Re: [rfc 37/45] x86_64: Support for fast per cpu operations

[H. Peter Anvin]

David Miller wrote:
> > There was, at some point, discussion about using the gcc TLS mechanism, 
> > which should permit even better code to be generated.  Unfortunately, it 
> > would require gcc to be able to reference %gs instead of %fs (and vice 
> > versa for i386), which I don't think is available in anything except 
> > maybe the most cutting-edge version of gcc.
>
> You can't use __thread because GCC will cache __thread computed
> addresses across context switches and cpu changes.
>
> It's been tried before on powerpc, it doesn't work.

OK, that pretty much answers that question.

	-hpa
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