[lttng-tools.git] / src / bin / lttng-relayd / viewer-stream.c

/*
 * 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
 * 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.
 */

#define _LGPL_SOURCE
#include <common/common.h>
#include <common/index/index.h>
#include <common/compat/string.h>

#include "lttng-relayd.h"
#include "viewer-stream.h"

static void viewer_stream_destroy(struct relay_viewer_stream *vstream)
{
	free(vstream->path_name);
	free(vstream->channel_name);
	free(vstream);
}

static void viewer_stream_destroy_rcu(struct rcu_head *head)
{
	struct relay_viewer_stream *vstream =
		caa_container_of(head, struct relay_viewer_stream, rcu_node);

	viewer_stream_destroy(vstream);
}

struct relay_viewer_stream *viewer_stream_create(struct relay_stream *stream,
		enum lttng_viewer_seek seek_t)
{
	struct relay_viewer_stream *vstream;

	vstream = zmalloc(sizeof(*vstream));
	if (!vstream) {
		PERROR("relay viewer stream zmalloc");
		goto error;
	}

	vstream->path_name = lttng_strndup(stream->path_name, LTTNG_VIEWER_PATH_MAX);
	if (vstream->path_name == NULL) {
		PERROR("relay viewer path_name alloc");
		goto error;
	}
	vstream->channel_name = lttng_strndup(stream->channel_name,
			LTTNG_VIEWER_NAME_MAX);
	if (vstream->channel_name == NULL) {
		PERROR("relay viewer channel_name alloc");
		goto error;
	}

	if (!stream_get(stream)) {
		ERR("Cannot get stream");
		goto error;
	}
	vstream->stream = stream;

	pthread_mutex_lock(&stream->lock);

	if (stream->is_metadata && stream->trace->viewer_metadata_stream) {
		ERR("Cannot attach viewer metadata stream to trace (busy).");
		goto error_unlock;
	}

	switch (seek_t) {
	case LTTNG_VIEWER_SEEK_BEGINNING:
	{
		uint64_t seq_tail = tracefile_array_get_seq_tail(stream->tfa);

		if (seq_tail == -1ULL) {
			/*
			 * Tail may not be initialized yet. Nonetheless, we know
			 * we want to send the first index once it becomes
			 * available.
			 */
			seq_tail = 0;
		}
		vstream->current_tracefile_id =
			tracefile_array_get_file_index_tail(stream->tfa);
		vstream->index_sent_seqcount = seq_tail;
		break;
	}
	case LTTNG_VIEWER_SEEK_LAST:
		vstream->current_tracefile_id =
			tracefile_array_get_file_index_head(stream->tfa);
		/*
		 * We seek at the very end of each stream, awaiting for
		 * a future packet to eventually come in.
		 *
		 * We don't need to check the head position for -1ULL since the
		 * increment will set it to 0.
		 */
		vstream->index_sent_seqcount =
				tracefile_array_get_seq_head(stream->tfa) + 1;
		break;
	default:
		goto error_unlock;
	}

	/*
	 * If we never received an index for the current stream, delay
	 * the opening of the index, otherwise open it right now.
	 */
	if (stream->index_received_seqcount == 0) {
		vstream->index_file = NULL;
	} else {
		vstream->index_file = lttng_index_file_open(vstream->path_name,
				vstream->channel_name,
				stream->tracefile_count,
				vstream->current_tracefile_id);
		if (!vstream->index_file) {
			goto error_unlock;
		}
	}

	if (seek_t == LTTNG_VIEWER_SEEK_LAST && vstream->index_file) {
		off_t lseek_ret;

		lseek_ret = lseek(vstream->index_file->fd, 0, SEEK_END);
		if (lseek_ret < 0) {
			goto error_unlock;
		}
	}
	if (stream->is_metadata) {
		rcu_assign_pointer(stream->trace->viewer_metadata_stream,
				vstream);
	}
	pthread_mutex_unlock(&stream->lock);

