Thread (47 messages) 47 messages, 8 authors, 2017-04-05

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

From: Kirill A. Shutemov <hidden>
Date: 2017-03-24 09:03:26
Also in: linux-arch, lkml

On Sun, Mar 19, 2017 at 02:25:08PM +0530, Aneesh Kumar K.V wrote:
quoted
quoted
quoted
So if I have done a successful mmap which returned > 128TB what should a
following mmap(0,...) return ? Should that now search the *full* address
space or below 128TB ?
No, I don't think so. And this implementation doesn't do this.

It's safer this way: if an library can't handle high addresses, it's
better not to switch it automagically to full address space if other part
of the process requested high address.
What is the epectation when the hint addr is below 128TB but addr + len >
128TB ? Should such mmap request fail ?
Considering that we have stack at the top (around 128TB) we may not be
able to get a free area for such a request. But I guess the idea here is
that if hint address is below 128TB, we behave as though our TASK_SIZE
is 128TB ? Is that correct ?
Right.

-- 
 Kirill A. Shutemov

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