linux-kernel - Re: [PATCH RFC v3 1/2] mm: Add personality flag to limit address to 47 bits

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Message-ID: <8734m6s428.fsf@mail.lhotse>
Date: Wed, 11 Sep 2024 23:38:55 +1000
From: Michael Ellerman <mpe@...erman.id.au>
To: Geert Uytterhoeven <geert@...ux-m68k.org>, Christophe Leroy
 <christophe.leroy@...roup.eu>
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Subject: Re: [PATCH RFC v3 1/2] mm: Add personality flag to limit address to
 47 bits

Geert Uytterhoeven <geert@...ux-m68k.org> writes:
> Hi Christophe,
>
> On Tue, Sep 10, 2024 at 11:21 AM Christophe Leroy
> <christophe.leroy@...roup.eu> wrote:
>> >>> diff --git a/include/uapi/linux/personality.h b/include/uapi/linux/personality.h
>> >>> index 49796b7756af..cd3b8c154d9b 100644
>> >>> --- a/include/uapi/linux/personality.h
>> >>> +++ b/include/uapi/linux/personality.h
>> >>> @@ -22,6 +22,7 @@ enum {
>> >>>     WHOLE_SECONDS =         0x2000000,
>> >>>     STICKY_TIMEOUTS =       0x4000000,
>> >>>     ADDR_LIMIT_3GB =        0x8000000,
>> >>> +   ADDR_LIMIT_47BIT =      0x10000000,
>> >>>   };
>> >>
>> >> I wonder if ADDR_LIMIT_128T would be clearer?
>> >>
>> >
>> > I don't follow, what does 128T represent?
>>
>> 128T is 128 Terabytes, that's the maximum size achievable with a 47BIT
>> address, that naming would be more consistant with the ADDR_LIMIT_3GB
>> just above that means a 3 Gigabytes limit.
>
> Hence ADDR_LIMIT_128TB?

Yes it should be 128TB. Typo by me.

cheers