Hi folks...

So, I decided I was tired of being flamed by Jonathan for "breaking" the
MIPS pmap (when in fact it was doing things w/ the upper-level VM data
structures that it should not have been) by saying that frobbing PG_CLEAN
was wrong...

So, on the train home last night and to work this morning, I implemented
real modified/referenced emulation for the MIPS pmap.  This should address
e.g. the MFS problems.  Side note, I'm actually surprised it worked at
all, looked like there were lots of cases with "modified" info would just
be thrown away.

Anyhow, unfortunately, I can't test it just yet (or even compile it)
because I need to get my DECstation 5000/200 running again (network
connectivity issues, swap out flaky RAM board, get it updated to a
current snapshot).

This means that I am going to need help with this.

If any of you can test a source-level patch (and make it compile if
it doesn't :-) on R3000 and/or R4000 systems, please get in touch with
me ASAP.

        -- Jason R. Thorpe <thorpej@nas.nasa.gov>