Re: [PATCH 26/26] x86/mm: allow to have userspace mappings above 47-bits

[Kirill A. Shutemov]

On Mon, Mar 20, 2017 at 11:08:41AM -0700, hpa@xxxxxxxxx wrote:
> This *better* be conditional on some kind of settable limit.  Having a
> barrier in the middle of the address space for no apparent reason to
> "clean" software is insane.

I had the same argument (on your side) before, but if you look on numbers
it's far from the middle of address space. The barrier is around 0.2% from
the start 56-bit address space.

And it's we have vdso/vvar/stack just below the barier anyway.

I don't think we would loose much if wouldn't not allow VMA to sit
across it.

-- 
 Kirill A. Shutemov