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| author | Bart Van Assche <bvanassche@acm.org> | 2019-06-28 13:07:45 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2019-06-29 09:38:05 -0600 |
| commit | fbbe7c86b483878da4a2ec7b899e0814195942af (patch) | |
| tree | c40d8d4a78836241d5df973396e3ad952909d22b /Documentation/block | |
| parent | 0c766e78bda6d4edf40779fc0cd48d0867a04d84 (diff) | |
| download | lwn-fbbe7c86b483878da4a2ec7b899e0814195942af.tar.gz lwn-fbbe7c86b483878da4a2ec7b899e0814195942af.zip | |
block, documentation: Document discard_zeroes_data, fua, max_discard_segments and write_zeroes_max_bytes
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'Documentation/block')
| -rw-r--r-- | Documentation/block/queue-sysfs.txt | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/Documentation/block/queue-sysfs.txt b/Documentation/block/queue-sysfs.txt index 1515dcf3dec4..b40b5b7cebd9 100644 --- a/Documentation/block/queue-sysfs.txt +++ b/Documentation/block/queue-sysfs.txt @@ -52,6 +52,16 @@ large discards are issued, setting this value lower will make Linux issue smaller discards and potentially help reduce latencies induced by large discard operations. +discard_zeroes_data (RO) +------------------------ +Obsolete. Always zero. + +fua (RO) +-------- +Whether or not the block driver supports the FUA flag for write requests. +FUA stands for Force Unit Access. If the FUA flag is set that means that +write requests must bypass the volatile cache of the storage device. + hw_sector_size (RO) ------------------- This is the hardware sector size of the device, in bytes. @@ -92,6 +102,10 @@ logical_block_size (RO) ----------------------- This is the logical block size of the device, in bytes. +max_discard_segments (RO) +------------------------- +The maximum number of DMA scatter/gather entries in a discard request. + max_hw_sectors_kb (RO) ---------------------- This is the maximum number of kilobytes supported in a single data transfer. @@ -218,6 +232,12 @@ 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. +write_zeroes_max_bytes (RO) +--------------------------- +For block drivers that support REQ_OP_WRITE_ZEROES, the maximum number of +bytes that can be zeroed at once. The value 0 means that REQ_OP_WRITE_ZEROES +is not supported. + zoned (RO) ---------- This indicates if the device is a zoned block device and the zone model of the |