Messages in this thread | | | Date | Wed, 11 Jul 2001 22:17:19 +0200 | From | Jens Axboe <> | Subject | Re: io_request_lock patch? |
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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.
-- Jens Axboe
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