Re: [PATCH 0/6] x86/cpu hotplug: Wake up offline CPU via mwait or nmi

[Paul E. McKenney]

On Wed, Jun 06, 2012 at 10:43:43AM +0200, Peter Zijlstra wrote:
> On Tue, 2012-06-05 at 15:12 -0700, Paul E. McKenney wrote:
> > > What I can't see is the isolated functional, aside from the above
> > > mentioned things, that's not strictly a per-cpu property, we can have a
> > > group that's isolated from the rest but not from each other.
> > 
> > I suspect that Thomas is thinking that the CPU is so idle that it no
> > longer has to participate in TLB invalidation or RCU.  (Thomas will
> > correct me if I am confused.)  But Peter, is that the level of idle
> > you are thinking of? 
> 
> No, we're talking about isolated, so its very much running something.

>From what I can see, if the CPU is running something, this is Thomas's
"Isolated functional" state rather than his "Isolated idle" state.
The isolated-idle state should not need to participate in TLB invalidation
or RCU, so that the CPU never ever needs to wake up while in the
isolated-idle state.

							Thanx, Paul

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