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-rw-r--r--kernel/time/Kconfig1
-rw-r--r--kernel/time/clockevents.c15
-rw-r--r--kernel/time/ntp.c2
-rw-r--r--kernel/time/tick-broadcast.c99
-rw-r--r--kernel/time/tick-common.c15
-rw-r--r--kernel/time/tick-internal.h11
-rw-r--r--kernel/time/tick-oneshot.c44
-rw-r--r--kernel/time/tick-sched.c26
8 files changed, 163 insertions, 50 deletions
diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig
index 8d53106a0a92..95ed42951e0a 100644
--- a/kernel/time/Kconfig
+++ b/kernel/time/Kconfig
@@ -3,7 +3,6 @@
#
config TICK_ONESHOT
bool
- default n
config NO_HZ
bool "Tickless System (Dynamic Ticks)"
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 3d1e3e1a1971..f8d968063cea 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -72,6 +72,16 @@ void clockevents_set_mode(struct clock_event_device *dev,
}
/**
+ * clockevents_shutdown - shutdown the device and clear next_event
+ * @dev: device to shutdown
+ */
+void clockevents_shutdown(struct clock_event_device *dev)
+{
+ clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
+ dev->next_event.tv64 = KTIME_MAX;
+}
+
+/**
* clockevents_program_event - Reprogram the clock event device.
* @expires: absolute expiry time (monotonic clock)
*
@@ -177,7 +187,7 @@ void clockevents_register_device(struct clock_event_device *dev)
/*
* Noop handler when we shut down an event device
*/
-static void clockevents_handle_noop(struct clock_event_device *dev)
+void clockevents_handle_noop(struct clock_event_device *dev)
{
}
@@ -199,7 +209,6 @@ void clockevents_exchange_device(struct clock_event_device *old,
* released list and do a notify add later.
*/
if (old) {
- old->event_handler = clockevents_handle_noop;
clockevents_set_mode(old, CLOCK_EVT_MODE_UNUSED);
list_del(&old->list);
list_add(&old->list, &clockevents_released);
@@ -207,7 +216,7 @@ void clockevents_exchange_device(struct clock_event_device *old,
if (new) {
BUG_ON(new->mode != CLOCK_EVT_MODE_UNUSED);
- clockevents_set_mode(new, CLOCK_EVT_MODE_SHUTDOWN);
+ clockevents_shutdown(new);
}
local_irq_restore(flags);
}
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 4c8d85421d24..9c114b726ab3 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -244,7 +244,7 @@ static void sync_cmos_clock(unsigned long dummy)
if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2)
fail = update_persistent_clock(now);
- next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec;
+ next.tv_nsec = (NSEC_PER_SEC / 2) - now.tv_nsec - (TICK_NSEC / 2);
if (next.tv_nsec <= 0)
next.tv_nsec += NSEC_PER_SEC;
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 31463d370b94..cb01cd8f919b 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -175,6 +175,8 @@ static void tick_do_periodic_broadcast(void)
*/
static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
{
+ ktime_t next;
+
tick_do_periodic_broadcast();
/*
@@ -185,10 +187,13 @@ static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
/*
* Setup the next period for devices, which do not have
- * periodic mode:
+ * periodic mode. We read dev->next_event first and add to it
+ * when the event alrady expired. clockevents_program_event()
+ * sets dev->next_event only when the event is really
+ * programmed to the device.
