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Commit 70471f2f authored by John Stultz's avatar John Stultz
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time: Add timekeeper lock 

Now that all the timekeeping variables are stored in
the timekeeper structure, add a new lock to protect the
structure.

For now, this lock nests under the xtime_lock for writes.

For readers, we don't need to take xtime_lock anymore.

CC: Thomas Gleixner <tglx@linutronix.de>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
parent 8fcce546
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Showing with 82 additions and 44 deletions
kernel/time/timekeeping.c
View file @ 70471f2f
......@@ -69,6 +69,9 @@ struct timekeeper {
struct timespec total_sleep_time;
/* 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;
......@@ -172,10 +175,17 @@ static inline s64 timekeeping_get_ns_raw(void)
/* must hold xtime_lock */
void timekeeping_leap_insert(int leapsecond)
{
unsigned long flags;
write_seqlock_irqsave(&timekeeper.lock, flags);
timekeeper.xtime.tv_sec += leapsecond;
timekeeper.wall_to_monotonic.tv_sec -= leapsecond;
update_vsyscall(&timekeeper.xtime, &timekeeper.wall_to_monotonic,
timekeeper.clock, timekeeper.mult);
write_sequnlock_irqrestore(&timekeeper.lock, flags);
}
/**
......@@ -222,7 +232,7 @@ void getnstimeofday(struct timespec *ts)
WARN_ON(timekeeping_suspended);
do {
seq = read_seqbegin(&xtime_lock);
seq = read_seqbegin(&timekeeper.lock);
*ts = timekeeper.xtime;
nsecs = timekeeping_get_ns();
......@@ -230,7 +240,7 @@ void getnstimeofday(struct timespec *ts)
/* If arch requires, add in gettimeoffset() */
nsecs += arch_gettimeoffset();
} while (read_seqretry(&xtime_lock, seq));
} while (read_seqretry(&timekeeper.lock, seq));
timespec_add_ns(ts, nsecs);
}
......@@ -245,7 +255,7 @@ ktime_t ktime_get(void)
WARN_ON(timekeeping_suspended);
do {
seq = read_seqbegin(&xtime_lock);
seq = read_seqbegin(&timekeeper.lock);
secs = timekeeper.xtime.tv_sec +
timekeeper.wall_to_monotonic.tv_sec;
nsecs = timekeeper.xtime.tv_nsec +
......@@ -254,7 +264,7 @@ ktime_t ktime_get(void)
/* If arch requires, add in gettimeoffset() */
nsecs += arch_gettimeoffset();
} while (read_seqretry(&xtime_lock, seq));
} while (read_seqretry(&timekeeper.lock, seq));
/*
* Use ktime_set/ktime_add_ns to create a proper ktime on
* 32-bit architectures without CONFIG_KTIME_SCALAR.
......@@ -280,14 +290,14 @@ void ktime_get_ts(struct timespec *ts)
WARN_ON(timekeeping_suspended);
do {
seq = read_seqbegin(&xtime_lock);
seq = read_seqbegin(&timekeeper.lock);
*ts = timekeeper.xtime;
tomono = timekeeper.wall_to_monotonic;
nsecs = timekeeping_get_ns();
/* If arch requires, add in gettimeoffset() */
nsecs += arch_gettimeoffset();
} while (read_seqretry(&xtime_lock, seq));
} while (read_seqretry(&timekeeper.lock, seq));
set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec,
ts->tv_nsec + tomono.tv_nsec + nsecs);
......@@ -315,7 +325,7 @@ void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real)
do {
u32 arch_offset;
seq = read_seqbegin(&xtime_lock);
seq = read_seqbegin(&timekeeper.lock);
*ts_raw = timekeeper.raw_time;
*ts_real = timekeeper.xtime;
......@@ -328,7 +338,7 @@ void getnstime_raw_and_real(struct timespec *ts_raw, struct timespec *ts_real)
nsecs_raw += arch_offset;
nsecs_real += arch_offset;
} while (read_seqretry(&xtime_lock, seq));
} while (read_seqretry(&timekeeper.lock, seq));
timespec_add_ns(ts_raw, nsecs_raw);
timespec_add_ns(ts_real, nsecs_real);
......@@ -362,12 +372,13 @@ EXPORT_SYMBOL(do_gettimeofday);
int do_settimeofday(const struct timespec *tv)
{
struct timespec ts_delta;
unsigned long flags;
unsigned long flags1,flags2;
if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
return -EINVAL;
write_seqlock_irqsave(&xtime_lock, flags);
write_seqlock_irqsave(&xtime_lock, flags1);
write_seqlock_irqsave(&timekeeper.lock, flags2);
timekeeping_forward_now();
......@@ -384,7 +395,8 @@ int do_settimeofday(const struct timespec *tv)
update_vsyscall(&timekeeper.xtime, &timekeeper.wall_to_monotonic,
timekeeper.clock, timekeeper.mult);
