Re: disk head scheduling
Arvind Sankar (arvinds@mit.edu)
Thu, 18 Mar 1999 14:49:08 -0500
On Thu, Mar 18, 1999 at 08:38:21PM +0100, Rik van Riel wrote:
> On Thu, 18 Mar 1999, Arvind Sankar wrote:
>
> > Another point is that IN_ORDER seems to be called only for two requests
> > on the same device, so no idea why it compares the device numbers.
>
> It compares device numbers because of partitions on
> one drive. It would be extremely bad for performance
> when Linux would be hopping from partition to partition
> without the aid of the elevator algorithm...
ah. Sorry. didn't look closely enough and thought there was one queue for
every rq_dev, since the call was
get_queue(req->rq_dev)
This means I need to fix my code, which btw has starvation problems... :(
-- arvind
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