Messages in this thread |  | | Date | Wed, 11 Jul 2001 14:05:54 -0700 | From | Mike Anderson <> | Subject | Re: io_request_lock patch? |
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Jens Axboe [axboe@suse.de] wrote: > On Thu, Jul 12 2001, Dipankar Sarma wrote: > > On Wed, Jul 11, 2001 at 09:20:22PM +0200, Jens Axboe wrote: > > > True. In theory it would be possible to do request slot stealing from > > > idle queues, in fact it's doable without adding any additional overhead > > > to struct request. I did discuss this with [someone, forgot who] last > > > year, when the per-queue slots where introduced. > > > > > > I'm not sure I want to do this though. If you have lots of disks, then > > > yes there will be some wastage if they are idle. IMO that's ok. What's > > > not ok and what I do want to fix is that slower devices get just as many > > > slots as a 15K disk for instance. For, say, floppy or CDROM devices we > > > really don't need to waste that much RAM. This will change for 2.5, not > > > before. > > > > Unless there is some serious evidence substantiating the need for > > stealing request slots from other devices to avoid starvation, it > > makes sense to avoid it and go for a simpler scheme. I suspect that device > > type based slot allocation should just suffice. > > My point exactly. And typically, if you have lots of queues you have > lots of RAM. A standard 128meg desktop machine does not waste a whole > lot.
I would vote for the simpler approach of slots. :-).
> > -- > Jens Axboe
-- Michael Anderson mike.anderson@us.ibm.com
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