write_sequnlock_irqrestore(&xtime_lock, flags);
write_sequnlock_irqrestore(&timekeeper.lock, flags2);
write_sequnlock_irqrestore(&xtime_lock, flags1);
/* signal hrtimers about time change */
clock_was_set();
......@@ -403,12 +415,13 @@ EXPORT_SYMBOL(do_settimeofday);
*/
int timekeeping_inject_offset(struct timespec *ts)
{
unsigned long flags;
unsigned long flags1,flags2;
if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
return -EINVAL;
write_seqlock_irqsave(&xtime_lock, flags);
write_seqlock_irqsave(&xtime_lock, flags1);
write_seqlock_irqsave(&timekeeper.lock, flags2);
timekeeping_forward_now();
......@@ -422,7 +435,8 @@ int timekeeping_inject_offset(struct timespec *ts)
update_vsyscall(&timekeeper.xtime, &timekeeper.wall_to_monotonic,
timekeeper.clock, timekeeper.mult);
write_sequnlock_irqrestore(&xtime_lock, flags);
write_sequnlock_irqrestore(&timekeeper.lock, flags2);
write_sequnlock_irqrestore(&xtime_lock, flags1);
/* signal hrtimers about time change */
clock_was_set();
......@@ -494,11 +508,11 @@ void getrawmonotonic(struct timespec *ts)
s64 nsecs;
do {
seq = read_seqbegin(&xtime_lock);
seq = read_seqbegin(&timekeeper.lock);
nsecs = timekeeping_get_ns_raw();
*ts = timekeeper.raw_time;
} while (read_seqretry(&xtime_lock, seq));
} while (read_seqretry(&timekeeper.lock, seq));
timespec_add_ns(ts, nsecs);
}
......@@ -514,24 +528,30 @@ int timekeeping_valid_for_hres(void)
int ret;
do {
seq = read_seqbegin(&xtime_lock);
seq = read_seqbegin(&timekeeper.lock);
ret = timekeeper.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
} while (read_seqretry(&xtime_lock, seq));
} while (read_seqretry(&timekeeper.lock, seq));
return ret;
}
/**
* timekeeping_max_deferment - Returns max time the clocksource can be deferred
*
* Caller must observe xtime_lock via read_seqbegin/read_seqretry to
* ensure that the clocksource does not change!
*/
u64 timekeeping_max_deferment(void)
{
return timekeeper.clock->max_idle_ns;
unsigned long seq;
u64 ret;
do {
seq = read_seqbegin(&timekeeper.lock);
ret = timekeeper.clock->max_idle_ns;
} while (read_seqretry(&timekeeper.lock, seq));
return ret;
}
/**
......@@ -576,10 +596,13 @@ void __init timekeeping_init(void)
read_persistent_clock(&now);
read_boot_clock(&boot);
write_seqlock_irqsave(&xtime_lock, flags);
seqlock_init(&timekeeper.lock);
write_seqlock_irqsave(&xtime_lock, flags);
ntp_init();
write_sequnlock_irqrestore(&xtime_lock, flags);
write_seqlock_irqsave(&timekeeper.lock, flags);
clock = clocksource_default_clock();
if (clock->enable)
clock->enable(clock);
......@@ -597,7 +620,7 @@ void __init timekeeping_init(void)
-boot.tv_sec, -boot.tv_nsec);
timekeeper.total_sleep_time.tv_sec = 0;
timekeeper.total_sleep_time.tv_nsec = 0;
write_sequnlock_irqrestore(&xtime_lock, flags);
write_sequnlock_irqrestore(&timekeeper.lock, flags);
}
/* time in seconds when suspend began */
......@@ -638,7 +661,7 @@ static void __timekeeping_inject_sleeptime(struct timespec *delta)
*/
void timekeeping_inject_sleeptime(struct timespec *delta)
{
unsigned long flags;
unsigned long flags1,flags2;
struct timespec ts;
/* Make sure we don't set the clock twice */
......@@ -646,7 +669,9 @@ void timekeeping_inject_sleeptime(struct timespec *delta)
if (!(ts.tv_sec == 0 && ts.tv_nsec == 0))
return;
write_seqlock_irqsave(&xtime_lock, flags);
write_seqlock_irqsave(&xtime_lock, flags1);
write_seqlock_irqsave(&timekeeper.lock, flags2);
timekeeping_forward_now();
__timekeeping_inject_sleeptime(delta);
......@@ -656,7 +681,8 @@ void timekeeping_inject_sleeptime(struct timespec *delta)
update_vsyscall(&timekeeper.xtime, &timekeeper.wall_to_monotonic,
timekeeper.clock, timekeeper.mult);
write_sequnlock_irqrestore(&xtime_lock, flags);
write_sequnlock_irqrestore(&timekeeper.lock, flags2);
write_sequnlock_irqrestore(&xtime_lock, flags1);
/* signal hrtimers about time change */
clock_was_set();
......@@ -672,14 +698,15 @@ void timekeeping_inject_sleeptime(struct timespec *delta)
*/
static void timekeeping_resume(void)
{
unsigned long flags;
unsigned long flags1,flags2;
struct timespec ts;
read_persistent_clock(&ts);
clocksource_resume();