*/
- for (;;) {
- ktime_t next = ktime_add(dev->next_event, tick_period);
+ for (next = dev->next_event; ;) {
+ next = ktime_add(next, tick_period);
if (!clockevents_program_event(dev, next, ktime_get()))
return;
@@ -205,7 +210,7 @@ static void tick_do_broadcast_on_off(void *why)
struct clock_event_device *bc, *dev;
struct tick_device *td;
unsigned long flags, *reason = why;
- int cpu;
+ int cpu, bc_stopped;
spin_lock_irqsave(&tick_broadcast_lock, flags);
@@ -223,14 +228,16 @@ static void tick_do_broadcast_on_off(void *why)
if (!tick_device_is_functional(dev))
goto out;
+ bc_stopped = cpus_empty(tick_broadcast_mask);
+
switch (*reason) {
case CLOCK_EVT_NOTIFY_BROADCAST_ON:
case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
if (!cpu_isset(cpu, tick_broadcast_mask)) {
cpu_set(cpu, tick_broadcast_mask);
- if (td->mode == TICKDEV_MODE_PERIODIC)
- clockevents_set_mode(dev,
- CLOCK_EVT_MODE_SHUTDOWN);
+ if (tick_broadcast_device.mode ==
+ TICKDEV_MODE_PERIODIC)
+ clockevents_shutdown(dev);
}
if (*reason == CLOCK_EVT_NOTIFY_BROADCAST_FORCE)
tick_broadcast_force = 1;
@@ -239,15 +246,17 @@ static void tick_do_broadcast_on_off(void *why)
if (!tick_broadcast_force &&
cpu_isset(cpu, tick_broadcast_mask)) {
cpu_clear(cpu, tick_broadcast_mask);
- if (td->mode == TICKDEV_MODE_PERIODIC)
+ if (tick_broadcast_device.mode ==
+ TICKDEV_MODE_PERIODIC)
tick_setup_periodic(dev, 0);
}
break;
}
- if (cpus_empty(tick_broadcast_mask))
- clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
- else {
+ if (cpus_empty(tick_broadcast_mask)) {
+ if (!bc_stopped)
+ clockevents_shutdown(bc);
+ } else if (bc_stopped) {
if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
tick_broadcast_start_periodic(bc);
else
@@ -298,7 +307,7 @@ void tick_shutdown_broadcast(unsigned int *cpup)
if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) {
if (bc && cpus_empty(tick_broadcast_mask))
- clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
+ clockevents_shutdown(bc);
}
spin_unlock_irqrestore(&tick_broadcast_lock, flags);
@@ -313,7 +322,7 @@ void tick_suspend_broadcast(void)
bc = tick_broadcast_device.evtdev;
if (bc)
- clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
+ clockevents_shutdown(bc);
spin_unlock_irqrestore(&tick_broadcast_lock, flags);
}
@@ -364,16 +373,8 @@ cpumask_t *tick_get_broadcast_oneshot_mask(void)
static int tick_broadcast_set_event(ktime_t expires, int force)
{
struct clock_event_device *bc = tick_broadcast_device.evtdev;
- ktime_t now = ktime_get();
- int res;
-
- for(;;) {
- res = clockevents_program_event(bc, expires, now);
- if (!res || !force)
- return res;
- now = ktime_get();
- expires = ktime_add(now, ktime_set(0, bc->min_delta_ns));
- }
+
+ return tick_dev_program_event(bc, expires, force);
}
int tick_resume_broadcast_oneshot(struct clock_event_device *bc)
@@ -491,14 +492,52 @@ static void tick_broadcast_clear_oneshot(int cpu)
cpu_clear(cpu, tick_broadcast_oneshot_mask);
}
+static void tick_broadcast_init_next_event(cpumask_t *mask, ktime_t expires)
+{
+ struct tick_device *td;
+ int cpu;
+
+ for_each_cpu_mask_nr(cpu, *mask) {
+ td = &per_cpu(tick_cpu_device, cpu);
+ if (td->evtdev)
+ td->evtdev->next_event = expires;
+ }
+}
+
/**
* tick_broadcast_setup_oneshot - setup the broadcast device
*/
void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
{
- bc->event_handler = tick_handle_oneshot_broadcast;
- clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
- bc->next_event.tv64 = KTIME_MAX;
+ /* Set it up only once ! */
+ if (bc->event_handler != tick_handle_oneshot_broadcast) {
+ int was_periodic = bc->mode == CLOCK_EVT_MODE_PERIODIC;
+ int cpu = smp_processor_id();
+ cpumask_t mask;
+
+ bc->event_handler = tick_handle_oneshot_broadcast;
+ clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
+
+ /* Take the do_timer update */
+ tick_do_timer_cpu = cpu;
+
+ /*
+ * We must be careful here. There might be other CPUs
+ * waiting for periodic broadcast. We need to set the
+ * oneshot_mask bits for those and program the
+ * broadcast device to fire.
