tick/xen: Provide and use tick_suspend_local() and tick_resume_local()

Xen calls on every cpu into tick_resume() which is just wrong.
tick_resume() is for the syscore global suspend/resume
invocation. What XEN really wants is a per cpu local resume
function.

Provide a tick_resume_local() function and use it in XEN.

Also provide a complementary tick_suspend_local() and modify
tick_unfreeze() and tick_freeze(), respectively, to use the
new local tick resume/suspend functions.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[ Combined two patches, rebased, modified subject/changelog. ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1698741.eezk9tnXtG@vostro.rjw.lan
[ Merged to latest timers/core. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 17 insertions, 7 deletions

diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 60e6c23..19cfb38 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -455,11 +455,26 @@ void tick_suspend_broadcast(void)
 	raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
 }
 
-int tick_resume_broadcast(void)
+/*
+ * This is called from tick_resume_local() on a resuming CPU. That's
+ * called from the core resume function, tick_unfreeze() and the magic XEN
+ * resume hackery.
+ *
+ * In none of these cases the broadcast device mode can change and the
+ * bit of the resuming CPU in the broadcast mask is safe as well.
+ */
+bool tick_resume_check_broadcast(void)
+{
+	if (tick_broadcast_device.mode == TICKDEV_MODE_ONESHOT)
+		return false;
+	else
+		return cpumask_test_cpu(smp_processor_id(), tick_broadcast_mask);
+}
+
+void tick_resume_broadcast(void)
 {
 	struct clock_event_device *bc;
 	unsigned long flags;
-	int broadcast = 0;
 
 	raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
 
@@ -472,8 +487,6 @@ int tick_resume_broadcast(void)
 		case TICKDEV_MODE_PERIODIC:
 			if (!cpumask_empty(tick_broadcast_mask))
 				tick_broadcast_start_periodic(bc);
-			broadcast = cpumask_test_cpu(smp_processor_id(),
-						     tick_broadcast_mask);
 			break;
 		case TICKDEV_MODE_ONESHOT:
 			if (!cpumask_empty(tick_broadcast_mask))
@@ -482,11 +495,8 @@ int tick_resume_broadcast(void)
 		}
 	}
 	raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
-
-	return broadcast;
 }
 
-
 #ifdef CONFIG_TICK_ONESHOT
 
 static cpumask_var_t tick_broadcast_oneshot_mask;