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authorLinus Torvalds <torvalds@linux-foundation.org>2008-09-06 19:33:26 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-09-06 19:33:26 -0700
commitf5325225658737e6c9cb8e24373e2c281a90be2a (patch)
treef1daf00b394b543876b6ffbfd67c050c3bb1b114 /kernel/time
parent4747832b56a95dbeb0cef4714e6fcc766eed0a95 (diff)
parent4ab6a219113197425ac112e35e1ec8062c69888e (diff)
Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: clocksource, acpi_pm.c: check for monotonicity clocksource, acpi_pm.c: use proper read function also in errata mode ntp: fix calculation of the next jiffie to trigger RTC sync x86: HPET: read back compare register before reading counter x86: HPET fix moronic 32/64bit thinko clockevents: broadcast fixup possible waiters HPET: make minimum reprogramming delta useful clockevents: prevent endless loop lockup clockevents: prevent multiple init/shutdown clockevents: enforce reprogram in oneshot setup clockevents: prevent endless loop in periodic broadcast handler clockevents: prevent clockevent event_handler ending up handler_noop
Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/clockevents.c3
-rw-r--r--kernel/time/ntp.c2
-rw-r--r--kernel/time/tick-broadcast.c78
-rw-r--r--kernel/time/tick-common.c1
-rw-r--r--kernel/time/tick-internal.h2
-rw-r--r--kernel/time/tick-oneshot.c46
6 files changed, 103 insertions, 29 deletions
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 3d1e3e1a197..1876b526c77 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -177,7 +177,7 @@ 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 +199,6 @@ 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);
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 5125ddd8196..1ad46f3df6e 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -245,7 +245,7 @@ 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 31463d370b9..2f5a38294bf 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);
@@ -223,6 +228,8 @@ 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:
@@ -245,9 +252,10 @@ static void tick_do_broadcast_on_off(void *why)
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_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
+ } else if (bc_stopped) {
if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
tick_broadcast_start_periodic(bc);
else
@@ -364,16 +372,8 @@ 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 +491,52 @@ 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;
+ }
}
/*
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index 80c4336f418..c4777193d56 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -161,6 +161,7 @@ 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;
diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index f13f2b7f4fd..0ffc2918ea6 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -17,6 +17,8 @@ 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 *));
diff --git a/kernel/time/tick-oneshot.c b/kernel/time/tick-oneshot.c
index 450c04935b6..2e35501e61d 100644
--- a/kernel/time/tick-oneshot.c
+++ b/kernel/time/tick-oneshot.c
@@ -23,24 +23,58 @@
#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) {
+ printk(KERN_WARNING "CE: __tick_program_event of %s is "
+ "stuck %llx %llx\n", dev->name ? dev->name : "?",
+ now.tv64, expires.tv64);
+ printk(KERN_WARNING
+ "CE: increasing min_delta_ns %ld to %ld nsec\n",
+ dev->min_delta_ns, dev->min_delta_ns << 1);
+ WARN_ON(1);
+
+ /* Double the min. delta and try again */
+ if (!dev->min_delta_ns)
+ dev->min_delta_ns = 5000;
+ else
+ 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 +95,7 @@ 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);
}
/**