diff --git a/man2/mlock.2 b/man2/mlock.2
index 3bbf08f41..be6bc799a 100644
--- a/man2/mlock.2
+++ b/man2/mlock.2
@@ -273,6 +273,9 @@ For
 is available since Linux 4.4.
 .SH CONFORMING TO
 POSIX.1-2001, POSIX.1-2008, SVr4.
+
+mlock2 ()
+is Linux specific.
 .SH AVAILABILITY
 On POSIX systems on which
 .BR mlock ()