• Coly Li's avatar
    bcache: set writeback_rate_update_seconds in range [1, 60] seconds · 7a5e3ecb
    Coly Li authored
    dc->writeback_rate_update_seconds can be set via sysfs and its value can
    be set to [1, ULONG_MAX].  It does not make sense to set such a large
    value, 60 seconds is long enough value considering the default 5 seconds
    works well for long time.
    
    Because dc->writeback_rate_update is a special delayed work, it re-arms
    itself inside the delayed work routine update_writeback_rate(). When
    stopping it by cancel_delayed_work_sync(), there should be a timeout to
    wait and make sure the re-armed delayed work is stopped too. A small max
    value of dc->writeback_rate_update_seconds is also helpful to decide a
    reasonable small timeout.
    
    This patch limits sysfs interface to set dc->writeback_rate_update_seconds
    in range of [1, 60] seconds, and replaces the hand-coded number by macros.
    
    Changelog:
    v2: fix a rebase typo in v4, which is pointed out by Michael Lyle.
    v1: initial version.
    Signed-off-by: default avatarColy Li <colyli@suse.de>
    Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
    Reviewed-by: default avatarMichael Lyle <mlyle@lyle.org>
    Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
    7a5e3ecb
writeback.c 17.1 KB