From: Jérémie Galarneau Date: Mon, 11 Mar 2019 21:25:45 +0000 (-0400) Subject: relayd: add the sessiond_trace_chunk_registry interface X-Git-Url: http://git.efficios.com/?p=lttng-tools.git;a=commitdiff_plain;h=0c1b0f77482b0d1856fefabc42978b82b5dd267c relayd: add the sessiond_trace_chunk_registry interface The sessiond_trace_chunk_registry interface allows the relay daemon to maintain an association between multiple consumer daemon connections originating from the same session daemon and a common trace chunk registry. This trace chunk registry allows separate, but related, connections to manipulate the same trace chunk. Signed-off-by: Jérémie Galarneau --- diff --git a/src/bin/lttng-relayd/Makefile.am b/src/bin/lttng-relayd/Makefile.am index cf56ea495..c95359e74 100644 --- a/src/bin/lttng-relayd/Makefile.am +++ b/src/bin/lttng-relayd/Makefile.am @@ -22,7 +22,8 @@ lttng_relayd_SOURCES = main.c lttng-relayd.h utils.h utils.c cmd.h \ connection.c connection.h \ viewer-session.c viewer-session.h \ tracefile-array.c tracefile-array.h \ - tcp_keep_alive.c tcp_keep_alive.h + tcp_keep_alive.c tcp_keep_alive.h \ + sessiond-trace-chunks.c sessiond-trace-chunks.h # link on liblttngctl for check if relayd is already alive. lttng_relayd_LDADD = -lurcu-common -lurcu \ diff --git a/src/bin/lttng-relayd/sessiond-trace-chunks.c b/src/bin/lttng-relayd/sessiond-trace-chunks.c new file mode 100644 index 000000000..31fbb3189 --- /dev/null +++ b/src/bin/lttng-relayd/sessiond-trace-chunks.c @@ -0,0 +1,463 @@ +/* + * Copyright (C) 2019 - Jérémie Galarneau + * + * 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 published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include "sessiond-trace-chunks.h" +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * Lifetime of trace chunks within the relay daemon. + * + * Trace chunks are shared accross connections initiated from a given + * session daemon. When a session is created by a consumer daemon, the + * UUID of its associated session daemon is transmitted (in the case of + * 2.11+ consumer daemons). + * + * The sessiond_trace_chunk_registry_new_session() and + * sessiond_trace_chunk_registry_session_closed() methods create and + * manage the reference count of lttng_trace_chunk_registry objects + * associated to the various sessiond instances served by the relay daemon. + * + * When all sessions associated with a given sessiond instance are + * destroyed, its registry is destroyed. + * + * lttng_trace_chunk objects are uniquely identified by the + * (sessiond_uuid, sessiond_session_id, chunk_id) tuple. If a trace chunk + * matching that tuple already exists, a new reference to the trace chunk + * is acquired and it is returned to the caller. Otherwise, a new trace + * chunk is created. This is how trace chunks are de-duplicated across + * multiple consumer daemons managed by the same session daemon. + * + * Note that trace chunks are always added to their matching + * lttng_trace_chunk_registry. They are automatically removed from the + * trace chunk registry when their reference count reaches zero. + */ + +/* + * It is assumed that the sessiond_trace_chunk_registry is created and + * destroyed by the same thread. + */ +struct sessiond_trace_chunk_registry { + /* Maps an lttng_uuid to an lttng_trace_chunk_registry. */ + struct cds_lfht *ht; +}; + +struct trace_chunk_registry_ht_key { + lttng_uuid sessiond_uuid; +}; + +struct trace_chunk_registry_ht_element { + struct trace_chunk_registry_ht_key key; + struct urcu_ref ref; + /* Node into the sessiond_trace_chunk_registry's hash table. */ + struct cds_lfht_node ht_node; + /* Used for defered call_rcu reclaim. */ + struct rcu_head rcu_node; + struct lttng_trace_chunk_registry *trace_chunk_registry; + struct sessiond_trace_chunk_registry *sessiond_trace_chunk_registry; +}; + +static +unsigned long trace_chunk_registry_ht_key_hash( + const struct trace_chunk_registry_ht_key *key) +{ + uint64_t uuid_h1 = ((uint64_t *) key->sessiond_uuid)[0]; + uint64_t uuid_h2 = ((uint64_t *) key->sessiond_uuid)[1]; + + return hash_key_u64(&uuid_h1, lttng_ht_seed) ^ + hash_key_u64(&uuid_h2, lttng_ht_seed); +} + +/* cds_lfht