+ */
+ mask = tick_broadcast_mask;
+ cpu_clear(cpu, mask);
+ cpus_or(tick_broadcast_oneshot_mask,
+ tick_broadcast_oneshot_mask, mask);
+
+ if (was_periodic && !cpus_empty(mask)) {
+ tick_broadcast_init_next_event(&mask, tick_next_period);
+ tick_broadcast_set_event(tick_next_period, 1);
+ } else
+ bc->next_event.tv64 = KTIME_MAX;
+ }
}
/*
@@ -538,4 +577,12 @@ void tick_shutdown_broadcast_oneshot(unsigned int *cpup)
spin_unlock_irqrestore(&tick_broadcast_lock, flags);
}
+/*
+ * Check, whether the broadcast device is in one shot mode
+ */
+int tick_broadcast_oneshot_active(void)
+{
+ return tick_broadcast_device.mode == TICKDEV_MODE_ONESHOT;
+}
+
#endif
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index 80c4336f4188..df12434b43ca 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -33,7 +33,7 @@ DEFINE_PER_CPU(struct tick_device, tick_cpu_device);
*/
ktime_t tick_next_period;
ktime_t tick_period;
-int tick_do_timer_cpu __read_mostly = -1;
+int tick_do_timer_cpu __read_mostly = TICK_DO_TIMER_BOOT;
DEFINE_SPINLOCK(tick_device_lock);
/*
@@ -109,7 +109,8 @@ void tick_setup_periodic(struct clock_event_device *dev, int broadcast)
if (!tick_device_is_functional(dev))
return;
- if (dev->features & CLOCK_EVT_FEAT_PERIODIC) {
+ if ((dev->features & CLOCK_EVT_FEAT_PERIODIC) &&
+ !tick_broadcast_oneshot_active()) {
clockevents_set_mode(dev, CLOCK_EVT_MODE_PERIODIC);
} else {
unsigned long seq;
@@ -148,7 +149,7 @@ static void tick_setup_device(struct tick_device *td,
* If no cpu took the do_timer update, assign it to
* this cpu:
*/
- if (tick_do_timer_cpu == -1) {
+ if (tick_do_timer_cpu == TICK_DO_TIMER_BOOT) {
tick_do_timer_cpu = cpu;
tick_next_period = ktime_get();
tick_period = ktime_set(0, NSEC_PER_SEC / HZ);
@@ -161,6 +162,7 @@ static void tick_setup_device(struct tick_device *td,
} else {
handler = td->evtdev->event_handler;
next_event = td->evtdev->next_event;
+ td->evtdev->event_handler = clockevents_handle_noop;
}
td->evtdev = newdev;
@@ -248,7 +250,7 @@ static int tick_check_new_device(struct clock_event_device *newdev)
* not give it back to the clockevents layer !
