diff --git a/man5/proc.5 b/man5/proc.5
index 45f061411..6c710c29b 100644
--- a/man5/proc.5
+++ b/man5/proc.5
@@ -4020,6 +4020,12 @@ on a system-wide basis.
 If this file contains the value 0, leases are disabled.
 A nonzero value enables leases.
 .TP
+.IR /proc/sys/fs/mount-max " (since Linux 4.9)"
+.\" commit d29216842a85c7970c536108e093963f02714498
+The value in this file specifies the maximum number of mounts that may exist
+in a mount namespace.
+The default vslue in this file is 100,000.
+.TP
 .IR /proc/sys/fs/mqueue " (since Linux 2.6.6)"
 This directory contains files
 .IR msg_max ", " msgsize_max ", and " queues_max ,