X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Fust-app.c;h=e496a5f5548f78975fba58d773da3c8aa45d8d58;hp=285467fbbacac990864a0871d18f200a0eb7f67b;hb=3a6922c6ab7b4d9455f517ac0bf86dfcede0ef3d;hpb=ee02239944bbb8b019bf5505bfc849fb0936e2f6

diff --git a/src/bin/lttng-sessiond/ust-app.c b/src/bin/lttng-sessiond/ust-app.c
index 285467fbb..e496a5f55 100644
--- a/src/bin/lttng-sessiond/ust-app.c
+++ b/src/bin/lttng-sessiond/ust-app.c
@@ -376,6 +376,8 @@ void delete_ust_app_channel_rcu(struct rcu_head *head)
  * Extract the lost packet or discarded events counter when the channel is
  * being deleted and store the value in the parent channel so we can
  * access it from lttng list and at stop/destroy.
+ *
+ * The session list lock must be held by the caller.
  */
 static
 void save_per_pid_lost_discarded_counters(struct ust_app_channel *ua_chan)
@@ -390,12 +392,22 @@ void save_per_pid_lost_discarded_counters(struct ust_app_channel *ua_chan)
 
 	rcu_read_lock();
 	session = session_find_by_id(ua_chan->session->tracing_id);
-	if (!session) {
-		ERR("Missing LTT session to get discarded events");
-		goto end;
-	}
-	if (!session->ust_session) {
-		ERR("Missing UST session to get discarded events");
+	if (!session || !session->ust_session) {
+		/*
+		 * Not finding the session is not an error because there are
+		 * multiple ways the channels can be torn down.
+		 *
+		 * 1) The session daemon can initiate the destruction of the
+		 *    ust app session after receiving a destroy command or
+		 *    during its shutdown/teardown.
+		 * 2) The application, since we are in per-pid tracing, is
+		 *    unregistering and tearing down its ust app session.
+		 *
+		 * Both paths are protected by the session list lock which
+		 * ensures that the accounting of lost packets and discarded
+		 * events is done exactly once. The session is then unpublished
+		 * from the session list, resulting in this condition.
+		 */
 		goto end;
 	}
 
@@ -426,6 +438,8 @@ end:
 /*
  * Delete ust app channel safely. RCU read lock must be held before calling
  * this function.
+ *
+ * The session list lock must be held by the caller.
  */
 static
 void delete_ust_app_channel(int sock, struct ust_app_channel *ua_chan,
@@ -537,7 +551,7 @@ ssize_t ust_app_push_metadata(struct ust_registry_session *registry,
 	char *metadata_str = NULL;
 	size_t len, offset, new_metadata_len_sent;
 	ssize_t ret_val;
-	uint64_t metadata_key;
+	uint64_t metadata_key, metadata_version;
 
 	assert(registry);
 	assert(socket);
@@ -567,6 +581,7 @@ ssize_t ust_app_push_metadata(struct ust_registry_session *registry,
 	offset = registry->metadata_len_sent;
 	len = registry->metadata_len - registry->metadata_len_sent;
 	new_metadata_len_sent = registry->metadata_len;
+	metadata_version = registry->metadata_version;
 	if (len == 0) {
 		DBG3("No metadata to push for metadata key %" PRIu64,
 				registry->metadata_key);
@@ -603,7 +618,7 @@ push_data:
 	 * different bidirectionnal communication sockets.
 	 */
 	ret = consumer_push_metadata(socket, metadata_key,
-			metadata_str, len, offset);
+			metadata_str, len, offset, metadata_version);
 	pthread_mutex_lock(&registry->lock);
 	if (ret < 0) {
 		/*
@@ -787,6 +802,8 @@ void delete_ust_app_session_rcu(struct rcu_head *head)
 /*
  * Delete ust app session safely. RCU read lock must be held before calling
  * this function.
+ *
+ * The session list lock must be held by the caller.
  */
 static
 void delete_ust_app_session(int sock, struct ust_app_session *ua_sess,
@@ -870,6 +887,11 @@ void delete_ust_app(struct ust_app *app)
 	int ret, sock;
 	struct ust_app_session *ua_sess, *tmp_ua_sess;
 
