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

[H. Peter Anvin]

Christoph Lameter wrote:
> Jeremy Fitzhardinge wrote:
>
> > Percpu on i386 hasn't been a point of discussion.  It works fine, and
> > has been working fine for a long time.  The same mechanism would work
> > fine on x86-64.  Its only "issue" is that it doesn't support the broken
> > gcc abi for stack-protector.
>
> Well that is one thing and then the scaling issues, and the support of the new cpu allocator, new arch independent cpu operations etc.
>
> > The problem is all zero-based percpu on x86-64.
>
> The zero based stuff will enable a lot of things. Please have a look at the cpu_alloc patchsets.

No argument this work is worthwhile.  The main issues on the table is 
the particular choice of offsets, and the handling of the virtual space 
-- I believe 2 MB mappings are too large, except perhaps as an option.

	-hpa

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