> [EMAIL PROTECTED] (Julian Elischer) writes:
>
> > we already use the gs register for SMP now..
> > what about the fs register?
> > I vaguely remember that the different segments could be used to achieve
> > this.... (%fs points to user space or something)
>
> You can't extend the address space that way, segments are all parts of
> the single 4GB address space described by the page mapping.
True, but you can reserve a part of the 4GB address space (say 128MB of it)
for partitioning into tiny (say 8MB) address spaces (which are still flat,
just small), for use by small processes, the idea being that all those small
processes will than share a single page table without compromising on memory
protection (the GDT is under full OS's control anyway), or the simplicity of
a flat address space (virtual addresses still start at 0 and continue till
the top of address space; the scheme is totally transparent.)
patryk.
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