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, 38 insertions, 17 deletions

diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index 1a60c2a..da796d6 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -374,40 +374,32 @@ void tick_shutdown(unsigned int *cpup)
 }
 
 /**
- * tick_suspend - Suspend the tick and the broadcast device
+ * tick_suspend_local - Suspend the local tick device
  *
- * Called from syscore_suspend() via timekeeping_suspend with only one
- * CPU online and interrupts disabled or from tick_unfreeze() under
- * tick_freeze_lock.
+ * Called from the local cpu for freeze with interrupts disabled.
  *
  * No locks required. Nothing can change the per cpu device.
  */
-void tick_suspend(void)
+static void tick_suspend_local(void)
 {
 	struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
 
 	clockevents_shutdown(td->evtdev);
-	tick_suspend_broadcast();
 }
 
 /**
- * tick_resume - Resume the tick and the broadcast device
+ * tick_resume_local - Resume the local tick device
  *
- * Called from syscore_resume() via timekeeping_resume with only one
- * CPU online and interrupts disabled or from tick_unfreeze() under
- * tick_freeze_lock.
+ * Called from the local CPU for unfreeze or XEN resume magic.
  *
  * No locks required. Nothing can change the per cpu device.
  */
-void tick_resume(void)
+void tick_resume_local(void)
 {
-	struct tick_device *td;
-	int broadcast;
+	struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
+	bool broadcast = tick_resume_check_broadcast();
 
-	broadcast = tick_resume_broadcast();
-	td = this_cpu_ptr(&tick_cpu_device);
 	clockevents_tick_resume(td->evtdev);
-
 	if (!broadcast) {
 		if (td->mode == TICKDEV_MODE_PERIODIC)
 			tick_setup_periodic(td->evtdev, 0);
@@ -416,6 +408,35 @@ void tick_resume(void)
 	}
 }
 
+/**
+ * tick_suspend - Suspend the tick and the broadcast device
+ *
+ * Called from syscore_suspend() via timekeeping_suspend with only one
+ * CPU online and interrupts disabled or from tick_unfreeze() under
+ * tick_freeze_lock.
+ *
+ * No locks required. Nothing can change the per cpu device.
+ */
+void tick_suspend(void)
+{
+	tick_suspend_local();
+	tick_suspend_broadcast();
+}
+
+/**
+ * tick_resume - Resume the tick and the broadcast device
+ *
+ * Called from syscore_resume() via timekeeping_resume with only one
+ * CPU online and interrupts disabled.
+ *
+ * No locks required. Nothing can change the per cpu device.
+ */
+void tick_resume(void)
+{
+	tick_resume_broadcast();
+	tick_resume_local();
+}
+
 static DEFINE_RAW_SPINLOCK(tick_freeze_lock);
 static unsigned int tick_freeze_depth;
 
@@ -436,7 +457,7 @@ void tick_freeze(void)
 	if (tick_freeze_depth == num_online_cpus()) {
 		timekeeping_suspend();
 	} else {
-		tick_suspend();
+		tick_suspend_local();
 	}
 
 	raw_spin_unlock(&tick_freeze_lock);