/* CPU private run queues */
DECLARE_CPULOCAL(struct proc *, run_q_head[NR_SCHED_QUEUES]); /* ptrs to ready list headers */
DECLARE_CPULOCAL(struct proc *, run_q_tail[NR_SCHED_QUEUES]); /* ptrs to ready list tails */
-DECLARE_CPULOCAL(int, cpu_is_idle); /* let the others know that you are idle */
+DECLARE_CPULOCAL(volatile int, cpu_is_idle); /* let the others know that you are idle */
DECLARE_CPULOCAL(volatile int, idle_interrupted); /* to interrupt busy-idle
while profiling */