Re: Configurable larger physical memory

Bernd Paysan (bernd.paysan@gmx.de)
Mon, 19 Apr 1999 00:04:58 +0200

Mitchell Blank Jr wrote:
> No, I there's another problem of people setting it as high as they
> possibly can ("hey, I might put 3G of ram in here someday...") without
> realizing that there are tradeoffs and they probably want the default.
> I think the question should be phrased as "Limit userspace memory to..."
> instead of "Maximum physical memory..." for this reason.

Hm, no, that doesn't make sense. Who would limit userspace memory?
Perhaps "Physical RAM/Userspace tradeoff" would be more appropriate, and
select

1GB RAM/3GB Userspace
2GB RAM/2GB Userspace
3GB RAM/1GB Userspace
4GB RAM/192MB Userspace

or something like that, and there certainly has to be documentation.
BTW: Is it really still necessary for the kernel to access all the
phyiscal RAM? I understand that it has to access memory mapped IO, and
it's own address space, but the rest? I can't see such a design in the
68k architecture specific part, or am I just missing something?

-- 
Bernd Paysan
"If you want it done right, you have to do it yourself"
http://www.jwdt.com/~paysan/


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