Re: [RFC PATCH 0/5] Refcount based Cpu Hotplug. V2

[Oleg Nesterov]

On 10/24, Gautham R Shenoy wrote:
>
> On Wed, Oct 24, 2007 at 10:04:41AM -0700, Christoph Lameter wrote:
> > On Wed, 24 Oct 2007, Gautham R Shenoy wrote:
> > 
> > > This is the version 2 of the refcount based cpu-hotplug "locking" 
> > > implementation. 
> > 
> > Uggh. This introduces a global lock that has to be taken always when 
> > scanning over cpus? 
> 
> Well, no! we take the global lock only while bumping up the refcount. 
> We don't hold the lock while scanning over the cpus. And this is
> definitely an improvement over the lock_cpu_hotplug() global mutex
> we have now.

Just to be sure I didn't miss something... preempt_disable() still works,
yes?

Oleg.

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