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authorLinus Torvalds <torvalds@linux-foundation.org>2009-09-18 09:15:24 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-18 09:15:24 -0700
commita03fdb7612874834d6847107198712d18b5242c7 (patch)
tree9ae81170509fd8b1c23d1b7e8edfa7a2203ffce3 /kernel
parent202c4675c55ddf6b443c7e057d2dff6b42ef71aa (diff)
parent12e09337fe238981cb0c87543306e23775d1a143 (diff)
Merge branch 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (34 commits) time: Prevent 32 bit overflow with set_normalized_timespec() clocksource: Delay clocksource down rating to late boot clocksource: clocksource_select must be called with mutex locked clocksource: Resolve cpu hotplug dead lock with TSC unstable, fix crash timers: Drop a function prototype clocksource: Resolve cpu hotplug dead lock with TSC unstable timer.c: Fix S/390 comments timekeeping: Fix invalid getboottime() value timekeeping: Fix up read_persistent_clock() breakage on sh timekeeping: Increase granularity of read_persistent_clock(), build fix time: Introduce CLOCK_REALTIME_COARSE x86: Do not unregister PIT clocksource on PIT oneshot setup/shutdown clocksource: Avoid clocksource watchdog circular locking dependency clocksource: Protect the watchdog rating changes with clocksource_mutex clocksource: Call clocksource_change_rating() outside of watchdog_lock timekeeping: Introduce read_boot_clock timekeeping: Increase granularity of read_persistent_clock() timekeeping: Update clocksource with stop_machine timekeeping: Add timekeeper read_clock helper functions timekeeping: Move NTP adjusted clock multiplier to struct timekeeper ... Fix trivial conflict due to MIPS lemote -> loongson renaming.
Diffstat (limited to 'kernel')
-rw-r--r--kernel/hrtimer.c57
-rw-r--r--kernel/posix-timers.c35
-rw-r--r--kernel/time.c9
-rw-r--r--kernel/time/clocksource.c529
-rw-r--r--kernel/time/jiffies.c6
-rw-r--r--kernel/time/ntp.c7
-rw-r--r--kernel/time/timekeeping.c535
-rw-r--r--kernel/timer.c28
8 files changed, 780 insertions, 426 deletions
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 05071bf6a37..c03f221fee4 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -48,37 +48,6 @@
#include <asm/uaccess.h>
-/**
- * ktime_get - get the monotonic time in ktime_t format
- *
- * returns the time in ktime_t format
- */
-ktime_t ktime_get(void)
-{
- struct timespec now;
-
- ktime_get_ts(&now);
-
- return timespec_to_ktime(now);
-}
-EXPORT_SYMBOL_GPL(ktime_get);
-
-/**
- * ktime_get_real - get the real (wall-) time in ktime_t format
- *
- * returns the time in ktime_t format
- */
-ktime_t ktime_get_real(void)
-{
- struct timespec now;
-
- getnstimeofday(&now);
-
- return timespec_to_ktime(now);
-}
-
-EXPORT_SYMBOL_GPL(ktime_get_real);
-
/*
* The timer bases:
*
@@ -106,31 +75,6 @@ DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
}
};
-/**
- * ktime_get_ts - get the monotonic clock in timespec format
- * @ts: pointer to timespec variable
- *
- * The function calculates the monotonic clock from the realtime
- * clock and the wall_to_monotonic offset and stores the result
- * in normalized timespec format in the variable pointed to by @ts.
- */
-void ktime_get_ts(struct timespec *ts)
-{
- struct timespec tomono;
- unsigned long seq;
-
- do {
- seq = read_seqbegin(&xtime_lock);
- getnstimeofday(ts);
- tomono = wall_to_monotonic;
-
- } while (read_seqretry(&xtime_lock, seq));
-
- set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec,
- ts->tv_nsec + tomono.tv_nsec);
-}
-EXPORT_SYMBOL_GPL(ktime_get_ts);
-
/*
* Get the coarse grained time at the softirq based on xtime and
* wall_to_monotonic.
@@ -1155,7 +1099,6 @@ static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
clock_id = CLOCK_MONOTONIC;
timer->base = &cpu_base->clock_base[clock_id];
- INIT_LIST_HEAD(&timer->cb_entry);
hrtimer_init_timer_hres(timer);
#ifdef CONFIG_TIMER_STATS
diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c
index d089d052c4a..495440779ce 100644
--- a/kernel/posix-timers.c
+++ b/kernel/posix-timers.c
@@ -242,6 +242,25 @@ static int posix_get_monotonic_raw(clockid_t which_clock, struct timespec *tp)
return 0;
}
+
+static int posix_get_realtime_coarse(clockid_t which_clock, struct timespec *tp)
+{
+ *tp = current_kernel_time();
+ return 0;
+}
+
+static int posix_get_monotonic_coarse(clockid_t which_clock,
+ struct timespec *tp)
+{
+ *tp = get_monotonic_coarse();
+ return 0;
+}
+
+int posix_get_coarse_res(const clockid_t which_clock, struct timespec *tp)
+{
+ *tp = ktime_to_timespec(KTIME_LOW_RES);
+ return 0;
+}
/*
* Initialize everything, well, just everything in Posix clocks/timers ;)
*/
@@ -262,10 +281,26 @@ static __init int init_posix_timers(void)
.timer_create = no_timer_create,
.nsleep = no_nsleep,
};
+ struct k_clock clock_realtime_coarse = {
+ .clock_getres = posix_get_coarse_res,
+ .clock_get = posix_get_realtime_coarse,
+ .clock_set = do_posix_clock_nosettime,
+ .timer_create = no_timer_create,
+ .nsleep = no_nsleep,
+ };
+ struct k_clock clock_monotonic_coarse = {
+ .clock_getres = posix_get_coarse_res,
+ .clock_get = posix_get_monotonic_coarse,
+ .clock_set = do_posix_clock_nosettime,
+ .timer_create = no_timer_create,
+ .nsleep = no_nsleep,
+ };
register_posix_clock(CLOCK_REALTIME, &clock_realtime);
register_posix_clock(CLOCK_MONOTONIC, &clock_monotonic);
register_posix_clock(CLOCK_MONOTONIC_RAW, &clock_monotonic_raw);
+ register_posix_clock(CLOCK_REALTIME_COARSE, &clock_realtime_coarse);
+ register_posix_clock(CLOCK_MONOTONIC_COARSE, &clock_monotonic_coarse);
posix_timers_cache = kmem_cache_create("posix_timers_cache",
sizeof (struct k_itimer), 0, SLAB_PANIC,
diff --git a/kernel/time.c b/kernel/time.c
index 29511943871..2e2e469a7fe 100644
--- a/kernel/time.c
+++ b/kernel/time.c
@@ -370,13 +370,20 @@ EXPORT_SYMBOL(mktime);
* 0 <= tv_nsec < NSEC_PER_SEC
* For negative values only the tv_sec field is negative !
*/
-void set_normalized_timespec(struct timespec *ts, time_t sec, long nsec)
+void set_normalized_timespec(struct timespec *ts, time_t sec, s64 nsec)
{
while (nsec >= NSEC_PER_SEC) {
+ /*
+ * The following asm() prevents the compiler from
+ * optimising this loop into a modulo operation. See
+ * also __iter_div_u64_rem() in include/linux/time.h
+ */
+ asm("" : "+rm"(nsec));
nsec -= NSEC_PER_SEC;
++sec;
}
while (nsec < 0) {
+ asm("" : "+rm"(nsec));
nsec += NSEC_PER_SEC;
--sec;
}
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 7466cb81125..09113347d32 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -21,7 +21,6 @@
*
* TODO WishList:
* o Allow clocksource drivers to be unregistered
- * o get rid of clocksource_jiffies extern
*/
#include <linux/clocksource.h>
@@ -30,6 +29,7 @@
#include <linux/module.h>
#include <linux/sched.h> /* for spin_unlock_irq() using preempt_count() m68k */
#include <linux/tick.h>
+#include <linux/kthread.h>
void timecounter_init(struct timecounter *tc,
const struct cyclecounter *cc,
@@ -107,50 +107,35 @@ u64 timecounter_cyc2time(struct timecounter *tc,
}
EXPORT_SYMBOL(timecounter_cyc2time);
-/* XXX - Would like a better way for initializing curr_clocksource */
-extern struct clocksource clocksource_jiffies;
-
/*[Clocksource internal variables]---------
* curr_clocksource:
- * currently selected clocksource. Initialized to clocksource_jiffies.
- * next_clocksource:
- * pending next selected clocksource.
+ * currently selected clocksource.
