Re: [patch for playing] 2.5.65 patch to support > 256 disks

Jens Axboe
2003-03-25T11:37:24Z

On Tue, Mar 25 2003, Jens Axboe wrote:
> On Tue, Mar 25 2003, Jens Axboe wrote:
> > Here's a patch that makes the request allocation (and io scheduler
> > private data) dynamic, with upper and lower bounds of 4 and 256
> > respectively. The numbers are a bit random - the 4 will allow us to make
> > progress, but it might be a smidgen too low. Perhaps 8 would be good.
> > 256 is twice as much as before, but that should be alright as long as
> > the io scheduler copes. BLKDEV_MAX_RQ and BLKDEV_MIN_RQ control these
> > two variables.
> >
> > We loose the old batching functionality, for now. I can resurrect that
> > if needed. It's a rough fit with the mempool, it doesn't _quite_ fit our
> > needs here. I'll probably end up doing a specialised block pool scheme
> > for this.
> >
> > Hasn't been tested all that much, it boots though :-)
>
> Here's a version with better lock handling. We drop the queue_lock for
> most parts of __make_request(), except the actual io scheduler calls.

That was buggy, fixing... Back later.

--
Jens Axboe