diff --git a/sys/conf/NOTES b/sys/conf/NOTES
index d30e1be289b..2191e572bb2 100644
--- a/sys/conf/NOTES
+++ b/sys/conf/NOTES
@@ -178,6 +178,11 @@ options 	ADAPTIVE_MUTEXES
 # and WITNESS options.
 options 	MUTEX_NOINLINE
 
+# MUTEX_WAKE_ALL changes the mutex unlock algorithm to wake all waiters
+# when a contested mutex is released rather than just awaking the highest
+# priority waiter.
+options 	MUTEX_WAKE_ALL
+
 # SMP Debugging Options:
 #
 # MUTEX_DEBUG enables various extra assertions in the mutex code.