Re: Memory Management - BSD vs Linux
Geert Uytterhoeven (Geert.Uytterhoeven@cs.kuleuven.ac.be)
Tue, 12 Aug 1997 18:22:38 +0200 (CEST)
On Tue, 12 Aug 1997, Malcolm Beattie wrote:
> Douglas Jardine writes:
> > I missed a couple of questions in my last mail:
> >
> > [7] In order to be able to run over different architectures, Linux
> > implements a 3-level page table. It then rolls the architecture
> > specific stuff into this 3-level organization. For example x86
> > has only 2-level page tables but these are appropriately munged
> > into the 3-level organization. My question is that, are there
> > any architectures out there for which this sort of transformation
> > won't work? i.e does the transformation take away enough from
> > the architectures strengths that other hacks are needed to be
> > able to get reasonable performance?
>
> I wondered about that too. An interesting example would be the
> inverted page tables of the RS6000 (and isn't PA-RISC either the
> same or weird in a similar way: I know there's DVMA fun for PA-RISC).
> Since nobody has tried porting Linux to RS6k (that I know about) and
The PPC601 is very similar to the RS/6000.
I'm not a PPC MMU expert, but AFAIK in Linux/PPC the `Intel style' MMU tree is
converted on the fly to a PPC MMU tree.
Greetings,
Geert
--
Geert Uytterhoeven Geert.Uytterhoeven@cs.kuleuven.ac.be
Wavelets, Linux/m68k on Amiga http://www.cs.kuleuven.ac.be/~geert/
Department of Computer Science -- Katholieke Universiteit Leuven -- Belgium