From: Boris Burkov boris@bur.io
commit ef9cddfe57d86aac6b509b550136395669159b30 upstream.
Currently, a limit of 0 results in a hard coded metering over 6 hours. Since the default is a set limit, I suspect no one truly depends on this rather arbitrary setting. Repurpose it for an arguably more useful "unlimited" mode, where the delay is 0.
Note that if block groups are too new, or go fully empty, there is still a delay associated with those conditions. Those delays implement heuristics for not trimming a region we are relatively likely to fully overwrite soon.
CC: stable@vger.kernel.org # 6.2+ Reviewed-by: Neal Gompa neal@gompa.dev Signed-off-by: Boris Burkov boris@bur.io Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/discard.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-)
--- a/fs/btrfs/discard.c +++ b/fs/btrfs/discard.c @@ -56,8 +56,6 @@ #define BTRFS_DISCARD_DELAY (120ULL * NSEC_PER_SEC) #define BTRFS_DISCARD_UNUSED_DELAY (10ULL * NSEC_PER_SEC)
-/* Target completion latency of discarding all discardable extents */ -#define BTRFS_DISCARD_TARGET_MSEC (6 * 60 * 60UL * MSEC_PER_SEC) #define BTRFS_DISCARD_MIN_DELAY_MSEC (1UL) #define BTRFS_DISCARD_MAX_DELAY_MSEC (1000UL) #define BTRFS_DISCARD_MAX_IOPS (1000U) @@ -577,6 +575,7 @@ void btrfs_discard_calc_delay(struct btr s32 discardable_extents; s64 discardable_bytes; u32 iops_limit; + unsigned long min_delay = BTRFS_DISCARD_MIN_DELAY_MSEC; unsigned long delay;
discardable_extents = atomic_read(&discard_ctl->discardable_extents); @@ -607,13 +606,19 @@ void btrfs_discard_calc_delay(struct btr }
iops_limit = READ_ONCE(discard_ctl->iops_limit); - if (iops_limit) + + if (iops_limit) { delay = MSEC_PER_SEC / iops_limit; - else - delay = BTRFS_DISCARD_TARGET_MSEC / discardable_extents; + } else { + /* + * Unset iops_limit means go as fast as possible, so allow a + * delay of 0. + */ + delay = 0; + min_delay = 0; + }
- delay = clamp(delay, BTRFS_DISCARD_MIN_DELAY_MSEC, - BTRFS_DISCARD_MAX_DELAY_MSEC); + delay = clamp(delay, min_delay, BTRFS_DISCARD_MAX_DELAY_MSEC); discard_ctl->delay_ms = delay;
spin_unlock(&discard_ctl->lock);