> We fall back to the rmap when it's obviously not smart to do so. There
> is still a lot of room for improvement in this function though, i.e.,
> it should be per VMA and NUMA aware.

Okay so it's more a question to tune the cross over heuristic. That
sounds much easier than replacing everything.

Of course long term it might be a problem to maintain too many 
different ways to do things, but I suppose short term it's a reasonable
strategy.

-Andi