Re: [dm-devel] [RFC PATCH 1/2] dm-mpath: interface change for preparation

[Kiyoshi Ueda <k-ueda ct jp nec com>]

Hi Vijay,

Thank you for the comment.

On 01/30/2009 01:42 PM +0900, Chauhan, Vijay wrote:
> Hi Kiyoshi/Alasdair,
> 
> Just a thought. As we are changing __choose_pgpath parameters
> in this patch, will it be good to use BIO rather than nr_bytes
> as parameter? Availability of BIO in loadbalancing interface can
> provide more flexibility for coming up with new load balancing
> in future.

I understand that very much.
But I'd like to keep independency of path-selector from the type
of I/O structure as much as possible, since both bio-based targets
and request-based targets may want to use the same path-selector
in the future.  (e.g. multipath, which is requset-based,
and mirror, which is bio-based.)

So if we need only a few arguments, non-structured parameters
would be good, I think.
Do you have any idea what other parameters in BIO are useful for
load balancing decision?

Thanks,
Kiyoshi Ueda