• Jens Axboe's avatar
    block: make /sys/block/<dev>/queue/discard_max_bytes writeable · 0034af03
    Jens Axboe authored
    Lots of devices support huge discard sizes these days. Depending
    on how the device handles them internally, huge discards can
    introduce massive latencies (hundreds of msec) on the device side.
    We have a sysfs file, discard_max_bytes, that advertises the max
    hardware supported discard size. Make this writeable, and split
    the settings into a soft and hard limit. This can be set from
    'discard_granularity' and up to the hardware limit.
    Add a new sysfs file, 'discard_max_hw_bytes', that shows the hw
    set limit.
    Reviewed-by: default avatarJeff Moyer <jmoyer@redhat.com>
    Signed-off-by: default avatarJens Axboe <axboe@fb.com>
blk-settings.c 27.4 KB