*/
if (tick_is_broadcast_device(curdev)) {
- clockevents_set_mode(curdev, CLOCK_EVT_MODE_SHUTDOWN);
+ clockevents_shutdown(curdev);
curdev = NULL;
}
clockevents_exchange_device(curdev, newdev);
@@ -299,7 +301,8 @@ static void tick_shutdown(unsigned int *cpup)
if (*cpup == tick_do_timer_cpu) {
int cpu = first_cpu(cpu_online_map);
- tick_do_timer_cpu = (cpu != NR_CPUS) ? cpu : -1;
+ tick_do_timer_cpu = (cpu != NR_CPUS) ? cpu :
+ TICK_DO_TIMER_NONE;
}
spin_unlock_irqrestore(&tick_device_lock, flags);
}
@@ -310,7 +313,7 @@ static void tick_suspend(void)
unsigned long flags;
spin_lock_irqsave(&tick_device_lock, flags);
- clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_SHUTDOWN);
+ clockevents_shutdown(td->evtdev);
spin_unlock_irqrestore(&tick_device_lock, flags);
}
diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index f13f2b7f4fd4..469248782c23 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -1,6 +1,10 @@
/*
* tick internal variable and functions used by low/high res code
*/
+
+#define TICK_DO_TIMER_NONE -1
+#define TICK_DO_TIMER_BOOT -2
+
DECLARE_PER_CPU(struct tick_device, tick_cpu_device);
extern spinlock_t tick_device_lock;
extern ktime_t tick_next_period;
@@ -10,6 +14,8 @@ 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 clockevents_shutdown(struct clock_event_device *dev);
+
/*
* NO_HZ / high resolution timer shared code
*/
@@ -17,6 +23,8 @@ extern void tick_handle_periodic(struct clock_event_device *dev);
extern void tick_setup_oneshot(struct clock_event_device *newdev,
void (*handler)(struct clock_event_device *),
ktime_t nextevt);
+extern int tick_dev_program_event(struct clock_event_device *dev,
+ ktime_t expires, int force);
extern int tick_program_event(ktime_t expires, int force);
extern void tick_oneshot_notify(void);
extern int tick_switch_to_oneshot(void (*handler)(struct clock_event_device *));
@@ -27,6 +35,7 @@ extern void 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_resume_broadcast_oneshot(struct clock_event_device *bc);
+extern int tick_broadcast_oneshot_active(void);
# else /* BROADCAST */
static inline void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
{
@@ -35,6 +44,7 @@ static inline void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
static inline void tick_broadcast_oneshot_control(unsigned long reason) { }
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; }
# endif /* !BROADCAST */
#else /* !ONESHOT */
@@ -64,6 +74,7 @@ static inline int tick_resume_broadcast_oneshot(struct clock_event_device *bc)
{
return 0;
}
+static inline int tick_broadcast_oneshot_active(void) { return 0; }
#endif /* !TICK_ONESHOT */
/*
diff --git a/kernel/time/tick-oneshot.c b/kernel/time/tick-oneshot.c
index 450c04935b66..2e8de678e767 100644
--- a/kernel/time/tick-oneshot.c
+++ b/kernel/time/tick-oneshot.c
@@ -23,24 +23,56 @@
#include "tick-internal.h"
/**
- * tick_program_event
+ * tick_program_event internal worker function
*/
-int tick_program_event(ktime_t expires, int force)
+int tick_dev_program_event(struct clock_event_device *dev, ktime_t expires,
+ int force)
{
- struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev;
ktime_t now = ktime_get();
+ int i;
- while (1) {
+ for (i = 0;;) {
int ret = clockevents_program_event(dev, expires, now);
if (!ret || !force)
return ret;
+
+ /*
+ * We tried 2 times to program the device with the given
+ * min_delta_ns. If that's not working then we double it
+ * and emit a warning.
