monitor_pipe,
-               sem_t *notification_thread_ready)
+               struct lttng_pipe *kernel_channel_monitor_pipe)
 {
        int ret;
        struct notification_thread_handle *handle;
@@ -97,6 +98,8 @@ struct notification_thread_handle *notification_thread_handle_create(
                goto end;
        }
 
+       sem_init(&handle->ready, 0, 0);
+
        event_pipe = lttng_pipe_open(FD_CLOEXEC);
        if (!event_pipe) {
                ERR("event_pipe creation");
@@ -142,7 +145,6 @@ struct notification_thread_handle *notification_thread_handle_create(
        } else {
                handle->channel_monitoring_pipes.kernel_consumer = -1;
        }
-       handle->notification_thread_ready = notification_thread_ready;
 end:
        return handle;
 error:
@@ -374,6 +376,21 @@ void fini_thread_state(struct notification_thread_state *state)
        lttng_poll_clean(&state->events);
 }
 
+static
+void mark_thread_as_ready(struct notification_thread_handle *handle)
+{
+       DBG("Marking notification thread as ready");
+       sem_post(&handle->ready);
+}
+
+static
+void wait_until_thread_is_ready(struct notification_thread_handle *handle)
+{
+       DBG("Waiting for notification thread to be ready");
+       sem_wait(&handle->ready);
+       DBG("Notification thread is ready");
+}
+
 static
 int init_thread_state(struct notification_thread_handle *handle,
                struct notification_thread_state *state)
@@ -448,7 +465,7 @@ int init_thread_state(struct notification_thread_handle *handle,
        if (!state->triggers_ht) {
                goto error;
        }
-       sem_post(handle->notification_thread_ready);
+       mark_thread_as_ready(handle);
 end:
        return 0;
 error:
@@ -496,6 +513,7 @@ end:
  * This thread services notification channel clients and commands received
  * from various lttng-sessiond components over a command queue.
  */
+static
 void *thread_notification(void *data)
 {
        int ret;
@@ -520,9 +538,6 @@ void *thread_notification(void *data)
                goto end;
        }
 
-       /* Ready to handle client connections. */
-       sessiond_notify_ready();
-
        while (true) {
                int fd_count, i;
 
@@ -628,3 +643,37 @@ error:
 end:
        return NULL;
 }
+
+static
+bool shutdown_notification_thread(void *thread_data)
+{
+       struct notification_thread_handle *handle = thread_data;
+
+       notification_thread_command_quit(handle);
+       return true;
+}
+
+bool launch_notification_thread(struct notification_thread_handle *handle)
+{
+       struct lttng_thread *thread;
+
+       thread = lttng_thread_create("Notification",
+                       thread_notification,
+                       shutdown_notification_thread,
+                       NULL,
+                       handle);
+       if (!thread) {
+               goto error;
+       }
+
+       /*
+        * Wait for the thread to be marked as "ready" before returning
+        * as other subsystems depend on the notification subsystem
+        * (e.g. rotation thread).
+        */
+       wait_until_thread_is_ready(handle);
+       lttng_thread_put(thread);
+       return true;
+error:
+       return false;
+}
index eb8beb0d800588c58293aeb1471c18a040d3f9a8..525adcc6a8124c6d97fdabc4c903bbb5c8371781 100644 (file)
@@ -48,10 +48,8 @@ struct notification_thread_handle {
                int ust64_consumer;
                int kernel_consumer;
        } channel_monitoring_pipes;
-       /*
-        * To inform the rotation thread we are ready.
-        */
-       sem_t *notification_thread_ready;
+       /* Used to wait for the launch of the notification thread. */
+       sem_t ready;
 };
 
 /**
@@ -215,11 +213,9 @@ struct notification_thread_state {
 struct notification_thread_handle *notification_thread_handle_create(
                struct lttng_pipe *ust32_channel_monitor_pipe,
                struct lttng_pipe *ust64_channel_monitor_pipe,
-               struct lttng_pipe *kernel_channel_monitor_pipe,
-               sem_t *notification_thread_ready);
+               struct lttng_pipe *kernel_channel_monitor_pipe);
 void notification_thread_handle_destroy(
                struct notification_thread_handle *handle);
-
-void *thread_notification(void *data);
+bool launch_notification_thread(struct notification_thread_handle *handle);
 
 #endif /* NOTIFICATION_THREAD_H */
index 64f958233cdc6ccb22ee671a5d5feb51fd6cae67..e8bd478e8db032934690979c86469b8de444d9f4 100644 (file)
@@ -75,7 +75,6 @@ struct rotation_thread_handle {
        struct rotation_thread_timer_queue *rotation_timer_queue;
        /* Access to the notification thread cmd_queue */
        struct notification_thread_handle *notification_thread_handle;
-       sem_t *notification_thread_ready;
 };
 
 static
@@ -169,8 +168,7 @@ void rotation_thread_handle_destroy(
 
 struct rotation_thread_handle *rotation_thread_handle_create(
                struct rotation_thread_timer_queue *rotation_timer_queue,
-               struct notification_thread_handle *notification_thread_handle,
-               sem_t *notification_thread_ready)
+               struct notification_thread_handle *notification_thread_handle)
 {
        struct rotation_thread_handle *handle;
 
@@ -181,7 +179,6 @@ struct rotation_thread_handle *rotation_thread_handle_create(
 
        handle->rotation_timer_queue = rotation_timer_queue;
        handle->notification_thread_handle = notification_thread_handle;
-       handle->notification_thread_ready = notification_thread_ready;
 
 end:
        return handle;
@@ -320,11 +317,6 @@ int init_thread_state(struct rotation_thread_handle *handle,
                goto end;
        }
 
-       /*
-        * We wait until the notification thread is ready to create the
-        * notification channel and add it to the poll_set.
-        */
-       sem_wait(handle->notification_thread_ready);
        rotate_notification_channel = lttng_notification_channel_create(
                        lttng_session_daemon_notification_endpoint);
        if (!rotate_notification_channel) {
index bb55e07fe96ff5f40d7825bc7523740b48854c89..c4516095622e3b9e35c76765db0f209e4d7a9c6f 100644 (file)
@@ -47,8 +47,7 @@ void rotation_thread_timer_queue_destroy(
 
 struct rotation_thread_handle *rotation_thread_handle_create(
                struct rotation_thread_timer_queue *rotation_timer_queue,
-               struct notification_thread_handle *notification_thread_handle,
-               sem_t *notification_thread_ready);
+               struct notification_thread_handle *notification_thread_handle);
 
 void rotation_thread_handle_destroy(
                struct rotation_thread_handle *handle);
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