rcu_read_unlock();
}
- call_rcu(&channel->node.head, free_channel_rcu);
+ channel->is_deleted = true;
+ call_rcu(&channel->node.head, free_channel_rcu);
end:
pthread_mutex_unlock(&channel->lock);
pthread_mutex_unlock(&consumer_data.lock);
unsigned long channel_hash;
pthread_mutex_lock(&channel->lock);
+ if (channel->is_deleted) {
+ /*
+ * The channel has been logically deleted and should no longer
+ * be used. It has released its reference to its current trace
+ * chunk and should not acquire a new one.
+ *
+ * Return success as there is nothing for the caller to do.
+ */
+ goto end;
+ }
/*
* A stream can transition to a state where it and its channel
* no longer belong to a trace chunk. For instance, this happens when
/* RCU lock for the relayd pointer */
rcu_read_lock();
-
assert(stream->net_seq_idx != (uint64_t) -1ULL ||
- stream->chan->trace_chunk);
+ stream->trace_chunk);
/* Flag that the current stream if set for network streaming. */
if (stream->net_seq_idx != (uint64_t) -1ULL) {
void consumer_del_metadata_stream(struct lttng_consumer_stream *stream,
struct lttng_ht *ht)
{
- struct lttng_consumer_channel *free_chan = NULL;
+ struct lttng_consumer_channel *channel = NULL;
+ bool free_channel = false;
assert(stream);
/*
DBG3("Consumer delete metadata stream %d", stream->wait_fd);
pthread_mutex_lock(&consumer_data.lock);
- pthread_mutex_lock(&stream->chan->lock);
+ /*
+ * Note that this assumes that a stream's channel is never changed and
+ * that the stream's lock doesn't need to be taken to sample its
+ * channel.
+ */
+ channel = stream->chan;
+ pthread_mutex_lock(&channel->lock);
pthread_mutex_lock(&stream->lock);
- if (stream->chan->metadata_cache) {
+ if (channel->metadata_cache) {
/* Only applicable to userspace consumers. */
- pthread_mutex_lock(&stream->chan->metadata_cache->lock);
+ pthread_mutex_lock(&channel->metadata_cache->lock);
}
/* Remove any reference to that stream. */
consumer_stream_destroy_buffers(stream);
/* Atomically decrement channel refcount since other threads can use it. */
- if (!uatomic_sub_return(&stream->chan->refcount, 1)
- && !uatomic_read(&stream->chan->nb_init_stream_left)) {
+ if (!uatomic_sub_return(&channel->refcount, 1)
+ && !uatomic_read(&channel->nb_init_stream_left)) {
/* Go for channel deletion! */
- free_chan = stream->chan;
+ free_channel = true;
}
+ stream->chan = NULL;
/*
* Nullify the stream reference so it is not used after deletion. The
* channel lock MUST be acquired before being able to check for a NULL
* pointer value.
*/
- stream->chan->metadata_stream = NULL;
+ channel->metadata_stream = NULL;
- if (stream->chan->metadata_cache) {
- pthread_mutex_unlock(&stream->chan->metadata_cache->lock);
+ if (channel->metadata_cache) {
+ pthread_mutex_unlock(&channel->metadata_cache->lock);
}
pthread_mutex_unlock(&stream->lock);
- pthread_mutex_unlock(&stream->chan->lock);
+ pthread_mutex_unlock(&channel->lock);
pthread_mutex_unlock(&consumer_data.lock);
- if (free_chan) {
- consumer_del_channel(free_chan);
+ if (free_channel) {
+ consumer_del_channel(channel);
}
lttng_trace_chunk_put(stream->trace_chunk);
stream->rotate_ready = true;
}
+ /*
+ * Active flush; has no effect if the production position
+ * is at a packet boundary.
+ */
ret = consumer_flush_buffer(stream, 1);
if (ret < 0) {
ERR("Failed to flush stream %" PRIu64 " during channel rotation",
}
if (!is_local_trace) {
+ /*
+ * The relay daemon control protocol expects a rotation
+ * position as "the sequence number of the first packet
+ * _after_ the current trace chunk.
+ *
+ * At the moment when the positions of the buffers are
+ * sampled, the production position does not necessarily
+ * sit at a packet boundary. The 'active' flush
+ * operation above will push the production position to
+ * the next packet boundary _if_ it is not already
+ * sitting at such a boundary.
+ *
+ * Assuming a current production position that is not
+ * on the bound of a packet, the 'target' sequence
+ * number is
+ * (consumed_pos / subbuffer_size) + 1
+ * Note the '+ 1' to ensure the current packet is
+ * part of the current trace chunk.
+ *
+ * However, if the production position is already at
+ * a packet boundary, the '+ 1' is not necessary as the
+ * last packet of the current chunk is already
+ * 'complete'.
+ */
const struct relayd_stream_rotation_position position = {
.stream_id = stream->relayd_stream_id,
- .rotate_at_seq_num = (stream->rotate_position /
- stream->max_sb_size) + 1,
+ .rotate_at_seq_num = (stream->rotate_position / stream->max_sb_size) +
+ !!(stream->rotate_position % stream->max_sb_size),
};
ret = lttng_dynamic_array_add_element(