Re: Using >1GB RAM

Alan Cox (alan@lxorguk.ukuu.org.uk)
Wed, 14 Jan 1998 00:33:34 +0000 (GMT)


> May I ask if what I shall do with the 2GB 4 CPU machine?
> If I can live with 2GB user space and 2GB kernel space, is it
> worth modifying the kernel? Please give me a rough estimate
> of the workload.

It shouldnt be that hard, and I'd like to see it done anyway. I don't have
2Gigs to test it but I suspect Ingo or me can knock you up a test patch easily

> I know that SunOS OpenServer can support up to 4GB memory though
> it is very expensive. How do they manage to do that?

You have to start flushing the TLB every time you enter kernel mode and
need to touch a physical memory object as opposed to kernels own data/bss
space. It could be added to Linux but 4Gb boxes arent the norm and there
is a performance hit for a kernel built that way.

Alan