Re: SCSI I/O performance problems when CONFIG_HIGHIO is off

Jens Axboe (axboe@suse.de)
Sat, 16 Nov 2002 09:18:28 +0100

On Fri, Nov 15 2002, Steve Lord wrote:
> Jens,
>
> As you know, for the last week or so I have been battling some
> performance issues in XFS and 2.4.20-rc1. Well, we finally found
> the culprit back in 2.4.20-pre2.
>
> When the block highmem patch was included, it added highmem_io to the
> scsi controller structure. This can only ever be set to one if
> CONFIG_HIGHIO is set. Yet there are several spots in the scsi
> code which test based on its value regardless.

Doh! You are right, this is a very stupid bug, thanks for catching it.
I'm on the road this weekend, I'' submit a patch to fix it as soon
as I get back.

> Jens, can you do something about this please?

Of course

> p.s. You now owe me a week's consulting some time ;-)

Indeed, sorry about that...

Jens

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