/*
* 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
* Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
-#define _GNU_SOURCE
+#define _LGPL_SOURCE
#include <assert.h>
#include <common/common.h>
#include <common/utils.h>
+#include <urcu/rculist.h>
#include "ctf-trace.h"
+#include "lttng-relayd.h"
+#include "stream.h"
static uint64_t last_relay_ctf_trace_id;
+static pthread_mutex_t last_relay_ctf_trace_id_lock = PTHREAD_MUTEX_INITIALIZER;
+
+static void rcu_destroy_ctf_trace(struct rcu_head *rcu_head)
+{
+ struct ctf_trace *trace =
+ caa_container_of(rcu_head, struct ctf_trace, rcu_node);
+
+ free(trace);
+}
/*
- * Try to destroy a ctf_trace object meaning that the refcount is decremented
- * and checked if down to 0 which will free it.
+ * Destroy a ctf trace and all stream contained in it.
+ *
+ * MUST be called with the RCU read side lock.
*/
-void ctf_trace_try_destroy(struct ctf_trace *obj)
+void ctf_trace_destroy(struct ctf_trace *trace)
+{
+ /*
+ * Getting to this point, every stream referenced by that trace
+ * have put back their ref since the've been closed by the
+ * control side.
+ */
+ assert(cds_list_empty(&trace->stream_list));
+ session_put(trace->session);
+ trace->session = NULL;
+ call_rcu(&trace->rcu_node, rcu_destroy_ctf_trace);
+}
+
+void ctf_trace_release(struct urcu_ref *ref)
{
- unsigned long ret_ref;
+ struct ctf_trace *trace =
+ caa_container_of(ref, struct ctf_trace, ref);
+ int ret;
+ struct lttng_ht_iter iter;
- if (!obj) {
- return;
- }
+ iter.iter.node = &trace->node.node;
+ ret = lttng_ht_del(trace->session->ctf_traces_ht, &iter);
+ assert(!ret);
+ ctf_trace_destroy(trace);
+}
- ret_ref = uatomic_add_return(&obj->refcount, -1);
- if (ret_ref == 0) {
- DBG("Freeing ctf_trace %" PRIu64, obj->id);
- free(obj);
+/*
+ * Should be called with RCU read-side lock held.
+ */
+bool ctf_trace_get(struct ctf_trace *trace)
+{
+ bool has_ref = false;
+
+ /* Confirm that the trace refcount has not reached 0. */
+ pthread_mutex_lock(&trace->reflock);
+ if (trace->ref.refcount != 0) {
+ has_ref = true;
+ urcu_ref_get(&trace->ref);
}
+ pthread_mutex_unlock(&trace->reflock);
+
+ return has_ref;
}
/*
- * Create and return an allocated ctf_trace object. NULL on error.
+ * Create and return an allocated ctf_trace. NULL on error.
+ * There is no "open" and "close" for a ctf_trace, but rather just a
+ * create and refcounting. Whenever all the streams belonging to a trace
+ * put their reference, its refcount drops to 0.
*/
-struct ctf_trace *ctf_trace_create(void)
+static struct ctf_trace *ctf_trace_create(struct relay_session *session,
+ char *path_name)
{
- struct ctf_trace *obj;
+ struct ctf_trace *trace;
- obj = zmalloc(sizeof(*obj));
- if (!obj) {
+ trace = zmalloc(sizeof(*trace));
+ if (!trace) {
PERROR("ctf_trace alloc");
goto error;
}
- obj->id = ++last_relay_ctf_trace_id;
- DBG("Created ctf_trace %" PRIu64, obj->id);
+ if (!session_get(session)) {
+ ERR("Cannot get session");
+ free(trace);
+ trace = NULL;
+ goto error;
+ }
+ trace->session = session;
+
+ CDS_INIT_LIST_HEAD(&trace->stream_list);
+
+ pthread_mutex_lock(&last_relay_ctf_trace_id_lock);
+ trace->id = ++last_relay_ctf_trace_id;
+ pthread_mutex_unlock(&last_relay_ctf_trace_id_lock);
+
+ lttng_ht_node_init_str(&trace->node, path_name);
+ trace->session = session;
+ urcu_ref_init(&trace->ref);
+ pthread_mutex_init(&trace->lock, NULL);
+ pthread_mutex_init(&trace->reflock, NULL);
+ pthread_mutex_init(&trace->stream_list_lock, NULL);
+ lttng_ht_add_str(session->ctf_traces_ht, &trace->node);
+
+ DBG("Created ctf_trace %" PRIu64 " with path: %s", trace->id, path_name);
error:
- return obj;
+ return trace;
}
/*
- * Check if we can assign the ctf_trace id and metadata stream to one or all
- * the streams with the same path_name (our unique ID for ctf traces).
