Subject: Re: CVS commit: src
To: Jason Thorpe <>
From: Jonathan Stone <jonathan@DSG.Stanford.EDU>
List: port-mips
Date: 12/05/1998 20:49:28

>IT WAS NEVER CHANGED!  This is the way it's been since, like, day one for


4.4BSD really did support other APIs than the one used by the hp300 pmap.

So, okay, you're saying that at some point the way the hp300 way was
decreed ``correct'' for NetBSD and other semanitcs were deemed
incorrect.  Which would be fine. No problem. The only gotcha is that
the decree was a bit quiet.

As I said to Castor *and* to you, I'm happy to do the right thing.
Castor says that the changes for UMV (which _are_ correct for UVM;
Michael and I ran them by Chuck) broke the old Mach-derived VM system.

Personaly I'd sooner just deprecate the old Mach VM on mips.  I take
it you' dhave no complaints if we just make the mips pmap module do
what you now say is ``right'', even if Castor says it breaks the old

I still think having the VM system depend on the pmap tracking
_reference_ bits, in order to correctly write back _dirty_ pages
(given that dirty bits *are* being correctly tracked) doesn't seem
``right'' -- because of TLB hardware which doesn't have reference bits.

I've said as much to Chuck. We'll see what happens.