md devices mounted with async

[Kris Kennaway]

RW wrote:

> But isn't the normal point of async to avoid having the cpu waiting for
> the disk with nothing to do. If there's nothing to block on, the cpu can
> be consistently utilized without async. I suppose with SMP it might
> help spread the work between cpus, but with a single cpu it seems like
> it would just end-up doing the same work in a different order.

Yes, but even on a single CPU your application can potentially dispatch 
more work in the meantime.  e.g. it could be doing other device or 
network I/O.

Kris