* clocksource_list:
* linked list with the registered clocksources
- * clocksource_lock:
- * protects manipulations to curr_clocksource and next_clocksource
- * and the clocksource_list
+ * clocksource_mutex:
+ * protects manipulations to curr_clocksource and the clocksource_list
* override_name:
* Name of the user-specified clocksource.
*/
-static struct clocksource *curr_clocksource = &clocksource_jiffies;
-static struct clocksource *next_clocksource;
-static struct clocksource *clocksource_override;
+static struct clocksource *curr_clocksource;
static LIST_HEAD(clocksource_list);
-static DEFINE_SPINLOCK(clocksource_lock);
+static DEFINE_MUTEX(clocksource_mutex);
static char override_name[32];
static int finished_booting;
-/* clocksource_done_booting - Called near the end of core bootup
- *
- * Hack to avoid lots of clocksource churn at boot time.
- * We use fs_initcall because we want this to start before
- * device_initcall but after subsys_initcall.
- */
-static int __init clocksource_done_booting(void)
-{
- finished_booting = 1;
- return 0;
-}
-fs_initcall(clocksource_done_booting);
-
#ifdef CONFIG_CLOCKSOURCE_WATCHDOG
+static void clocksource_watchdog_work(struct work_struct *work);
+
static LIST_HEAD(watchdog_list);
static struct clocksource *watchdog;
static struct timer_list watchdog_timer;
+static DECLARE_WORK(watchdog_work, clocksource_watchdog_work);
static DEFINE_SPINLOCK(watchdog_lock);
static cycle_t watchdog_last;
-static unsigned long watchdog_resumed;
+static int watchdog_running;
+
+static int clocksource_watchdog_kthread(void *data);
+static void __clocksource_change_rating(struct clocksource *cs, int rating);
/*
* Interval: 0.5sec Threshold: 0.0625s
@@ -158,135 +143,249 @@ static unsigned long watchdog_resumed;
#define WATCHDOG_INTERVAL (HZ >> 1)
#define WATCHDOG_THRESHOLD (NSEC_PER_SEC >> 4)
-static void clocksource_ratewd(struct clocksource *cs, int64_t delta)
+static void clocksource_watchdog_work(struct work_struct *work)
{
- if (delta > -WATCHDOG_THRESHOLD && delta < WATCHDOG_THRESHOLD)
- return;
+ /*
+ * If kthread_run fails the next watchdog scan over the
+ * watchdog_list will find the unstable clock again.
+ */
+ kthread_run(clocksource_watchdog_kthread, NULL, "kwatchdog");
+}
+static void __clocksource_unstable(struct clocksource *cs)
+{
+ cs->flags &= ~(CLOCK_SOURCE_VALID_FOR_HRES | CLOCK_SOURCE_WATCHDOG);
+ cs->flags |= CLOCK_SOURCE_UNSTABLE;
+ if (finished_booting)
+ schedule_work(&watchdog_work);
+}
+
+static void clocksource_unstable(struct clocksource *cs, int64_t delta)
+{
printk(KERN_WARNING "Clocksource %s unstable (delta = %Ld ns)\n",
cs->name, delta);
- cs->flags &= ~(CLOCK_SOURCE_VALID_FOR_HRES | CLOCK_SOURCE_WATCHDOG);
- clocksource_change_rating(cs, 0);
- list_del(&cs->wd_list);
+ __clocksource_unstable(cs);
+}
+
+/**
+ * clocksource_mark_unstable - mark clocksource unstable via watchdog
+ * @cs: clocksource to be marked unstable
+ *
+ * This function is called instead of clocksource_change_rating from
+ * cpu hotplug code to avoid a deadlock between the clocksource mutex
+ * and the cpu hotplug mutex. It defers the update of the clocksource
+ * to the watchdog thread.
+ */
+void clocksource_mark_unstable(struct clocksource *cs)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&watchdog_lock, flags);
+ if (!(cs->flags & CLOCK_SOURCE_UNSTABLE)) {
+ if (list_empty(&cs->wd_list))
+ list_add(&cs->wd_list, &watchdog_list);
+ __clocksource_unstable(cs);
+ }
+ spin_unlock_irqrestore(&watchdog_lock, flags);
}
static void clocksource_watchdog(unsigned long data)
{
- struct clocksource *cs, *tmp;
+ struct clocksource *cs;
cycle_t csnow, wdnow;
int64_t wd_nsec, cs_nsec;
- int resumed;
+ int next_cpu;
spin_lock(&watchdog_lock);
-
- resumed = test_and_clear_bit(0, &watchdog_resumed);
+ if (!watchdog_running)
+ goto out;
wdnow = watchdog->read(watchdog);
- wd_nsec = cyc2ns(watchdog, (wdnow - watchdog_last) & watchdog->mask);
+ wd_nsec = clocksource_cyc2ns((wdnow - watchdog_last) & watchdog->mask,
+ watchdog->mult, watchdog->shift);
watchdog_last = wdnow;
- list_for_each_entry_safe(cs, tmp, &watchdog_list, wd_list) {
- csnow = cs->read(cs);
+ list_for_each_entry(cs, &watchdog_list, wd_list) {
- if (unlikely(resumed)) {
- cs->wd_last = csnow;
+ /* Clocksource already marked unstable? */
+ if (cs->flags & CLOCK_SOURCE_UNSTABLE) {
+ if (finished_booting)
+ schedule_work(&watchdog_work);
continue;
}
- /* Initialized ? */
+ csnow = cs->read(cs);
+
+ /* Clocksource initialized ? */
if (!(cs->flags & CLOCK_SOURCE_WATCHDOG)) {
- if ((cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) &&
- (watchdog->flags & CLOCK_SOURCE_IS_CONTINUOUS)) {
- cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES;
- /*
- * We just marked the clocksource as
- * highres-capable, notify the rest of the
- * system as well so that we transition
- * into high-res mode:
- */
- tick_clock_notify();
- }
cs->flags |= CLOCK_SOURCE_WATCHDOG;
cs->wd_last = csnow;
- } else {
- cs_nsec = cyc2ns(cs, (csnow - cs->wd_last) & cs->mask);
- cs->wd_last = csnow;
- /* Check the delta. Might remove from the list ! */
- clocksource_ratewd(cs, cs_nsec - wd_nsec);
+ continue;
}
- }
- if (!list_empty(&watchdog_list)) {
- /*
- * Cycle through CPUs to check if the CPUs stay
- * synchronized to each other.
- */
- int next_cpu = cpumask_next(raw_smp_processor_id(),
- cpu_online_mask);
+ /* Check the deviation from the watchdog clocksource. */
+ cs_nsec = clocksource_cyc2ns((csnow - cs->wd_last) &
+ cs->mask, cs->mult, cs->shift);
+ cs->wd_last = csnow;
+ if (abs(cs_nsec - wd_nsec) > WATCHDOG_THRESHOLD) {
+ clocksource_unstable(cs, cs_nsec - wd_nsec);
+ continue;
+ }
- if (next_cpu >= nr_cpu_ids)
- next_cpu = cpumask_first(cpu_online_mask);
- watchdog_timer.expires += WATCHDOG_INTERVAL;
- add_timer_on(&watchdog_timer, next_cpu);
+ if (!(cs->flags & CLOCK_SOURCE_VALID_FOR_HRES) &&
+ (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) &&
+ (watchdog->flags & CLOCK_SOURCE_IS_CONTINUOUS)) {
+ cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES;
+ /*
+ * We just marked the clocksource as highres-capable,
+ * notify the rest of the system as well so that we
+ * transition into high-res mode:
+ */
+ tick_clock_notify();
+ }
}
+
+ /*
+ * Cycle through CPUs to check if the CPUs stay synchronized
+ * to each other.
