X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng-relayd%2Fsession.c;h=d1c2098f8591a3a8c9c5e87b022f43e8fff627ee;hp=46d9cc66a587cfe6bbbb4520998e605217295e74;hb=ce3f3ba3aee62c0a317b448c2f19578ab7f057e4;hpb=6c1c0768320135c6936c371b09731851b508c023 diff --git a/src/bin/lttng-relayd/session.c b/src/bin/lttng-relayd/session.c index 46d9cc66a..d1c2098f8 100644 --- a/src/bin/lttng-relayd/session.c +++ b/src/bin/lttng-relayd/session.c @@ -1,6 +1,7 @@ /* * Copyright (C) 2013 - Julien Desfossez * David Goulet + * 2015 - Mathieu Desnoyers * * 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 @@ -16,31 +17,27 @@ * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ -#define _GNU_SOURCE #define _LGPL_SOURCE #include +#include +#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; @@ -57,30 +54,62 @@ struct relay_session *session_create(void) 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); @@ -88,97 +117,134 @@ struct relay_session *session_find_by_id(struct lttng_ht *ht, uint64_t 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); + if (!sessions_ht) { + return; + } - /* - * 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); }