Fix: lttng-consumerd: cpu hotplug: send "streams_sent" command

When creating a new channel, the streams being sent to the relayd are
kept invisible to the live client until the "streams_sent" command is
received. This ensures the client does not see a partial stream set.

This "streams_sent" command needs to be sent on CPU hotplug too,
otherwise the live client handling within relayd is not aware of those
streams (they are never published).

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

diff --git a/src/common/consumer/consumer.h b/src/common/consumer/consumer.h
index 6a38e50e55a0a5a9b8c3d6eea784a718379b594d..7375373c76113ab791a5e06027e8f0599a1494f6 100644 (file)
--- a/src/common/consumer/consumer.h
+++ b/src/common/consumer/consumer.h
@@ -224,6 +224,8 @@ struct lttng_consumer_channel {
        uint64_t discarded_events;
        /* Total number of missed packets due to overwriting (overwrite). */
        uint64_t lost_packets;
+
+       bool streams_sent_to_relayd;
 };
 
 /*

diff --git a/src/common/kernel-consumer/kernel-consumer.c b/src/common/kernel-consumer/kernel-consumer.c
index 3554b8f05ec98fe5ddfeb0c7969552f778efdf69..c7c1413104b4a0dec3b34e63fc8e1efbf6b8242e 100644 (file)
--- a/src/common/kernel-consumer/kernel-consumer.c
+++ b/src/common/kernel-consumer/kernel-consumer.c
@@ -196,6 +196,7 @@ int lttng_kconsumer_snapshot_channel(uint64_t key, char *path,
                                ERR("sending streams sent to relayd");
                                goto end_unlock;
                        }
+                       channel->streams_sent_to_relayd = true;
                }
 
                ret = kernctl_buffer_flush(stream->wait_fd);
@@ -741,6 +742,19 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                                consumer_stream_free(new_stream);
                                goto end_nosignal;
                        }
+
+                       /*
+                        * If adding an extra stream to an already
+                        * existing channel (e.g. cpu hotplug), we need
+                        * to send the "streams_sent" command to relayd.
+                        */
+                       if (channel->streams_sent_to_relayd) {
+                               ret = consumer_send_relayd_streams_sent(
+                                               new_stream->net_seq_idx);
+                               if (ret < 0) {
+                                       goto end_nosignal;
+                               }
+                       }
                }
 
                /* Get the right pipe where the stream will be sent. */
@@ -834,6 +848,7 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                        if (ret < 0) {
                                goto end_nosignal;
                        }
+                       channel->streams_sent_to_relayd = true;
                }
                break;
        }