	/* Globally visible after the add unique. */
	lttng_ht_node_init_u64(&vstream->stream_n, stream->stream_handle);
	lttng_ht_add_unique_u64(viewer_streams_ht, &vstream->stream_n);

	pthread_mutex_init(&vstream->reflock, NULL);
	urcu_ref_init(&vstream->ref);

	return vstream;

error_unlock:
	pthread_mutex_unlock(&stream->lock);
error:
	if (vstream) {
		viewer_stream_destroy(vstream);
	}
	return NULL;
}

static void viewer_stream_unpublish(struct relay_viewer_stream *vstream)
{
	int ret;
	struct lttng_ht_iter iter;

	iter.iter.node = &vstream->stream_n.node;
	ret = lttng_ht_del(viewer_streams_ht, &iter);
	assert(!ret);
}

static void viewer_stream_release(struct urcu_ref *ref)
{
	struct relay_viewer_stream *vstream = caa_container_of(ref,
			struct relay_viewer_stream, ref);

	if (vstream->stream->is_metadata) {
		rcu_assign_pointer(vstream->stream->trace->viewer_metadata_stream, NULL);
	}

	viewer_stream_unpublish(vstream);

	if (vstream->stream_fd) {
		stream_fd_put(vstream->stream_fd);
		vstream->stream_fd = NULL;
	}
	if (vstream->index_file) {
		lttng_index_file_put(vstream->index_file);
		vstream->index_file = NULL;
	}
	if (vstream->stream) {
		stream_put(vstream->stream);
		vstream->stream = NULL;
	}
	call_rcu(&vstream->rcu_node, viewer_stream_destroy_rcu);
}

/* Must be called with RCU read-side lock held. */
bool viewer_stream_get(struct relay_viewer_stream *vstream)
{
	bool has_ref = false;

	pthread_mutex_lock(&vstream->reflock);
	if (vstream->ref.refcount != 0) {
		has_ref = true;
		urcu_ref_get(&vstream->ref);
	}
	pthread_mutex_unlock(&vstream->reflock);

	return has_ref;
}

/*
 * Get viewer stream by id.
 *
 * Return viewer stream if found else NULL.
 */
struct relay_viewer_stream *viewer_stream_get_by_id(uint64_t id)
{
	struct lttng_ht_node_u64 *node;
	struct lttng_ht_iter iter;
	struct relay_viewer_stream *vstream = NULL;

	rcu_read_lock();
	lttng_ht_lookup(viewer_streams_ht, &id, &iter);
	node = lttng_ht_iter_get_node_u64(&iter);
	if (!node) {
		DBG("Relay viewer stream %" PRIu64 " not found", id);
		goto end;
	}
	vstream = caa_container_of(node, struct relay_viewer_stream, stream_n);
	if (!viewer_stream_get(vstream)) {
		vstream = NULL;
	}
end:
	rcu_read_unlock();
	return vstream;
}

void viewer_stream_put(struct relay_viewer_stream *vstream)
{
	rcu_read_lock();
	pthread_mutex_lock(&vstream->reflock);
	urcu_ref_put(&vstream->ref, viewer_stream_release);
	pthread_mutex_unlock(&vstream->reflock);
	rcu_read_unlock();
}

/*
 * Rotate a stream to the next tracefile.
 *
 * Must be called with the rstream lock held.
 * Returns 0 on success, 1 on EOF, a negative value on error.
 */
int viewer_stream_rotate(struct relay_viewer_stream *vstream)
{
	int ret;
	struct relay_stream *stream = vstream->stream;
	uint64_t new_id;

	/* Detect the last tracefile to open. */
	if (stream->index_received_seqcount
			== vstream->index_sent_seqcount
			&& stream->trace->session->connection_closed) {
		ret = 1;
		goto end;
	}

	if (stream->tracefile_count == 0) {
		/* Ignore rotation, there is none to do. */
		ret = 0;
		goto end;
	}

	/*
	 * Try to move to the next file.
	 */
	new_id = (vstream->current_tracefile_id + 1)
			% stream->tracefile_count;
	if (tracefile_array_seq_in_file(stream->tfa, new_id,
			vstream->index_sent_seqcount)) {
		vstream->current_tracefile_id = new_id;
	} else {
		uint64_t seq_tail = tracefile_array_get_seq_tail(stream->tfa);

		/*
		 * This can only be reached on overwrite, which implies there
		 * has been data written at some point, which will have set the
		 * tail.
		 */
		assert(seq_tail != -1ULL);
		/*
		 * We need to resync because we lag behind tail.
		 */
		vstream->current_tracefile_id =
			tracefile_array_get_file_index_tail(stream->tfa);
		vstream->index_sent_seqcount = seq_tail;
	}

	if (vstream->index_file) {
		lttng_index_file_put(vstream->index_file);
		vstream->index_file = NULL;
	}
	if (vstream->stream_fd) {
		stream_fd_put(vstream->stream_fd);
		vstream->stream_fd = NULL;
	}

	vstream->index_file = lttng_index_file_open(vstream->path_name,
			vstream->channel_name,
			stream->tracefile_count,
			vstream->current_tracefile_id);
	if (!vstream->index_file) {
		ret = -1;
		goto end;
	} else {
		ret = 0;
	}
end:
	return ret;
}

void print_viewer_streams(void)
{
	struct lttng_ht_iter iter;
	struct relay_viewer_stream *vstream;

	if (!viewer_streams_ht) {
		return;
	}

	rcu_read_lock();
	cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, vstream,
			stream_n.node) {
		if (!viewer_stream_get(vstream)) {
			continue;
		}
		DBG("vstream %p refcount %ld stream %" PRIu64 " trace %" PRIu64
			" session %" PRIu64,
			vstream,
			vstream->ref.refcount,
			vstream->stream->stream_handle,
			vstream->stream->trace->id,
			vstream->stream->trace->session->id);
		viewer_stream_put(vstream);
	}
	rcu_read_unlock();
}
Commit	Line	Data
2f8f53af DG	1	/*
	2	* Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
	3	* David Goulet <dgoulet@efficios.com>
7591bab1	4	* 2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
2f8f53af DG	5	*
	6	* This program is free software; you can redistribute it and/or modify it
	7	* under the terms of the GNU General Public License, version 2 only, as
	8	* published by the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it will be useful, but WITHOUT
	11	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	12	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	13	* more details.
	14	*
	15	* You should have received a copy of the GNU General Public License along with
	16	* this program; if not, write to the Free Software Foundation, Inc., 51
	17	* Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
	18	*/
	19
6c1c0768	20	#define _LGPL_SOURCE
2f8f53af DG	21	#include <common/common.h>
2f8f53af DG	22	#include <common/index/index.h>
f5436bfc	23	#include <common/compat/string.h>
2f8f53af DG	24
	25	#include "lttng-relayd.h"
	26	#include "viewer-stream.h"
	27
7591bab1	28	static void viewer_stream_destroy(struct relay_viewer_stream *vstream)
2f8f53af	29	{
7591bab1 MD	30	free(vstream->path_name);
	31	free(vstream->channel_name);
	32	free(vstream);
2f8f53af DG	33	}
2f8f53af DG	34
7591bab1	35	static void viewer_stream_destroy_rcu(struct rcu_head *head)
2f8f53af	36	{
7591bab1	37	struct relay_viewer_stream *vstream =
2f8f53af DG	38	caa_container_of(head, struct relay_viewer_stream, rcu_node);
2f8f53af DG	39
7591bab1	40	viewer_stream_destroy(vstream);
2f8f53af DG	41	}
	42
	43	struct relay_viewer_stream viewer_stream_create(struct relay_stream stream,
7591bab1	44	enum lttng_viewer_seek seek_t)
2f8f53af DG	45	{
	46	struct relay_viewer_stream *vstream;
	47