+ */
+ next_cpu = cpumask_next(raw_smp_processor_id(), cpu_online_mask);
+ if (next_cpu >= nr_cpu_ids)
+ next_cpu = cpumask_first(cpu_online_mask);
+ watchdog_timer.expires += WATCHDOG_INTERVAL;
+ add_timer_on(&watchdog_timer, next_cpu);
+out:
spin_unlock(&watchdog_lock);
}
+
+static inline void clocksource_start_watchdog(void)
+{
+ if (watchdog_running || !watchdog || list_empty(&watchdog_list))
+ return;
+ init_timer(&watchdog_timer);
+ watchdog_timer.function = clocksource_watchdog;
+ watchdog_last = watchdog->read(watchdog);
+ watchdog_timer.expires = jiffies + WATCHDOG_INTERVAL;
+ add_timer_on(&watchdog_timer, cpumask_first(cpu_online_mask));
+ watchdog_running = 1;
+}
+
+static inline void clocksource_stop_watchdog(void)
+{
+ if (!watchdog_running || (watchdog && !list_empty(&watchdog_list)))
+ return;
+ del_timer(&watchdog_timer);
+ watchdog_running = 0;
+}
+
+static inline void clocksource_reset_watchdog(void)
+{
+ struct clocksource *cs;
+
+ list_for_each_entry(cs, &watchdog_list, wd_list)
+ cs->flags &= ~CLOCK_SOURCE_WATCHDOG;
+}
+
static void clocksource_resume_watchdog(void)
{
- set_bit(0, &watchdog_resumed);
+ unsigned long flags;
+
+ spin_lock_irqsave(&watchdog_lock, flags);
+ clocksource_reset_watchdog();
+ spin_unlock_irqrestore(&watchdog_lock, flags);
}
-static void clocksource_check_watchdog(struct clocksource *cs)
+static void clocksource_enqueue_watchdog(struct clocksource *cs)
{
- struct clocksource *cse;
unsigned long flags;
spin_lock_irqsave(&watchdog_lock, flags);
if (cs->flags & CLOCK_SOURCE_MUST_VERIFY) {
- int started = !list_empty(&watchdog_list);
-
+ /* cs is a clocksource to be watched. */
list_add(&cs->wd_list, &watchdog_list);
- if (!started && watchdog) {
- watchdog_last = watchdog->read(watchdog);
- watchdog_timer.expires = jiffies + WATCHDOG_INTERVAL;
- add_timer_on(&watchdog_timer,
- cpumask_first(cpu_online_mask));
- }
+ cs->flags &= ~CLOCK_SOURCE_WATCHDOG;
} else {
+ /* cs is a watchdog. */
if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS)
cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES;
-
+ /* Pick the best watchdog. */
if (!watchdog || cs->rating > watchdog->rating) {
- if (watchdog)
- del_timer(&watchdog_timer);
watchdog = cs;
- init_timer(&watchdog_timer);
- watchdog_timer.function = clocksource_watchdog;
-
/* Reset watchdog cycles */
- list_for_each_entry(cse, &watchdog_list, wd_list)
- cse->flags &= ~CLOCK_SOURCE_WATCHDOG;
- /* Start if list is not empty */
- if (!list_empty(&watchdog_list)) {
- watchdog_last = watchdog->read(watchdog);
- watchdog_timer.expires =
- jiffies + WATCHDOG_INTERVAL;
- add_timer_on(&watchdog_timer,
- cpumask_first(cpu_online_mask));
- }
+ clocksource_reset_watchdog();
+ }
+ }
+ /* Check if the watchdog timer needs to be started. */
+ clocksource_start_watchdog();
+ spin_unlock_irqrestore(&watchdog_lock, flags);
+}
+
+static void clocksource_dequeue_watchdog(struct clocksource *cs)
+{
+ struct clocksource *tmp;
+ unsigned long flags;
+
+ spin_lock_irqsave(&watchdog_lock, flags);
+ if (cs->flags & CLOCK_SOURCE_MUST_VERIFY) {
+ /* cs is a watched clocksource. */
+ list_del_init(&cs->wd_list);
+ } else if (cs == watchdog) {
+ /* Reset watchdog cycles */
+ clocksource_reset_watchdog();
+ /* Current watchdog is removed. Find an alternative. */
+ watchdog = NULL;
+ list_for_each_entry(tmp, &clocksource_list, list) {
+ if (tmp == cs || tmp->flags & CLOCK_SOURCE_MUST_VERIFY)
+ continue;
+ if (!watchdog || tmp->rating > watchdog->rating)
+ watchdog = tmp;
}
}
+ cs->flags &= ~CLOCK_SOURCE_WATCHDOG;
+ /* Check if the watchdog timer needs to be stopped. */
+ clocksource_stop_watchdog();
spin_unlock_irqrestore(&watchdog_lock, flags);
}
-#else
-static void clocksource_check_watchdog(struct clocksource *cs)
+
+static int clocksource_watchdog_kthread(void *data)
+{
+ struct clocksource *cs, *tmp;
+ unsigned long flags;
+ LIST_HEAD(unstable);
+
+ mutex_lock(&clocksource_mutex);
+ spin_lock_irqsave(&watchdog_lock, flags);
+ list_for_each_entry_safe(cs, tmp, &watchdog_list, wd_list)
+ if (cs->flags & CLOCK_SOURCE_UNSTABLE) {
+ list_del_init(&cs->wd_list);
+ list_add(&cs->wd_list, &unstable);
+ }
+ /* Check if the watchdog timer needs to be stopped. */
+ clocksource_stop_watchdog();
+ spin_unlock_irqrestore(&watchdog_lock, flags);
+
+ /* Needs to be done outside of watchdog lock */
+ list_for_each_entry_safe(cs, tmp, &unstable, wd_list) {
+ list_del_init(&cs->wd_list);
+ __clocksource_change_rating(cs, 0);
+ }
+ mutex_unlock(&clocksource_mutex);
+ return 0;
+}
+
+#else /* CONFIG_CLOCKSOURCE_WATCHDOG */
+
+static void clocksource_enqueue_watchdog(struct clocksource *cs)
{
if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS)
cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES;
}
+static inline void clocksource_dequeue_watchdog(struct clocksource *cs) { }
static inline void clocksource_resume_watchdog(void) { }
-#endif
+static inline int clocksource_watchdog_kthread(void *data) { return 0; }
+
+#endif /* CONFIG_CLOCKSOURCE_WATCHDOG */
/**
* clocksource_resume - resume the clocksource(s)
@@ -294,18 +393,16 @@ static inline void clocksource_resume_watchdog(void) { }
void clocksource_resume(void)
{
struct clocksource *cs;
- unsigned long flags;
- spin_lock_irqsave(&clocksource_lock, flags);
+ mutex_lock(&clocksource_mutex);
- list_for_each_entry(cs, &clocksource_list, list) {
+ list_for_each_entry(cs, &clocksource_list, list)
if (cs->resume)
cs->resume();
- }
clocksource_resume_watchdog();
- spin_unlock_irqrestore(&clocksource_lock, flags);
+ mutex_unlock(&clocksource_mutex);
}
/**
@@ -320,75 +417,94 @@ void clocksource_touch_watchdog(void)
clocksource_resume_watchdog();
}
+#ifdef CONFIG_GENERIC_TIME
+
/**
- * clocksource_get_next - Returns the selected clocksource
+ * clocksource_select - Select the best clocksource available
+ *
+ * Private function. Must hold clocksource_mutex when called.
*
+ * Select the clocksource with the best rating, or the clocksource,
+ * which is selected by userspace override.
*/
-struct clocksource *clocksource_get_next(void)
+static void clocksource_select(void)
{
- unsigned long flags;
+ struct clocksource *best, *cs;
- spin_lock_irqsave(&clocksource_lock, flags);
- if (next_clocksource && finished_booting) {
- curr_clocksource = next_clocksource;
- next_clocksource = NULL;
+ if (!finished_booting || list_empty(&clocksource_list))
+ return;
+ /* First clocksource on the list has the best rating. */
+ best = list_first_entry(&clocksource_list, struct clocksource, list);
+ /* Check for the override clocksource. */
+ list_for_each_entry(cs, &clocksource_list, list) {
+ if (strcmp(cs->name, override_name) != 0)
+ continue;
+ /*
+ * Check to make sure we don't switch to a non-highres
+ * capable clocksource if the tick code is in oneshot
+ * mode (highres or nohz)
+ */
+ if (!(cs->flags & CLOCK_SOURCE_VALID_FOR_HRES) &&
+ tick_oneshot_mode_active()) {
+ /* Override clocksource cannot be used. */
+ printk(KERN_WARNING "Override clocksource %s is not "
+ "HRT compatible. Cannot switch while in "
+ "HRT/NOHZ mode\n", cs->name);
+ override_name[0] = 0;
+ } else
+ /* Override clocksource can be used. */
+ best = cs;
+ break;
+ }
+ if (curr_clocksource != best) {
+ printk(KERN_INFO "Switching to clocksource %s\n", best->name);
+ curr_clocksource = best;
+ timekeeping_notify(curr_clocksource);
}
- spin_unlock_irqrestore(&clocksource_lock, flags);
-
- return curr_clocksource;
}
-/**
- * select_clocksource - Selects the best registered clocksource.
- *
- * Private function. Must hold clocksource_lock when called.
+#else /* CONFIG_GENERIC_TIME */
+
+static inline void clocksource_select(void) { }
+
+#endif
+
+/*
+ * clocksource_done_booting - Called near the end of core bootup
*
- * Select the clocksource with the best rating, or the clocksource,
- * which is selected by userspace override.
