tick_dep_set_task
tick_dep_set_task(current, TICK_DEP_BIT_RCU); // CPU bound, so need tick.
tick_dep_set_task(current, TICK_DEP_BIT_RCU); // CPU bound, so need tick.
tick_dep_set_task(current, TICK_DEP_BIT_RCU);
tick_dep_set_task(p, TICK_DEP_BIT_POSIX_TIMER);