Re: Problem with aacraid driver in 2.5.63-bk-latest

Mark Haverkamp
2003-03-13T15:42:13Z

On Wed, 2003-03-12 at 17:06, Alan Cox wrote:
> On Wed, 2003-03-12 at 23:55, Douglas Gilbert wrote:
> > /*
> > * Limit max queue depth on a single lun to 256 for now. Remember,
> > * we allocate a struct scsi_command for each of these and keep it
> > * around forever. Too deep of a depth just wastes memory.
> > */
> > if(tags > 256)
> > return;
> > ....
>
> I can see the memory consideration. However the thing can really handle big
> queues well. Possibly we should be setting the queue to 512 / somefunction(volumes)
> though to avoid the worst case overcommit here
>

Does the cmd_per_lun element of the Scsi_Host_Template structure serve
more than one purpose? In scsi_alloc_sdev it is passed into
scsi_adjust_queue_depth. In the aacraid case this is 512. Later the
aacraid driver (in aac_slave_configure) sets the queue depth to either
128 for tagged or 1 if not.

Mark.
--
Mark Haverkamp <markh@osdl.org>