+ * Hack to avoid lots of clocksource churn at boot time.
+ * We use fs_initcall because we want this to start before
+ * device_initcall but after subsys_initcall.
*/
-static struct clocksource *select_clocksource(void)
+static int __init clocksource_done_booting(void)
{
- struct clocksource *next;
-
- if (list_empty(&clocksource_list))
- return NULL;
-
- if (clocksource_override)
- next = clocksource_override;
- else
- next = list_entry(clocksource_list.next, struct clocksource,
- list);
+ finished_booting = 1;
- if (next == curr_clocksource)
- return NULL;
+ /*
+ * Run the watchdog first to eliminate unstable clock sources
+ */
+ clocksource_watchdog_kthread(NULL);
- return next;
+ mutex_lock(&clocksource_mutex);
+ clocksource_select();
+ mutex_unlock(&clocksource_mutex);
+ return 0;
}
+fs_initcall(clocksource_done_booting);
/*
* Enqueue the clocksource sorted by rating
*/
-static int clocksource_enqueue(struct clocksource *c)
+static void clocksource_enqueue(struct clocksource *cs)
{
- struct list_head *tmp, *entry = &clocksource_list;
+ struct list_head *entry = &clocksource_list;
+ struct clocksource *tmp;
- list_for_each(tmp, &clocksource_list) {
- struct clocksource *cs;
-
- cs = list_entry(tmp, struct clocksource, list);
- if (cs == c)
- return -EBUSY;
+ list_for_each_entry(tmp, &clocksource_list, list)
/* Keep track of the place, where to insert */
- if (cs->rating >= c->rating)
- entry = tmp;
- }
- list_add(&c->list, entry);
-
- if (strlen(c->name) == strlen(override_name) &&
- !strcmp(c->name, override_name))
- clocksource_override = c;
-
- return 0;
+ if (tmp->rating >= cs->rating)
+ entry = &tmp->list;
+ list_add(&cs->list, entry);
}
/**
@@ -397,52 +513,48 @@ static int clocksource_enqueue(struct clocksource *c)
*
* Returns -EBUSY if registration fails, zero otherwise.
*/
-int clocksource_register(struct clocksource *c)
+int clocksource_register(struct clocksource *cs)
{
- unsigned long flags;
- int ret;
-
- spin_lock_irqsave(&clocksource_lock, flags);
- ret = clocksource_enqueue(c);
- if (!ret)
- next_clocksource = select_clocksource();
- spin_unlock_irqrestore(&clocksource_lock, flags);
- if (!ret)
- clocksource_check_watchdog(c);
- return ret;
+ mutex_lock(&clocksource_mutex);
+ clocksource_enqueue(cs);
+ clocksource_select();
+ clocksource_enqueue_watchdog(cs);
+ mutex_unlock(&clocksource_mutex);
+ return 0;
}
EXPORT_SYMBOL(clocksource_register);
+static void __clocksource_change_rating(struct clocksource *cs, int rating)
+{
+ list_del(&cs->list);
+ cs->rating = rating;
+ clocksource_enqueue(cs);
+ clocksource_select();
+}
+
/**
* clocksource_change_rating - Change the rating of a registered clocksource
- *
*/
void clocksource_change_rating(struct clocksource *cs, int rating)
{
- unsigned long flags;
-
- spin_lock_irqsave(&clocksource_lock, flags);
- list_del(&cs->list);
- cs->rating = rating;
- clocksource_enqueue(cs);
- next_clocksource = select_clocksource();
- spin_unlock_irqrestore(&clocksource_lock, flags);
+ mutex_lock(&clocksource_mutex);
+ __clocksource_change_rating(cs, rating);
+ mutex_unlock(&clocksource_mutex);
}
+EXPORT_SYMBOL(clocksource_change_rating);
/**
* clocksource_unregister - remove a registered clocksource
*/
void clocksource_unregister(struct clocksource *cs)
{
- unsigned long flags;
-
- spin_lock_irqsave(&clocksource_lock, flags);
+ mutex_lock(&clocksource_mutex);
+ clocksource_dequeue_watchdog(cs);
list_del(&cs->list);
- if (clocksource_override == cs)
- clocksource_override = NULL;
- next_clocksource = select_clocksource();
- spin_unlock_irqrestore(&clocksource_lock, flags);
+ clocksource_select();
+ mutex_unlock(&clocksource_mutex);
}
+EXPORT_SYMBOL(clocksource_unregister);
#ifdef CONFIG_SYSFS
/**
@@ -458,9 +570,9 @@ sysfs_show_current_clocksources(struct sys_device *dev,
{
ssize_t count = 0;
- spin_lock_irq(&clocksource_lock);
+ mutex_lock(&clocksource_mutex);
count = snprintf(buf, PAGE_SIZE, "%s\n", curr_clocksource->name);
- spin_unlock_irq(&clocksource_lock);
+ mutex_unlock(&clocksource_mutex);
return count;
}
@@ -478,9 +590,7 @@ static ssize_t sysfs_override_clocksource(struct sys_device *dev,
struct sysdev_attribute *attr,
const char *buf, size_t count)
{
- struct clocksource *ovr = NULL;
size_t ret = count;
- int len;
/* strings from sysfs write are not 0 terminated! */
if (count >= sizeof(override_name))
@@ -490,44 +600,14 @@ static ssize_t sysfs_override_clocksource(struct sys_device *dev,
if (buf[count-1] == '\n')
count--;
- spin_lock_irq(&clocksource_lock);
+ mutex_lock(&clocksource_mutex);
if (count > 0)
memcpy(override_name, buf, count);
override_name[count] = 0;
+ clocksource_select();
- len = strlen(override_name);
- if (len) {
- struct clocksource *cs;
-
- ovr = clocksource_override;
- /* try to select it: */
- list_for_each_entry(cs, &clocksource_list, list) {
- if (strlen(cs->name) == len &&
- !strcmp(cs->name, override_name))
- ovr = cs;
- }
- }
-
- /*
- * Check to make sure we don't switch to a non-highres capable
- * clocksource if the tick code is in oneshot mode (highres or nohz)
- */
- if (tick_oneshot_mode_active() && ovr &&
- !(ovr->flags & CLOCK_SOURCE_VALID_FOR_HRES)) {
- printk(KERN_WARNING "%s clocksource is not HRT compatible. "
- "Cannot switch while in HRT/NOHZ mode\n", ovr->name);
- ovr = NULL;
- override_name[0] = 0;
- }
-
- /* Reselect, when the override name has changed */
- if (ovr != clocksource_override) {
- clocksource_override = ovr;
- next_clocksource = select_clocksource();
- }
-
- spin_unlock_irq(&clocksource_lock);
+ mutex_unlock(&clocksource_mutex);
return ret;
}
@@ -547,7 +627,7 @@ sysfs_show_available_clocksources(struct sys_device *dev,
struct clocksource *src;
ssize_t count = 0;
- spin_lock_irq(&clocksource_lock);
+ mutex_lock(&clocksource_mutex);
list_for_each_entry(src, &clocksource_list, list) {
/*
* Don't show non-HRES clocksource if the tick code is
@@ -559,7 +639,7 @@ sysfs_show_available_clocksources(struct sys_device *dev,
max((ssize_t)PAGE_SIZE - count, (ssize_t)0),
"%s ", src->name);
}
- spin_unlock_irq(&clocksource_lock);
+ mutex_unlock(&clocksource_mutex);
count += snprintf(buf + count,
max((ssize_t)PAGE_SIZE - count, (ssize_t)0), "\n");
@@ -614,11 +694,10 @@ device_initcall(init_clocksource_sysfs);
*/
static int __init boot_override_clocksource(char* str)
{
- unsigned long flags;
- spin_lock_irqsave(&clocksource_lock, flags);
+ mutex_lock(&clocksource_mutex);
if (str)
strlcpy(override_name, str, sizeof(override_name));
- spin_unlock_irqrestore(&clocksource_lock, flags);
+ mutex_unlock(&clocksource_mutex);
return 1;
}
diff --git a/kernel/time/jiffies.c b/kernel/time/jiffies.c
index c3f6c30816e..5404a845690 100644
--- a/kernel/time/jiffies.c
+++ b/kernel/time/jiffies.c
@@ -61,7 +61,6 @@ struct clocksource clocksource_jiffies = {
.read = jiffies_read,
.mask = 0xffffffff, /*32bits*/
.mult = NSEC_PER_JIFFY << JIFFIES_SHIFT, /* details above */
- .mult_orig = NSEC_PER_JIFFY << JIFFIES_SHIFT,
.shift = JIFFIES_SHIFT,
};
@@ -71,3 +70,8 @@ static int __init init_jiffies_clocksource(void)
}
core_initcall(init_jiffies_clocksource);
+
+struct clocksource * __init __weak clocksource_default_clock(void)
+{
+ return &clocksource_jiffies;
+}
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 7fc64375ff4..4800f933910 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -194,8 +194,7 @@ static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer)
