On 2014/10/24 23:36, Peter Zijlstra wrote:
>> +
>> +static void freezer_idle(int cpu)
>> +{
>> + struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
>> + struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
>> +
>> + stop_critical_timings();
>> +
>> + while (suspend_freeze_wake == -1) {
>> + int next_state;
>> +
>> + /*
>> + * interrupt must be disabled before cpu enters idle
>> + */
>> + local_irq_disable();
>> +
>> + next_state = cpuidle_select(drv, dev);
>> + if (next_state < 0) {
>> + arch_cpu_idle();
>> + continue;
>> + }
>> + /*
>> + * cpuidle_enter will return with interrupt enabled
>> + */
>> + cpuidle_enter(drv, dev, next_state);
>> + }
>> +
>> + if (suspend_freeze_wake == cpu)
>> + kick_all_cpus_sync();
>> +
>
> So I disabled IRQs here
>
>> + start_critical_timings();
>> +}
>> +
>> +static void freezer_resume_tk(int cpu)
>> +{
>> + if (tick_do_timer_cpu != cpu)
>> + return;
>> +
>> cpuidle_pause();
>> cpuidle_use_deepest_state(false);
>> +
>
> Such that they would still be disabled here
>
>> + local_irq_disable();
>> + timekeeping_resume();
>> + local_irq_enable();
>> +}
>> +
>> +static void freezer_resume_clkevt(int cpu)
>> +{
>> + if (tick_do_timer_cpu == cpu)
>> + return;
>> +
>> + touch_softlockup_watchdog();
>> + clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL);
>
> And here.
>
>> + local_irq_disable();
>> + hrtimers_resume();
>> + local_irq_enable();
>> +}
>> +
>> +typedef void (*freezer_fn)(int);
>> +
>> +static freezer_fn freezer_func[FREEZER_EXIT] = {
>> + NULL,
>> + freezer_pick_tk,
>> + freezer_suspend_clkevt,
>> + freezer_suspend_tk,
>> + freezer_idle,
>> + freezer_resume_tk,
>> + freezer_resume_clkevt,
>> +};
>
> Because this is a stop_machine callback, which are nominally run with
> IRQs disabled.
>
>> +static int freezer_stopper_fn(void *arg)
>> +{
>> + struct freezer_data *fd = arg;
>> + enum freezer_state state = FREEZER_NONE;
>> + int cpu = smp_processor_id();
>> +
>> + do {
>> + cpu_relax();
>> + if (fd->state != state) {
>> + state = fd->state;
>> + if (freezer_func[state])
>> + (*freezer_func[state])(cpu);
>> + ack_state(fd);
>> + }
>> + } while (fd->state != FREEZER_EXIT);
>> + return 0;
>> +}
>
> Now I suppose the problem is with cpu_pause() which needs IPIs to
> complete?
Yes, cpu_pause() will invoke smp IPI functions which need interrupt is
enabled. So I changed irq ops like above. Actually, I have an early
version to move cpuidle_pause()/cpuidle_resume() out of stop_machine(),
that might be a better solution?
Thanks,
-Aubrey
--
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/
