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authorLinus Torvalds <torvalds@linux-foundation.org>2012-10-12 15:17:48 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2012-10-12 15:17:48 +0200
commit03d3602a833715f83ea53b9feb078b9c4c5f6c1a (patch)
tree7b63ec6753dd65e61392017e1aba2ee1e6b4bcd1 /kernel
parentMerge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/k... (diff)
parenttimekeeping: Cast raw_interval to u64 to avoid shift overflow (diff)
downloadlinux-03d3602a833715f83ea53b9feb078b9c4c5f6c1a.tar.xz
linux-03d3602a833715f83ea53b9feb078b9c4c5f6c1a.zip
Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer core update from Thomas Gleixner: - Bug fixes (one for a longstanding dead loop issue) - Rework of time related vsyscalls - Alarm timer updates - Jiffies updates to remove compile time dependencies * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: timekeeping: Cast raw_interval to u64 to avoid shift overflow timers: Fix endless looping between cascade() and internal_add_timer() time/jiffies: bring back unconditional LATCH definition time: Convert x86_64 to using new update_vsyscall time: Only do nanosecond rounding on GENERIC_TIME_VSYSCALL_OLD systems time: Introduce new GENERIC_TIME_VSYSCALL time: Convert CONFIG_GENERIC_TIME_VSYSCALL to CONFIG_GENERIC_TIME_VSYSCALL_OLD time: Move update_vsyscall definitions to timekeeper_internal.h time: Move timekeeper structure to timekeeper_internal.h for vsyscall changes jiffies: Remove compile time assumptions about CLOCK_TICK_RATE jiffies: Kill unused TICK_USEC_TO_NSEC alarmtimer: Rename alarmtimer_remove to alarmtimer_dequeue alarmtimer: Remove unused helpers & defines alarmtimer: Use hrtimer per-alarm instead of per-base alarmtimer: Implement minimum alarm interval for allowing suspend
Diffstat (limited to 'kernel')
-rw-r--r--kernel/time.c2
-rw-r--r--kernel/time/Kconfig4
-rw-r--r--kernel/time/alarmtimer.c118
-rw-r--r--kernel/time/jiffies.c32
-rw-r--r--kernel/time/timekeeping.c117
-rw-r--r--kernel/timer.c10
6 files changed, 119 insertions, 164 deletions
diff --git a/kernel/time.c b/kernel/time.c
index ba744cf80696..d226c6a3fd28 100644
--- a/kernel/time.c
+++ b/kernel/time.c
@@ -30,7 +30,7 @@
#include <linux/export.h>
#include <linux/timex.h>
#include <linux/capability.h>
-#include <linux/clocksource.h>
+#include <linux/timekeeper_internal.h>
#include <linux/errno.h>
#include <linux/syscalls.h>
#include <linux/security.h>
diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig
index fd42bd452b75..8601f0db1261 100644
--- a/kernel/time/Kconfig
+++ b/kernel/time/Kconfig
@@ -16,6 +16,10 @@ config ARCH_CLOCKSOURCE_DATA
config GENERIC_TIME_VSYSCALL
bool
+# Timekeeping vsyscall support
+config GENERIC_TIME_VSYSCALL_OLD
+ bool
+
# ktime_t scalar 64bit nsec representation
config KTIME_SCALAR
bool
diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index aa27d391bfc8..f11d83b12949 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -37,7 +37,6 @@
static struct alarm_base {
spinlock_t lock;
struct timerqueue_head timerqueue;
- struct hrtimer timer;
ktime_t (*gettime)(void);
clockid_t base_clockid;
} alarm_bases[ALARM_NUMTYPE];
@@ -46,6 +45,8 @@ static struct alarm_base {
static ktime_t freezer_delta;
static DEFINE_SPINLOCK(freezer_delta_lock);
+static struct wakeup_source *ws;
+
#ifdef CONFIG_RTC_CLASS
/* rtc timer and device for setting alarm wakeups at suspend */
static struct rtc_timer rtctimer;
@@ -130,50 +131,35 @@ static inline void alarmtimer_rtc_timer_init(void) { }
* @base: pointer to the base where the timer is being run
* @alarm: pointer to alarm being enqueued.
*
- * Adds alarm to a alarm_base timerqueue and if necessary sets
- * an hrtimer to run.
+ * Adds alarm to a alarm_base timerqueue
*
* Must hold base->lock when calling.
