From f9824952ee1cd02ae1a74e35e0e8653f8a4db772 Mon Sep 17 00:00:00 2001 From: Damien Le Moal Date: Fri, 30 Nov 2018 14:36:24 +0900 Subject: block: update sysfs documentation 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 Signed-off-by: Jens Axboe --- Documentation/block/queue-sysfs.txt | 29 ++++++++++++++++++++++++++++- 1 file changed, 28 insertions(+), 1 deletion(-) (limited to 'Documentation/block') diff --git a/Documentation/block/queue-sysfs.txt b/Documentation/block/queue-sysfs.txt index 2c1e67058fd3..39e286d7afc9 100644 --- a/Documentation/block/queue-sysfs.txt +++ b/Documentation/block/queue-sysfs.txt @@ -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 , February 2009 -- cgit v1.2.3-55-g7522