On Fri, Feb 06, 2015 at 05:14:54PM +0100, Peter Zijlstra wrote: > On Fri, Feb 06, 2015 at 02:20:13AM +0100, Rafael J. Wysocki wrote: > > void freeze_wake(void) > > { > > + unsigned long flags; > > + > > + spin_lock_irqsave(&suspend_freeze_lock, flags); > > + if (suspend_freeze_state > FREEZE_STATE_NONE) { > > + suspend_freeze_state = FREEZE_STATE_WAKE; > > + wake_up(&suspend_freeze_wait_head); > > + } > > + spin_unlock_irqrestore(&suspend_freeze_lock, flags); > > } > > > > +static void enter_freeze_proper(struct cpuidle_driver *drv, > > + struct cpuidle_device *dev, int index) > > +{ > > + tick_freeze(); > > + drv->states[index].enter_freeze(dev, drv, index); > > + /* > > + * timekeeping_resume() that will be called by tick_unfreeze() for the > > + * last CPU executing it calls functions containing RCU read-side > > + * critical sections, so tell RCU about that. > > + */ > > + RCU_NONIDLE(tick_unfreeze()); > > +} > > So I'm a wee bit confused; if we use an enter_freeze() state that keeps > interrupts disabled; who is going to call the freeze_wake() thing?
Ah, I think I see, so we wake up, keep the interrupt pending, re-enable the tick and time and everybody, then re-enable interrupts, take the interrupt and go around the idle loop to find we need a reschedule etc.. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/