Re: [RFC 00/15] x86_64: Optimize percpu accesses

From: Arjan van de Ven
Date: Wed Jul 09 2008 - 16:40:58 EST


On Wed, 09 Jul 2008 13:11:03 -0700
Jeremy Fitzhardinge <jeremy@xxxxxxxx> wrote:

> Ingo Molnar wrote:
> > Note that the zero-based percpu problems are completely unrelated
> > to stackprotector. I was able to hit them with a
> > stackprotector-disabled gcc-4.2.3 environment.
>
> The only reason we need to keep a zero-based pda is to support
> stack-protector. If we drop drop it, we can drop the pda - and its
> special zero-based properties - entirely.

what's wrong with zero based btw?

do they stop us from using gcc's __thread keyword for per cpu variables
or something? (*that* would be a nice feature)

or does it stop us from putting the per cpu variables starting from
offset 4096 onwards?

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