match function */ +static +int trace_chunk_registry_ht_key_match(struct cds_lfht_node *node, + const void *_key) +{ + const struct trace_chunk_registry_ht_key *key = + (struct trace_chunk_registry_ht_key *) _key; + struct trace_chunk_registry_ht_element *registry; + + registry = container_of(node, typeof(*registry), ht_node); + return lttng_uuid_is_equal(key->sessiond_uuid, + registry->key.sessiond_uuid); +} + +static +void trace_chunk_registry_ht_element_free(struct rcu_head *node) +{ + struct trace_chunk_registry_ht_element *element = + container_of(node, typeof(*element), rcu_node); + + lttng_trace_chunk_registry_destroy(element->trace_chunk_registry); + free(element); +} + +static +void trace_chunk_registry_ht_element_release(struct urcu_ref *ref) +{ + struct trace_chunk_registry_ht_element *element = + container_of(ref, typeof(*element), ref); + char uuid_str[UUID_STR_LEN]; + + lttng_uuid_to_str(element->key.sessiond_uuid, uuid_str); + + DBG("Destroying trace chunk registry associated to sessiond {%s}", + uuid_str); + if (element->sessiond_trace_chunk_registry) { + /* Unpublish. */ + rcu_read_lock(); + cds_lfht_del(element->sessiond_trace_chunk_registry->ht, + &element->ht_node); + rcu_read_unlock(); + element->sessiond_trace_chunk_registry = NULL; + } + + /* Defered reclaim of the object */ + call_rcu(&element->rcu_node, trace_chunk_registry_ht_element_free); +} + +static +bool trace_chunk_registry_ht_element_get( + struct trace_chunk_registry_ht_element *element) +{ + return urcu_ref_get_unless_zero(&element->ref); +} + +static +void trace_chunk_registry_ht_element_put( + struct trace_chunk_registry_ht_element *element) +{ + urcu_ref_put(&element->ref, trace_chunk_registry_ht_element_release); +} + +/* Acquires a reference to the returned element on behalf of the caller. */ +static +struct trace_chunk_registry_ht_element *trace_chunk_registry_ht_element_find( + struct sessiond_trace_chunk_registry *sessiond_registry, + const struct trace_chunk_registry_ht_key *key) +{ + struct trace_chunk_registry_ht_element *element = NULL; + struct cds_lfht_node *node; + struct cds_lfht_iter iter; + + rcu_read_lock(); + cds_lfht_lookup(sessiond_registry->ht, + trace_chunk_registry_ht_key_hash(key), + trace_chunk_registry_ht_key_match, + key, + &iter); + node = cds_lfht_iter_get_node(&iter); + if (node) { + element = container_of(node, typeof(*element), ht_node); + /* + * Only consider the look-up as successful if a reference + * could be acquired. + */ + if (!trace_chunk_registry_ht_element_get(element)) { + element = NULL; + } + } + rcu_read_unlock(); + return element; +} + +static +int trace_chunk_registry_ht_element_create( + struct sessiond_trace_chunk_registry *sessiond_registry, + const struct trace_chunk_registry_ht_key *key) +{ + int ret = 0; + struct trace_chunk_registry_ht_element *new_element; + struct lttng_trace_chunk_registry *trace_chunk_registry; + char uuid_str[UUID_STR_LEN]; + + lttng_uuid_to_str(key->sessiond_uuid, uuid_str); + + trace_chunk_registry = lttng_trace_chunk_registry_create(); + if (!trace_chunk_registry) { + ret = -1; + goto end; + } + + new_element = zmalloc(sizeof(*new_element)); + if (!new_element) { + ret = -1; + goto end; + } + + memcpy(&new_element->key, key, sizeof(new_element->key)); + urcu_ref_init(&new_element->ref); + cds_lfht_node_init(&new_element->ht_node); + new_element->trace_chunk_registry = trace_chunk_registry; + + /* Attempt to publish the new element. */ + rcu_read_lock(); + while (1) { + struct cds_lfht_node *published_node; + struct trace_chunk_registry_ht_element *published_element; + + published_node = cds_lfht_add_unique(sessiond_registry->ht, + trace_chunk_registry_ht_key_hash(&new_element->key), + trace_chunk_registry_ht_key_match, + &new_element->key, + &new_element->ht_node); + if (published_node == &new_element->ht_node) { + /* New element published successfully. */ + DBG("Created trace chunk registry for sessiond {%s}", + uuid_str); + new_element->sessiond_trace_chunk_registry = + sessiond_registry; + break; + } + + /* + * An equivalent element was published during the creation of + * this element. Attempt to acquire a reference