Re: elevator priorities vs. full request queues

[Jens Axboe <axboe@suse.de>]

On Tue, Jul 13 2004, Werner Almesberger wrote:
> > Maybe it would be more logical to assign 'default' priority in
> > bio_init(), in fact?
> 
> What made me shy away from this is that bio_init and bio_alloc
> seem to get called from contexts where "current" wouldn't
> necessarily have anything to do with the process that has
> actually initiated the IO.
> 
> For example, I'm not sure if the calls from ide-scsi.c, when
> it builds requests piece by piece, are safe in this regard.

That's not really what I meant - 'default' priority isn't tied to the
process. It's just that if default io prio was something other than 0,
then it would make sense to set it there. Say if the range was 0-15, and
you wanted 7 to be 'in the middle' default priority.

But I suppose you just want io submission to set it, in which case it
doesn't matter what bio_init() sets it to.

-- 
Jens Axboe