diff --git a/man2/mmap.2 b/man2/mmap.2
index 385f3bfd5..a5a8eb47a 100644
--- a/man2/mmap.2
+++ b/man2/mmap.2
@@ -222,8 +222,10 @@ part of the existing mapping(s) will be discarded.
 If the specified address cannot be used,
 .BR mmap ()
 will fail.
-Because requiring a fixed address for a mapping is less portable,
-the use of this option is discouraged.
+Software that aspires to be portable should use this option with care, keeping
+in mind that the exact layout of a process' memory map is allowed to change
+significantly between kernel versions, C library versions, and operating system
+releases.
 .TP
 .B MAP_GROWSDOWN
 This flag is used for stacks.