*/
static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
{
+ if (alarm->state & ALARMTIMER_STATE_ENQUEUED)
+ timerqueue_del(&base->timerqueue, &alarm->node);
+
timerqueue_add(&base->timerqueue, &alarm->node);
alarm->state |= ALARMTIMER_STATE_ENQUEUED;
-
- if (&alarm->node == timerqueue_getnext(&base->timerqueue)) {
- hrtimer_try_to_cancel(&base->timer);
- hrtimer_start(&base->timer, alarm->node.expires,
- HRTIMER_MODE_ABS);
- }
}
/**
- * alarmtimer_remove - Removes an alarm timer from an alarm_base timerqueue
+ * alarmtimer_dequeue - Removes an alarm timer from an alarm_base timerqueue
* @base: pointer to the base where the timer is running
* @alarm: pointer to alarm being removed
*
- * Removes alarm to a alarm_base timerqueue and if necessary sets
- * a new timer to run.
+ * Removes alarm to a alarm_base timerqueue
*
* Must hold base->lock when calling.
*/
-static void alarmtimer_remove(struct alarm_base *base, struct alarm *alarm)
+static void alarmtimer_dequeue(struct alarm_base *base, struct alarm *alarm)
{
- struct timerqueue_node *next = timerqueue_getnext(&base->timerqueue);
-
if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
return;
timerqueue_del(&base->timerqueue, &alarm->node);
alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
-
- if (next == &alarm->node) {
- hrtimer_try_to_cancel(&base->timer);
- next = timerqueue_getnext(&base->timerqueue);
- if (!next)
- return;
- hrtimer_start(&base->timer, next->expires, HRTIMER_MODE_ABS);
- }
}
@@ -188,42 +174,23 @@ static void alarmtimer_remove(struct alarm_base *base, struct alarm *alarm)
*/
static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
{
- struct alarm_base *base = container_of(timer, struct alarm_base, timer);
- struct timerqueue_node *next;
+ struct alarm *alarm = container_of(timer, struct alarm, timer);
+ struct alarm_base *base = &alarm_bases[alarm->type];
unsigned long flags;
- ktime_t now;
int ret = HRTIMER_NORESTART;
int restart = ALARMTIMER_NORESTART;
spin_lock_irqsave(&base->lock, flags);
- now = base->gettime();
- while ((next = timerqueue_getnext(&base->timerqueue))) {
- struct alarm *alarm;
- ktime_t expired = next->expires;
-
- if (expired.tv64 > now.tv64)
- break;
-
- alarm = container_of(next, struct alarm, node);
-
- timerqueue_del(&base->timerqueue, &alarm->node);
- alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
-
- alarm->state |= ALARMTIMER_STATE_CALLBACK;
- spin_unlock_irqrestore(&base->lock, flags);
- if (alarm->function)
- restart = alarm->function(alarm, now);
- spin_lock_irqsave(&base->lock, flags);
- alarm->state &= ~ALARMTIMER_STATE_CALLBACK;
+ alarmtimer_dequeue(base, alarm);
+ spin_unlock_irqrestore(&base->lock, flags);
- if (restart != ALARMTIMER_NORESTART) {
- timerqueue_add(&base->timerqueue, &alarm->node);
- alarm->state |= ALARMTIMER_STATE_ENQUEUED;
- }
- }
+ if (alarm->function)
+ restart = alarm->function(alarm, base->gettime());
- if (next) {
- hrtimer_set_expires(&base->timer, next->expires);
+ spin_lock_irqsave(&base->lock, flags);
+ if (restart != ALARMTIMER_NORESTART) {
+ hrtimer_set_expires(&alarm->timer, alarm->node.expires);
+ alarmtimer_enqueue(base, alarm);
ret = HRTIMER_RESTART;
}
spin_unlock_irqrestore(&base->lock, flags);
@@ -250,6 +217,7 @@ static int alarmtimer_suspend(struct device *dev)
unsigned long flags;
