Re: regarding the x86_64 zero-based percpu patches

Christoph Lameter
2009-01-15T21:01:50Z

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.