On Nov 26, 2015 6:35 PM, "erik quanstrom" <quanstro@quanstro.net> wrote:

> > By the way, are there any structs more than 4K in Linux? Are there any
in plan 9?
>
> since that 4k is really pagesz, on amd64 that would be 2mb.  there's no
compelling reason on
> 64-bit machines to start at the bottom instead of the middle.

IIRC i think there was a special case with PAE as well so to speak for
Linux where 36-bit is used from CPU. I remember that in that case pud, pmd
and pgd are used but 0 page map is treated as a more kernel specific
implementation

Though i might be wrong.