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[Python-Dev] How can we use 48bit pointer safely?


Not only that, but afaik  Linux could simply raise that 57bit virtual
to 64bit virtual without previous
warning on any version change.

On 30 March 2018 at 08:55, Ronald Oussoren <ronaldoussoren at mac.com> wrote:
>
>
> On Mar 30, 2018, at 08:31 AM, INADA Naoki <songofacandy at gmail.com> wrote:
>
> Hi,
>
> As far as I know, most amd64 and arm64 systems use only 48bit address
> spaces.
> (except [1])
>
> [1]
> https://software.intel.com/sites/default/files/managed/2b/80/5-level_paging_white_paper.pdf
>
> It means there are some chance to compact some data structures.
> I point two examples below.
>
> My question is; can we use 48bit pointer safely?
>
>
> Not really, at least some CPUs can also address more memory than that. See
> <https://lwn.net/Articles/717293/> which talks about Linux support for
> 57-bit virtual addresses and 52-bit physical addresses.
>
> Ronald
>
>
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