clockevents: Make tick handover explicit
clockevents_notify() is a leftover from the early design of the
clockevents facility. It's really not a notification mechanism,
it's a multiplex call. We are way better off to have explicit
calls instead of this monstrosity.
Split out the tick_handover call and invoke it explicitely from
the hotplug code. Temporary solution will be cleaned up in later
patches.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[ Rebase ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1658173.RkEEILFiQZ@vostro.rjw.lan
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/kernel/cpu.c b/kernel/cpu.c
index af5db20..eba7eaa 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -339,6 +339,8 @@
return err;
cpu_notify(CPU_DYING | param->mod, param->hcpu);
+ /* Give up timekeeping duties */
+ tick_handover_do_timer();
/* Park the stopper thread */
kthread_park(current);
return 0;
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index be9abf3..88fb3b9 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -655,10 +655,6 @@
raw_spin_lock_irqsave(&clockevents_lock, flags);
switch (reason) {
- case CLOCK_EVT_NOTIFY_CPU_DYING:
- tick_handover_do_timer(arg);
- break;
-
case CLOCK_EVT_NOTIFY_CPU_DEAD:
tick_shutdown_broadcast_oneshot(arg);
tick_shutdown_broadcast(arg);
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 721d29b..6a7a64e 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -1707,10 +1707,6 @@
break;
#ifdef CONFIG_HOTPLUG_CPU
- case CPU_DYING:
- case CPU_DYING_FROZEN:
- clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DYING, &scpu);
- break;
case CPU_DEAD:
case CPU_DEAD_FROZEN:
{
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index e28ba5c..055c868 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -332,20 +332,23 @@
tick_install_broadcast_device(newdev);
}
+#ifdef CONFIG_HOTPLUG_CPU
/*
* Transfer the do_timer job away from a dying cpu.
*
- * Called with interrupts disabled.
+ * Called with interrupts disabled. Not locking required. If
+ * tick_do_timer_cpu is owned by this cpu, nothing can change it.
*/
-void tick_handover_do_timer(int *cpup)
+void tick_handover_do_timer(void)
{
- if (*cpup == tick_do_timer_cpu) {
+ if (tick_do_timer_cpu == smp_processor_id()) {
int cpu = cpumask_first(cpu_online_mask);
tick_do_timer_cpu = (cpu < nr_cpu_ids) ? cpu :
TICK_DO_TIMER_NONE;
}
}
+#endif
/*
* Shutdown an event device on a given cpu:
diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index 0266f9d..aabcb5d 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -20,7 +20,6 @@
extern void tick_setup_periodic(struct clock_event_device *dev, int broadcast);
extern void tick_handle_periodic(struct clock_event_device *dev);
extern void tick_check_new_device(struct clock_event_device *dev);
-extern void tick_handover_do_timer(int *cpup);
extern void tick_shutdown(unsigned int *cpup);
extern void tick_suspend(void);
extern void tick_resume(void);