add discard option -d to swapon

Signed-off-by: Matt Whitlock <busybox@mattwhitlock.name>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/util-linux/Config.src b/util-linux/Config.src
index 5a8b0063b..c1cd6daa4 100644
--- a/util-linux/Config.src
+++ b/util-linux/Config.src
@@ -599,6 +599,15 @@ config SWAPONOFF
           space. If you are not using any swap space, you can leave this
           option disabled.
 
+config FEATURE_SWAPON_DISCARD
+        bool "Support discard option -d"
+        default y
+        depends on SWAPONOFF
+        help
+          Enable support for discarding swap area blocks at swapon and/or as
+          the kernel frees them. This option enables both the -d option on
+          'swapon' and the 'discard' option for swap entries in /etc/fstab.
+
 config FEATURE_SWAPON_PRI
         bool "Support priority option -p"
         default y