X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Fconsumer%2Fconsumer-metadata-cache.c;h=5eee4014265f42566776ea34645a0f08504fbde0;hp=48257c299750aa0953016808766c6a634a17c65e;hb=8e1ef46e89a86865736a62d2def88f70acb0be55;hpb=c8fea79c745d42ea8143b7020ae11b4fc2da0d8a

diff --git a/src/common/consumer/consumer-metadata-cache.c b/src/common/consumer/consumer-metadata-cache.c
index 48257c299..5eee40142 100644
--- a/src/common/consumer/consumer-metadata-cache.c
+++ b/src/common/consumer/consumer-metadata-cache.c
@@ -70,6 +70,76 @@ end:
 	return ret;
 }
 
+/*
+ * Reset the metadata cache.
+ */
+static
+void metadata_cache_reset(struct consumer_metadata_cache *cache)
+{
+	memset(cache->data, 0, cache->cache_alloc_size);
+	cache->max_offset = 0;
+}
+
+/*
+ * Check if the metadata cache version changed.
+ * If it did, reset the metadata cache.
+ * The metadata cache lock MUST be held.
+ *
+ * Returns 0 on success, a negative value on error.
+ */
+static
+int metadata_cache_check_version(struct consumer_metadata_cache *cache,
+		uint64_t version)
+{
+	int ret = 0;
+
+	if (cache->version == version) {
+		goto end;
+	}
+
+	DBG("Metadata cache version update to %" PRIu64, version);
+	metadata_cache_reset(cache);
+	cache->version = version;
+
+end:
+	return ret;
+}
+
+/*
+ * Write a character on the metadata poll pipe to wake the metadata thread.
+ * Returns 0 on success, -1 on error.
+ */
+int consumer_metadata_wakeup_pipe(const struct lttng_consumer_channel *channel)
+{
+	int ret = 0;
+	const char dummy = 'c';
+
+	if (channel->monitor && channel->metadata_stream) {
+		ssize_t write_ret;
+
+		write_ret = lttng_write(channel->metadata_stream->ust_metadata_poll_pipe[1],
+				&dummy, 1);
+		if (write_ret < 1) {
+			if (errno == EWOULDBLOCK) {
+				/*
+				 * This is fine, the metadata poll thread
+				 * is having a hard time keeping-up, but
+				 * it will eventually wake-up and consume
+				 * the available data.
+				 */
+				ret = 0;
+                        } else {
+				PERROR("Wake-up UST metadata pipe");
+				ret = -1;
+				goto end;
+                        }
+                }
+	}
+
+end:
+	return ret;
+}
+
 /*
  * Write metadata to the cache, extend the cache if necessary. We support
  * overlapping updates, but they need to be contiguous. Send the
@@ -79,16 +149,22 @@ end:
  * Return 0 on success, a negative value on error.
  */
 int consumer_metadata_cache_write(struct lttng_consumer_channel *channel,
-		unsigned int offset, unsigned int len, char *data)
+		unsigned int offset, unsigned int len, uint64_t version,
+		char *data)
 {
 	int ret = 0;
-	int size_ret;
 	struct consumer_metadata_cache *cache;
 
 	assert(channel);
 	assert(channel->metadata_cache);
 
 	cache = channel->metadata_cache;
+
+	ret = metadata_cache_check_version(cache, version);
+	if (ret < 0) {
+		goto end;
+	}
+
 	DBG("Writing %u bytes from offset %u in metadata cache", len, offset);
 
 	if (offset + len > cache->cache_alloc_size) {
@@ -102,18 +178,8 @@ int consumer_metadata_cache_write(struct lttng_consumer_channel *channel,
 
 	memcpy(cache->data + offset, data, len);
 	if (offset + len > cache->max_offset) {
-		char dummy = 'c';
-
 		cache->max_offset = offset + len;
-		if (channel->monitor) {
-			size_ret = lttng_write(channel->metadata_stream->ust_metadata_poll_pipe[1],
-					&dummy, 1);
-			if (size_ret < 1) {
-				ERR("Wakeup UST metadata pipe");
-				ret = -1;
-				goto end;
-			}
-		}
+		ret = consumer_metadata_wakeup_pipe(channel);
 	}
 
 end:
@@ -207,9 +273,9 @@ int consumer_metadata_cache_flushed(struct lttng_consumer_channel *channel,
 		pthread_mutex_lock(&channel->lock);
 	}
 	pthread_mutex_lock(&channel->timer_lock);
-	pthread_mutex_lock(&channel->metadata_cache->lock);
-
 	metadata_stream = channel->metadata_stream;
+	pthread_mutex_lock(&metadata_stream->lock);
+	pthread_mutex_lock(&channel->metadata_cache->lock);
 
 	if (!metadata_stream) {
 		/*
@@ -229,6 +295,7 @@ int consumer_metadata_cache_flushed(struct lttng_consumer_channel *channel,
 	}
 
 	pthread_mutex_unlock(&channel->metadata_cache->lock);
+	pthread_mutex_unlock(&metadata_stream->lock);
 	pthread_mutex_unlock(&channel->timer_lock);
 	if (!timer) {
 		pthread_mutex_unlock(&channel->lock);