to the one that + * was already published and release the reference to the copy + * we created if successful. + */ + published_element = container_of(published_node, + typeof(*published_element), ht_node); + if (trace_chunk_registry_ht_element_get(published_element)) { + DBG("Acquired reference to trace chunk registry of sessiond {%s}", + uuid_str); + trace_chunk_registry_ht_element_put(new_element); + new_element = NULL; + break; + } + /* + * A reference to the previously published element could not + * be acquired. Hence, retry to publish our copy of the + * element. + */ + } + rcu_read_unlock(); +end: + if (ret < 0) { + ERR("Failed to create trace chunk registry for session daemon {%s}", + uuid_str); + } + return ret; +} + +struct sessiond_trace_chunk_registry *sessiond_trace_chunk_registry_create(void) +{ + struct sessiond_trace_chunk_registry *sessiond_registry = + zmalloc(sizeof(*sessiond_registry)); + + if (!sessiond_registry) { + goto end; + } + + sessiond_registry->ht = cds_lfht_new(DEFAULT_HT_SIZE, + 1, 0, CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL); + if (!sessiond_registry->ht) { + goto error; + } + +end: + return sessiond_registry; +error: + sessiond_trace_chunk_registry_destroy(sessiond_registry); + return NULL; +} + +void sessiond_trace_chunk_registry_destroy( + struct sessiond_trace_chunk_registry *sessiond_registry) +{ + int ret = cds_lfht_destroy(sessiond_registry->ht, NULL); + + assert(!ret); + free(sessiond_registry); +} + +int sessiond_trace_chunk_registry_session_created( + struct sessiond_trace_chunk_registry *sessiond_registry, + const lttng_uuid sessiond_uuid) +{ + int ret = 0; + struct trace_chunk_registry_ht_key key; + struct trace_chunk_registry_ht_element *element; + + lttng_uuid_copy(key.sessiond_uuid, sessiond_uuid); + + element = trace_chunk_registry_ht_element_find(sessiond_registry, &key); + if (element) { + char uuid_str[UUID_STR_LEN]; + + lttng_uuid_to_str(sessiond_uuid, uuid_str); + DBG("Acquired reference to trace chunk registry of sessiond {%s}", + uuid_str); + goto end; + } else { + ret = trace_chunk_registry_ht_element_create( + sessiond_registry, &key); + } +end: + return ret; +} + +int sessiond_trace_chunk_registry_session_destroyed( + struct sessiond_trace_chunk_registry *sessiond_registry, + const lttng_uuid sessiond_uuid) +{ + int ret = 0; + struct trace_chunk_registry_ht_key key; + struct trace_chunk_registry_ht_element *element; + char uuid_str[UUID_STR_LEN]; + + lttng_uuid_to_str(sessiond_uuid, uuid_str); + lttng_uuid_copy(key.sessiond_uuid, sessiond_uuid); + + element = trace_chunk_registry_ht_element_find(sessiond_registry, &key); + if (element) { + DBG("Releasing reference to trace chunk registry of sessiond {%s}", + uuid_str); + /* + * Release the reference held by the session and the reference + * acquired through the "find" operation. + */ + trace_chunk_registry_ht_element_put(element); + trace_chunk_registry_ht_element_put(element); + } else { + ERR("Failed to find trace chunk registry of sessiond {%s}", + uuid_str); + ret = -1; + } + return ret; +} + +struct lttng_trace_chunk *sessiond_trace_chunk_registry_publish_chunk( + struct sessiond_trace_chunk_registry *sessiond_registry, + const lttng_uuid sessiond_uuid, uint64_t session_id, + struct lttng_trace_chunk *new_chunk) +{ + enum lttng_trace_chunk_status status; + uint64_t chunk_id; + bool is_anonymous_chunk; + struct trace_chunk_registry_ht_key key; + struct trace_chunk_registry_ht_element *element = NULL; + char uuid_str[UUID_STR_LEN]; + char chunk_id_str[MAX_INT_DEC_LEN(typeof(chunk_id))] = "-1"; + struct lttng_trace_chunk *published_chunk = NULL; + + lttng_uuid_to_str(sessiond_uuid, uuid_str); + lttng_uuid_copy(key.sessiond_uuid, sessiond_uuid); + + status = lttng_trace_chunk_get_id(new_chunk, &chunk_id); + if (status == LTTNG_TRACE_CHUNK_STATUS_OK) { + int ret; + + ret = snprintf(chunk_id_str, sizeof(chunk_id_str), "%" PRIu64, + chunk_id); + if (ret < 0) { + lttng_strncpy(chunk_id_str, "-1", sizeof(chunk_id_str)); + WARN("Failed to format trace chunk id"); + } + is_anonymous_chunk = false; + } else if (status == LTTNG_TRACE_CHUNK_STATUS_NONE) { + is_anonymous_chunk = true; + } else { + ERR("Failed to get trace chunk id"); + goto end; + } + + DBG("Attempting to publish trace chunk: sessiond {%s}, session_id = " + "%" PRIu64 ", chunk_id = %s", + uuid_str, session_id, + is_anonymous_chunk ? "anonymous" : chunk_id_str); + + element = trace_chunk_registry_ht_element_find(sessiond_registry, &key); + if (!element) { + ERR("Failed to find registry of sessiond {%s}", uuid_str); + goto end; + } + + published_chunk = lttng_trace_chunk_registry_publish_chunk( + element->trace_chunk_registry, session_id, new_chunk); +end: + trace_chunk_registry_ht_element_put(element); + return published_chunk; +} + +struct lttng_trace_chunk * +sessiond_trace_chunk_registry_get_anonymous_chunk( + struct sessiond_trace_chunk_registry *sessiond_registry, + const lttng_uuid sessiond_uuid, + uint64_t session_id) +{ + struct lttng_trace_chunk *chunk = NULL; + struct trace_chunk_registry_ht_element *element; + struct trace_chunk_registry_ht_key key; + char uuid_str[UUID_STR_LEN]; + + lttng_uuid_to_str(sessiond_uuid, uuid_str); + + lttng_uuid_copy(key.sessiond_uuid, sessiond_uuid); + element = trace_chunk_registry_ht_element_find(sessiond_registry, &key); + if (!element) { + ERR("Failed to find trace chunk registry of sessiond {%s}", + uuid_str); + goto end; + } + + chunk = lttng_trace_chunk_registry_find_anonymous_chunk( + element->trace_chunk_registry, + session_id); + trace_chunk_registry_ht_element_put(element); +end: + return chunk; +} + +struct lttng_trace_chunk * +sessiond_trace_chunk_registry_get_chunk( + struct sessiond_trace_chunk_registry *sessiond_registry, + const lttng_uuid sessiond_uuid, + uint64_t session_id, uint64_t chunk_id) +{ + struct lttng_trace_chunk *chunk = NULL; + struct trace_chunk_registry_ht_element *element; + struct trace_chunk_registry_ht_key key; + char uuid_str[UUID_STR_LEN]; + + lttng_uuid_to_str(sessiond_uuid, uuid_str); + + lttng_uuid_copy(key.sessiond_uuid, sessiond_uuid); + element = trace_chunk_registry_ht_element_find(sessiond_registry, &key); + if (!element) { + ERR("Failed to find trace chunk registry of sessiond {%s}", + uuid_str); + goto end; + } + + chunk = lttng_trace_chunk_registry_find_chunk( + element->trace_chunk_registry, + session_id, chunk_id); + trace_chunk_registry_ht_element_put(element); +end: + return chunk; +} diff --git a/src/bin/lttng-relayd/sessiond-trace-chunks.h b/src/bin/lttng-relayd/sessiond-trace-chunks.h new file mode 100644 index 000000000..39804679c --- /dev/null +++ b/src/bin/lttng-relayd/sessiond-trace-chunks.h @@ -0,0 +1,58 @@ +/* + * Copyright (C) 2019 - Jérémie Galarneau + * + * 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 + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program; if not, write to the Free Software Foundation, Inc., 51 + * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#ifndef SESSIOND_TRACE_CHUNK_REGISTRY_H +#define SESSIOND_TRACE_CHUNK_REGISTRY_H + +#include +#include +#include + +struct sessiond_trace_chunk_registry; + +struct sessiond_trace_chunk_registry * +sessiond_trace_chunk_registry_create(void); + +void sessiond_trace_chunk_registry_destroy( + struct sessiond_trace_chunk_registry *sessiond_registry); + +int sessiond_trace_chunk_registry_session_created( + struct sessiond_trace_chunk_registry *sessiond_registry, + const lttng_uuid sessiond_uuid); + +int sessiond_trace_chunk_registry_session_destroyed( + struct sessiond_trace_chunk_registry *sessiond_registry, + const lttng_uuid sessiond_uuid); + +struct lttng_trace_chunk *sessiond_trace_chunk_registry_publish_chunk( + struct sessiond_trace_chunk_registry *sessiond_registry, + const lttng_uuid sessiond_uuid, uint64_t session_id, + struct lttng_trace_chunk *chunk); + +struct lttng_trace_chunk * +sessiond_trace_chunk_registry_get_anonymous_chunk( + struct sessiond_trace_chunk_registry *sessiond_registry, + const lttng_uuid sessiond_uuid, + uint64_t session_id); + +struct lttng_trace_chunk * +sessiond_trace_chunk_registry_get_chunk( + struct sessiond_trace_chunk_registry *sessiond_registry, + const lttng_uuid sessiond_uuid, + uint64_t session_id, uint64_t chunk_id); + +#endif /* SESSIOND_TRACE_CHUNK_REGISTRY_H */