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Date: Fri, 3 Apr 2015 01:26:41 -0700
From: tip-bot for Thomas Gleixner <tipbot@...or.com>
To: linux-tip-commits@...r.kernel.org
Cc: hpa@...or.com, mingo@...nel.org, akpm@...ux-foundation.org,
peterz@...radead.org, rafael.j.wysocki@...el.com,
linux-kernel@...r.kernel.org, john.stultz@...aro.org,
tglx@...utronix.de, torvalds@...ux-foundation.org
Subject: [tip:timers/core] clockevents: Make tick handover explicit
Commit-ID: 52c063d1adbc16c76e70fffa20727fcd4e9343b3
Gitweb: http://git.kernel.org/tip/52c063d1adbc16c76e70fffa20727fcd4e9343b3
Author: Thomas Gleixner <tglx@...utronix.de>
AuthorDate: Fri, 3 Apr 2015 02:37:24 +0200
Committer: Ingo Molnar <mingo@...nel.org>
CommitDate: Fri, 3 Apr 2015 08:44:36 +0200
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@...utronix.de>
[ Rebase ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: John Stultz <john.stultz@...aro.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Link: http://lkml.kernel.org/r/1658173.RkEEILFiQZ@vostro.rjw.lan
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
include/linux/clockchips.h | 1 -
include/linux/tick.h | 2 ++
kernel/cpu.c | 2 ++
kernel/time/clockevents.c | 4 ----
kernel/time/hrtimer.c | 4 ----
kernel/time/tick-common.c | 9 ++++++---
kernel/time/tick-internal.h | 1 -
7 files changed, 10 insertions(+), 13 deletions(-)
diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h
index f97f498..f4bde22 100644
--- a/include/linux/clockchips.h
+++ b/include/linux/clockchips.h
@@ -11,7 +11,6 @@
/* Clock event notification values */
enum clock_event_nofitiers {
CLOCK_EVT_NOTIFY_ADD,
- CLOCK_EVT_NOTIFY_CPU_DYING,
CLOCK_EVT_NOTIFY_CPU_DEAD,
};
diff --git a/include/linux/tick.h b/include/linux/tick.h
index 6119321..2c68fa3 100644
--- a/include/linux/tick.h
+++ b/include/linux/tick.h
@@ -19,12 +19,14 @@ extern void tick_unfreeze(void);
extern void tick_suspend_local(void);
/* Should be core only, but XEN resume magic and ARM BL switcher require it */
extern void tick_resume_local(void);
+extern void tick_handover_do_timer(void);
#else /* CONFIG_GENERIC_CLOCKEVENTS */
static inline void tick_init(void) { }
static inline void tick_freeze(void) { }
static inline void tick_unfreeze(void) { }
static inline void tick_suspend_local(void) { }
static inline void tick_resume_local(void) { }
+static inline void tick_handover_do_timer(void) { }
#endif /* !CONFIG_GENERIC_CLOCKEVENTS */
#ifdef CONFIG_TICK_ONESHOT
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 @@ static int __ref take_cpu_down(void *_param)
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 @@ int clockevents_notify(unsigned long reason, void *arg)
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 @@ static int hrtimer_cpu_notify(struct notifier_block *self,
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 @@ out_bc:
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 int tick_do_timer_cpu __read_mostly;
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);
--
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