2f8f53af DG	48	vstream = zmalloc(sizeof(*vstream));
	49	if (!vstream) {
	50	PERROR("relay viewer stream zmalloc");
	51	goto error;
	52	}
	53
f5436bfc	54	vstream->path_name = lttng_strndup(stream->path_name, LTTNG_VIEWER_PATH_MAX);
b272577e MD	55	if (vstream->path_name == NULL) {
	56	PERROR("relay viewer path_name alloc");
	57	goto error;
	58	}
f5436bfc	59	vstream->channel_name = lttng_strndup(stream->channel_name,
2f8f53af	60	LTTNG_VIEWER_NAME_MAX);
b272577e MD	61	if (vstream->channel_name == NULL) {
	62	PERROR("relay viewer channel_name alloc");
	63	goto error;
	64	}
2f8f53af	65
a44ca2ca MD	66	if (!stream_get(stream)) {
	67	ERR("Cannot get stream");
	68	goto error;
	69	}
	70	vstream->stream = stream;
	71
	72	pthread_mutex_lock(&stream->lock);
	73
	74	if (stream->is_metadata && stream->trace->viewer_metadata_stream) {
	75	ERR("Cannot attach viewer metadata stream to trace (busy).");
	76	goto error_unlock;
	77	}
	78
2f8f53af	79	switch (seek_t) {
c4e361a4	80	case LTTNG_VIEWER_SEEK_BEGINNING:
a44ca2ca MD	81	{
	82	uint64_t seq_tail = tracefile_array_get_seq_tail(stream->tfa);
	83
	84	if (seq_tail == -1ULL) {
	85	/*
	86	* Tail may not be initialized yet. Nonetheless, we know
	87	* we want to send the first index once it becomes
	88	* available.
	89	*/
	90	seq_tail = 0;
	91	}
	92	vstream->current_tracefile_id =
	93	tracefile_array_get_file_index_tail(stream->tfa);
	94	vstream->index_sent_seqcount = seq_tail;
2f8f53af	95	break;
a44ca2ca	96	}
c4e361a4	97	case LTTNG_VIEWER_SEEK_LAST:
a44ca2ca MD	98	vstream->current_tracefile_id =
	99	tracefile_array_get_file_index_head(stream->tfa);
	100	/*
	101	* We seek at the very end of each stream, awaiting for
	102	* a future packet to eventually come in.
	103	*
	104	* We don't need to check the head position for -1ULL since the
	105	* increment will set it to 0.
	106	*/
	107	vstream->index_sent_seqcount =
	108	tracefile_array_get_seq_head(stream->tfa) + 1;
2f8f53af DG	109	break;
2f8f53af DG	110	default:
a44ca2ca	111	goto error_unlock;
2f8f53af	112	}
2f8f53af	113
2f8f53af	114	/*
a44ca2ca MD	115	* If we never received an index for the current stream, delay
a44ca2ca MD	116	* the opening of the index, otherwise open it right now.
2f8f53af	117	*/
a44ca2ca	118	if (stream->index_received_seqcount == 0) {
f8f3885c	119	vstream->index_file = NULL;
2f8f53af	120	} else {
f8f3885c MD	121	vstream->index_file = lttng_index_file_open(vstream->path_name,
f8f3885c MD	122	vstream->channel_name,
7591bab1 MD	123	stream->tracefile_count,
7591bab1 MD	124	vstream->current_tracefile_id);
f8f3885c	125	if (!vstream->index_file) {
7591bab1	126	goto error_unlock;
2f8f53af	127	}
2f8f53af DG	128	}
2f8f53af DG	129
f8f3885c	130	if (seek_t == LTTNG_VIEWER_SEEK_LAST && vstream->index_file) {
2f8f53af DG	131	off_t lseek_ret;
2f8f53af DG	132
f8f3885c	133	lseek_ret = lseek(vstream->index_file->fd, 0, SEEK_END);
2f8f53af	134	if (lseek_ret < 0) {
7591bab1	135	goto error_unlock;
2f8f53af	136	}
7591bab1	137	}
7591bab1 MD	138	if (stream->is_metadata) {
	139	rcu_assign_pointer(stream->trace->viewer_metadata_stream,
	140	vstream);
2f8f53af	141	}
a44ca2ca	142	pthread_mutex_unlock(&stream->lock);
2f8f53af	143
7591bab1 MD	144	/* Globally visible after the add unique. */