case TIME_OK:
break;
case TIME_INS:
- xtime.tv_sec--;
- wall_to_monotonic.tv_sec++;
+ timekeeping_leap_insert(-1);
time_state = TIME_OOP;
printk(KERN_NOTICE
"Clock: inserting leap second 23:59:60 UTC\n");
@@ -203,9 +202,8 @@ static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer)
res = HRTIMER_RESTART;
break;
case TIME_DEL:
- xtime.tv_sec++;
+ timekeeping_leap_insert(1);
time_tai--;
- wall_to_monotonic.tv_sec--;
time_state = TIME_WAIT;
printk(KERN_NOTICE
"Clock: deleting leap second 23:59:59 UTC\n");
@@ -219,7 +217,6 @@ static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer)
time_state = TIME_OK;
break;
}
- update_vsyscall(&xtime, clock);
write_sequnlock(&xtime_lock);
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index e8c77d9c633..fb0f46fa1ec 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -18,7 +18,117 @@
#include <linux/jiffies.h>
#include <linux/time.h>
#include <linux/tick.h>
+#include <linux/stop_machine.h>
+
+/* Structure holding internal timekeeping values. */
+struct timekeeper {
+ /* Current clocksource used for timekeeping. */
+ struct clocksource *clock;
+ /* The shift value of the current clocksource. */
+ int shift;
+
+ /* Number of clock cycles in one NTP interval. */
+ cycle_t cycle_interval;
+ /* Number of clock shifted nano seconds in one NTP interval. */
+ u64 xtime_interval;
+ /* Raw nano seconds accumulated per NTP interval. */
+ u32 raw_interval;
+
+ /* Clock shifted nano seconds remainder not stored in xtime.tv_nsec. */
+ u64 xtime_nsec;
+ /* Difference between accumulated time and NTP time in ntp
+ * shifted nano seconds. */
+ s64 ntp_error;
+ /* Shift conversion between clock shifted nano seconds and
+ * ntp shifted nano seconds. */
+ int ntp_error_shift;
+ /* NTP adjusted clock multiplier */
+ u32 mult;
+};
+
+struct timekeeper timekeeper;
+
+/**
+ * timekeeper_setup_internals - Set up internals to use clocksource clock.
+ *
+ * @clock: Pointer to clocksource.
+ *
+ * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
+ * pair and interval request.
+ *
+ * Unless you're the timekeeping code, you should not be using this!
+ */
+static void timekeeper_setup_internals(struct clocksource *clock)
+{
+ cycle_t interval;
+ u64 tmp;
+
+ timekeeper.clock = clock;
+ clock->cycle_last = clock->read(clock);
+ /* Do the ns -> cycle conversion first, using original mult */
+ tmp = NTP_INTERVAL_LENGTH;
+ tmp <<= clock->shift;
+ tmp += clock->mult/2;
+ do_div(tmp, clock->mult);
+ if (tmp == 0)
+ tmp = 1;
+
+ interval = (cycle_t) tmp;
+ timekeeper.cycle_interval = interval;
+
+ /* Go back from cycles -> shifted ns */
+ timekeeper.xtime_interval = (u64) interval * clock->mult;
+ timekeeper.raw_interval =
+ ((u64) interval * clock->mult) >> clock->shift;
+
+ timekeeper.xtime_nsec = 0;
+ timekeeper.shift = clock->shift;
+
+ timekeeper.ntp_error = 0;
+ timekeeper.ntp_error_shift = NTP_SCALE_SHIFT - clock->shift;
+
+ /*
+ * The timekeeper keeps its own mult values for the currently
+ * active clocksource. These value will be adjusted via NTP
+ * to counteract clock drifting.
+ */
+ timekeeper.mult = clock->mult;
+}
+
+/* Timekeeper helper functions. */
+static inline s64 timekeeping_get_ns(void)
+{
+ cycle_t cycle_now, cycle_delta;
+ struct clocksource *clock;
+
+ /* read clocksource: */
+ clock = timekeeper.clock;
+ cycle_now = clock->read(clock);
+
+ /* calculate the delta since the last update_wall_time: */
+ cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
+
+ /* return delta convert to nanoseconds using ntp adjusted mult. */
+ return clocksource_cyc2ns(cycle_delta, timekeeper.mult,
+ timekeeper.shift);
+}
+
+static inline s64 timekeeping_get_ns_raw(void)
+{
+ cycle_t cycle_now, cycle_delta;
+ struct clocksource *clock;
+
+ /* read clocksource: */
+ clock = timekeeper.clock;
+ cycle_now = clock->read(clock);
+
+ /* calculate the delta since the last update_wall_time: */
+ cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
+
+ /* return delta convert to nanoseconds using ntp adjusted mult. */
+ return clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift);
+}
/*
* This read-write spinlock protects us from races in SMP while
@@ -44,7 +154,12 @@ __cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock);
*/
struct timespec xtime __attribute__ ((aligned (16)));
struct timespec wall_to_monotonic __attribute__ ((aligned (16)));
-static unsigned long total_sleep_time; /* seconds */
+static struct timespec total_sleep_time;
+
+/*
+ * The raw monotonic time for the CLOCK_MONOTONIC_RAW posix clock.
+ */
+struct timespec raw_time;
/* flag for if timekeeping is suspended */
int __read_mostly timekeeping_suspended;
@@ -56,35 +171,44 @@ void update_xtime_cache(u64 nsec)
timespec_add_ns(&xtime_cache, nsec);
}
-struct clocksource *clock;
-
+/* must hold xtime_lock */
+void timekeeping_leap_insert(int leapsecond)
+{
+ xtime.tv_sec += leapsecond;
+ wall_to_monotonic.tv_sec -= leapsecond;
+ update_vsyscall(&xtime, timekeeper.clock);
+}
#ifdef CONFIG_GENERIC_TIME
+
/**
- * clocksource_forward_now - update clock to the current time
+ * timekeeping_forward_now - update clock to the current time
*
* Forward the current clock to update its state since the last call to
* update_wall_time(). This is useful before significant clock changes,
* as it avoids having to deal with this time offset explicitly.
*/
-static void clocksource_forward_now(void)
+static void timekeeping_forward_now(void)
{
cycle_t cycle_now, cycle_delta;
+ struct clocksource *clock;
s64 nsec;
- cycle_now = clocksource_read(clock);
+ clock = timekeeper.clock;
+ cycle_now = clock->read(clock);
cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
clock->cycle_last = cycle_now;
- nsec = cyc2ns(clock, cycle_delta);
+ nsec = clocksource_cyc2ns(cycle_delta, timekeeper.mult,
+ timekeeper.shift);
/* If arch requires, add in gettimeoffset() */
nsec += arch_gettimeoffset();
timespec_add_ns(&xtime, nsec);
- nsec = ((s64)cycle_delta * clock->mult_orig) >> clock->shift;
- clock->raw_time.tv_nsec += nsec;
+ nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift);
+ timespec_add_ns(&raw_time, nsec);
}
/**
@@ -95,7 +219,6 @@ static void clocksource_forward_now(void)
*/
void getnstimeofday(struct timespec *ts)
{
- cycle_t cycle_now, cycle_delta;
unsigned long seq;
s64 nsecs;
@@ -105,15 +228,7 @@ void getnstimeofday(struct timespec *ts)
seq = read_seqbegin(&xtime_lock);
*ts = xtime;
-
- /* read clocksource: */
- cycle_now = clocksource_read(clock);
-
- /* calculate the delta since the last update_wall_time: */
- cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
-
- /* convert to nanoseconds: */
- nsecs = cyc2ns(clock, cycle_delta);
+ nsecs = timekeeping_get_ns();
/* If arch requires, add in gettimeoffset() */
nsecs += arch_gettimeoffset();
@@ -125,6 +240,57 @@ void getnstimeofday(struct timespec *ts)
EXPORT_SYMBOL(getnstimeofday);
+ktime_t ktime_get(void)
+{
+ unsigned int seq;
+ s64 secs, nsecs;
+
+ WARN_ON(timekeeping_suspended);
+
+ do {
+ seq = read_seqbegin(&xtime_lock);
+ secs = xtime.tv_sec + wall_to_monotonic.tv_sec;
+ nsecs = xtime.tv_nsec + wall_to_monotonic.tv_nsec;
+ nsecs += timekeeping_get_ns();
+
+ } while (read_seqretry(&xtime_lock, seq));
+ /*
+ * Use ktime_set/ktime_add_ns to create a proper ktime on
+ * 32-bit architectures without CONFIG_KTIME_SCALAR.