- *
- * The given stream MUST be new and NOT visible (in any hash table).
+ * Return a ctf_trace if found by id in the given hash table else NULL.
+ * Hold a reference on the ctf_trace, and must be paired with
+ * ctf_trace_put().
*/
-void ctf_trace_assign(struct lttng_ht *ht, struct relay_stream *stream)
+struct ctf_trace *ctf_trace_get_by_path_or_create(struct relay_session *session,
+ char *path_name)
{
+ struct lttng_ht_node_str *node;
struct lttng_ht_iter iter;
- struct relay_stream *tmp_stream;
+ struct ctf_trace *trace = NULL;
- assert(ht);
- assert(stream);
+ rcu_read_lock();
+ lttng_ht_lookup(session->ctf_traces_ht, (void *) path_name, &iter);
+ node = lttng_ht_iter_get_node_str(&iter);
+ if (!node) {
+ DBG("CTF Trace path %s not found", path_name);
+ goto end;
+ }
+ trace = caa_container_of(node, struct ctf_trace, node);
+ if (!ctf_trace_get(trace)) {
+ trace = NULL;
+ }
+end:
+ rcu_read_unlock();
+ if (!trace) {
+ /* Try to create */
+ trace = ctf_trace_create(session, path_name);
+ }
+ return trace;
+}
+
+void ctf_trace_put(struct ctf_trace *trace)
+{
+ rcu_read_lock();
+ pthread_mutex_lock(&trace->reflock);
+ urcu_ref_put(&trace->ref, ctf_trace_release);
+ pthread_mutex_unlock(&trace->reflock);
+ rcu_read_unlock();
+}
+
+int ctf_trace_close(struct ctf_trace *trace)
+{
+ struct relay_stream *stream;
rcu_read_lock();
- cds_lfht_for_each_entry_duplicate(ht->ht,
- ht->hash_fct((void *) stream->path_name, lttng_ht_seed),
- ht->match_fct, (void *) stream->path_name,
- &iter.iter, tmp_stream, ctf_trace_node.node) {
- if (stream->metadata_flag) {
- /*
- * The new stream is the metadata stream for this trace,
- * assign the ctf_trace pointer to all the streams in
- * this bucket.
- */
- pthread_mutex_lock(&tmp_stream->lock);
- tmp_stream->ctf_trace = stream->ctf_trace;
- uatomic_inc(&tmp_stream->ctf_trace->refcount);
- pthread_mutex_unlock(&tmp_stream->lock);
- DBG("Assigned ctf_trace %" PRIu64 " to stream %" PRIu64,
- tmp_stream->ctf_trace->id, tmp_stream->stream_handle);
- } else if (tmp_stream->ctf_trace) {
- /*
- * The ctf_trace already exists for this bucket,
- * just assign the pointer to the new stream and exit.
- */
- stream->ctf_trace = tmp_stream->ctf_trace;
- uatomic_inc(&stream->ctf_trace->refcount);
- DBG("Assigned ctf_trace %" PRIu64 " to stream %" PRIu64,
- tmp_stream->ctf_trace->id, tmp_stream->stream_handle);
- goto end;
- } else {
- /*
- * We don't know yet the ctf_trace ID (no metadata has been added),
- * so leave it there until the metadata stream arrives.
- */
- goto end;
- }
+ cds_list_for_each_entry_rcu(stream, &trace->stream_list,
+ stream_node) {
+ /*
+ * Close stream since the connection owning the trace is being
+ * torn down.
+ */
+ try_stream_close(stream);
}
+ rcu_read_unlock();
+ /*
+ * Since all references to the trace are held by its streams, we
+ * don't need to do any self-ref put.
+ */
+ return 0;
+}
+struct relay_viewer_stream *ctf_trace_get_viewer_metadata_stream(struct ctf_trace *trace)
+{
+ struct relay_viewer_stream *vstream;
+
+ rcu_read_lock();
+ vstream = rcu_dereference(trace->viewer_metadata_stream);
+ if (!vstream) {
+ goto end;
+ }
+ if (!viewer_stream_get(vstream)) {
+ vstream = NULL;
+ }
end:
rcu_read_unlock();
- return;
+ return vstream;
}
-
projects / lttng-tools.git / blobdiff