diff --git a/lib/librte_eal/common/include/rte_memory.h b/lib/librte_eal/common/include/rte_memory.h
index 857773ca44..aab9f6fe59 100644
--- a/lib/librte_eal/common/include/rte_memory.h
+++ b/lib/librte_eal/common/include/rte_memory.h
@@ -339,6 +339,10 @@ typedef void (*rte_mem_event_callback_t)(enum rte_mem_event event_type,
  *       therefore some functions (e.g. `rte_memseg_walk()`) will cause a
  *       deadlock when called from within such callbacks.
  *
+ * @note mem event callbacks not being supported is an expected error condition,
+ *       so user code needs to handle this situation. In these cases, return
+ *       value will be -1, and rte_errno will be set to ENOTSUP.
+ *
  * @param name
  *   Name associated with specified callback to be added to the list.
  *
@@ -399,6 +403,10 @@ typedef int (*rte_mem_alloc_validator_t)(int socket_id,
  *       therefore some functions (e.g. `rte_memseg_walk()`) will cause a
  *       deadlock when called from within such callbacks.
  *
+ * @note validator callbacks not being supported is an expected error condition,
+ *       so user code needs to handle this situation. In these cases, return
+ *       value will be -1, and rte_errno will be set to ENOTSUP.
+ *
  * @param name
  *   Name associated with specified callback to be added to the list.
  *