[v5,0/7] Improve the performance for zoned UFS devices

Message

Bart Van Assche July 31, 2023, 10:14 p.m. UTC

Hi Jens,

This patch series improves small write IOPS by a factor of four (+300%) for
zoned UFS devices on my test setup with a UFSHCI 3.0 controller. Please
consider this patch series for the next merge window.

Thank you,

Bart.

Changes compared to v4:
 - Dropped the patch that introduces the REQ_NO_ZONE_WRITE_LOCK flag.
 - Dropped the null_blk patch and added two scsi_debug patches instead.
 - Dropped the f2fs patch.
 - Split the patch for the UFS driver into two patches.
 - Modified several patch descriptions and source code comments.
 - Renamed dd_use_write_locking() into dd_use_zone_write_locking().
 - Moved the list_sort() call from scsi_unjam_host() into scsi_eh_flush_done_q()
   such that sorting happens just before reinserting.
 - Removed the scsi_cmd_retry_allowed() call from scsi_check_sense() to make
   sure that the retry counter is adjusted once per retry instead of twice.

Changes compared to v3:
 - Restored the patch that introduces QUEUE_FLAG_NO_ZONE_WRITE_LOCK. That patch
   had accidentally been left out from v2.
 - In patch "block: Introduce the flag REQ_NO_ZONE_WRITE_LOCK", improved the
   patch description and added the function blk_no_zone_write_lock().
 - In patch "block/mq-deadline: Only use zone locking if necessary", moved the
   blk_queue_is_zoned() call into dd_use_write_locking().
 - In patch "fs/f2fs: Disable zone write locking", set REQ_NO_ZONE_WRITE_LOCK
   from inside __bio_alloc() instead of in f2fs_submit_write_bio().

Changes compared to v2:
 - Renamed the request queue flag for disabling zone write locking.
 - Introduced a new request flag for disabling zone write locking.
 - Modified the mq-deadline scheduler such that zone write locking is only
   disabled if both flags are set.
 - Added an F2FS patch that sets the request flag for disabling zone write
   locking.
 - Only disable zone write locking in the UFS driver if auto-hibernation is
   disabled.

Changes compared to v1:
 - Left out the patches that are already upstream.
 - Switched the approach in patch "scsi: Retry unaligned zoned writes" from
   retrying immediately to sending unaligned write commands to the SCSI error
   handler.

Bart Van Assche (7):
  scsi: scsi_debug: Support disabling zone write locking
  scsi: scsi_debug: Support injecting unaligned write errors
  scsi: ufs: Split an if-condition
  scsi: ufs: Disable zone write locking
  scsi: core: Report error list information in debugfs
  scsi: core: Add a precondition check in scsi_eh_scmd_add()
  scsi: scsi_debug: Support injecting unaligned write errors

 drivers/scsi/scsi_debug.c   | 21 +++++++++++++++--
 drivers/scsi/scsi_debugfs.c | 25 ++++++++++++++++++---
 drivers/scsi/scsi_error.c   |  1 +
 drivers/ufs/core/ufshcd.c   | 45 ++++++++++++++++++++++++++++++++++---
 4 files changed, 84 insertions(+), 8 deletions(-)