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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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