Commit e50404a8 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by David Sterba
Browse files

btrfs: discard: speed up async discard up to iops_limit 



Instead of using iops_limit only for cutting off extremes, calculate the
discard delay directly from it, so it closely follows iops_limit and
doesn't under-discard even though quotas are not saturated.

The iops limit could be hit more often in some cases and could increase
the discard rate.

Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 480a8ec8

fs/btrfs/discard.c

+5 −5
Original line number Diff line number Diff line
@@ -519,7 +519,6 @@ void btrfs_discard_calc_delay(struct btrfs_discard_ctl *discard_ctl) 
	s64 discardable_bytes;

	u32 iops_limit;

	unsigned long delay;

	unsigned long lower_limit = BTRFS_DISCARD_MIN_DELAY_MSEC;



	discardable_extents = atomic_read(&discard_ctl->discardable_extents);

	if (!discardable_extents)
@@ -550,11 +549,12 @@ void btrfs_discard_calc_delay(struct btrfs_discard_ctl *discard_ctl) 


	iops_limit = READ_ONCE(discard_ctl->iops_limit);

	if (iops_limit)

		lower_limit = max_t(unsigned long, lower_limit,

				    MSEC_PER_SEC / iops_limit);



		delay = MSEC_PER_SEC / iops_limit;

	else

		delay = BTRFS_DISCARD_TARGET_MSEC / discardable_extents;

	delay = clamp(delay, lower_limit, BTRFS_DISCARD_MAX_DELAY_MSEC);



	delay = clamp(delay, BTRFS_DISCARD_MIN_DELAY_MSEC,

		      BTRFS_DISCARD_MAX_DELAY_MSEC);

	discard_ctl->delay = msecs_to_jiffies(delay);



	spin_unlock(&discard_ctl->lock);