- if (stream->chan->output == CONSUMER_CHANNEL_MMAP) {
- stream->read_subbuffer_ops.get_next_subbuffer =
- get_next_subbuffer_mmap;
- } else {
- stream->read_subbuffer_ops.get_next_subbuffer =
- get_next_subbuffer_splice;
+ int ret = 0;
+
+ if (stream->metadata_flag && stream->chan->is_live) {
+ DBG("Attempting to enable metadata bucketization for live consumers");
+ if (is_get_next_check_metadata_available(stream->wait_fd)) {
+ DBG("Kernel tracer supports get_next_subbuffer_metadata_check, metadata will be accumulated until a coherent state is reached");
+ stream->read_subbuffer_ops.get_next_subbuffer =
+ get_next_subbuffer_metadata_check;
+ ret = consumer_stream_enable_metadata_bucketization(
+ stream);
+ if (ret) {
+ goto end;
+ }
+ } else {
+ /*
+ * The kernel tracer version is too old to indicate
+ * when the metadata stream has reached a "coherent"
+ * (parseable) point.
+ *
+ * This means that a live viewer may see an incoherent
+ * sequence of metadata and fail to parse it.
+ */
+ WARN("Kernel tracer does not support get_next_subbuffer_metadata_check which may cause live clients to fail to parse the metadata stream");
+ metadata_bucket_destroy(stream->metadata_bucket);
+ stream->metadata_bucket = NULL;
+ }
+ }
+
+ if (!stream->read_subbuffer_ops.get_next_subbuffer) {
+ if (stream->chan->output == CONSUMER_CHANNEL_MMAP) {
+ stream->read_subbuffer_ops.get_next_subbuffer =
+ get_next_subbuffer_mmap;
+ } else {
+ stream->read_subbuffer_ops.get_next_subbuffer =
+ get_next_subbuffer_splice;
+ }