Messages in this thread | | | Date | Thu, 10 Jul 2008 10:25:45 -0700 | From | Jeremy Fitzhardinge <> | Subject | Re: [RFC 00/15] x86_64: Optimize percpu accesses |
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Christoph Lameter wrote: > Jeremy Fitzhardinge wrote: > > >> You want to virtually map the percpu area? How and when would it get >> extended? >> > > It would get extended when cpu_alloc() is called and the allocator finds that there is no per cpu memory available. >
Which, I take it, allocates percpu memory. It would have the same caveats as vmalloc memory, with respect to accessing it during fault handlers and nmi handlers, I take it.
How would cpu_alloc() actually get used? It doesn't make much sense for general code, since we don't have the notion of a percpu pointer to memory (vs a pointer to percpu memory). Is the intended use for allocating percpu memory in modules? What other uses?
J
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