Re: KIOBUFS ??

[Jens Axboe]

On Wed, Jan 10 2001, Andre Hedrick wrote:
> 
> LT,
> 
> Will this maddness insure that the granularity of the request will be
> dependent to the k_dev_t?  Specifically, can one make KIOBUFS do the
> sizing of buffer to match the ideal or specified size limits imposed by a
> given block device?  Otherwise I will need to design an sub-request layer
> to reduce the pain of restarting the entire request because of the huge
> DMA-PRD-Chain that has no clue how to report error location and allow a
> restart from NxPRD's before the error.

Take a look at the XFS tree. I wrote IDE kiobuf support for that, and
it simply doesn't take the request the queue before it has been
completed (which may take many start-ups for a huge request). But unless
you can make the prd table bigger (which doesn't make much sense anyway),
I don't see any harm in setting up sg for each iteration.

-- 
* Jens Axboe <[e-mail]>
* SuSE Labs