diff --git a/man2/mmap.2 b/man2/mmap.2
index 4637b9845..f7e6f4fdf 100644
--- a/man2/mmap.2
+++ b/man2/mmap.2
@@ -403,6 +403,7 @@ is supported for private mappings only since Linux 2.6.23.
 .BR MAP_STACK " (since Linux 2.6.27)"
 Allocate the mapping at an address suitable for a process
 or thread stack.
+.IP
 This flag is currently a no-op,
 but is used in the glibc threading implementation so that
 if some architectures require special treatment for stack allocations,
@@ -412,6 +413,9 @@ support can later be transparently implemented for glibc.
 .\" http://thread.gmane.org/gmane.linux.kernel/720412
 .\" "pthread_create() slow for many threads; also time to revisit 64b
 .\"  context switch optimization?"
+A further reason to employ this flag is portability:
+.BR MAP_SHARED
+exists (and has an effect) on some other systems (e.g., some of the BSDs).
 .TP
 .BR MAP_SYNC " (since Linux 4.15)"
 This flag is available only with the