diff --git a/Documentation/ABI/testing/sysfs-block-zram b/Documentation/ABI/testing/sysfs-block-zram
index c1513c7..04c9a59 100644
--- a/Documentation/ABI/testing/sysfs-block-zram
+++ b/Documentation/ABI/testing/sysfs-block-zram
@@ -98,3 +98,11 @@
 		The backing_dev file is read-write and set up backing
 		device for zram to write incompressible pages.
 		For using, user should enable CONFIG_ZRAM_WRITEBACK.
+
+What:		/sys/block/zram<id>/idle
+Date:		November 2018
+Contact:	Minchan Kim <minchan@kernel.org>
+Description:
+		idle file is write-only and mark zram slot as idle.
+		If system has mounted debugfs, user can see which slots
+		are idle via /sys/kernel/debug/zram/zram<id>/block_state