Re: disk head scheduling
Arvind Sankar (arvinds@mit.edu)
Fri, 19 Mar 1999 13:52:56 -0500
On Fri, Mar 19, 1999 at 07:04:57PM +0100, Ingo Molnar wrote:
>
> On Fri, 19 Mar 1999, Stephen C. Tweedie wrote:
>
> > > no, all requests (for all devices) are in a single 'queue'. (Per-major
> > > device queues is candidate 2.3 feature, it's really simple)
> >
> > No, each major has its own queue, defined either by the
> > blkdev[major].queue() strategy function or by
> > blkdev[major].current_request. As far as IN_ORDER is concerned, it will
> > only ever look at one such queue at a time.
>
> oops, i got confused by the fact that i only have SCSI disks, which all
> have the same request queue. But this is due to SCSI_MAJOR ...
>
> -- mingo
Should this be changed? IDE has the same major number for pairs of disks
on the same controller, but they have different request queues. It shouldn't
be too difficult to implement it, right?
Or it because scsi controllers do their own scheduling anyway?
-- arvind
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