You could do worse than Mach ports

[a]

Terry Lambert wrote:
Matthew Dillon wrote:

   Even something like cryptfs can conceivably, if a crypto chip is
   present, use DMA to directly access the data without it having to be
   mapped.  And if it isn't, so what?  You wind up mapping the data and
   take the performance hit.  Just because you might have to do it for
   some subsystems doesn't mean you should go and burden *ALL* the
   subsystems with that kind of overhead.


Cache coherency.  It's a big problem.  Given the design information
disclosed so far, the assumptions tend to make me believe that the
coherency model would not work for NUMA, IA64 (more than 4 CPU),
SPARC, PPC, and a number of other platforms.
Could someone address this issue?