X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=src%2Fcommon%2Fconsumer%2Fconsumer-stream.cpp;h=f9807cb0173f4bf6f4a7c0e9f838afb4631c16ec;hb=6653fca60fdb6bf4ea4781bfee8304832d6a7e83;hp=fbaf4aef502e69ea3d8937863df6aa68e0ccbdee;hpb=97535efaa975ca52bf02c2d5e76351bfd2e3defa;p=lttng-tools.git

diff --git a/src/common/consumer/consumer-stream.cpp b/src/common/consumer/consumer-stream.cpp
index fbaf4aef5..f9807cb01 100644
--- a/src/common/consumer/consumer-stream.cpp
+++ b/src/common/consumer/consumer-stream.cpp
@@ -13,15 +13,19 @@
 #include <unistd.h>
 
 #include <common/common.h>
+#include <common/consumer/consumer-timer.h>
+#include <common/consumer/consumer-timer.h>
+#include <common/consumer/consumer.h>
+#include <common/consumer/consumer.h>
+#include <common/consumer/metadata-bucket.h>
+#include <common/consumer/metadata-bucket.h>
 #include <common/index/index.h>
 #include <common/kernel-consumer/kernel-consumer.h>
+#include <common/kernel-ctl/kernel-ctl.h>
+#include <common/macros.h>
 #include <common/relayd/relayd.h>
 #include <common/ust-consumer/ust-consumer.h>
 #include <common/utils.h>
-#include <common/consumer/consumer.h>
-#include <common/consumer/consumer-timer.h>
-#include <common/consumer/metadata-bucket.h>
-#include <common/kernel-ctl/kernel-ctl.h>
 
 #include "consumer-stream.h"
 
@@ -51,6 +55,12 @@ static void consumer_stream_data_unlock_all(struct lttng_consumer_stream *stream
 	pthread_mutex_unlock(&stream->chan->lock);
 }
 
+static void consumer_stream_data_assert_locked_all(struct lttng_consumer_stream *stream)
+{
+	ASSERT_LOCKED(stream->lock);
+	ASSERT_LOCKED(stream->chan->lock);
+}
+
 static void consumer_stream_metadata_lock_all(struct lttng_consumer_stream *stream)
 {
 	consumer_stream_data_lock_all(stream);
@@ -63,6 +73,12 @@ static void consumer_stream_metadata_unlock_all(struct lttng_consumer_stream *st
 	consumer_stream_data_unlock_all(stream);
 }
 
+static void consumer_stream_metadata_assert_locked_all(struct lttng_consumer_stream *stream)
+{
+	ASSERT_LOCKED(stream->metadata_rdv_lock);
+	consumer_stream_data_assert_locked_all(stream);
+}
+
 /* Only used for data streams. */
 static int consumer_stream_update_stats(struct lttng_consumer_stream *stream,
 		const struct stream_subbuffer *subbuf)
@@ -403,6 +419,7 @@ static int consumer_stream_sync_metadata_index(
 		const struct stream_subbuffer *subbuffer,
 		struct lttng_consumer_local_data *ctx)
 {
+	bool missed_metadata_flush;
 	int ret;
 
 	/* Block until all the metadata is sent. */
@@ -415,18 +432,34 @@ static int consumer_stream_sync_metadata_index(
 
 	pthread_mutex_lock(&stream->metadata_timer_lock);
 	stream->waiting_on_metadata = false;
-	if (stream->missed_metadata_flush) {
+	missed_metadata_flush = stream->missed_metadata_flush;
+	if (missed_metadata_flush) {
 		stream->missed_metadata_flush = false;
-		pthread_mutex_unlock(&stream->metadata_timer_lock);
-		(void) stream->read_subbuffer_ops.send_live_beacon(stream);
-	} else {
-		pthread_mutex_unlock(&stream->metadata_timer_lock);
 	}
+	pthread_mutex_unlock(&stream->metadata_timer_lock);
 	if (ret < 0) {
 		goto end;
 	}
 
 	ret = consumer_stream_send_index(stream, subbuffer, ctx);
+	/*
+	 * Send the live inactivity beacon to handle the situation where
+	 * the live timer is prevented from sampling this stream
+	 * because the stream lock was being held while this stream is
+	 * waiting on metadata. This ensures live viewer progress in the
+	 * unlikely scenario where a live timer would be prevented from
+	 * locking a stream lock repeatedly due to a steady flow of
+	 * incoming metadata, for a stream which is mostly inactive.
+	 *
+	 * It is important to send the inactivity beacon packet to
+	 * relayd _after_ sending the index associated with the data
+	 * that was just sent, otherwise this can cause live viewers to
+	 * observe timestamps going backwards between an inactivity
+	 * beacon and a following trace packet.
+	 */
+	if (missed_metadata_flush) {
+		(void) stream->read_subbuffer_ops.send_live_beacon(stream);
+	}
 end:
 	return ret;
 }
@@ -711,6 +744,8 @@ struct lttng_consumer_stream *consumer_stream_create(
 				consumer_stream_metadata_lock_all;
 		stream->read_subbuffer_ops.unlock =
 				consumer_stream_metadata_unlock_all;
+		stream->read_subbuffer_ops.assert_locked =
+				consumer_stream_metadata_assert_locked_all;
 		stream->read_subbuffer_ops.pre_consume_subbuffer =
 				metadata_stream_check_version;
 	} else {
@@ -739,6 +774,8 @@ struct lttng_consumer_stream *consumer_stream_create(
 		stream->read_subbuffer_ops.lock = consumer_stream_data_lock_all;
 		stream->read_subbuffer_ops.unlock =
 				consumer_stream_data_unlock_all;
+		stream->read_subbuffer_ops.assert_locked =
+				consumer_stream_data_assert_locked_all;
 		stream->read_subbuffer_ops.pre_consume_subbuffer =
 				consumer_stream_update_stats;
 	}