+ */
+ return ktime_add_ns(ktime_set(secs, 0), nsecs);
+}
+EXPORT_SYMBOL_GPL(ktime_get);
+
+/**
+ * ktime_get_ts - get the monotonic clock in timespec format
+ * @ts: pointer to timespec variable
+ *
+ * The function calculates the monotonic clock from the realtime
+ * clock and the wall_to_monotonic offset and stores the result
+ * in normalized timespec format in the variable pointed to by @ts.
+ */
+void ktime_get_ts(struct timespec *ts)
+{
+ struct timespec tomono;
+ unsigned int seq;
+ s64 nsecs;
+
+ WARN_ON(timekeeping_suspended);
+
+ do {
+ seq = read_seqbegin(&xtime_lock);
+ *ts = xtime;
+ tomono = wall_to_monotonic;
+ nsecs = timekeeping_get_ns();
+
+ } while (read_seqretry(&xtime_lock, seq));
+
+ set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec,
+ ts->tv_nsec + tomono.tv_nsec + nsecs);
+}
+EXPORT_SYMBOL_GPL(ktime_get_ts);
+
/**
* do_gettimeofday - Returns the time of day in a timeval
* @tv: pointer to the timeval to be set
@@ -157,7 +323,7 @@ int do_settimeofday(struct timespec *tv)
write_seqlock_irqsave(&xtime_lock, flags);
- clocksource_forward_now();
+ timekeeping_forward_now();
ts_delta.tv_sec = tv->tv_sec - xtime.tv_sec;
ts_delta.tv_nsec = tv->tv_nsec - xtime.tv_nsec;
@@ -167,10 +333,10 @@ int do_settimeofday(struct timespec *tv)
update_xtime_cache(0);
- clock->error = 0;
+ timekeeper.ntp_error = 0;
ntp_clear();
- update_vsyscall(&xtime, clock);
+ update_vsyscall(&xtime, timekeeper.clock);
write_sequnlock_irqrestore(&xtime_lock, flags);
@@ -187,44 +353,97 @@ EXPORT_SYMBOL(do_settimeofday);
*
* Accumulates current time interval and initializes new clocksource
*/
-static void change_clocksource(void)
+static int change_clocksource(void *data)
{
struct clocksource *new, *old;
- new = clocksource_get_next();
+ new = (struct clocksource *) data;
+
+ timekeeping_forward_now();
+ if (!new->enable || new->enable(new) == 0) {
+ old = timekeeper.clock;
+ timekeeper_setup_internals(new);
+ if (old->disable)
+ old->disable(old);
+ }
+ return 0;
+}
- if (clock == new)
+/**
+ * timekeeping_notify - Install a new clock source
+ * @clock: pointer to the clock source
+ *
+ * This function is called from clocksource.c after a new, better clock
+ * source has been registered. The caller holds the clocksource_mutex.
+ */
+void timekeeping_notify(struct clocksource *clock)
+{
+ if (timekeeper.clock == clock)
return;
+ stop_machine(change_clocksource, clock, NULL);
+ tick_clock_notify();
+}
- clocksource_forward_now();
+#else /* GENERIC_TIME */
- if (clocksource_enable(new))
- return;
+static inline void timekeeping_forward_now(void) { }
- new->raw_time = clock->raw_time;
- old = clock;
- clock = new;
- clocksource_disable(old);
+/**
+ * ktime_get - get the monotonic time in ktime_t format
+ *
+ * returns the time in ktime_t format
+ */
+ktime_t ktime_get(void)
+{
+ struct timespec now;
- clock->cycle_last = 0;
- clock->cycle_last = clocksource_read(clock);
- clock->error = 0;
- clock->xtime_nsec = 0;
- clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH);
+ ktime_get_ts(&now);
- tick_clock_notify();
+ return timespec_to_ktime(now);
+}
+EXPORT_SYMBOL_GPL(ktime_get);
- /*
- * We're holding xtime lock and waking up klogd would deadlock
- * us on enqueue. So no printing!
- printk(KERN_INFO "Time: %s clocksource has been installed.\n",
- clock->name);
- */
+/**
+ * ktime_get_ts - get the monotonic clock in timespec format
+ * @ts: pointer to timespec variable
+ *
+ * The function calculates the monotonic clock from the realtime
+ * clock and the wall_to_monotonic offset and stores the result
+ * in normalized timespec format in the variable pointed to by @ts.
+ */
+void ktime_get_ts(struct timespec *ts)
+{
+ struct timespec tomono;
+ unsigned long seq;
+
+ do {
+ seq = read_seqbegin(&xtime_lock);
+ getnstimeofday(ts);
+ tomono = wall_to_monotonic;
+
+ } while (read_seqretry(&xtime_lock, seq));
+
+ set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec,
+ ts->tv_nsec + tomono.tv_nsec);
}
-#else
-static inline void clocksource_forward_now(void) { }
-static inline void change_clocksource(void) { }
-#endif
+EXPORT_SYMBOL_GPL(ktime_get_ts);
+
+#endif /* !GENERIC_TIME */
+
+/**
+ * ktime_get_real - get the real (wall-) time in ktime_t format
+ *
+ * returns the time in ktime_t format
+ */
+ktime_t ktime_get_real(void)
+{
+ struct timespec now;
+
+ getnstimeofday(&now);
+
+ return timespec_to_ktime(now);
+}
+EXPORT_SYMBOL_GPL(ktime_get_real);
/**
* getrawmonotonic - Returns the raw monotonic time in a timespec
@@ -236,21 +455,11 @@ void getrawmonotonic(struct timespec *ts)
{
unsigned long seq;
s64 nsecs;
- cycle_t cycle_now, cycle_delta;
do {
seq = read_seqbegin(&xtime_lock);
-
- /* read clocksource: */
- cycle_now = clocksource_read(clock);
-
- /* calculate the delta since the last update_wall_time: */
- cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
-
- /* convert to nanoseconds: */
- nsecs = ((s64)cycle_delta * clock->mult_orig) >> clock->shift;
-
- *ts = clock->raw_time;
+ nsecs = timekeeping_get_ns_raw();
+ *ts = raw_time;
} while (read_seqretry(&xtime_lock, seq));
@@ -270,7 +479,7 @@ int timekeeping_valid_for_hres(void)
do {
seq = read_seqbegin(&xtime_lock);
- ret = clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
+ ret = timekeeper.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
} while (read_seqretry(&xtime_lock, seq));
@@ -278,17 +487,33 @@ int timekeeping_valid_for_hres(void)
}
/**
- * read_persistent_clock - Return time in seconds from the persistent clock.
+ * read_persistent_clock - Return time from the persistent clock.
*
* Weak dummy function for arches that do not yet support it.
- * Returns seconds from epoch using the battery backed persistent clock.
- * Returns zero if unsupported.
+ * Reads the time from the battery backed persistent clock.
+ * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
*
* XXX - Do be sure to remove it once all arches implement it.
*/
-unsigned long __attribute__((weak)) read_persistent_clock(void)
+void __attribute__((weak)) read_persistent_clock(struct timespec *ts)
{
- return 0;
+ ts->tv_sec = 0;
+ ts->tv_nsec = 0;
+}
+
+/**
+ * read_boot_clock - Return time of the system start.
+ *
+ * Weak dummy function for arches that do not yet support it.
+ * Function to read the exact time the system has been started.
+ * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
+ *
+ * XXX - Do be sure to remove it once all arches implement it.
