Re: Non-uniform address spaces

[Jim Blandy <jimb@codesourcery.com>]

Michael Eager <eager@eagercon.com> writes:
>>> One problem may be that it may not be clear whether one has a
>>> pointer to a linear code space or to a distributed NUMA data space.
>>> It might be reasonable to model the linear code space as a 64-bit
>>> CORE_ADDR, with the top half zero, while a NUMA address has non-zero
>>> values in the top half.  (I don't know if there might be alias
>>> problems, where zero might be valid for the top half of a NUMA address.)
>>
>> I think this isn't going to be a problem, but it's hard to tell.  Can
>> you think of a specific case where we wouldn't be able to tell which
>> we have?
>
> Only if the <processor,thread> component of a NUMA address can be
> zero, and looks like a linear address.

I guess what I've been getting at is, why do we need to represent both
NUMA and linear addresses?  If linear addresses refer to specific
subsets of the grand unified NUMA address space, then we should simply
declare CORE_ADDR to hold NUMA addresses, and make sure that linear
addresses always get converted to NUMA addresses at a point where we
have enough context to do so.