[0/2] btrfs: adjust async discard tuning

Message

Boris Burkov April 5, 2023, 4:20 p.m. UTC

Since discard=async became the implicit default in btrfs in the
6.2 kernel, there have been numerous complaints about discard being
too spread out on workstation systems. This results in situations like
a users drive not being idle for an unexpectedly long period of time.

This is caused by a relatively low default iops limit of 10, so this
series raises the default limit to 1000 (1ms delay) and modifies a
weird fallback behavior for limit=0 to be interpreted as unlimited.

Link: https://lore.kernel.org/linux-btrfs/[e-mail]/T/#m6ebdeb475809ed7714b21b8143103fb7e5a966da
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2182228
Link: https://www.reddit.com/r/archlinux/comments/121htxn/btrfs_discard_storm_on_62x_kernel/

Boris Burkov (2):
  btrfs: set default discard iops_limit to 1000
  btrfs: reinterpret async discard iops_limit=0 as no delay

 fs/btrfs/discard.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)