struct rtc_device *rtc;
int i;
+ int ret;
spin_lock_irqsave(&freezer_delta_lock, flags);
min = freezer_delta;
@@ -279,8 +247,10 @@ static int alarmtimer_suspend(struct device *dev)
if (min.tv64 == 0)
return 0;
- /* XXX - Should we enforce a minimum sleep time? */
- WARN_ON(min.tv64 < NSEC_PER_SEC);
+ if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) {
+ __pm_wakeup_event(ws, 2 * MSEC_PER_SEC);
+ return -EBUSY;
+ }
/* Setup an rtc timer to fire that far in the future */
rtc_timer_cancel(rtc, &rtctimer);
@@ -288,9 +258,11 @@ static int alarmtimer_suspend(struct device *dev)
now = rtc_tm_to_ktime(tm);
now = ktime_add(now, min);
- rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0));
-
- return 0;
+ /* Set alarm, if in the past reject suspend briefly to handle */
+ ret = rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0));
+ if (ret < 0)
+ __pm_wakeup_event(ws, MSEC_PER_SEC);
+ return ret;
}
#else
static int alarmtimer_suspend(struct device *dev)
@@ -324,6 +296,9 @@ void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
{
timerqueue_init(&alarm->node);
+ hrtimer_init(&alarm->timer, alarm_bases[type].base_clockid,
+ HRTIMER_MODE_ABS);
+ alarm->timer.function = alarmtimer_fired;
alarm->function = function;
alarm->type = type;
alarm->state = ALARMTIMER_STATE_INACTIVE;
@@ -334,17 +309,19 @@ void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
* @alarm: ptr to alarm to set
* @start: time to run the alarm
*/
-void alarm_start(struct alarm *alarm, ktime_t start)
+int alarm_start(struct alarm *alarm, ktime_t start)
{
struct alarm_base *base = &alarm_bases[alarm->type];
unsigned long flags;
+ int ret;
spin_lock_irqsave(&base->lock, flags);
- if (alarmtimer_active(alarm))
- alarmtimer_remove(base, alarm);
alarm->node.expires = start;
alarmtimer_enqueue(base, alarm);
+ ret = hrtimer_start(&alarm->timer, alarm->node.expires,
+ HRTIMER_MODE_ABS);
spin_unlock_irqrestore(&base->lock, flags);
+ return ret;
}
/**
@@ -358,18 +335,12 @@ int alarm_try_to_cancel(struct alarm *alarm)
{
struct alarm_base *base = &alarm_bases[alarm->type];
unsigned long flags;
- int ret = -1;
- spin_lock_irqsave(&base->lock, flags);
-
- if (alarmtimer_callback_running(alarm))
- goto out;
+ int ret;
- if (alarmtimer_is_queued(alarm)) {
- alarmtimer_remove(base, alarm);
- ret = 1;
- } else
- ret = 0;
-out:
+ spin_lock_irqsave(&base->lock, flags);
+ ret = hrtimer_try_to_cancel(&alarm->timer);
+ if (ret >= 0)
+ alarmtimer_dequeue(base, alarm);
spin_unlock_irqrestore(&base->lock, flags);
return ret;
}
@@ -802,10 +773,6 @@ static int __init alarmtimer_init(void)
for (i = 0; i < ALARM_NUMTYPE; i++) {
timerqueue_init_head(&alarm_bases[i].timerqueue);
spin_lock_init(&alarm_bases[i].lock);
- hrtimer_init(&alarm_bases[i].timer,
- alarm_bases[i].base_clockid,
- HRTIMER_MODE_ABS);
- alarm_bases[i].timer.function = alarmtimer_fired;
}
error = alarmtimer_rtc_interface_setup();
@@ -821,6 +788,7 @@ static int __init alarmtimer_init(void)
error = PTR_ERR(pdev);
goto out_drv;
}
+ ws = wakeup_source_register("alarmtimer");
return 0;
out_drv:
diff --git a/kernel/time/jiffies.c b/kernel/time/jiffies.c
index 46da0537c10b..6629bf7b5285 100644
--- a/kernel/time/jiffies.c
+++ b/kernel/time/jiffies.c
@@ -37,7 +37,7 @@
* requested HZ value. It is also not recommended
* for "tick-less" systems.
