tick_work
cancel_delayed_work(&sched->tick_work);
struct delayed_work tick_work;
tick_work.work);
flush_work(&ptdev->scheduler->tick_work.work);
cancel_delayed_work_sync(&sched->tick_work);
disable_delayed_work_sync(&sched->tick_work);
INIT_DELAYED_WORK(&sched->tick_work, tick_work);
static struct tick_work __percpu *tick_work_cpu;
struct tick_work *twork = container_of(dwork, struct tick_work, work);
struct tick_work *twork;
struct tick_work *twork;
tick_work_cpu = alloc_percpu(struct tick_work);