/*
* Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
* David Goulet <dgoulet@efficios.com>
+ * 2015 - Mathieu Desnoyers <mathieu.desnoyers@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
#define _GNU_SOURCE
#define _LGPL_SOURCE
#include <common/common.h>
+#include <urcu/rculist.h>
+#include "lttng-relayd.h"
#include "ctf-trace.h"
#include "session.h"
#include "stream.h"
/* Global session id used in the session creation. */
static uint64_t last_relay_session_id;
-
-static void rcu_destroy_session(struct rcu_head *head)
-{
- struct relay_session *session =
- caa_container_of(head, struct relay_session, rcu_node);
-
- free(session);
-}
+static pthread_mutex_t last_relay_session_id_lock = PTHREAD_MUTEX_INITIALIZER;
/*
* Create a new session by assigning a new session ID.
*
* Return allocated session or else NULL.
*/
-struct relay_session *session_create(void)
+struct relay_session *session_create(const char *session_name,
+ const char *hostname, uint32_t live_timer,
+ bool snapshot, uint32_t major, uint32_t minor)
{
struct relay_session *session;
goto error;
}
- pthread_mutex_init(&session->viewer_ready_lock, NULL);
+ pthread_mutex_lock(&last_relay_session_id_lock);
session->id = ++last_relay_session_id;
+ pthread_mutex_unlock(&last_relay_session_id_lock);
+
+ session->major = major;
+ session->minor = minor;
lttng_ht_node_init_u64(&session->session_n, session->id);
+ urcu_ref_init(&session->ref);
+ CDS_INIT_LIST_HEAD(&session->recv_list);
+ pthread_mutex_init(&session->lock, NULL);
+ pthread_mutex_init(&session->reflock, NULL);
+ pthread_mutex_init(&session->recv_list_lock, NULL);
+
+ strncpy(session->session_name, session_name,
+ sizeof(session->session_name));
+ strncpy(session->hostname, hostname,
+ sizeof(session->hostname));
+ session->live_timer = live_timer;
+ session->snapshot = snapshot;
+
+ lttng_ht_add_unique_u64(sessions_ht, &session->session_n);
error:
return session;
}
+/* Should be called with RCU read-side lock held. */
+bool session_get(struct relay_session *session)
+{
+ bool has_ref = false;
+
+ pthread_mutex_lock(&session->reflock);
+ if (session->ref.refcount != 0) {
+ has_ref = true;
+ urcu_ref_get(&session->ref);
+ }
+ pthread_mutex_unlock(&session->reflock);
+
+ return has_ref;
+}
+
/*
- * Lookup a session within the given hash table and session id. RCU read side
- * lock MUST be acquired before calling this and as long as the caller has a
- * reference to the object.
+ * Lookup a session within the session hash table using the session id
+ * as key. A session reference is taken when a session is returned.
+ * session_put() must be called on that session.
*
* Return session or NULL if not found.
*/
-struct relay_session *session_find_by_id(struct lttng_ht *ht, uint64_t id)
+struct relay_session *session_get_by_id(uint64_t id)
{
struct relay_session *session = NULL;
struct lttng_ht_node_u64 *node;
struct lttng_ht_iter iter;
- assert(ht);
-
- lttng_ht_lookup(ht, &id, &iter);
+ rcu_read_lock();
+ lttng_ht_lookup(sessions_ht, &id, &iter);
node = lttng_ht_iter_get_node_u64(&iter);
if (!node) {
DBG("Session find by ID %" PRIu64 " id NOT found", id);
}
session = caa_container_of(node, struct relay_session, session_n);
DBG("Session find by ID %" PRIu64 " id found", id);
-
+ if (!session_get(session)) {
+ session = NULL;
+ }
end:
+ rcu_read_unlock();
return session;
}
+static void rcu_destroy_session(struct rcu_head *rcu_head)
+{
+ struct relay_session *session =
+ caa_container_of(rcu_head, struct relay_session,
+ rcu_node);
+ /*
+ * Since each trace has a reference on the session, it means
+ * that if we are at the point where we teardown the session, no
+ * trace belonging to that session exist at this point.
+ * Calling lttng_ht_destroy in call_rcu worker thread so we
+ * don't hold the RCU read-side lock while calling it.
+ */
+ lttng_ht_destroy(session->ctf_traces_ht);
+ free(session);
+}
+
/*
* Delete session from the given hash table.
*
* Return lttng ht del error code being 0 on success and 1 on failure.
