diff --git a/UPDATING b/UPDATING
index 0391baf9b966..28e28cd34ea5 100644
--- a/UPDATING
+++ b/UPDATING
@@ -26,6 +26,12 @@ NOTE TO PEOPLE WHO THINK THAT FreeBSD 13.x IS SLOW:
 	disable the most expensive debugging functionality run
 	"ln -s 'abort:false,junk:false' /etc/malloc.conf".)
 
+20190913:
+	ntpd no longer by default locks its pages in memory, allowing them
+	to be paged out by the kernel. Use rlimit memlock to restore
+	historic BSD behaviour. For example, add "rlimit memlock 32"
+	to ntp.conf to lock up to 32 MB of ntpd address space in memory.
+
 20190823:
 	Several of ping6's options have been renamed for better consistency
 	with ping.  If you use any of -ARWXaghmrtwx, you must update your
diff --git a/usr.sbin/ntp/config.h b/usr.sbin/ntp/config.h
index 56dbfedba6ec..b26dd4178858 100644
--- a/usr.sbin/ntp/config.h
+++ b/usr.sbin/ntp/config.h
@@ -287,7 +287,7 @@
 #define DEFAULT_HZ 100
 
 /* Default number of megabytes for RLIMIT_MEMLOCK */
-#define DFLT_RLIMIT_MEMLOCK 32
+#define DFLT_RLIMIT_MEMLOCK -1
 
 /* Default number of 4k pages for RLIMIT_STACK */
 #define DFLT_RLIMIT_STACK 50
diff --git a/usr.sbin/ntp/ntpd/ntp.conf b/usr.sbin/ntp/ntpd/ntp.conf
index 3a2ff63cd25a..8d154ca36dbc 100644
--- a/usr.sbin/ntp/ntpd/ntp.conf
+++ b/usr.sbin/ntp/ntpd/ntp.conf
@@ -102,3 +102,11 @@ restrict ::1
 # Use either leapfile in /etc/ntp or periodically updated leapfile in /var/db.
 #leapfile "/etc/ntp/leap-seconds"
 leapfile "/var/db/ntpd.leap-seconds.list"
+
+# Specify the number of megabytes of memory that should be allocated and
+# locked. -1 (default) means "do not lock the process into memory".
+# 0 means "lock whatever memory the process wants into memory". Any other
+# number means to lock up to that number of megabytes into memory.
+# 0 may result in a segfault when ASLR with stack gap randomization
+# is enabled.
+#rlimit memlock 32