*/
-#define NSEC_PER_JIFFY ((u32)((((u64)NSEC_PER_SEC)<<8)/SHIFTED_HZ))
+#define NSEC_PER_JIFFY ((NSEC_PER_SEC+HZ/2)/HZ)
/* Since jiffies uses a simple NSEC_PER_JIFFY multiplier
* conversion, the .shift value could be zero. However
@@ -95,3 +95,33 @@ struct clocksource * __init __weak clocksource_default_clock(void)
{
return &clocksource_jiffies;
}
+
+struct clocksource refined_jiffies;
+
+int register_refined_jiffies(long cycles_per_second)
+{
+ u64 nsec_per_tick, shift_hz;
+ long cycles_per_tick;
+
+
+
+ refined_jiffies = clocksource_jiffies;
+ refined_jiffies.name = "refined-jiffies";
+ refined_jiffies.rating++;
+
+ /* Calc cycles per tick */
+ cycles_per_tick = (cycles_per_second + HZ/2)/HZ;
+ /* shift_hz stores hz<<8 for extra accuracy */
+ shift_hz = (u64)cycles_per_second << 8;
+ shift_hz += cycles_per_tick/2;
+ do_div(shift_hz, cycles_per_tick);
+ /* Calculate nsec_per_tick using shift_hz */
+ nsec_per_tick = (u64)NSEC_PER_SEC << 8;
+ nsec_per_tick += (u32)shift_hz/2;
+ do_div(nsec_per_tick, (u32)shift_hz);
+
+ refined_jiffies.mult = ((u32)nsec_per_tick) << JIFFIES_SHIFT;
+
+ clocksource_register(&refined_jiffies);
+ return 0;
+}
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 5ce06a3fa91e..e424970bb562 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -8,6 +8,7 @@
*
*/
+#include <linux/timekeeper_internal.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/percpu.h>
@@ -21,61 +22,6 @@
#include <linux/tick.h>
#include <linux/stop_machine.h>
-/* Structure holding internal timekeeping values. */
-struct timekeeper {
- /* Current clocksource used for timekeeping. */
- struct clocksource *clock;
- /* NTP adjusted clock multiplier */
- u32 mult;
- /* The shift value of the current clocksource. */
- u32 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;
- /* shifted nano seconds left over when rounding cycle_interval */
- s64 xtime_remainder;
- /* Raw nano seconds accumulated per NTP interval. */
- u32 raw_interval;
-
- /* Current CLOCK_REALTIME time in seconds */
- u64 xtime_sec;
- /* Clock shifted nano seconds */
- 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. */
- u32 ntp_error_shift;
-
- /*
- * wall_to_monotonic is what we need to add to xtime (or xtime corrected
- * for sub jiffie times) to get to monotonic time. Monotonic is pegged
- * at zero at system boot time, so wall_to_monotonic will be negative,
- * however, we will ALWAYS keep the tv_nsec part positive so we can use
- * the usual normalization.
- *
- * wall_to_monotonic is moved after resume from suspend for the
- * monotonic time not to jump. We need to add total_sleep_time to
- * wall_to_monotonic to get the real boot based time offset.
- *
- * - wall_to_monotonic is no longer the boot time, getboottime must be
- * used instead.
- */
- struct timespec wall_to_monotonic;
- /* Offset clock monotonic -> clock realtime */
- ktime_t offs_real;
- /* time spent in suspend */
- struct timespec total_sleep_time;
- /* Offset clock monotonic -> clock boottime */
- ktime_t offs_boot;
- /* The raw monotonic time for the CLOCK_MONOTONIC_RAW posix clock. */
- struct timespec raw_time;
- /* Seqlock for all timekeeper values */
- seqlock_t lock;
-};
static struct timekeeper timekeeper;
@@ -96,15 +42,6 @@ static inline void tk_normalize_xtime(struct timekeeper *tk)
}
}
-static struct timespec tk_xtime(struct timekeeper *tk)
-{
- struct timespec ts;
-
- ts.tv_sec = tk->xtime_sec;
- ts.tv_nsec = (long)(tk->xtime_nsec >> tk->shift);
- return ts;
-}
-
static void tk_set_xtime(struct timekeeper *tk, const struct timespec *ts)
{
tk->xtime_sec = ts->tv_sec;
@@ -246,14 +183,11 @@ static inline s64 timekeeping_get_ns_raw(struct timekeeper *tk)
/* must hold write on timekeeper.lock */
static void timekeeping_update(struct timekeeper *tk, bool clearntp)
{
- struct timespec xt;
-
if (clearntp) {
tk->ntp_error = 0;
ntp_clear();
}
- xt = tk_xtime(tk);
- update_vsyscall(&xt, &tk->wall_to_monotonic, tk->clock, tk->mult);
+ update_vsyscall(tk);
}
/**
@@ -1113,7 +1047,7 @@ static cycle_t logarithmic_accumulation(struct timekeeper *tk, cycle_t offset,
accumulate_nsecs_to_secs(tk);
/* Accumulate raw time */
- raw_nsecs = tk->raw_interval << shift;
+ raw_nsecs = (u64)tk->raw_interval << shift;
raw_nsecs += tk->raw_time.tv_nsec;
if (raw_nsecs >= NSEC_PER_SEC) {
u64 raw_secs = raw_nsecs;
@@ -1130,6 +1064,33 @@ static cycle_t logarithmic_accumulation(struct timekeeper *tk, cycle_t offset,
return offset;
}
+#ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD
+static inline void old_vsyscall_fixup(struct timekeeper *tk)
+{
+ s64 remainder;
+
+ /*
+ * Store only full nanoseconds into xtime_nsec after rounding
+ * it up and add the remainder to the error difference.
