Messages in this thread | | | Date | Thu, 14 Mar 2002 09:38:54 -0800 | From | Andrew Morton <> | Subject | Re: Question about the ide related ioctl's BLK* in 2.5.7-pre1 kernel |
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Martin Dalecki wrote: > > Andrew Morton wrote: > > Roberto Nibali wrote: > > > >>Hi, > >> > >>What for are BLKRAGET, BLKFRAGET and BLKSECTGET still needed? > >> > > > > They got collaterally damaged in the IDE "cleanup". The patch at > > http://www.zip.com.au/~akpm/linux/patches/2.5/2.5.6/dallocbase-10-readahead.patch > > resurrects them. > > This is WRONG. What I did here was just removal of unused code. > They got obsoleted by the BIO infrastructure changes.
Actually, it's right.
In mid-February you asserted that the IDE readahead controls were inoperative. You said:
> You are missing one simple thing: The removed values doen't control > ANYTHING!
I asked:
> Please explain, in detail, why /proc/ide/hdX/settings:file_readhead > no longer controls the readhead for that device. If this is > the case in thr current 2.4 kernel, or if it will become the > case if/when the IDE patches are merged then that needs fixing. >
You didn't answer.
I tested them. They still worked.
I also said:
> > Look, I agree that the current readhead controls are junk, and > do not belong in the driver layer at all. All I'm saying is > that we need per-device controls, for whatever scheme we end > up using for readhead in 2.5. We really don't want to have > the same sized readhead for CDROMs, floppies and super-duper > RAID arrays.
Then the device-driver-based readahead controls got taken out.
I really do agree that it was a pile of crap. I've turned them into a property of the request queue, which is a more appropriate place for them.
In my current patch, the per-queue readahead parameter is controlled via the old ioctls. Probably, these will be retired in favour of /proc/iosched, when that turns up.
In the meantime, I *need* those tunables for ongoing development.
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