+	/*
+	 * The session list lock must be held during this function to guarantee
+	 * the existence of ua_sess.
+	 */
+	session_lock_list();
 	/* Delete ust app sessions info */
 	sock = app->sock;
 	app->sock = -1;
@@ -908,6 +930,7 @@ void delete_ust_app(struct ust_app *app)
 
 	DBG2("UST app pid %d deleted", app->pid);
 	free(app);
+	session_unlock_list();
 }
 
 /*
@@ -928,6 +951,8 @@ void delete_ust_app_rcu(struct rcu_head *head)
 /*
  * Delete the session from the application ht and delete the data structure by
  * freeing every object inside and releasing them.
+ *
+ * The session list lock must be held by the caller.
  */
 static void destroy_app_session(struct ust_app *app,
 		struct ust_app_session *ua_sess)
@@ -2796,9 +2821,6 @@ static int send_channel_uid_to_ust(struct buffer_reg_channel *reg_chan,
 			(void) release_ust_app_stream(-1, &stream, app);
 			if (ret == -EPIPE || ret == -LTTNG_UST_ERR_EXITING) {
 				ret = -ENOTCONN; /* Caused by app exiting. */
-				goto error_stream_unlock;
-			} else if (ret < 0) {
-				goto error_stream_unlock;
 			}
 			goto error_stream_unlock;
 		}
@@ -4625,6 +4647,155 @@ int ust_app_flush_session(struct ltt_ust_session *usess)
 	return ret;
 }
 
+static
+int ust_app_clear_quiescent_app_session(struct ust_app *app,
+		struct ust_app_session *ua_sess)
+{
+	int ret = 0;
+	struct lttng_ht_iter iter;
+	struct ust_app_channel *ua_chan;
+	struct consumer_socket *socket;
+
+	DBG("Clearing stream quiescent state for ust app pid %d", app->pid);
+
+	rcu_read_lock();
+
+	if (!app->compatible) {
+		goto end_not_compatible;
+	}
+
+	pthread_mutex_lock(&ua_sess->lock);
+
+	if (ua_sess->deleted) {
+		goto end_unlock;
+	}
+
+	health_code_update();
+
+	socket = consumer_find_socket_by_bitness(app->bits_per_long,
+			ua_sess->consumer);
+	if (!socket) {
+		ERR("Failed to find consumer (%" PRIu32 ") socket",
+				app->bits_per_long);
+		ret = -1;
+		goto end_unlock;
+	}
+
+	/* Clear quiescent state. */
+	switch (ua_sess->buffer_type) {
+	case LTTNG_BUFFER_PER_PID:
+		cds_lfht_for_each_entry(ua_sess->channels->ht, &iter.iter,
+				ua_chan, node.node) {
+			health_code_update();
+			ret = consumer_clear_quiescent_channel(socket,
+					ua_chan->key);
+			if (ret) {
+				ERR("Error clearing quiescent state for consumer channel");
+				ret = -1;
+				continue;
+			}
+		}
+		break;
+	case LTTNG_BUFFER_PER_UID:
+	default:
+		assert(0);
+		ret = -1;
+		break;
+	}
+
+	health_code_update();
+
+end_unlock:
+	pthread_mutex_unlock(&ua_sess->lock);
+
+end_not_compatible:
+	rcu_read_unlock();
+	health_code_update();
+	return ret;
+}
+
+/*
+ * Clear quiescent state in each stream for all applications for a
+ * specific UST session.
+ * Called with UST session lock held.
+ */
+static
+int ust_app_clear_quiescent_session(struct ltt_ust_session *usess)
+
+{
+	int ret = 0;
+
+	DBG("Clearing stream quiescent state for all ust apps");
+
+	rcu_read_lock();
+
+	switch (usess->buffer_type) {
+	case LTTNG_BUFFER_PER_UID:
+	{
+		struct lttng_ht_iter iter;
+		struct buffer_reg_uid *reg;
+
+		/*
+		 * Clear quiescent for all per UID buffers associated to
+		 * that session.
+		 */
+		cds_list_for_each_entry(reg, &usess->buffer_reg_uid_list, lnode) {
+			struct consumer_socket *socket;
+			struct buffer_reg_channel *reg_chan;
+
+			/* Get associated consumer socket.*/
+			socket = consumer_find_socket_by_bitness(
+					reg->bits_per_long, usess->consumer);
+			if (!socket) {
+				/*
+				 * Ignore request if no consumer is found for
+				 * the session.
+				 */
+				continue;
+			}
+
+			cds_lfht_for_each_entry(reg->registry->channels->ht,
+					&iter.iter, reg_chan, node.node) {
+				/*
+				 * The following call will print error values so
+				 * the return code is of little importance
+				 * because whatever happens, we have to try them
+				 * all.
+				 */
+				(void) consumer_clear_quiescent_channel(socket,
+						reg_chan->consumer_key);
+			}
+		}
+		break;
+	}
+	case LTTNG_BUFFER_PER_PID:
+	{
+		struct ust_app_session *ua_sess;
+		struct lttng_ht_iter iter;
+		struct ust_app *app;
+
+		cds_lfht_for_each_entry(ust_app_ht->ht, &iter.iter, app,
+				pid_n.node) {
+			ua_sess = lookup_session_by_app(usess, app);
+			if (ua_sess == NULL) {
+				continue;
+			}
+			(void) ust_app_clear_quiescent_app_session(app,
+					ua_sess);
+		}
+		break;
+	}
+	default:
+		ret = -1;
+		assert(0);
+		break;
+	}
+
+	rcu_read_unlock();
+	health_code_update();
+	return ret;
+}
+
 /*
  * Destroy a specific UST session in apps.
  */
@@ -4683,6 +4854,14 @@ int ust_app_start_trace_all(struct ltt_ust_session *usess)
 
