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clockevents: Provide explicit broadcast 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 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 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: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tony Lindgren <tony@atomide.com>
Link: http://lkml.kernel.org/r/8086559.ttsuS0n1Xr@vostro.rjw.lan
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Thomas Gleixner 2015-04-03 02:01:10 +02:00 committed by Ingo Molnar
parent 3ff70551a9
commit 592a438ff3
4 changed files with 57 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
include/linux/tick.h
View File

@ -42,6 +42,31 @@ extern void hotplug_cpu__broadcast_tick_pull(int dead_cpu);
static inline void hotplug_cpu__broadcast_tick_pull(int dead_cpu) { }
#endif
enum tick_broadcast_mode {
TICK_BROADCAST_OFF,
TICK_BROADCAST_ON,
TICK_BROADCAST_FORCE,
};
#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 */
static inline void tick_broadcast_enable(void)
{
tick_broadcast_control(TICK_BROADCAST_ON);
}
static inline void tick_broadcast_disable(void)
{
tick_broadcast_control(TICK_BROADCAST_OFF);
}
static inline void tick_broadcast_force(void)
{
tick_broadcast_control(TICK_BROADCAST_FORCE);
}
#ifdef CONFIG_NO_HZ_COMMON
extern int tick_nohz_tick_stopped(void);
extern void tick_nohz_idle_enter(void);

6
kernel/time/clockevents.c
View File

@ -656,9 +656,13 @@ int clockevents_notify(unsigned long reason, void *arg)
switch (reason) {
case CLOCK_EVT_NOTIFY_BROADCAST_ON:
tick_broadcast_enable();
break;
case CLOCK_EVT_NOTIFY_BROADCAST_OFF:
tick_broadcast_disable();
break;
case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
tick_broadcast_on_off(reason, arg);
tick_broadcast_force();
break;
case CLOCK_EVT_NOTIFY_BROADCAST_ENTER:

62
kernel/time/tick-broadcast.c
View File

@ -33,7 +33,7 @@ static cpumask_var_t tick_broadcast_mask;
static cpumask_var_t tick_broadcast_on;
static cpumask_var_t tmpmask;
static DEFINE_RAW_SPINLOCK(tick_broadcast_lock);
static int tick_broadcast_force;
static int tick_broadcast_forced;
#ifdef CONFIG_TICK_ONESHOT
static void tick_broadcast_clear_oneshot(int cpu);
@ -326,49 +326,54 @@ unlock:
raw_spin_unlock(&tick_broadcast_lock);
}
/*
* Powerstate information: The system enters/leaves a state, where
* affected devices might stop
/**
* tick_broadcast_control - Enable/disable or force broadcast mode
* @mode: The selected broadcast mode
*
* Called when the system enters a state where affected tick devices
* might stop. Note: TICK_BROADCAST_FORCE cannot be undone.
*
* Called with interrupts disabled, so clockevents_lock is not
* required here because the local clock event device cannot go away
* under us.
*/
static void tick_do_broadcast_on_off(unsigned long *reason)
void tick_broadcast_control(enum tick_broadcast_mode mode)
{
struct clock_event_device *bc, *dev;
struct tick_device *td;
unsigned long flags;
int cpu, bc_stopped;
raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
cpu = smp_processor_id();
td = &per_cpu(tick_cpu_device, cpu);
td = this_cpu_ptr(&tick_cpu_device);
dev = td->evtdev;
bc = tick_broadcast_device.evtdev;
/*
* Is the device not affected by the powerstate ?
*/
if (!dev || !(dev->features & CLOCK_EVT_FEAT_C3STOP))
goto out;
return;
if (!tick_device_is_functional(dev))
goto out;
return;
raw_spin_lock(&tick_broadcast_lock);
cpu = smp_processor_id();
bc = tick_broadcast_device.evtdev;
bc_stopped = cpumask_empty(tick_broadcast_mask);
switch (*reason) {
case CLOCK_EVT_NOTIFY_BROADCAST_ON:
case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
switch (mode) {
case TICK_BROADCAST_FORCE:
tick_broadcast_forced = 1;
case TICK_BROADCAST_ON:
cpumask_set_cpu(cpu, tick_broadcast_on);
if (!cpumask_test_and_set_cpu(cpu, tick_broadcast_mask)) {
if (tick_broadcast_device.mode ==
TICKDEV_MODE_PERIODIC)
clockevents_shutdown(dev);
}
if (*reason == CLOCK_EVT_NOTIFY_BROADCAST_FORCE)
tick_broadcast_force = 1;
break;
case CLOCK_EVT_NOTIFY_BROADCAST_OFF:
if (tick_broadcast_force)
case TICK_BROADCAST_OFF:
if (tick_broadcast_forced)
break;
cpumask_clear_cpu(cpu, tick_broadcast_on);
if (!tick_device_is_functional(dev))
@ -390,22 +395,9 @@ static void tick_do_broadcast_on_off(unsigned long *reason)
else
tick_broadcast_setup_oneshot(bc);
}
out:
raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
}
/*
* Powerstate information: The system enters/leaves a state, where
* affected devices might stop.
*/
void tick_broadcast_on_off(unsigned long reason, int *oncpu)
{
if (!cpumask_test_cpu(*oncpu, cpu_online_mask))
printk(KERN_ERR "tick-broadcast: ignoring broadcast for "
"offline CPU #%d\n", *oncpu);
else
tick_do_broadcast_on_off(&reason);
raw_spin_unlock(&tick_broadcast_lock);
}
EXPORT_SYMBOL_GPL(tick_broadcast_control);
/*
* Set the periodic handler depending on broadcast on/off

2
kernel/time/tick-internal.h
View File

@ -53,7 +53,6 @@ extern ssize_t sysfs_get_uname(const char *buf, char *dst, size_t cnt);
extern int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu);
extern void tick_install_broadcast_device(struct clock_event_device *dev);
extern int tick_is_broadcast_device(struct clock_event_device *dev);
extern void tick_broadcast_on_off(unsigned long reason, int *oncpu);
extern void tick_shutdown_broadcast(unsigned int *cpup);
extern void tick_suspend_broadcast(void);
extern void tick_resume_broadcast(void);
@ -68,7 +67,6 @@ static inline void tick_install_broadcast_device(struct clock_event_device *dev)
static inline int tick_is_broadcast_device(struct clock_event_device *dev) { return 0; }
static inline int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu) { return 0; }
static inline void tick_do_periodic_broadcast(struct clock_event_device *d) { }
static inline void tick_broadcast_on_off(unsigned long reason, int *oncpu) { }
static inline void tick_shutdown_broadcast(unsigned int *cpup) { }
static inline void tick_suspend_broadcast(void) { }
static inline void tick_resume_broadcast(void) { }