On Thu, 13 May 2021 09:49:12 -0700, Bart Van Assche wrote:
> With the current implementation of the UFS driver active_queues is 1
> instead of 0 if all UFS request queues are idle. That causes
> hctx_may_queue() to divide the queue depth by 2 when queueing a request
> and hence reduces the usable queue depth.
>
> The shared tag set code in the block layer keeps track of the number of
> active request queues. blk_mq_tag_busy() is called before a request is
> queued onto a hwq and blk_mq_tag_idle() is called some time after the hwq
> became idle. blk_mq_tag_idle() is called from inside blk_mq_timeout_work().
> Hence, blk_mq_tag_idle() is only called if a timer is associated with each
> request that is submitted to a request queue that shares a tag set with
> another request queue. Hence this patch that adds a blk_mq_start_request()
> call in ufshcd_exec_dev_cmd(). This patch doubles the queue depth on my
> test setup from 16 to 32.
>
> [...]
Applied to 5.13/scsi-fixes, thanks!
[1/1] ufs: Increase the usable queue depth
https://git.kernel.org/mkp/scsi/c/d0b2b70eb12e
--
Martin K. Petersen Oracle Linux Engineering