 	rcu_read_lock();
 
+	/*
+	 * In a start-stop-start use-case, we need to clear the quiescent state
+	 * of each channel set by the prior stop command, thus ensuring that a
+	 * following stop or destroy is sure to grab a timestamp_end near those
+	 * operations, even if the packet is empty.
+	 */
+	(void) ust_app_clear_quiescent_session(usess);
+
 	cds_lfht_for_each_entry(ust_app_ht->ht, &iter.iter, app, pid_n.node) {
 		ret = ust_app_start_trace(usess, app);
 		if (ret < 0) {
@@ -5024,54 +5203,6 @@ end:
 	return ret;
 }
 
-/*
- * Calibrate registered applications.
- */
-int ust_app_calibrate_glb(struct lttng_ust_calibrate *calibrate)
-{
-	int ret = 0;
-	struct lttng_ht_iter iter;
-	struct ust_app *app;
-
-	rcu_read_lock();
-
-	cds_lfht_for_each_entry(ust_app_ht->ht, &iter.iter, app, pid_n.node) {
-		if (!app->compatible) {
-			/*
-			 * TODO: In time, we should notice the caller of this error by
-			 * telling him that this is a version error.
-			 */
-			continue;
-		}
-
-		health_code_update();
-
-		pthread_mutex_lock(&app->sock_lock);
-		ret = ustctl_calibrate(app->sock, calibrate);
-		pthread_mutex_unlock(&app->sock_lock);
-		if (ret < 0) {
-			switch (ret) {
-			case -ENOSYS:
-				/* Means that it's not implemented on the tracer side. */
-				ret = 0;
-				break;
-			default:
-				DBG2("Calibrate app PID %d returned with error %d",
-						app->pid, ret);
-				break;
-			}
-		}
-	}
-
-	DBG("UST app global domain calibration finished");
-
-	rcu_read_unlock();
-
-	health_code_update();
-
-	return ret;
-}
-
 /*
  * Receive registration and populate the given msg structure.
  *
@@ -5701,7 +5832,6 @@ int ust_app_snapshot_record(struct ltt_ust_session *usess,
 		uint64_t nb_packets_per_stream)
 {
 	int ret = 0;
-	unsigned int snapshot_done = 0;
 	struct lttng_ht_iter iter;
 	struct ust_app *app;
 	char pathname[PATH_MAX];
@@ -5753,7 +5883,6 @@ int ust_app_snapshot_record(struct ltt_ust_session *usess,
 			if (ret < 0) {
 				goto error;
 			}
-			snapshot_done = 1;
 		}
 		break;
 	}
@@ -5806,7 +5935,6 @@ int ust_app_snapshot_record(struct ltt_ust_session *usess,
 			if (ret < 0) {
 				goto error;
 			}
-			snapshot_done = 1;
 		}
 		break;
 	}
@@ -5815,15 +5943,6 @@ int ust_app_snapshot_record(struct ltt_ust_session *usess,
 		break;
 	}
 
