Messages in this thread | | | Date | Mon, 28 Apr 2003 19:13:53 +0200 | From | Andi Kleen <> | Subject | Re: [Lse-tech] Re: maximum possible memory limit .. |
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> Cool. Sorry to be pestering about the 64-bit limits, but can we really > use 2^64 bytes of memory on ia64/ppc64/x86-64 etc.? (AFAIK, 64-bit > arches don't suffer from a small ZONE_LOWMEM.)
No. The hardware have far smaller physical limits.
Current AMD64 CPUs are limited to 40bit physical, 48bit virtal (the virtual limit per process in the current Linux kernel is 39bits)
Itanium 2 afaik support a bit more 50bits (51 or 52, I forgot) physical, probably more virtual.
Other 64bit architectures are somewhere inbetween.
The actual limit in the machines is even less. You will have a hard time to find an affordable machine (64bit or not) with more than 8 DIMM slots. That's 16GB Max with 2GB DIMMs.
-Andi
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