*/
-int session_delete(struct lttng_ht *ht, struct relay_session *session)
+static int session_delete(struct relay_session *session)
{
struct lttng_ht_iter iter;
- assert(ht);
- assert(session);
-
iter.iter.node = &session->session_n.node;
- return lttng_ht_del(ht, &iter);
+ return lttng_ht_del(sessions_ht, &iter);
}
-/*
- * The caller MUST be from the viewer thread since the viewer refcount is
- * decremented. With this calue down to 0, it will try to destroy the session.
- */
-void session_viewer_try_destroy(struct lttng_ht *ht,
- struct relay_session *session)
+
+static void destroy_session(struct relay_session *session)
{
- unsigned long ret_ref;
+ int ret;
- assert(session);
+ ret = session_delete(session);
+ assert(!ret);
+ call_rcu(&session->rcu_node, rcu_destroy_session);
+}
- ret_ref = uatomic_add_return(&session->viewer_refcount, -1);
- if (ret_ref == 0) {
- session_try_destroy(ht, session);
- }
+void session_release(struct urcu_ref *ref)
+{
+ struct relay_session *session =
+ caa_container_of(ref, struct relay_session, ref);
+
+ destroy_session(session);
}
-/*
- * Should only be called from the main streaming thread since it does not touch
- * the viewer refcount. If this refcount is down to 0, destroy the session only
- * and only if the session deletion succeeds. This is done because the viewer
- * *and* the streaming thread can both concurently try to destroy the session
- * thus the first come first serve.
- */
-void session_try_destroy(struct lttng_ht *ht, struct relay_session *session)
+void session_put(struct relay_session *session)
{
- int ret = 0;
- unsigned long ret_ref;
+ rcu_read_lock();
+ pthread_mutex_lock(&session->reflock);
+ urcu_ref_put(&session->ref, session_release);
+ pthread_mutex_unlock(&session->reflock);
+ rcu_read_unlock();
+}
- assert(session);
+int session_close(struct relay_session *session)
+{
+ int ret = 0;
+ struct ctf_trace *trace;
+ struct lttng_ht_iter iter;
+ struct relay_stream *stream;
+
+ pthread_mutex_lock(&session->lock);
+ DBG("closing session %" PRIu64 ": is conn already closed %d",
+ session->id, session->connection_closed);
+ if (session->connection_closed) {
+ ret = -1;
+ goto unlock;
+ }
+ session->connection_closed = true;
+unlock:
+ pthread_mutex_unlock(&session->lock);
+ if (ret) {
+ return ret;
+ }
- ret_ref = uatomic_read(&session->viewer_refcount);
- if (ret_ref == 0 && session->close_flag) {
- if (ht) {
- ret = session_delete(ht, session);
- }
- if (!ret) {
- /* Only destroy the session if the deletion was successful. */
- session_destroy(session);
+ rcu_read_lock();
+ cds_lfht_for_each_entry(session->ctf_traces_ht->ht,
+ &iter.iter, trace, node.node) {
+ ret = ctf_trace_close(trace);
+ if (ret) {
+ goto rcu_unlock;
}
}
+ cds_list_for_each_entry_rcu(stream, &session->recv_list,
+ recv_node) {
+ /* Close streams which have not been published yet. */
+ try_stream_close(stream);
+ }
+rcu_unlock:
+ rcu_read_unlock();
+ if (ret) {
+ return ret;
+ }
+ /* Put self-reference from create. */
+ session_put(session);
+ return ret;
}
-/*
- * Destroy a session object.
- *
- * This function must *NOT* be called with an RCU read lock held since
- * the session's ctf_traces_ht is destroyed.
- */
-void session_destroy(struct relay_session *session)
+void print_sessions(void)
{
- struct ctf_trace *ctf_trace;
struct lttng_ht_iter iter;
+ struct relay_session *session;
- assert(session);
-
- DBG("Relay destroying session %" PRIu64, session->id);
-
- /*
- * Empty the ctf trace hash table which will destroy the stream contained
- * in that table.
- */
rcu_read_lock();
- cds_lfht_for_each_entry(session->ctf_traces_ht->ht, &iter.iter, ctf_trace,
- node.node) {
- ctf_trace_delete(session->ctf_traces_ht, ctf_trace);
- ctf_trace_destroy(ctf_trace);
+ cds_lfht_for_each_entry(sessions_ht->ht, &iter.iter, session,
+ session_n.node) {
+ if (!session_get(session)) {
+ continue;
+ }
+ DBG("session %p refcount %ld session %" PRIu64,
+ session,
+ session->ref.refcount,
+ session->id);
+ session_put(session);
}
rcu_read_unlock();
- lttng_ht_destroy(session->ctf_traces_ht);
-
- call_rcu(&session->rcu_node, rcu_destroy_session);
}
projects / lttng-tools.git / blobdiff