+ * XXX - This is necessary to avoid small 1ns inconsistnecies caused
+ * by truncating the remainder in vsyscalls. However, it causes
+ * additional work to be done in timekeeping_adjust(). Once
+ * the vsyscall implementations are converted to use xtime_nsec
+ * (shifted nanoseconds), and CONFIG_GENERIC_TIME_VSYSCALL_OLD
+ * users are removed, this can be killed.
+ */
+ remainder = tk->xtime_nsec & ((1ULL << tk->shift) - 1);
+ tk->xtime_nsec -= remainder;
+ tk->xtime_nsec += 1ULL << tk->shift;
+ tk->ntp_error += remainder << tk->ntp_error_shift;
+
+}
+#else
+#define old_vsyscall_fixup(tk)
+#endif
+
+
+
/**
* update_wall_time - Uses the current clocksource to increment the wall time
*
@@ -1141,7 +1102,6 @@ static void update_wall_time(void)
cycle_t offset;
int shift = 0, maxshift;
unsigned long flags;
- s64 remainder;
write_seqlock_irqsave(&tk->lock, flags);
@@ -1183,20 +1143,11 @@ static void update_wall_time(void)
/* correct the clock when NTP error is too big */
timekeeping_adjust(tk, offset);
-
/*
- * Store only full nanoseconds into xtime_nsec after rounding
- * it up and add the remainder to the error difference.
- * XXX - This is necessary to avoid small 1ns inconsistnecies caused
- * by truncating the remainder in vsyscalls. However, it causes
- * additional work to be done in timekeeping_adjust(). Once
- * the vsyscall implementations are converted to use xtime_nsec
- * (shifted nanoseconds), this can be killed.
- */
- remainder = tk->xtime_nsec & ((1ULL << tk->shift) - 1);
- tk->xtime_nsec -= remainder;
- tk->xtime_nsec += 1ULL << tk->shift;
- tk->ntp_error += remainder << tk->ntp_error_shift;
+ * XXX This can be killed once everyone converts
+ * to the new update_vsyscall.
+ */
+ old_vsyscall_fixup(tk);
/*
* Finally, make sure that after the rounding
diff --git a/kernel/timer.c b/kernel/timer.c
index d5de1b2292aa..367d00858482 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -63,6 +63,7 @@ EXPORT_SYMBOL(jiffies_64);
#define TVR_SIZE (1 << TVR_BITS)
#define TVN_MASK (TVN_SIZE - 1)
#define TVR_MASK (TVR_SIZE - 1)
+#define MAX_TVAL ((unsigned long)((1ULL << (TVR_BITS + 4*TVN_BITS)) - 1))
struct tvec {
struct list_head vec[TVN_SIZE];
@@ -359,11 +360,12 @@ __internal_add_timer(struct tvec_base *base, struct timer_list *timer)
vec = base->tv1.vec + (base->timer_jiffies & TVR_MASK);
} else {
int i;
- /* If the timeout is larger than 0xffffffff on 64-bit
- * architectures then we use the maximum timeout:
+ /* If the timeout is larger than MAX_TVAL (on 64-bit
+ * architectures or with CONFIG_BASE_SMALL=1) then we
+ * use the maximum timeout.
*/
- if (idx > 0xffffffffUL) {
- idx = 0xffffffffUL;
+ if (idx > MAX_TVAL) {
+ idx = MAX_TVAL;
expires = idx + base->timer_jiffies;
}
i = (expires >> (TVR_BITS + 3 * TVN_BITS)) & TVN_MASK;