-	if (!snapshot_done) {
-		/*
-		 * If no snapshot was made and we are not in the error path, this means
-		 * that there are no buffers thus no (prior) application to snapshot
-		 * data from so we have simply NO data.
-		 */
-		ret = -ENODATA;
-	}
-
 error:
 	rcu_read_unlock();
 	return ret;
@@ -5920,9 +6039,11 @@ int ust_app_uid_get_channel_runtime_stats(uint64_t ust_session_id,
 	if (overwrite) {
 		ret = consumer_get_lost_packets(ust_session_id,
 				consumer_chan_key, consumer, lost);
+		*discarded = 0;
 	} else {
 		ret = consumer_get_discarded_events(ust_session_id,
 				consumer_chan_key, consumer, discarded);
+		*lost = 0;
 	}
 
 end:
@@ -5965,16 +6086,83 @@ int ust_app_pid_get_channel_runtime_stats(struct ltt_ust_session *usess,
 		if (overwrite) {
 			ret = consumer_get_lost_packets(usess->id, ua_chan->key,
 					consumer, lost);
+			*discarded = 0;
 			goto end;
 		} else {
 			ret = consumer_get_discarded_events(usess->id,
 					ua_chan->key, consumer, discarded);
+			*lost = 0;
 			goto end;
 		}
+	}
+
+end:
+	rcu_read_unlock();
+	return ret;
+}
+
+static
+int ust_app_regenerate_statedump(struct ltt_ust_session *usess,
+		struct ust_app *app)
+{
+	int ret = 0;
+	struct ust_app_session *ua_sess;
+
+	DBG("Regenerating the metadata for ust app pid %d", app->pid);
+
+	rcu_read_lock();
+
+	ua_sess = lookup_session_by_app(usess, app);
+	if (ua_sess == NULL) {
+		/* The session is in teardown process. Ignore and continue. */
 		goto end;
 	}
 
+	pthread_mutex_lock(&ua_sess->lock);
+
+	if (ua_sess->deleted) {
+		goto end_unlock;
+	}
+
+	pthread_mutex_lock(&app->sock_lock);
+	ret = ustctl_regenerate_statedump(app->sock, ua_sess->handle);
+	pthread_mutex_unlock(&app->sock_lock);
+
+end_unlock:
+	pthread_mutex_unlock(&ua_sess->lock);
+
 end:
 	rcu_read_unlock();
+	health_code_update();
 	return ret;
 }
+
+/*
+ * Regenerate the statedump for each app in the session.
+ */
+int ust_app_regenerate_statedump_all(struct ltt_ust_session *usess)
+{
+	int ret = 0;
+	struct lttng_ht_iter iter;
+	struct ust_app *app;
+
+	DBG("Regenerating the metadata for all UST apps");
+
+	rcu_read_lock();
+
+	cds_lfht_for_each_entry(ust_app_ht->ht, &iter.iter, app, pid_n.node) {
+		if (!app->compatible) {
+			continue;
+		}
+
+		ret = ust_app_regenerate_statedump(usess, app);
+		if (ret < 0) {
+			/* Continue to the next app even on error */
+			continue;
+		}
+	}
+
+	rcu_read_unlock();
+
+	return 0;
+}