Pull hardirq and softirq nesting updates from Frederic Weisbecker,
which fix nesting related stack overruns such as:
http://lkml.kernel.org/r/
1378330796.4321.50.camel%40pasglop
Beyond being a fix, this series also optimizes and reorganizes arch
hardirq/softirq stack processing to be faster and more robust.
Signed-off-by: Ingo Molnar <mingo@kernel.org>