+ */
+void __attribute__((weak)) read_boot_clock(struct timespec *ts)
+{
+ ts->tv_sec = 0;
+ ts->tv_nsec = 0;
}
/*
@@ -296,29 +521,40 @@ unsigned long __attribute__((weak)) read_persistent_clock(void)
*/
void __init timekeeping_init(void)
{
+ struct clocksource *clock;
unsigned long flags;
- unsigned long sec = read_persistent_clock();
+ struct timespec now, boot;
+
+ read_persistent_clock(&now);
+ read_boot_clock(&boot);
write_seqlock_irqsave(&xtime_lock, flags);
ntp_init();
- clock = clocksource_get_next();
- clocksource_enable(clock);
- clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH);
- clock->cycle_last = clocksource_read(clock);
-
- xtime.tv_sec = sec;
- xtime.tv_nsec = 0;
+ clock = clocksource_default_clock();
+ if (clock->enable)
+ clock->enable(clock);
+ timekeeper_setup_internals(clock);
+
+ xtime.tv_sec = now.tv_sec;
+ xtime.tv_nsec = now.tv_nsec;
+ raw_time.tv_sec = 0;
+ raw_time.tv_nsec = 0;
+ if (boot.tv_sec == 0 && boot.tv_nsec == 0) {
+ boot.tv_sec = xtime.tv_sec;
+ boot.tv_nsec = xtime.tv_nsec;
+ }
set_normalized_timespec(&wall_to_monotonic,
- -xtime.tv_sec, -xtime.tv_nsec);
+ -boot.tv_sec, -boot.tv_nsec);
update_xtime_cache(0);
- total_sleep_time = 0;
+ total_sleep_time.tv_sec = 0;
+ total_sleep_time.tv_nsec = 0;
write_sequnlock_irqrestore(&xtime_lock, flags);
}
/* time in seconds when suspend began */
-static unsigned long timekeeping_suspend_time;
+static struct timespec timekeeping_suspend_time;
/**
* timekeeping_resume - Resumes the generic timekeeping subsystem.
@@ -331,24 +567,24 @@ static unsigned long timekeeping_suspend_time;
static int timekeeping_resume(struct sys_device *dev)
{
unsigned long flags;
- unsigned long now = read_persistent_clock();
+ struct timespec ts;
+
+ read_persistent_clock(&ts);
clocksource_resume();
write_seqlock_irqsave(&xtime_lock, flags);
- if (now && (now > timekeeping_suspend_time)) {
- unsigned long sleep_length = now - timekeeping_suspend_time;
-
- xtime.tv_sec += sleep_length;
- wall_to_monotonic.tv_sec -= sleep_length;
- total_sleep_time += sleep_length;
+ if (timespec_compare(&ts, &timekeeping_suspend_time) > 0) {
+ ts = timespec_sub(ts, timekeeping_suspend_time);
+ xtime = timespec_add_safe(xtime, ts);
+ wall_to_monotonic = timespec_sub(wall_to_monotonic, ts);
+ total_sleep_time = timespec_add_safe(total_sleep_time, ts);
}
update_xtime_cache(0);
/* re-base the last cycle value */
- clock->cycle_last = 0;
- clock->cycle_last = clocksource_read(clock);
- clock->error = 0;
+ timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock);
+ timekeeper.ntp_error = 0;
timekeeping_suspended = 0;
write_sequnlock_irqrestore(&xtime_lock, flags);
@@ -366,10 +602,10 @@ static int timekeeping_suspend(struct sys_device *dev, pm_message_t state)
{
unsigned long flags;
- timekeeping_suspend_time = read_persistent_clock();
+ read_persistent_clock(&timekeeping_suspend_time);
write_seqlock_irqsave(&xtime_lock, flags);
- clocksource_forward_now();
+ timekeeping_forward_now();
timekeeping_suspended = 1;
write_sequnlock_irqrestore(&xtime_lock, flags);
@@ -404,7 +640,7 @@ device_initcall(timekeeping_init_device);
* If the error is already larger, we look ahead even further
* to compensate for late or lost adjustments.
*/
-static __always_inline int clocksource_bigadjust(s64 error, s64 *interval,
+static __always_inline int timekeeping_bigadjust(s64 error, s64 *interval,
s64 *offset)
{
s64 tick_error, i;
@@ -420,7 +656,7 @@ static __always_inline int clocksource_bigadjust(s64 error, s64 *interval,
* here. This is tuned so that an error of about 1 msec is adjusted
* within about 1 sec (or 2^20 nsec in 2^SHIFT_HZ ticks).
*/
- error2 = clock->error >> (NTP_SCALE_SHIFT + 22 - 2 * SHIFT_HZ);
+ error2 = timekeeper.ntp_error >> (NTP_SCALE_SHIFT + 22 - 2 * SHIFT_HZ);
error2 = abs(error2);
for (look_ahead = 0; error2 > 0; look_ahead++)
error2 >>= 2;
@@ -429,8 +665,8 @@ static __always_inline int clocksource_bigadjust(s64 error, s64 *interval,
* Now calculate the error in (1 << look_ahead) ticks, but first
* remove the single look ahead already included in the error.
*/
- tick_error = tick_length >> (NTP_SCALE_SHIFT - clock->shift + 1);
- tick_error -= clock->xtime_interval >> 1;
+ tick_error = tick_length >> (timekeeper.ntp_error_shift + 1);
+ tick_error -= timekeeper.xtime_interval >> 1;
error = ((error - tick_error) >> look_ahead) + tick_error;
/* Finally calculate the adjustment shift value. */
@@ -455,18 +691,18 @@ static __always_inline int clocksource_bigadjust(s64 error, s64 *interval,
* this is optimized for the most common adjustments of -1,0,1,
* for other values we can do a bit more work.
*/
-static void clocksource_adjust(s64 offset)
+static void timekeeping_adjust(s64 offset)
{
- s64 error, interval = clock->cycle_interval;
+ s64 error, interval = timekeeper.cycle_interval;
int adj;
- error = clock->error >> (NTP_SCALE_SHIFT - clock->shift - 1);
+ error = timekeeper.ntp_error >> (timekeeper.ntp_error_shift - 1);
if (error > interval) {
error >>= 2;
if (likely(error <= interval))
adj = 1;
else
- adj = clocksource_bigadjust(error, &interval, &offset);
+ adj = timekeeping_bigadjust(error, &interval, &offset);
} else if (error < -interval) {
error >>= 2;
if (likely(error >= -interval)) {
@@ -474,15 +710,15 @@ static void clocksource_adjust(s64 offset)
interval = -interval;
offset = -offset;
} else
- adj = clocksource_bigadjust(error, &interval, &offset);
+ adj = timekeeping_bigadjust(error, &interval, &offset);
} else
return;
- clock->mult += adj;
- clock->xtime_interval += interval;
- clock->xtime_nsec -= offset;
- clock->error -= (interval - offset) <<
- (NTP_SCALE_SHIFT - clock->shift);
+ timekeeper.mult += adj;
+ timekeeper.xtime_interval += interval;
+ timekeeper.xtime_nsec -= offset;
+ timekeeper.ntp_error -= (interval - offset) <<
+ timekeeper.ntp_error_shift;
}
/**
@@ -492,53 +728,59 @@ static void clocksource_adjust(s64 offset)
*/
void update_wall_time(void)
{
+ struct clocksource *clock;
cycle_t offset;
+ u64 nsecs;
/* Make sure we're fully resumed: */
if (unlikely(timekeeping_suspended))
return;
+ clock = timekeeper.clock;
#ifdef CONFIG_GENERIC_TIME
- offset = (clocksource_read(clock) - clock->cycle_last) & clock->mask;
+ offset = (clock->read(clock) - clock->cycle_last) & clock->mask;
#else
- offset = clock->cycle_interval;
+ offset = timekeeper.cycle_interval;
#endif
- clock->xtime_nsec = (s64)xtime.tv_nsec << clock->shift;
+ timekeeper.xtime_nsec = (s64)xtime.tv_nsec << timekeeper.shift;
/* normally this loop will run just once, however in the
* case of lost or late ticks, it will accumulate correctly.
*/
- while (offset >= clock->cycle_interval) {
+ while (offset >= timekeeper.cycle_interval) {
+ u64 nsecps = (u64)NSEC_PER_SEC << timekeeper.shift;
+
/* accumulate one interval */
- offset -= clock->cycle_interval;
- clock->cycle_last += clock->cycle_interval;
+ offset -= timekeeper.cycle_interval;
+ clock->cycle_last += timekeeper.cycle_interval;
- clock->xtime_nsec += clock->xtime_interval;
- if (clock->xtime_nsec >= (u64)NSEC_PER_SEC << clock->shift) {
- clock->xtime_nsec -= (u64)NSEC_PER_SEC << clock->shift;
+ timekeeper.xtime_nsec += timekeeper.xtime_interval;
+ if (timekeeper.xtime_nsec >= nsecps) {
+ timekeeper.xtime_nsec -= nsecps;
xtime.tv_sec++;
second_overflow();
}
- clock->raw_time.tv_nsec += clock->raw_interval;
- if (clock->raw_time.tv_nsec >= NSEC_PER_SEC) {
- clock->raw_time.tv_nsec -= NSEC_PER_SEC;
- clock->raw_time.tv_sec++;
+ raw_time.tv_nsec += timekeeper.raw_interval;
+ if (raw_time.tv_nsec >= NSEC_PER_SEC) {
+ raw_time.tv_nsec -= NSEC_PER_SEC;
+ raw_time.tv_sec++;
}
/* accumulate error between NTP and clock interval */
- clock->error += tick_length;
- clock->error -= clock->xtime_interval << (NTP_SCALE_SHIFT - clock->shift);
+ timekeeper.ntp_error += tick_length;
+ timekeeper.ntp_error -= timekeeper.xtime_interval <<
+ timekeeper.ntp_error_shift;
}
/* correct the clock when NTP error is too big */
- clocksource_adjust(offset);
+ timekeeping_adjust(offset);
/*
* Since in the loop above, we accumulate any amount of time
* in xtime_nsec over a second into xtime.tv_sec, its possible for
* xtime_nsec to be fairly small after the loop. Further, if we're
- * slightly speeding the clocksource up in clocksource_adjust(),
+ * slightly speeding the clocksource up in timekeeping_adjust(),
* its possible the required corrective factor to xtime_nsec could
* cause it to underflow.
