--- /dev/null
+/*
+ * Copyright (C) 2019 - Jérémie Galarneau <jeremie.galarneau@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 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 <urcu.h>
+#include <urcu/rculfhash.h>
+#include <urcu/ref.h>
+#include <common/macros.h>
+#include <common/hashtable/hashtable.h>
+#include <common/hashtable/utils.h>
+#include <common/trace-chunk-registry.h>
+#include <common/defaults.h>
+#include <common/error.h>
+#include <common/string-utils/format.h>
+#include <stdio.h>
+#include <inttypes.h>
+
+/*
+ * 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;
+}
projects / lttng-tools.git / commitdiff
