return ret;
}
+static
+void metadata_stream_reset_cache_consumed_position(
+ struct lttng_consumer_stream *stream)
+{
+ ASSERT_LOCKED(stream->lock);
+
+ DBG("Reset metadata cache of session %" PRIu64,
+ stream->chan->session_id);
+ stream->ust_metadata_pushed = 0;
+}
+
/*
* Receive the metadata updates from the sessiond. Supports receiving
* overlapping metadata, but is needs to always belong to a contiguous
{
int ret, ret_code = LTTCOMM_CONSUMERD_SUCCESS;
char *metadata_str;
+ enum consumer_metadata_cache_write_status cache_write_status;
DBG("UST consumer push metadata key %" PRIu64 " of len %" PRIu64, key, len);
health_code_update();
pthread_mutex_lock(&channel->metadata_cache->lock);
- ret = consumer_metadata_cache_write(channel, offset, len, version,
- metadata_str);
- if (ret < 0) {
+ cache_write_status = consumer_metadata_cache_write(
+ channel, offset, len, version, metadata_str);
+ pthread_mutex_unlock(&channel->metadata_cache->lock);
+ switch (cache_write_status) {
+ case CONSUMER_METADATA_CACHE_WRITE_STATUS_NO_CHANGE:
+ /*
+ * The write entirely overlapped with existing contents of the
+ * same metadata version (same content); there is nothing to do.
+ */
+ break;
+ case CONSUMER_METADATA_CACHE_WRITE_STATUS_INVALIDATED:
+ /*
+ * The metadata cache was invalidated (previously pushed
+ * content has been overwritten). Reset the stream's consumed
+ * metadata position to ensure the metadata poll thread consumes
+ * the whole cache.
+ */
+ pthread_mutex_lock(&channel->metadata_stream->lock);
+ metadata_stream_reset_cache_consumed_position(
+ channel->metadata_stream);
+ pthread_mutex_unlock(&channel->metadata_stream->lock);
+ /* Fall-through. */
+ case CONSUMER_METADATA_CACHE_WRITE_STATUS_APPENDED_CONTENT:
+ /*
+ * In both cases, the metadata poll thread has new data to
+ * consume.
+ */
+ ret = consumer_metadata_wakeup_pipe(channel);
+ if (ret) {
+ ret_code = LTTCOMM_CONSUMERD_ERROR_METADATA;
+ goto end_free;
+ }
+ break;
+ case CONSUMER_METADATA_CACHE_WRITE_STATUS_ERROR:
/* Unable to handle metadata. Notify session daemon. */
ret_code = LTTCOMM_CONSUMERD_ERROR_METADATA;
/*
* not have been updated which could create an infinite loop below when
* waiting for the metadata cache to be flushed.
*/
- pthread_mutex_unlock(&channel->metadata_cache->lock);
goto end_free;
+ default:
+ abort();
}
- pthread_mutex_unlock(&channel->metadata_cache->lock);
if (!wait) {
goto end_free;
return ustctl_stream_close_wakeup_fd(stream->ustream);
}
-static
-void metadata_stream_reset_cache_consumed_position(
- struct lttng_consumer_stream *stream)
-{
- DBG("Reset metadata cache of session %" PRIu64,
- stream->chan->session_id);
- stream->ust_metadata_pushed = 0;
-}
-
/*
* Write up to one packet from the metadata cache to the channel.
*
- * Returns the number of bytes pushed in the cache, or a negative value
- * on error.
+ * Returns the number of bytes pushed from the cache into the ring buffer, or a
+ * negative value on error.
*/
static
int commit_one_metadata_packet(struct lttng_consumer_stream *stream)
* awaiting on metadata to be pushed out.
*
* The RCU read side lock must be held by the caller.
- *
- * Return 0 if new metadatda is available, EAGAIN if the metadata stream
- * is empty or a negative value on error.
*/
-int lttng_ustconsumer_sync_metadata(struct lttng_consumer_local_data *ctx,
+enum sync_metadata_status lttng_ustconsumer_sync_metadata(
+ struct lttng_consumer_local_data *ctx,
struct lttng_consumer_stream *metadata_stream)
{
int ret;
- int retry = 0;
+ enum sync_metadata_status status;
struct lttng_consumer_channel *metadata_channel;
assert(ctx);
ret = lttng_ustconsumer_request_metadata(ctx, metadata_channel, 0, 0);
pthread_mutex_lock(&metadata_stream->lock);
if (ret < 0) {
+ status = SYNC_METADATA_STATUS_ERROR;
goto end;
}
if (consumer_stream_is_deleted(metadata_stream)) {
DBG("Metadata stream %" PRIu64 " was deleted during the metadata synchronization",
metadata_stream->key);
- ret = 0;
+ status = SYNC_METADATA_STATUS_NO_DATA;
goto end;
}
ret = commit_one_metadata_packet(metadata_stream);
- if (ret <= 0) {
+ if (ret < 0) {
+ status = SYNC_METADATA_STATUS_ERROR;
goto end;
} else if (ret > 0) {
- retry = 1;
+ status = SYNC_METADATA_STATUS_NEW_DATA;
+ } else /* ret == 0 */ {
+ status = SYNC_METADATA_STATUS_NO_DATA;
+ goto end;
}
ret = ustctl_snapshot(metadata_stream->ustream);
if (ret < 0) {
- if (errno != EAGAIN) {
- ERR("Sync metadata, taking UST snapshot");
- goto end;
- }
- DBG("No new metadata when syncing them.");
- /* No new metadata, exit. */
- ret = ENODATA;
+ ERR("Failed to take a snapshot of the metadata ring-buffer positions, ret = %d", ret);
+ status = SYNC_METADATA_STATUS_ERROR;
goto end;
}
- /*
- * After this flush, we still need to extract metadata.
- */
- if (retry) {
- ret = EAGAIN;
- }
-
end:
- return ret;
+ return status;
}
/*
assert(stream);
assert(stream->ustream);
+ ASSERT_LOCKED(stream->lock);
DBG("UST consumer checking data pending");
uint64_t contiguous, pushed;
/* Ease our life a bit. */
+ pthread_mutex_lock(&stream->chan->metadata_cache->lock);
contiguous = stream->chan->metadata_cache->max_offset;
+ pthread_mutex_unlock(&stream->chan->metadata_cache->lock);
pushed = stream->ust_metadata_pushed;
/*
projects / lttng-tools.git / blobdiff