X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=src%2Fcommon%2Fust-consumer%2Fust-consumer.c;h=03bc5fc5e84b2487f85ba417c801ffbd2759c854;hb=8d18bcaede97b6d87e434310da9c13d269983c77;hp=832c44371455de237d8b7e8da77ad2440d0441fe;hpb=6f1177cf8de79015ed38f48749029c81240b0eb6;p=lttng-tools.git

diff --git a/src/common/ust-consumer/ust-consumer.c b/src/common/ust-consumer/ust-consumer.c
index 832c44371..03bc5fc5e 100644
--- a/src/common/ust-consumer/ust-consumer.c
+++ b/src/common/ust-consumer/ust-consumer.c
@@ -47,6 +47,7 @@
 #include <common/utils.h>
 #include <common/index/index.h>
 #include <common/consumer/consumer.h>
+#include <common/optional.h>
 
 #include "ust-consumer.h"
 
@@ -1240,7 +1241,7 @@ static int snapshot_channel(struct lttng_consumer_channel *channel,
 
 			subbuf_view = lttng_buffer_view_init(
 					subbuf_addr, 0, padded_len);
-			read_len = lttng_consumer_on_read_subbuffer_mmap(ctx,
+			read_len = lttng_consumer_on_read_subbuffer_mmap(
 					stream, &subbuf_view, padded_len - len);
 			if (use_relayd) {
 				if (read_len != len) {
@@ -2447,7 +2448,7 @@ int commit_one_metadata_packet(struct lttng_consumer_stream *stream)
 	assert(write_len != 0);
 	if (write_len < 0) {
 		ERR("Writing one metadata packet");
-		ret = -1;
+		ret = write_len;
 		goto end;
 	}
 	stream->ust_metadata_pushed += write_len;
@@ -2793,28 +2794,88 @@ static int get_next_subbuffer_metadata(struct lttng_consumer_stream *stream,
 		struct stream_subbuffer *subbuffer)
 {
 	int ret;
+	bool cache_empty;
+	bool got_subbuffer;
+	bool coherent;
+	bool buffer_empty;
+	unsigned long consumed_pos, produced_pos;
 
-	ret = ustctl_get_next_subbuf(stream->ustream);
-	if (ret) {
-		ret = commit_one_metadata_packet(stream);
-		if (ret < 0) {
-			goto end;
-		} else if (ret == 0) {
-			/* Not an error, the cache is empty. */
-			ret = -ENODATA;
-			goto end;
+	do {
+		ret = ustctl_get_next_subbuf(stream->ustream);
+		if (ret == 0) {
+			got_subbuffer = true;
+		} else {
+			got_subbuffer = false;
+			if (ret != -EAGAIN) {
+				/* Fatal error. */
+				goto end;
+			}
 		}
 
-		ret = ustctl_get_next_subbuf(stream->ustream);
-		if (ret) {
-			goto end;
+		/*
+		 * Determine if the cache is empty and ensure that a sub-buffer
+		 * is made available if the cache is not empty.
+		 */
+		if (!got_subbuffer) {
+			ret = commit_one_metadata_packet(stream);
+			if (ret < 0 && ret != -ENOBUFS) {
+				goto end;
+			} else if (ret == 0) {
+				/* Not an error, the cache is empty. */
+				cache_empty = true;
+				ret = -ENODATA;
+				goto end;
+			} else {
+				cache_empty = false;
+			}
+		} else {
+			pthread_mutex_lock(&stream->chan->metadata_cache->lock);
+			cache_empty = stream->chan->metadata_cache->max_offset ==
+				      stream->ust_metadata_pushed;
+			pthread_mutex_unlock(&stream->chan->metadata_cache->lock);
 		}
-	}
+	} while (!got_subbuffer);
 
+	/* Populate sub-buffer infos and view. */
 	ret = get_next_subbuffer_common(stream, subbuffer);
 	if (ret) {
 		goto end;
 	}
+
+	ret = lttng_ustconsumer_sample_snapshot_positions(stream);
+	if (ret < 0) {
+		/*
+		 * -EAGAIN is not expected since we got a sub-buffer and haven't
+		 * pushed the consumption position yet (on put_next).
+		 */
+		PERROR("Failed to take a snapshot of metadata buffer positions");
+		goto end;
+	}
+
+	ret = lttng_ustconsumer_get_consumed_snapshot(stream, &consumed_pos);
+	if (ret) {
+		PERROR("Failed to get metadata consumed position");
+		goto end;
+	}
+
+	ret = lttng_ustconsumer_get_produced_snapshot(stream, &produced_pos);
+	if (ret) {
+		PERROR("Failed to get metadata produced position");
+		goto end;
+	}
+
+	/* Last sub-buffer of the ring buffer ? */
+	buffer_empty = (consumed_pos + stream->max_sb_size) == produced_pos;
+
+	/*
+	 * The sessiond registry lock ensures that coherent units of metadata
+	 * are pushed to the consumer daemon at once. Hence, if a sub-buffer is
+	 * acquired, the cache is empty, and it is the only available sub-buffer
+	 * available, it is safe to assume that it is "coherent".
+	 */
+	coherent = got_subbuffer && cache_empty && buffer_empty;
+
+	LTTNG_OPTIONAL_SET(&subbuffer->info.metadata.coherent, coherent);
 end:
 	return ret;
 }
@@ -2834,9 +2895,11 @@ static int signal_metadata(struct lttng_consumer_stream *stream,
 	return pthread_cond_broadcast(&stream->metadata_rdv) ? -errno : 0;
 }
 
-static void lttng_ustconsumer_set_stream_ops(
+static int lttng_ustconsumer_set_stream_ops(
 		struct lttng_consumer_stream *stream)
 {
+	int ret = 0;
+
 	stream->read_subbuffer_ops.on_wake_up = consumer_stream_ust_on_wake_up;
 	if (stream->metadata_flag) {
 		stream->read_subbuffer_ops.get_next_subbuffer =
@@ -2845,7 +2908,14 @@ static void lttng_ustconsumer_set_stream_ops(
 				extract_metadata_subbuffer_info;
 		stream->read_subbuffer_ops.reset_metadata =
 				metadata_stream_reset_cache;
-		stream->read_subbuffer_ops.on_sleep = signal_metadata;
+		if (stream->chan->is_live) {
+			stream->read_subbuffer_ops.on_sleep = signal_metadata;
+			ret = consumer_stream_enable_metadata_bucketization(
+					stream);
+			if (ret) {
+				goto end;
+			}
+		}
 	} else {
 		stream->read_subbuffer_ops.get_next_subbuffer =
 				get_next_subbuffer;
@@ -2859,6 +2929,8 @@ static void lttng_ustconsumer_set_stream_ops(
 	}
 
 	stream->read_subbuffer_ops.put_next_subbuffer = put_next_subbuffer;
+end:
+	return ret;
 }
 
 /*