Re: [BK PATCHES] add ata scsi driver

Jens Axboe
2003-05-26T19:20:14Z

On Mon, May 26 2003, James Bottomley wrote:
> On Mon, 2003-05-26 at 15:07, Jens Axboe wrote:
> > Alright, so what do you need? Start out with X tags, shrink to Y (based
> > on repeated queue full conditions)? Anything else?
>
> Actually, it's easier than that: just an API to alter the number of tags
> in the block layer (really only the size of your internal hash table).
> The actual heuristics of when to alter the queue depth is the province
> of the individual drivers (although Doug Ledford was going to come up
> with a generic implementation).

That's actually what I meant, that the SCSI layer would call down into
the block layer to set the size. I don't/want to know about queue full
conditions.

The internal memory requirements for the queue table is small (a bit per
tag), so I think we can basically get away with just decrementing
->max_depth.

--
Jens Axboe