Re: Bio pool & scsi scatter gather pool usage

[Andrew Morton <akpm@zip.com.au>]

Alan Cox wrote:
> 
> > Perhaps, but calls are expensive. Repeated calls down stacked block
> > devices will add up. In only the most unusually cases will there
> 
> You don't need to repeatedly query. At bind time you can compute the
> limit for any device heirarchy and be done with it.
> 

S'pose so.  The ideal request size is variable, based
on the alignment.  So for exampe if the start block is
halfway into a stripe, the ideal BIO size is half a stripe.

But that's a pretty simple table to generate once-off,
as you say.

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