write_seqlock_irqsave(&xtime_lock, flags);
write_seqlock_irqsave(&xtime_lock, flags1);
write_seqlock_irqsave(&timekeeper.lock, flags2);
if (timespec_compare(&ts, &timekeeping_suspend_time) > 0) {
ts = timespec_sub(ts, timekeeping_suspend_time);
......@@ -689,7 +716,8 @@ static void timekeeping_resume(void)
timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock);
timekeeper.ntp_error = 0;
timekeeping_suspended = 0;
write_sequnlock_irqrestore(&xtime_lock, flags);
write_sequnlock_irqrestore(&timekeeper.lock, flags2);
write_sequnlock_irqrestore(&xtime_lock, flags1);
touch_softlockup_watchdog();
......@@ -701,13 +729,14 @@ static void timekeeping_resume(void)
static int timekeeping_suspend(void)
{
unsigned long flags;
unsigned long flags1,flags2;
struct timespec delta, delta_delta;
static struct timespec old_delta;
read_persistent_clock(&timekeeping_suspend_time);
write_seqlock_irqsave(&xtime_lock, flags);
write_seqlock_irqsave(&xtime_lock, flags1);
write_seqlock_irqsave(&timekeeper.lock, flags2);
timekeeping_forward_now();
timekeeping_suspended = 1;
......@@ -730,7 +759,8 @@ static int timekeeping_suspend(void)
timekeeping_suspend_time =
timespec_add(timekeeping_suspend_time, delta_delta);
}
write_sequnlock_irqrestore(&xtime_lock, flags);
write_sequnlock_irqrestore(&timekeeper.lock, flags2);
write_sequnlock_irqrestore(&xtime_lock, flags1);
clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL);
clocksource_suspend();
......@@ -983,10 +1013,13 @@ static void update_wall_time(void)
struct clocksource *clock;
cycle_t offset;
int shift = 0, maxshift;
unsigned long flags;
write_seqlock_irqsave(&timekeeper.lock, flags);
/* Make sure we're fully resumed: */
if (unlikely(timekeeping_suspended))
return;
goto out;
clock = timekeeper.clock;
......@@ -1067,6 +1100,10 @@ static void update_wall_time(void)
/* check to see if there is a new clocksource to use */
update_vsyscall(&timekeeper.xtime, &timekeeper.wall_to_monotonic,
timekeeper.clock, timekeeper.mult);
out:
write_sequnlock_irqrestore(&timekeeper.lock, flags);
}
/**
......@@ -1112,13 +1149,13 @@ void get_monotonic_boottime(struct timespec *ts)
WARN_ON(timekeeping_suspended);
do {
seq = read_seqbegin(&xtime_lock);
seq = read_seqbegin(&timekeeper.lock);
*ts = timekeeper.xtime;
tomono = timekeeper.wall_to_monotonic;
sleep = timekeeper.total_sleep_time;
nsecs = timekeeping_get_ns();
} while (read_seqretry(&xtime_lock, seq));
} while (read_seqretry(&timekeeper.lock, seq));
set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec + sleep.tv_sec,
ts->tv_nsec + tomono.tv_nsec + sleep.tv_nsec + nsecs);
......@@ -1169,10 +1206,10 @@ struct timespec current_kernel_time(void)
unsigned long seq;
do {
seq = read_seqbegin(&xtime_lock);
seq = read_seqbegin(&timekeeper.lock);
now = timekeeper.xtime;
} while (read_seqretry(&xtime_lock, seq));
} while (read_seqretry(&timekeeper.lock, seq));
return now;
}
......@@ -1184,11 +1221,11 @@ struct timespec get_monotonic_coarse(void)
unsigned long seq;
do {
seq = read_seqbegin(&xtime_lock);
seq = read_seqbegin(&timekeeper.lock);
now = timekeeper.xtime;
mono = timekeeper.wall_to_monotonic;
} while (read_seqretry(&xtime_lock, seq));
} while (read_seqretry(&timekeeper.lock, seq));
set_normalized_timespec(&now, now.tv_sec + mono.tv_sec,
now.tv_nsec + mono.tv_nsec);
......@@ -1220,11 +1257,11 @@ void get_xtime_and_monotonic_and_sleep_offset(struct timespec *xtim,
unsigned long seq;
do {
seq = read_seqbegin(&xtime_lock);
seq = read_seqbegin(&timekeeper.lock);
*xtim = timekeeper.xtime;
*wtom = timekeeper.wall_to_monotonic;
*sleep = timekeeper.total_sleep_time;
} while (read_seqretry(&xtime_lock, seq));
} while (read_seqretry(&timekeeper.lock, seq));
}
/**
......@@ -1236,9 +1273,10 @@ ktime_t ktime_get_monotonic_offset(void)
struct timespec wtom;
do {
seq = read_seqbegin(&xtime_lock);
seq = read_seqbegin(&timekeeper.lock);
wtom = timekeeper.wall_to_monotonic;
} while (read_seqretry(&xtime_lock, seq));
} while (read_seqretry(&timekeeper.lock, seq));
return timespec_to_ktime(wtom);
}
......
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