Re: Moving mac68k to 8K pages?

[Rin Okuyama <rokuyama.rk%gmail.com@localhost>]

Hi,

On 2019/02/08 19:34, David Brownlee wrote:
> On Fri, 8 Feb 2019 at 07:53, Martin Husemann <martin%duskware.de@localhost> wrote:
> > On Fri, Feb 08, 2019 at 04:40:29AM +0000, John Klos wrote:
> > > Are there any good reasons to not switch mac68k to 8K pages, at very least
> > > until someone gets around to rewriting the PMAP?
> >
> > Haven't thought about it in detail but things to consider:
> >   - it wastes a bit of space on tiny memory machines
> >   - does it break binary comptability?
>
> I would expect that the latter *should* be fine - based on history for
> NetBSD/vax switching from 1k to 4k pages :)
>
> How reasonable would it to make it a explicit kernel option for m68k -
> defaulting to 8k, but settable to 4k specifically for low memory
> machines.

PGSHIFT is not hardcoded into userland stuff unlike Linux ;-).
Binaries for mac68k (PGSHIFT = 12) work on amiga (PGSHIFT = 13),
and vice versa.

Thanks,
rin