Change from direct comparison of ->pid with zero to is_idle_task().
Signed-off-by: NPaul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>