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

From: H. Peter Anvin
Date: Wed Jul 09 2008 - 17:23:03 EST


Eric W. Biederman wrote:

But we can pick an arbitrary point where %gs points at.

Hmm. This whole thing is even sillier then I thought.
Why can't we access per cpu vars as:
%gs:(per_cpu__var - __per_cpu_start) ?

If we can subtract constants and allow the linker to perform that resolution
at link. A zero based per cpu segment becomes a moot issue.


And then we're back here again!

Supposedly the linker buggers up, although we don't have conclusive evidence...

-hpa

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