[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-common.c b/kernel/time/tick-common.c
index 43ba1bd..bfda3f7 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -298,18 +298,17 @@
spin_unlock_irqrestore(&tick_device_lock, flags);
}
-static void tick_suspend_periodic(void)
+static void tick_suspend(void)
{
struct tick_device *td = &__get_cpu_var(tick_cpu_device);
unsigned long flags;
spin_lock_irqsave(&tick_device_lock, flags);
- if (td->mode == TICKDEV_MODE_PERIODIC)
- clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_SHUTDOWN);
+ clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_SHUTDOWN);
spin_unlock_irqrestore(&tick_device_lock, flags);
}
-static void tick_resume_periodic(void)
+static void tick_resume(void)
{
struct tick_device *td = &__get_cpu_var(tick_cpu_device);
unsigned long flags;
@@ -317,6 +316,8 @@
spin_lock_irqsave(&tick_device_lock, flags);
if (td->mode == TICKDEV_MODE_PERIODIC)
tick_setup_periodic(td->evtdev, 0);
+ else
+ tick_resume_oneshot();
spin_unlock_irqrestore(&tick_device_lock, flags);
}
@@ -348,13 +349,13 @@
break;
case CLOCK_EVT_NOTIFY_SUSPEND:
- tick_suspend_periodic();
+ tick_suspend();
tick_suspend_broadcast();
break;
case CLOCK_EVT_NOTIFY_RESUME:
if (!tick_resume_broadcast())
- tick_resume_periodic();
+ tick_resume();
break;
default: