On 6/9/26 14:18, Sumit Saxena wrote:

iorequest_cnt and iodone_cnt are updated on every command dispatch and
completion, often from different CPUs on high queue depth workloads.
Using adjacent atomic_t fields causes cache line contention between the
submission and completion paths.

Extend the same treatment to ioerr_cnt and iotmo_cnt so all four iostat
counters in struct scsi_device use struct percpu_counter.

Suggested-by: John Garry <john.g.garry@oracle.com>
Signed-off-by: Sumit Saxena <sumit.saxena@broadcom.com>
---
  drivers/scsi/scsi_error.c  |  4 ++--
  drivers/scsi/scsi_lib.c    | 10 +++++-----
  drivers/scsi/scsi_scan.c   |  8 ++++++++
  drivers/scsi/scsi_sysfs.c  | 23 ++++++++++++++---------
  drivers/scsi/sd.c          |  2 +-
  include/scsi/scsi_device.h |  9 +++++----
  6 files changed, 35 insertions(+), 21 deletions(-)

Good idea.

Reviewed-by: Hannes Reinecke <hare@kernel.org>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@suse.de                                +49 911 74053 688
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