hrtimers: Support resuming with two or more CPUs online (but stopped)

[~andy/linux] / kernel / hrtimer.c

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index fd4b13b131f8db23fb17055caf5d33e23bec7b50..e86827e94c9ab31f26a12b896e5480da8f8b3e4b 100644 (file)
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -773,15 +773,24 @@ void clock_was_set(void)
 
 /*
  * During resume we might have to reprogram the high resolution timer
- * interrupt (on the local CPU):
+ * interrupt on all online CPUs.  However, all other CPUs will be
+ * stopped with IRQs interrupts disabled so the clock_was_set() call
+ * must be deferred to the softirq.
+ *
+ * The one-shot timer has already been programmed to fire immediately
+ * (see tick_resume_oneshot()) and this interrupt will trigger the
+ * softirq to run early enough to correctly reprogram the timers on
+ * all CPUs.
  */
 void hrtimers_resume(void)
 {
+       struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
+
        WARN_ONCE(!irqs_disabled(),
                  KERN_INFO "hrtimers_resume() called with IRQs enabled!");
 
-       retrigger_next_event(NULL);
-       timerfd_clock_was_set();
+       cpu_base->clock_was_set = 1;
+       __raise_softirq_irqoff(HRTIMER_SOFTIRQ);
 }
 
 static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)