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SubjectRe: [PATCH RFC idle 1/3] x86: Avoid invoking RCU when CPU is idle
On Thu, Feb 02, 2012 at 02:54:30AM +0100, Frederic Weisbecker wrote:
> On Wed, Feb 01, 2012 at 04:43:22PM -0800, Paul E. McKenney wrote:
> > From: "Paul E. McKenney" <paul.mckenney@linaro.org>
> >
> > The idle loop is a quiscent state for RCU, which means that RCU ignores
> > CPUs that have told RCU that they are idle via rcu_idle_enter(). There
> > are nevertheless quite a few places where idle CPUs use RCU, most commonly
> > indirectly via tracing. This patch fixes these problems for x86.
> >
> > Many of these bugs have been in the kernel for quite some time, but
> > Frederic's recent change now gives warnings.
> >
> > This patch takes the straightforward approach of pushing the
> > rcu_idle_enter()/rcu_idle_exit() pair further down into the core
> > of the idle loop.
>
> I guess this is about the trace_power_*() things, right?

Indeed it is! Alternative suggestions gladly accepted. ;-)

Thanx, Paul

> Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
>
> Thanks.
>



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