	145	lttng_ht_node_init_u64(&vstream->stream_n, stream->stream_handle);
	146	lttng_ht_add_unique_u64(viewer_streams_ht, &vstream->stream_n);
	147
	148	pthread_mutex_init(&vstream->reflock, NULL);
	149	urcu_ref_init(&vstream->ref);
	150
2f8f53af DG	151	return vstream;
2f8f53af DG	152
7591bab1 MD	153	error_unlock:
7591bab1 MD	154	pthread_mutex_unlock(&stream->lock);
2f8f53af DG	155	error:
2f8f53af DG	156	if (vstream) {
7591bab1	157	viewer_stream_destroy(vstream);
2f8f53af DG	158	}
	159	return NULL;
	160	}
	161
7591bab1	162	static void viewer_stream_unpublish(struct relay_viewer_stream *vstream)
2f8f53af DG	163	{
	164	int ret;
	165	struct lttng_ht_iter iter;
	166
7591bab1	167	iter.iter.node = &vstream->stream_n.node;
2f8f53af DG	168	ret = lttng_ht_del(viewer_streams_ht, &iter);
	169	assert(!ret);
	170	}
	171
7591bab1	172	static void viewer_stream_release(struct urcu_ref *ref)
2f8f53af	173	{
7591bab1 MD	174	struct relay_viewer_stream *vstream = caa_container_of(ref,
7591bab1 MD	175	struct relay_viewer_stream, ref);
2a174661	176
7591bab1 MD	177	if (vstream->stream->is_metadata) {
7591bab1 MD	178	rcu_assign_pointer(vstream->stream->trace->viewer_metadata_stream, NULL);
2a174661	179	}
2f8f53af	180
7591bab1 MD	181	viewer_stream_unpublish(vstream);
	182
	183	if (vstream->stream_fd) {
	184	stream_fd_put(vstream->stream_fd);
	185	vstream->stream_fd = NULL;
2f8f53af	186	}
f8f3885c MD	187	if (vstream->index_file) {
	188	lttng_index_file_put(vstream->index_file);
	189	vstream->index_file = NULL;
7591bab1 MD	190	}
	191	if (vstream->stream) {
	192	stream_put(vstream->stream);
	193	vstream->stream = NULL;
	194	}
	195	call_rcu(&vstream->rcu_node, viewer_stream_destroy_rcu);
	196	}
	197
	198	/* Must be called with RCU read-side lock held. */
	199	bool viewer_stream_get(struct relay_viewer_stream *vstream)
	200	{
	201	bool has_ref = false;
	202
	203	pthread_mutex_lock(&vstream->reflock);
	204	if (vstream->ref.refcount != 0) {
	205	has_ref = true;
	206	urcu_ref_get(&vstream->ref);
2f8f53af	207	}
7591bab1	208	pthread_mutex_unlock(&vstream->reflock);
2f8f53af	209
7591bab1	210	return has_ref;
2f8f53af DG	211	}
	212
	213	/*
7591bab1	214	* Get viewer stream by id.
2f8f53af	215	*
7591bab1	216	* Return viewer stream if found else NULL.
2f8f53af	217	*/
7591bab1	218	struct relay_viewer_stream *viewer_stream_get_by_id(uint64_t id)
2f8f53af DG	219	{
	220	struct lttng_ht_node_u64 *node;
	221	struct lttng_ht_iter iter;
7591bab1	222	struct relay_viewer_stream *vstream = NULL;
2f8f53af	223
7591bab1	224	rcu_read_lock();
2f8f53af DG	225	lttng_ht_lookup(viewer_streams_ht, &id, &iter);
	226	node = lttng_ht_iter_get_node_u64(&iter);
	227	if (!node) {
	228	DBG("Relay viewer stream %" PRIu64 " not found", id);
	229	goto end;
	230	}
7591bab1 MD	231	vstream = caa_container_of(node, struct relay_viewer_stream, stream_n);
	232	if (!viewer_stream_get(vstream)) {
	233	vstream = NULL;
	234	}
2f8f53af	235	end:
7591bab1 MD	236	rcu_read_unlock();
	237	return vstream;
	238	}
	239
	240	void viewer_stream_put(struct relay_viewer_stream *vstream)
	241	{
	242	rcu_read_lock();
	243	pthread_mutex_lock(&vstream->reflock);
	244	urcu_ref_put(&vstream->ref, viewer_stream_release);
	245	pthread_mutex_unlock(&vstream->reflock);
