[PATCH] clockevents: Fix suspend/resume to disk hangs
I finally found a dual core box, which survives suspend/resume without
crashing in the middle of nowhere. Sigh, I never figured out from the
code and the bug reports what's going on.
The observed hangs are caused by a stale state transition of the clock
event devices, which keeps the RCU synchronization away from completion,
when the non boot CPU is brought back up.
The suspend/resume in oneshot mode needs the similar care as the
periodic mode during suspend to RAM. My assumption that the state
transitions during the different shutdown/bringups of s2disk would go
through the periodic boot phase and then switch over to highres resp.
nohz mode were simply wrong.
Add the appropriate suspend / resume handling for the non periodic
modes.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 5567745..eadfce2 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -307,12 +307,19 @@
spin_lock_irqsave(&tick_broadcast_lock, flags);
bc = tick_broadcast_device.evtdev;
- if (bc) {
- if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC &&
- !cpus_empty(tick_broadcast_mask))
- tick_broadcast_start_periodic(bc);
- broadcast = cpu_isset(smp_processor_id(), tick_broadcast_mask);
+ if (bc) {
+ switch (tick_broadcast_device.mode) {
+ case TICKDEV_MODE_PERIODIC:
+ if(!cpus_empty(tick_broadcast_mask))
+ tick_broadcast_start_periodic(bc);
+ broadcast = cpu_isset(smp_processor_id(),
+ tick_broadcast_mask);
+ break;
+ case TICKDEV_MODE_ONESHOT:
+ broadcast = tick_resume_broadcast_oneshot(bc);
+ break;
+ }
}
spin_unlock_irqrestore(&tick_broadcast_lock, flags);
@@ -347,6 +354,16 @@
}
}
+int tick_resume_broadcast_oneshot(struct clock_event_device *bc)
+{
+ clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
+
+ if(!cpus_empty(tick_broadcast_oneshot_mask))
+ tick_broadcast_set_event(ktime_get(), 1);
+
+ return cpu_isset(smp_processor_id(), tick_broadcast_oneshot_mask);
+}
+
/*
* Reprogram the broadcast device:
*