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authorThomas Gleixner <tglx@linutronix.de>2015-04-03 02:05:15 +0200
committerIngo Molnar <mingo@kernel.org>2015-04-03 08:44:33 +0200
commit1fe5d5c3c9ba0c4ade18e3325cba0ffe35127941 (patch)
treeb07d74d6468aa0bf1e2b107bb82d62b9fe6638d4
parent89feddbfe7023ccfb4a6d7f5e3f5161d91b28b18 (diff)
downloadop-kernel-dev-1fe5d5c3c9ba0c4ade18e3325cba0ffe35127941.zip
op-kernel-dev-1fe5d5c3c9ba0c4ade18e3325cba0ffe35127941.tar.gz
clockevents: Provide explicit broadcast oneshot control functions
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 broadcast oneshot control into a separate function and provide inline helpers. Switch clockevents_notify() over. This will go away once all callers are converted. This also gets rid of the nested locking of clockevents_lock and broadcast_lock. The broadcast oneshot control functions do not require clockevents_lock. Only the managing functions (setup/shutdown/suspend/resume of the broadcast device require clockevents_lock. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Alexandre Courbot <gnurou@gmail.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Len Brown <lenb@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Warren <swarren@wwwdotorg.org> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Tony Lindgren <tony@atomide.com> Link: http://lkml.kernel.org/r/13000649.8qZuEDV0OA@vostro.rjw.lan Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--include/linux/tick.h19
-rw-r--r--kernel/time/clockevents.c4
-rw-r--r--kernel/time/tick-broadcast.c28
-rw-r--r--kernel/time/tick-internal.h2
4 files changed, 39 insertions, 14 deletions
diff --git a/include/linux/tick.h b/include/linux/tick.h
index 4bb2363..6119321 100644
--- a/include/linux/tick.h
+++ b/include/linux/tick.h
@@ -48,12 +48,23 @@ enum tick_broadcast_mode {
TICK_BROADCAST_FORCE,
};
+enum tick_broadcast_state {
+ TICK_BROADCAST_EXIT,
+ TICK_BROADCAST_ENTER,
+};
+
#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
extern void tick_broadcast_control(enum tick_broadcast_mode mode);
#else
static inline void tick_broadcast_control(enum tick_broadcast_mode mode) { }
#endif /* BROADCAST */
+#if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_TICK_ONESHOT)
+extern int tick_broadcast_oneshot_control(enum tick_broadcast_state state);
+#else
+static inline int tick_broadcast_oneshot_control(enum tick_broadcast_state state) { return 0; }
+#endif
+
static inline void tick_broadcast_enable(void)
{
tick_broadcast_control(TICK_BROADCAST_ON);
@@ -66,6 +77,14 @@ static inline void tick_broadcast_force(void)
{
tick_broadcast_control(TICK_BROADCAST_FORCE);
}
+static inline int tick_broadcast_enter(void)
+{
+ return tick_broadcast_oneshot_control(TICK_BROADCAST_ENTER);
+}
+static inline void tick_broadcast_exit(void)
+{
+ tick_broadcast_oneshot_control(TICK_BROADCAST_EXIT);
+}
#ifdef CONFIG_NO_HZ_COMMON
extern int tick_nohz_tick_stopped(void);
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index dba0b83..7791b1c 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -656,8 +656,10 @@ int clockevents_notify(unsigned long reason, void *arg)
switch (reason) {
case CLOCK_EVT_NOTIFY_BROADCAST_ENTER:
+ tick_broadcast_enter();
+ break;
case CLOCK_EVT_NOTIFY_BROADCAST_EXIT:
- ret = tick_broadcast_oneshot_control(reason);
+ tick_broadcast_exit();
break;
case CLOCK_EVT_NOTIFY_CPU_DYING:
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 1a0bee0..55e43f2 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -687,18 +687,23 @@ void hotplug_cpu__broadcast_tick_pull(int deadcpu)
raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
}
-/*
- * Powerstate information: The system enters/leaves a state, where
- * affected devices might stop
+/**
+ * tick_broadcast_oneshot_control - Enter/exit broadcast oneshot mode
+ * @state: The target state (enter/exit)
+ *
+ * The system enters/leaves a state, where affected devices might stop
* Returns 0 on success, -EBUSY if the cpu is used to broadcast wakeups.
+ *
+ * Called with interrupts disabled, so clockevents_lock is not
+ * required here because the local clock event device cannot go away
+ * under us.
*/
-int tick_broadcast_oneshot_control(unsigned long reason)
+int tick_broadcast_oneshot_control(enum tick_broadcast_state state)
{
struct clock_event_device *bc, *dev;
struct tick_device *td;
- unsigned long flags;
- ktime_t now;
int cpu, ret = 0;
+ ktime_t now;
/*
* Periodic mode does not care about the enter/exit of power
@@ -711,17 +716,17 @@ int tick_broadcast_oneshot_control(unsigned long reason)
* We are called with preemtion disabled from the depth of the
* idle code, so we can't be moved away.
*/
- cpu = smp_processor_id();
- td = &per_cpu(tick_cpu_device, cpu);
+ td = this_cpu_ptr(&tick_cpu_device);
dev = td->evtdev;
if (!(dev->features & CLOCK_EVT_FEAT_C3STOP))
return 0;
+ raw_spin_lock(&tick_broadcast_lock);
bc = tick_broadcast_device.evtdev;
+ cpu = smp_processor_id();
- raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
- if (reason == CLOCK_EVT_NOTIFY_BROADCAST_ENTER) {
+ if (state == TICK_BROADCAST_ENTER) {
if (!cpumask_test_and_set_cpu(cpu, tick_broadcast_oneshot_mask)) {
WARN_ON_ONCE(cpumask_test_cpu(cpu, tick_broadcast_pending_mask));
broadcast_shutdown_local(bc, dev);
@@ -813,9 +818,10 @@ int tick_broadcast_oneshot_control(unsigned long reason)
}
}
out:
- raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
+ raw_spin_unlock(&tick_broadcast_lock);
return ret;
}
+EXPORT_SYMBOL_GPL(tick_broadcast_oneshot_control);
/*
* Reset the one shot broadcast for a cpu
diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index 62e331d..0266f9d 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -117,7 +117,6 @@ static inline int tick_check_oneshot_change(int allow_nohz) { return 0; }
/* Functions related to oneshot broadcasting */
#if defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) && defined(CONFIG_TICK_ONESHOT)
extern void tick_broadcast_setup_oneshot(struct clock_event_device *bc);
-extern int tick_broadcast_oneshot_control(unsigned long reason);
extern void tick_broadcast_switch_to_oneshot(void);
extern void tick_shutdown_broadcast_oneshot(unsigned int *cpup);
extern int tick_broadcast_oneshot_active(void);
@@ -126,7 +125,6 @@ bool tick_broadcast_oneshot_available(void);
extern struct cpumask *tick_get_broadcast_oneshot_mask(void);
#else /* !(BROADCAST && ONESHOT): */
static inline void tick_broadcast_setup_oneshot(struct clock_event_device *bc) { BUG(); }
-static inline int tick_broadcast_oneshot_control(unsigned long reason) { return 0; }
static inline void tick_broadcast_switch_to_oneshot(void) { }
static inline void tick_shutdown_broadcast_oneshot(unsigned int *cpup) { }
static inline int tick_broadcast_oneshot_active(void) { return 0; }
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