--- zzzz-none-000/linux-3.10.107/Documentation/ABI/testing/sysfs-block-dm	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/Documentation/ABI/testing/sysfs-block-dm	2021-02-04 17:41:59.000000000 +0000
@@ -23,3 +23,25 @@
 		Contains the value 1 while the device is suspended.
 		Otherwise it contains 0. Read-only attribute.
 Users:		util-linux, device-mapper udev rules
+
+What:		/sys/block/dm-<num>/dm/rq_based_seq_io_merge_deadline
+Date:		March 2015
+KernelVersion:	4.1
+Contact:	dm-devel@redhat.com
+Description:	Allow control over how long a request that is a
+		reasonable merge candidate can be queued on the request
+		queue.  The resolution of this deadline is in
+		microseconds (ranging from 1 to 100000 usecs).
+		Setting this attribute to 0 (the default) will disable
+		request-based DM's merge heuristic and associated extra
+		accounting.  This attribute is not applicable to
+		bio-based DM devices so it will only ever report 0 for
+		them.
+
+What:		/sys/block/dm-<num>/dm/use_blk_mq
+Date:		March 2015
+KernelVersion:	4.1
+Contact:	dm-devel@redhat.com
+Description:	Request-based Device-mapper blk-mq I/O path mode.
+		Contains the value 1 if the device is using blk-mq.
+		Otherwise it contains 0. Read-only attribute.