*
@@ -550,24 +792,25 @@ void update_wall_time(void)
* We'll correct this error next time through this function, when
* xtime_nsec is not as small.
*/
- if (unlikely((s64)clock->xtime_nsec < 0)) {
- s64 neg = -(s64)clock->xtime_nsec;
- clock->xtime_nsec = 0;
- clock->error += neg << (NTP_SCALE_SHIFT - clock->shift);
+ if (unlikely((s64)timekeeper.xtime_nsec < 0)) {
+ s64 neg = -(s64)timekeeper.xtime_nsec;
+ timekeeper.xtime_nsec = 0;
+ timekeeper.ntp_error += neg << timekeeper.ntp_error_shift;
}
/* store full nanoseconds into xtime after rounding it up and
* add the remainder to the error difference.
*/
- xtime.tv_nsec = ((s64)clock->xtime_nsec >> clock->shift) + 1;
- clock->xtime_nsec -= (s64)xtime.tv_nsec << clock->shift;
- clock->error += clock->xtime_nsec << (NTP_SCALE_SHIFT - clock->shift);
+ xtime.tv_nsec = ((s64) timekeeper.xtime_nsec >> timekeeper.shift) + 1;
+ timekeeper.xtime_nsec -= (s64) xtime.tv_nsec << timekeeper.shift;
+ timekeeper.ntp_error += timekeeper.xtime_nsec <<
+ timekeeper.ntp_error_shift;
- update_xtime_cache(cyc2ns(clock, offset));
+ nsecs = clocksource_cyc2ns(offset, timekeeper.mult, timekeeper.shift);
+ update_xtime_cache(nsecs);
/* check to see if there is a new clocksource to use */
- change_clocksource();
- update_vsyscall(&xtime, clock);
+ update_vsyscall(&xtime, timekeeper.clock);
}
/**
@@ -583,9 +826,12 @@ void update_wall_time(void)
*/
void getboottime(struct timespec *ts)
{
- set_normalized_timespec(ts,
- - (wall_to_monotonic.tv_sec + total_sleep_time),
- - wall_to_monotonic.tv_nsec);
+ struct timespec boottime = {
+ .tv_sec = wall_to_monotonic.tv_sec + total_sleep_time.tv_sec,
+ .tv_nsec = wall_to_monotonic.tv_nsec + total_sleep_time.tv_nsec
+ };
+
+ set_normalized_timespec(ts, -boottime.tv_sec, -boottime.tv_nsec);
}
/**
@@ -594,7 +840,7 @@ void getboottime(struct timespec *ts)
*/
void monotonic_to_bootbased(struct timespec *ts)
{
- ts->tv_sec += total_sleep_time;
+ *ts = timespec_add_safe(*ts, total_sleep_time);
}
unsigned long get_seconds(void)
@@ -603,6 +849,10 @@ unsigned long get_seconds(void)
}
EXPORT_SYMBOL(get_seconds);
+struct timespec __current_kernel_time(void)
+{
+ return xtime_cache;
+}
struct timespec current_kernel_time(void)
{
@@ -618,3 +868,20 @@ struct timespec current_kernel_time(void)
return now;
}
EXPORT_SYMBOL(current_kernel_time);
+
+struct timespec get_monotonic_coarse(void)
+{
+ struct timespec now, mono;
+ unsigned long seq;
+
+ do {
+ seq = read_seqbegin(&xtime_lock);
+
+ now = xtime_cache;
+ mono = wall_to_monotonic;
+ } while (read_seqretry(&xtime_lock, seq));
+
+ set_normalized_timespec(&now, now.tv_sec + mono.tv_sec,
+ now.tv_nsec + mono.tv_nsec);
+ return now;
+}
diff --git a/kernel/timer.c b/kernel/timer.c
index a3d25f41501..bbb51074680 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -72,6 +72,7 @@ struct tvec_base {
spinlock_t lock;
struct timer_list *running_timer;
unsigned long timer_jiffies;
+ unsigned long next_timer;
struct tvec_root tv1;
struct tvec tv2;
struct tvec tv3;
@@ -622,6 +623,9 @@ __mod_timer(struct timer_list *timer, unsigned long expires,
if (timer_pending(timer)) {
detach_timer(timer, 0);
+ if (timer->expires == base->next_timer &&
+ !tbase_get_deferrable(timer->base))
+ base->next_timer = base->timer_jiffies;
ret = 1;
} else {
if (pending_only)
@@ -663,6 +667,9 @@ __mod_timer(struct timer_list *timer, unsigned long expires,
}
timer->expires = expires;
+ if (time_before(timer->expires, base->next_timer) &&
+ !tbase_get_deferrable(timer->base))
+ base->next_timer = timer->expires;
internal_add_timer(base, timer);
out_unlock:
@@ -781,6 +788,9 @@ void add_timer_on(struct timer_list *timer, int cpu)
spin_lock_irqsave(&base->lock, flags);
timer_set_base(timer, base);
debug_timer_activate(timer);
+ if (time_before(timer->expires, base->next_timer) &&
+ !tbase_get_deferrable(timer->base))
+ base->next_timer = timer->expires;
internal_add_timer(base, timer);
/*
* Check whether the other CPU is idle and needs to be
@@ -817,6 +827,9 @@ int del_timer(struct timer_list *timer)
base = lock_timer_base(timer, &flags);
if (timer_pending(timer)) {
detach_timer(timer, 1);
+ if (timer->expires == base->next_timer &&
+ !tbase_get_deferrable(timer->base))
+ base->next_timer = base->timer_jiffies;
ret = 1;
}
spin_unlock_irqrestore(&base->lock, flags);
@@ -850,6 +863,9 @@ int try_to_del_timer_sync(struct timer_list *timer)
ret = 0;
if (timer_pending(timer)) {
detach_timer(timer, 1);
+ if (timer->expires == base->next_timer &&
+ !tbase_get_deferrable(timer->base))
+ base->next_timer = base->timer_jiffies;
ret = 1;
}
out:
@@ -1007,8 +1023,8 @@ static inline void __run_timers(struct tvec_base *base)
#ifdef CONFIG_NO_HZ
/*
* Find out when the next timer event is due to happen. This
- * is used on S/390 to stop all activity when a cpus is idle.
- * This functions needs to be called disabled.
+ * is used on S/390 to stop all activity when a CPU is idle.
+ * This function needs to be called with interrupts disabled.
*/
static unsigned long __next_timer_interrupt(struct tvec_base *base)
{
@@ -1134,7 +1150,9 @@ unsigned long get_next_timer_interrupt(unsigned long now)
unsigned long expires;
spin_lock(&base->lock);
- expires = __next_timer_interrupt(base);
+ if (time_before_eq(base->next_timer, base->timer_jiffies))
+ base->next_timer = __next_timer_interrupt(base);
+ expires = base->next_timer;
spin_unlock(&base->lock);
if (time_before_eq(expires, now))
@@ -1522,6 +1540,7 @@ static int __cpuinit init_timers_cpu(int cpu)
INIT_LIST_HEAD(base->tv1.vec + j);
base->timer_jiffies = jiffies;
+ base->next_timer = base->timer_jiffies;
return 0;
}
@@ -1534,6 +1553,9 @@ static void migrate_timer_list(struct tvec_base *new_base, struct list_head *hea
timer = list_first_entry(head, struct timer_list, entry);
detach_timer(timer, 0);
timer_set_base(timer, new_base);
+ if (time_before(timer->expires, new_base->next_timer) &&
+ !tbase_get_deferrable(timer->base))
+ new_base->next_timer = timer->expires;
internal_add_timer(new_base, timer);
}
}