[patch, take #3] high-res timers: resume fix

Ingo Molnar
2007-04-07T10:05:15Z

* Rafael J. Wysocki <rjw@sisk.pl> wrote:

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

doh! :) Find new patch below :-/ Soeren, please test this one.

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 ++++++++++++
kernel/timer.c | 2 +-
3 files changed, 16 insertions(+), 1 deletion(-)

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)
Index: linux/kernel/timer.c
===================================================================
--- linux.orig/kernel/timer.c
+++ linux/kernel/timer.c
@@ -1016,7 +1016,7 @@ static int timekeeping_resume(struct sys
clockevents_notify(CLOCK_EVT_NOTIFY_RESUME, NULL);

/* Resume hrtimers */
- clock_was_set();
+ hres_timers_resume();

return 0;
}