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

From	"Kirill A. Shutemov" <kirill@shutemov.name>
Newsgroups	linux.kernel
Subject	Re: [PATCH 26/26] x86/mm: allow to have userspace mappings above 47-bits
Date	2017-03-24 10:10 +0100
Message-ID	<totom-7Is-9@gated-at.bofh.it> (permalink)
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On Mon, Mar 20, 2017 at 11:08:41AM -0700, hpa@zytor.com 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

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Re: [PATCH 26/26] x86/mm: allow to have userspace mappings above 47-bits "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> - 2017-03-17 21:40 +0100
  Re: [PATCH 26/26] x86/mm: allow to have userspace mappings above  47-bits "Kirill A. Shutemov" <kirill@shutemov.name> - 2017-03-18 18:10 +0100
    Re: [PATCH 26/26] x86/mm: allow to have userspace mappings above 47-bits "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> - 2017-03-19 09:30 +0100
      Re: [PATCH 26/26] x86/mm: allow to have userspace mappings above 47-bits "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> - 2017-03-19 14:10 +0100
        Re: [PATCH 26/26] x86/mm: allow to have userspace mappings above  47-bits "Kirill A. Shutemov" <kirill@shutemov.name> - 2017-03-24 10:10 +0100
      Re: [PATCH 26/26] x86/mm: allow to have userspace mappings above 47-bits Michael Ellerman <mpe@ellerman.id.au> - 2017-03-20 10:20 +0100
      Re: [PATCH 26/26] x86/mm: allow to have userspace mappings above 47-bits hpa@zytor.com - 2017-03-20 19:10 +0100
        Re: [PATCH 26/26] x86/mm: allow to have userspace mappings above  47-bits Matthew Wilcox <willy@infradead.org> - 2017-03-20 20:40 +0100
        Re: [PATCH 26/26] x86/mm: allow to have userspace mappings above  47-bits "Kirill A. Shutemov" <kirill@shutemov.name> - 2017-03-24 10:10 +0100

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