Re: regarding the x86_64 zero-based percpu patches

From: Christoph Lameter
Date: Thu Jan 15 2009 - 16:01:52 EST


On Thu, 15 Jan 2009, Rusty Russell wrote:

> I don't think moving per-cpu areas is going to fly. We do put complex
> datastructures in there. And you're going to need preempt_disable() on
> all per-cpu ops on many archs to make it work (assuming you use
> stop_machine to do the realloc. Even a rough audit quickly becomes
> overwhelming: 20 of the first 1/4 of DECLARE_PER_CPUs are non-movable
> datastructures.

Ok then lets go for dynamically growing per cpu areas using 2M virtual
mappings.... At least on 64 bit that should be fine.
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