Document call_rcu() usage

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>

diff --git a/urcu-defer.h b/urcu-defer.h
index ac2f53b1728c63c4359ab9cc3cc601a63b57cb53..e32156c010fdeae325c54b28ee17bb1e72d8d3ec 100644 (file)
--- a/urcu-defer.h
+++ b/urcu-defer.h
@@ -38,6 +38,10 @@
  * Each thread queuing memory reclamation must be registered with
  * rcu_defer_register_thread(). rcu_defer_unregister_thread() should be
  * called before the thread exits.
+ *
+ * *NEVER* use call_rcu()/rcu_defer_queue() within a RCU read-side critical
+ * section, because this primitive need to call synchronize_rcu() if the thread
+ * queue is full.
  */
 
 #define call_rcu               rcu_defer_queue