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

[H. Peter Anvin]

Christoph Lameter wrote:
> There will be no additional overhead since the memory already mapped 1-1 using 2MB TLBs and we want to use the same for the percpu areas. This is similar to the vmemmap solution.

THAT sounds strange.  If you're using dedicated virtual maps (which is 
what you're responding to here) then you will *always* have additional 
TLB pressure.  Furthermore, if you use 2 MB pages, you:

a) can only allocate full 2 MB pages, which is expensive for the static 
users and difficult for the dynamic users;

b) increase pressure in the relatively small 2 MB TLB.

	-hpa
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