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-rw-r--r--Documentation/ABI/testing/sysfs-block-dm22
1 files changed, 22 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-block-dm b/Documentation/ABI/testing/sysfs-block-dm
index 87ca5691e29b..f9f2339b9a0a 100644
--- a/Documentation/ABI/testing/sysfs-block-dm
+++ b/Documentation/ABI/testing/sysfs-block-dm
@@ -23,3 +23,25 @@ Description: Device-mapper device suspend state.
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.