Re: [patch] high-res timers: resume fix

Rafael J. Wysocki
2007-04-07T09:59:24Z

On Saturday, 7 April 2007 11:49, Ingo Molnar wrote:
>
> find updated patch below - only the patch description changed: i removed
> the 'UP' thing (patch has relevance on SMP too), and added Thomas' ack.
>
> Ingo
>
> ---------------------------->
> Subject: [patch] high-res timers: resume fix
> From: Ingo Molnar <mingo@elte.hu>
>
> Soeren Sonnenburg reported that upon resume he is getting
> this backtrace:
>
> [<c0119637>] smp_apic_timer_interrupt+0x57/0x90
> [<c0142d30>] retrigger_next_event+0x0/0xb0
> [<c0104d30>] apic_timer_interrupt+0x28/0x30
> [<c0142d30>] retrigger_next_event+0x0/0xb0
> [<c0140068>] __kfifo_put+0x8/0x90
> [<c0130fe5>] on_each_cpu+0x35/0x60
> [<c0143538>] clock_was_set+0x18/0x20
> [<c0135cdc>] timekeeping_resume+0x7c/0xa0
> [<c02aabe1>] __sysdev_resume+0x11/0x80
> [<c02ab0c7>] sysdev_resume+0x47/0x80
> [<c02b0b05>] device_power_up+0x5/0x10
>
> it turns out that on resume we mistakenly re-enable interrupts.
> Do the timer retrigger only on the current CPU.
>
> Signed-off-by: Ingo Molnar <mingo@elte.hu>
> Acked-by: Thomas Gleixner <tglx@linutronix.de>
> ---
> include/linux/hrtimer.h | 3 +++
> kernel/hrtimer.c | 12 ++++++++++++
> 2 files changed, 15 insertions(+)
>
> Index: linux/include/linux/hrtimer.h
> ===================================================================
> --- linux.orig/include/linux/hrtimer.h
> +++ linux/include/linux/hrtimer.h
> @@ -206,6 +206,7 @@ struct hrtimer_cpu_base {
> struct clock_event_device;
>
> extern void clock_was_set(void);
> +extern void hres_timers_resume(void);
> extern void hrtimer_interrupt(struct clock_event_device *dev);
>
> /*
> @@ -236,6 +237,8 @@ static inline ktime_t hrtimer_cb_get_tim
> */
> static inline void clock_was_set(void) { }
>
> +static inline void hres_timers_resume(void) { }
> +
> /*
> * In non high resolution mode the time reference is taken from
> * the base softirq time variable.
> Index: linux/kernel/hrtimer.c
> ===================================================================
> --- linux.orig/kernel/hrtimer.c
> +++ linux/kernel/hrtimer.c
> @@ -459,6 +459,18 @@ void clock_was_set(void)
> }
>
> /*
> + * During resume we might have to reprogram the high resolution timer
> + * interrupt (on the local CPU):
> + */
> +void hres_timers_resume(void)
> +{
> + WARN_ON_ONCE(num_online_cpus() > 1);
> +
> + /* Retrigger the CPU local events: */
> + retrigger_next_event(NULL);
> +}
> +
> +/*
> * Check, whether the timer is on the callback pending list
> */
> static inline int hrtimer_cb_pending(const struct hrtimer *timer)
> -

Hm, I'm probably missing something obvious, but where is it going to be called
from?

Rafael