Re: [patch] Reorganize the cpufreq cpu hotplug locking to not be totally bizare

[Srivatsa Vaddagiri <vatsa@in.ibm.com>]

On Wed, Jul 26, 2006 at 11:03:06PM +0200, Arjan van de Ven wrote:
> rwsems unfortunately help you zilch; an rwsem is just a mutex with a
> performance tweak, but from the deadlock perspective it's really a
> mutex.

ah ..didnt realize that. 

> I'm really starting to feel that the hotplug lock would have been better
> of being a refcount (with a waitqueue for zero) than a lock. While
> "refcount+waitqueue" sort of IS a lock, the semantics make more sense
> imo...

I think that will work, although you now need to deal with a global or per-cpu 
refcount now. Later is more cache-friendly, but dont think we have ready 
refcounting APIs for that?

-- 
Regards,
vatsa
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