Yes. Thank you for the comment.
I have two concerns to do that.
(1) technical concern
If there is fixed device-wide limitation and there are so many groups,
the number of request descriptors distributed to each group can be too
few. My only idea for this is to make device-wide limitation flexible,
but I'm not sure if it is the best or even can be allowed.
(2) implementation concern
Now the limitation is done by generic block layer which doesn't know
about grouping. The idea in my head to solve this is to add a new
interface on elevator_ops to ask IO scheduler if a new request can
Anyway, simple RFC patch first and testing it would be preferable,
NEC Corporation of America