On Sun, 7 Feb 2021 17:20:16 +0800, Ming Lei wrote:
> scsi uses one global atomic variable to track queue depth for each
> LUN/request queue. This way can't scale well when there is lots of CPU
> cores and the disk is very fast. Broadcom guys has complained that their
> high end HBA can't reach top performance because .device_busy is
> operated in IO path.
>
> Replace the atomic variable sdev->device_busy with sbitmap for
> tracking scsi device queue depth.
>
> [...]
Applied to 5.13/scsi-queue, thanks!
[01/13] sbitmap: remove sbitmap_clear_bit_unlock
https://git.kernel.org/mkp/scsi/c/46d2a5813454
[02/13] sbitmap: maintain allocation round_robin in sbitmap
https://git.kernel.org/mkp/scsi/c/ed9eb92974bc
[03/13] sbitmap: add helpers for updating allocation hint
https://git.kernel.org/mkp/scsi/c/a523156a9303
[04/13] sbitmap: move allocation hint into sbitmap
https://git.kernel.org/mkp/scsi/c/30d4ee6f3a9d
[05/13] sbitmap: export sbitmap_weight
https://git.kernel.org/mkp/scsi/c/d9ba7618bec3
[06/13] sbitmap: add helper of sbitmap_calculate_shift
https://git.kernel.org/mkp/scsi/c/5d747419d20e
[07/13] blk-mq: add callbacks for storing & retrieving budget token
https://git.kernel.org/mkp/scsi/c/9dda23635dbe
[08/13] blk-mq: return budget token from .get_budget callback
https://git.kernel.org/mkp/scsi/c/cd4ef15a289a
[09/13] scsi: put hot fields of scsi_host_template into one cacheline
https://git.kernel.org/mkp/scsi/c/a8474e7b28a0
[10/13] megaraid_sas: v2 replace sdev_busy with local counter
https://git.kernel.org/mkp/scsi/c/d7afc2ed1447
[11/13] scsi: add scsi_device_busy() to read sdev->device_busy
https://git.kernel.org/mkp/scsi/c/c300d1182331
[12/13] scsi: make sure sdev->queue_depth is <= max(shost->can_queue, 1024)
https://git.kernel.org/mkp/scsi/c/b0a4b45dc841
[13/13] scsi: replace sdev->device_busy with sbitmap
https://git.kernel.org/mkp/scsi/c/62b38e49fcf7
--
Martin K. Petersen Oracle Linux Engineering