+ */
+ if (++i > 2) {
+ /* Increase the min. delta and try again */
+ if (!dev->min_delta_ns)
+ dev->min_delta_ns = 5000;
+ else
+ dev->min_delta_ns += dev->min_delta_ns >> 1;
+
+ printk(KERN_WARNING
+ "CE: %s increasing min_delta_ns to %lu nsec\n",
+ dev->name ? dev->name : "?",
+ dev->min_delta_ns << 1);
+
+ i = 0;
+ }
+
now = ktime_get();
- expires = ktime_add(now, ktime_set(0, dev->min_delta_ns));
+ expires = ktime_add_ns(now, dev->min_delta_ns);
}
}
/**
+ * tick_program_event
+ */
+int tick_program_event(ktime_t expires, int force)
+{
+ struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev;
+
+ return tick_dev_program_event(dev, expires, force);
+}
+
+/**
* tick_resume_onshot - resume oneshot mode
*/
void tick_resume_oneshot(void)
@@ -61,7 +93,7 @@ void tick_setup_oneshot(struct clock_event_device *newdev,
{
newdev->event_handler = handler;
clockevents_set_mode(newdev, CLOCK_EVT_MODE_ONESHOT);
- clockevents_program_event(newdev, next_event, ktime_get());
+ tick_dev_program_event(newdev, next_event, 1);
}
/**
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index b33be61c0f6b..a547be11cf97 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -20,6 +20,7 @@
#include <linux/profile.h>
#include <linux/sched.h>
#include <linux/tick.h>
+#include <linux/module.h>
#include <asm/irq_regs.h>
@@ -75,6 +76,9 @@ static void tick_do_update_jiffies64(ktime_t now)
incr * ticks);
}
do_timer(++ticks);
+
+ /* Keep the tick_next_period variable up to date */
+ tick_next_period = ktime_add(last_jiffies_update, tick_period);
}
write_sequnlock(&xtime_lock);
}
@@ -187,9 +191,17 @@ u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time)
{
struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
- *last_update_time = ktime_to_us(ts->idle_lastupdate);
+ if (!tick_nohz_enabled)
+ return -1;
+
+ if (ts->idle_active)
+ *last_update_time = ktime_to_us(ts->idle_lastupdate);
+ else
+ *last_update_time = ktime_to_us(ktime_get());
+
return ktime_to_us(ts->idle_sleeptime);
}
+EXPORT_SYMBOL_GPL(get_cpu_idle_time_us);
/**
* tick_nohz_stop_sched_tick - stop the idle tick from the idle task
@@ -221,7 +233,7 @@ void tick_nohz_stop_sched_tick(int inidle)
*/
if (unlikely(!cpu_online(cpu))) {
if (cpu == tick_do_timer_cpu)
- tick_do_timer_cpu = -1;
+ tick_do_timer_cpu = TICK_DO_TIMER_NONE;
}
if (unlikely(ts->nohz_mode == NOHZ_MODE_INACTIVE))
@@ -258,7 +270,7 @@ void tick_nohz_stop_sched_tick(int inidle)
next_jiffies = get_next_timer_interrupt(last_jiffies);
delta_jiffies = next_jiffies - last_jiffies;
- if (rcu_needs_cpu(cpu))
+ if (rcu_needs_cpu(cpu) || printk_needs_cpu(cpu))
delta_jiffies = 1;
/*
* Do not stop the tick, if we are only one off
@@ -303,7 +315,7 @@ void tick_nohz_stop_sched_tick(int inidle)
* invoked.
*/
if (cpu == tick_do_timer_cpu)
- tick_do_timer_cpu = -1;
+ tick_do_timer_cpu = TICK_DO_TIMER_NONE;
ts->idle_sleeps++;
@@ -468,7 +480,7 @@ static void tick_nohz_handler(struct clock_event_device *dev)
* this duty, then the jiffies update is still serialized by
* xtime_lock.
*/
- if (unlikely(tick_do_timer_cpu == -1))
+ if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_NONE))
tick_do_timer_cpu = cpu;
/* Check, if the jiffies need an update */
@@ -570,7 +582,7 @@ static enum hrtimer_restart tick_sched_timer(struct hrtimer *timer)
* this duty, then the jiffies update is still serialized by
* xtime_lock.
*/
- if (unlikely(tick_do_timer_cpu == -1))
+ if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_NONE))
tick_do_timer_cpu = cpu;
#endif
@@ -622,7 +634,7 @@ void tick_setup_sched_timer(void)
*/
hrtimer_init(&ts->sched_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
ts->sched_timer.function = tick_sched_timer;
- ts->sched_timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
+ ts->sched_timer.cb_mode = HRTIMER_CB_IRQSAFE_PERCPU;
/* Get the next period (per cpu) */
hrtimer_set_expires(&ts->sched_timer, tick_init_jiffy_update());
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-27 11:07:13 +0000