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From(Eric W. Biederman)
DateThu, 10 Jul 2008 12:18:25 -0700
SubjectRe: [RFC 00/15] x86_64: Optimize percpu accesses
Jeremy Fitzhardinge <jeremy@goop.org> writes:

> Eric W. Biederman wrote:
>> I think we can get away with just simply realloc'ing the percpu area
>> on each cpu. No fancy table manipulations required. Just update
>> the base pointer in %gs and in someplace global.
>>
>
> It's perfectly legitimate to take the address of a percpu variable and store it
> somewhere. We can't move them around.

Really? I guess there are cases where that makes sense. It is a pretty
rare case though. Especially when you are not talking about doing it temporarily
with preemption disabled. There are few enough users of the API I think we can
certainly explore the cost of forbidding in the general case of storing the
address of a percpu variable.

Eric



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