	246	rcu_read_unlock();
	247	}
	248
2f8f53af DG	249	/*
	250	* Rotate a stream to the next tracefile.
	251	*
7591bab1	252	* Must be called with the rstream lock held.
2f8f53af DG	253	* Returns 0 on success, 1 on EOF, a negative value on error.
2f8f53af DG	254	*/
7591bab1	255	int viewer_stream_rotate(struct relay_viewer_stream *vstream)
2f8f53af DG	256	{
2f8f53af DG	257	int ret;
7591bab1	258	struct relay_stream *stream = vstream->stream;
a44ca2ca	259	uint64_t new_id;
2f8f53af	260
7591bab1	261	/* Detect the last tracefile to open. */
a44ca2ca MD	262	if (stream->index_received_seqcount
a44ca2ca MD	263	== vstream->index_sent_seqcount
7591bab1 MD	264	&& stream->trace->session->connection_closed) {
7591bab1 MD	265	ret = 1;
2a174661 DG	266	goto end;
2a174661 DG	267	}
2f8f53af	268
7591bab1 MD	269	if (stream->tracefile_count == 0) {
	270	/* Ignore rotation, there is none to do. */
	271	ret = 0;
2f8f53af DG	272	goto end;
	273	}
	274
a44ca2ca MD	275	/*
	276	* Try to move to the next file.
	277	*/
	278	new_id = (vstream->current_tracefile_id + 1)
	279	% stream->tracefile_count;
	280	if (tracefile_array_seq_in_file(stream->tfa, new_id,
	281	vstream->index_sent_seqcount)) {
	282	vstream->current_tracefile_id = new_id;
2f8f53af	283	} else {
a44ca2ca MD	284	uint64_t seq_tail = tracefile_array_get_seq_tail(stream->tfa);
	285
	286	/*
	287	* This can only be reached on overwrite, which implies there
	288	* has been data written at some point, which will have set the
	289	* tail.
	290	*/
	291	assert(seq_tail != -1ULL);
	292	/*
	293	* We need to resync because we lag behind tail.
	294	*/
7591bab1	295	vstream->current_tracefile_id =
a44ca2ca MD	296	tracefile_array_get_file_index_tail(stream->tfa);
a44ca2ca MD	297	vstream->index_sent_seqcount = seq_tail;
2f8f53af	298	}
2f8f53af	299
f8f3885c MD	300	if (vstream->index_file) {
	301	lttng_index_file_put(vstream->index_file);
	302	vstream->index_file = NULL;
2f8f53af	303	}
7591bab1 MD	304	if (vstream->stream_fd) {
	305	stream_fd_put(vstream->stream_fd);
	306	vstream->stream_fd = NULL;
2f8f53af	307	}
2f8f53af	308
f8f3885c MD	309	vstream->index_file = lttng_index_file_open(vstream->path_name,
f8f3885c MD	310	vstream->channel_name,
7591bab1 MD	311	stream->tracefile_count,
7591bab1 MD	312	vstream->current_tracefile_id);
f8f3885c MD	313	if (!vstream->index_file) {
f8f3885c MD	314	ret = -1;
7591bab1	315	goto end;
7591bab1	316	} else {
f8f3885c	317	ret = 0;
2f8f53af	318	}
2f8f53af	319	end:
2f8f53af DG	320	return ret;
2f8f53af DG	321	}
7591bab1 MD	322
	323	void print_viewer_streams(void)
	324	{
	325	struct lttng_ht_iter iter;
	326	struct relay_viewer_stream *vstream;
	327
ce3f3ba3 JG	328	if (!viewer_streams_ht) {
	329	return;
	330	}
	331
7591bab1 MD	332	rcu_read_lock();
	333	cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, vstream,
	334	stream_n.node) {
	335	if (!viewer_stream_get(vstream)) {
	336	continue;
	337	}
	338	DBG("vstream %p refcount %ld stream %" PRIu64 " trace %" PRIu64
	339	" session %" PRIu64,
	340	vstream,
	341	vstream->ref.refcount,
	342	vstream->stream->stream_handle,
	343	vstream->stream->trace->id,
	344	vstream->stream->trace->session->id);
	345	viewer_stream_put(vstream);
	346	}
	347	rcu_read_unlock();
	348	}