doc: update block/queue-sysfs.txt entries
Add descriptions for dax, io_poll, and write_same_max_bytes files.
Signed-off-by: Joe Lawrence <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
diff --git a/Documentation/block/queue-sysfs.txt b/Documentation/block/queue-sysfs.txt
index d515d58..2a39040 100644
--- a/Documentation/block/queue-sysfs.txt
+++ b/Documentation/block/queue-sysfs.txt
@@ -14,6 +14,12 @@
This file allows to turn off the disk entropy contribution. Default
value of this file is '1'(on).
+dax (RO)
+--------
+This file indicates whether the device supports Direct Access (DAX),
+used by CPU-addressable storage to bypass the pagecache. It shows '1'
+if true, '0' if not.
+
discard_granularity (RO)
-----------------------
This shows the size of internal allocation of the device in bytes, if
@@ -46,6 +52,12 @@
-------------------
This is the hardware sector size of the device, in bytes.
+io_poll (RW)
+------------
+When read, this file shows the total number of block IO polls and how
+many returned success. Writing '0' to this file will disable polling
+for this device. Writing any non-zero value will enable this feature.
+
iostats (RW)
-------------
This file is used to control (on/off) the iostats accounting of the
@@ -151,5 +163,11 @@
setting from "write back" to "write through", since that will also
eliminate cache flushes issued by the kernel.
+write_same_max_bytes (RO)
+-------------------------
+This is the number of bytes the device can write in a single write-same
+command. A value of '0' means write-same is not supported by this
+device.
+
Jens Axboe <[email protected]>, February 2009
