X-Git-Url: https://git.verplant.org/?a=blobdiff_plain;f=src%2Fdaemon%2Fmeta_data.c;h=29236e2f18563760279d9f3868b2a748e1e1a8a4;hb=a7b0cdea4f6a0f8d29ade21ae058182f720dd432;hp=e1d0ec5b71f17a9a284b1a37745416accece939a;hpb=1fc00932fd49fa535551cc4bba09c4e4be059ab4;p=collectd.git

diff --git a/src/daemon/meta_data.c b/src/daemon/meta_data.c
index e1d0ec5b..29236e2f 100644
--- a/src/daemon/meta_data.c
+++ b/src/daemon/meta_data.c
@@ -214,6 +214,17 @@ static meta_entry_t *md_entry_lookup (meta_data_t *md, /* {{{ */
 } /* }}} meta_entry_t *md_entry_lookup */
 
 /*
+ * Each value_list_t*, as it is going through the system, is handled by exactly
+ * one thread. Plugins which pass a value_list_t* to another thread, e.g. the
+ * rrdtool plugin, must create a copy first. The meta data within a
+ * value_list_t* is not thread safe and doesn't need to be.
+ *
+ * The meta data associated with cache entries are a different story. There, we
+ * need to ensure exclusive locking to prevent leaks and other funky business.
+ * This is ensured by the uc_meta_data_get_*() functions.
+ */
+
+/*
  * Public functions
  */
 meta_data_t *meta_data_create (void) /* {{{ */