Re: [PATCH 3/3] scsi: core: Improve IOPS in case of host-wide tags

John Garry
2025-09-12T14:38:41Z

On 11/09/2025 18:37, Bart Van Assche wrote:
> On 9/11/25 1:15 AM, John Garry wrote:
>> this can race with a call to scsi_change_queue_depth() (which may free
>> sdev->budget_map.map), right?
>>
>> scsi_change_queue_depth() does not seem to do any queue freezing.
>
> Hi John,
>

It was not specifically freezing which I was concerned with. It was how
with the freeing of the sbitmap now looks racy. Just resizing the
sbitmap would not have such issues. I mentioned queue freezing as queue
freezing was introduced in scsi_realloc_sdev_budget_map() for freeing
the queue - I'm not sure why, though.

> Are there any SCSI devices left about which we care and for which queue
> depth tracking is important?

many drivers still set .track_queue_depth