Re: [PATCH] Fix disk statistic reporting to include all disks

From: Bill Wilson (
Date: Wed Aug 30 2000 - 11:49:15 EST

On 30-Aug-2000 Jens Axboe wrote:
>> and just remove the drive_stat_acct() thing completely.
> Agreed, I've implemented this and ripped the stats out of kstat. Patch
> coming soon :-)
> We do then loose the ability to tell when we've started a new request,
> now we just account all buffers as a new request. Not a big deal, IMHO.
> But do you just want per-queue stats, and not care about minors at all?

Won't we loose some important info by not looking at minors? hda and
hdb are minors of IDE0_MAJOR, etc. Is this data distinguishable in the queues?

>> That way, we'd have a per-queue "this many reads, this many writes".
>> The /proc code would have to find all the queues, but that shouldn't be
>> too bad either. At least we wouldn't have the current silly disk_index()
>> stuff (which is all done in a timing-critical routine).
> No big deal, for now I just have the proc code doing blk_get_queue for
> every major. That code is hardly performance critical ;-)

True for the kernel, but there are some user land apps that read /proc/stat
quite frequently (10 per second) so some performance tuning might be
worth it. There could be a linked list field in the blk_dev[] array
which links all entries that have had statistics collected. Then the /proc
code does not have to blk_get_queue on every major.

Bill Wilson <>

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