[RFC][PATCH] net drivers and cache alignment

One of the [many] nice properties of the traditional Don Becker drivers has been that often the driver-private structures are arranged such that  the structure is broken up on cacheline boundaries.  The RX thread has a cacheline, the TX thread has a cacheline, etc.  Jes Sorensen also independently, in his review of 8139cp.c, suggested that the driver-private struct be update with attention to cacheline boundaries.

Early next year, I would like to start cleaning up some of the net drivers along these lines (no pun intended).  To make it easier for vendors and random coders to cacheline-align struct members, I would like to make more explicit these cacheline boundaries, in a manner that is portable between 32-bit and 64-bit systems.

I attach a sample implementation, and request feedback on this approach.   The general idea is to make implementing this sort of concept "harder to screw up."