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block: update sysfs documentation

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Add the description of the zoned, nr_zones and chunk_sectors sysfs queue
attributes to Documentation/block/queue-sysfs.txt. The description of
the zoned and chunk_sector attributes are mostly copied from
ABI/testing/sysfs-block (added a typo fix). While at it, also fix a
typo in the description of the io_poll_delay attribute.

nr_zones description is also added to ABI/testing/sysfs-block and
contact email address updated for the zoned attribute.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Damien Le Moal 2018-11-30 14:36:24 +09:00 committed by Jens Axboe
parent 38a3499f6d
commit f9824952ee
2 changed files with 38 additions and 3 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

12
Documentation/ABI/testing/sysfs-block
View file

@ -244,7 +244,7 @@ Description:
What: /sys/block/<disk>/queue/zoned
Date: September 2016
Contact: Damien Le Moal <damien.lemoal@hgst.com>
Contact: Damien Le Moal <damien.lemoal@wdc.com>
Description:
zoned indicates if the device is a zoned block device
and the zone model of the device if it is indeed zoned.
@ -259,6 +259,14 @@ Description:
zone commands, they will be treated as regular block
devices and zoned will report "none".
What: /sys/block/<disk>/queue/nr_zones
Date: November 2018
Contact: Damien Le Moal <damien.lemoal@wdc.com>
Description:
nr_zones indicates the total number of zones of a zoned block
device ("host-aware" or "host-managed" zone model). For regular
block devices, the value is always 0.
What: /sys/block/<disk>/queue/chunk_sectors
Date: September 2016
Contact: Hannes Reinecke <hare@suse.com>
@ -268,6 +276,6 @@ Description:
indicates the size in 512B sectors of the RAID volume
stripe segment. For a zoned block device, either
host-aware or host-managed, chunk_sectors indicates the
size of 512B sectors of the zones of the device, with
size in 512B sectors of the zones of the device, with
the eventual exception of the last zone of the device
which may be smaller.

29
Documentation/block/queue-sysfs.txt
View file

@ -64,7 +64,7 @@ guess, the kernel will put the process issuing IO to sleep for an amount
of time, before entering a classic poll loop. This mode might be a
little slower than pure classic polling, but it will be more efficient.
If set to a value larger than 0, the kernel will put the process issuing
IO to sleep for this amont of microseconds before entering classic
IO to sleep for this amount of microseconds before entering classic
polling.
iostats (RW)
@ -194,4 +194,31 @@ blk-throttle makes decision based on the samplings. Lower time means cgroups
have more smooth throughput, but higher CPU overhead. This exists only when
CONFIG_BLK_DEV_THROTTLING_LOW is enabled.
zoned (RO)
----------
This indicates if the device is a zoned block device and the zone model of the
device if it is indeed zoned. The possible values indicated by zoned are
"none" for regular block devices and "host-aware" or "host-managed" for zoned
block devices. The characteristics of host-aware and host-managed zoned block
devices are described in the ZBC (Zoned Block Commands) and ZAC
(Zoned Device ATA Command Set) standards. These standards also define the
"drive-managed" zone model. However, since drive-managed zoned block devices
do not support zone commands, they will be treated as regular block devices
and zoned will report "none".
nr_zones (RO)
-------------
For zoned block devices (zoned attribute indicating "host-managed" or
"host-aware"), this indicates the total number of zones of the device.
This is always 0 for regular block devices.
chunk_sectors (RO)
------------------
This has different meaning depending on the type of the block device.
For a RAID device (dm-raid), chunk_sectors indicates the size in 512B sectors
of the RAID volume stripe segment. For a zoned block device, either host-aware
or host-managed, chunk_sectors indicates the size in 512B sectors of the zones
of the device, with the eventual exception of the last zone of the device which
may be smaller.
Jens Axboe <jens.axboe@oracle.com>, February 2009