time: Rework timekeeping functions to take timekeeper ptr as argument
As part of cleaning up the timekeeping code, this patch converts
a number of internal functions to takei a timekeeper ptr as an
argument, so that the internal functions don't access the global
timekeeper structure directly. This allows for further optimizations
to reduce lock hold time later.
This patch has been updated to include more consistent usage of the
timekeeper value, by making sure it is always passed as a argument
to non top-level functions.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Link: http://lkml.kernel.org/r/1342156917-25092-9-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index aeeaab8..5980e90 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -127,14 +127,14 @@
*
* Unless you're the timekeeping code, you should not be using this!
*/
-static void timekeeper_setup_internals(struct clocksource *clock)
+static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock)
{
cycle_t interval;
u64 tmp, ntpinterval;
struct clocksource *old_clock;
- old_clock = timekeeper.clock;
- timekeeper.clock = clock;
+ old_clock = tk->clock;
+ tk->clock = clock;
clock->cycle_last = clock->read(clock);
/* Do the ns -> cycle conversion first, using original mult */
@@ -147,64 +147,64 @@
tmp = 1;
interval = (cycle_t) tmp;
- timekeeper.cycle_interval = interval;
+ tk->cycle_interval = interval;
/* Go back from cycles -> shifted ns */
- timekeeper.xtime_interval = (u64) interval * clock->mult;
- timekeeper.xtime_remainder = ntpinterval - timekeeper.xtime_interval;
- timekeeper.raw_interval =
+ tk->xtime_interval = (u64) interval * clock->mult;
+ tk->xtime_remainder = ntpinterval - tk->xtime_interval;
+ tk->raw_interval =
((u64) interval * clock->mult) >> clock->shift;
/* if changing clocks, convert xtime_nsec shift units */
if (old_clock) {
int shift_change = clock->shift - old_clock->shift;
if (shift_change < 0)
- timekeeper.xtime_nsec >>= -shift_change;
+ tk->xtime_nsec >>= -shift_change;
else
- timekeeper.xtime_nsec <<= shift_change;
+ tk->xtime_nsec <<= shift_change;
}
- timekeeper.shift = clock->shift;
+ tk->shift = clock->shift;
- timekeeper.ntp_error = 0;
- timekeeper.ntp_error_shift = NTP_SCALE_SHIFT - clock->shift;
+ tk->ntp_error = 0;
+ tk->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;
+ tk->mult = clock->mult;
}
/* Timekeeper helper functions. */
-static inline s64 timekeeping_get_ns(void)
+static inline s64 timekeeping_get_ns(struct timekeeper *tk)
{
cycle_t cycle_now, cycle_delta;
struct clocksource *clock;
s64 nsec;
/* read clocksource: */
- clock = timekeeper.clock;
+ clock = tk->clock;
cycle_now = clock->read(clock);
/* calculate the delta since the last update_wall_time: */
cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
- nsec = cycle_delta * timekeeper.mult + timekeeper.xtime_nsec;
- nsec >>= timekeeper.shift;
+ nsec = cycle_delta * tk->mult + tk->xtime_nsec;
+ nsec >>= tk->shift;
/* If arch requires, add in gettimeoffset() */
return nsec + arch_gettimeoffset();
}
-static inline s64 timekeeping_get_ns_raw(void)
+static inline s64 timekeeping_get_ns_raw(struct timekeeper *tk)
{
cycle_t cycle_now, cycle_delta;
struct clocksource *clock;
s64 nsec;
/* read clocksource: */
- clock = timekeeper.clock;
+ clock = tk->clock;
cycle_now = clock->read(clock);
/* calculate the delta since the last update_wall_time: */
@@ -217,27 +217,26 @@
return nsec + arch_gettimeoffset();
}
-static void update_rt_offset(void)
+static void update_rt_offset(struct timekeeper *tk)
{
- struct timespec tmp, *wtm = &timekeeper.wall_to_monotonic;
+ struct timespec tmp, *wtm = &tk->wall_to_monotonic;
set_normalized_timespec(&tmp, -wtm->tv_sec, -wtm->tv_nsec);
- timekeeper.offs_real = timespec_to_ktime(tmp);
+ tk->offs_real = timespec_to_ktime(tmp);
}
/* must hold write on timekeeper.lock */
-static void timekeeping_update(bool clearntp)
+static void timekeeping_update(struct timekeeper *tk, bool clearntp)
{
struct timespec xt;
if (clearntp) {
- timekeeper.ntp_error = 0;
+ tk->ntp_error = 0;
ntp_clear();
}
- update_rt_offset();
- xt = tk_xtime(&timekeeper);
- update_vsyscall(&xt, &timekeeper.wall_to_monotonic,
- timekeeper.clock, timekeeper.mult);
+ update_rt_offset(tk);
+ xt = tk_xtime(tk);
+ update_vsyscall(&xt, &tk->wall_to_monotonic, tk->clock, tk->mult);
}
@@ -248,26 +247,26 @@
* update_wall_time(). This is useful before significant clock changes,
* as it avoids having to deal with this time offset explicitly.
*/
-static void timekeeping_forward_now(void)
+static void timekeeping_forward_now(struct timekeeper *tk)
{
cycle_t cycle_now, cycle_delta;
struct clocksource *clock;
s64 nsec;
- clock = timekeeper.clock;
+ clock = tk->clock;
cycle_now = clock->read(clock);
cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
clock->cycle_last = cycle_now;
- timekeeper.xtime_nsec += cycle_delta * timekeeper.mult;
+ tk->xtime_nsec += cycle_delta * tk->mult;
/* If arch requires, add in gettimeoffset() */
- timekeeper.xtime_nsec += arch_gettimeoffset() << timekeeper.shift;
+ tk->xtime_nsec += arch_gettimeoffset() << tk->shift;
- tk_normalize_xtime(&timekeeper);
+ tk_normalize_xtime(tk);
nsec = clocksource_cyc2ns(cycle_delta, clock->mult, clock->shift);
- timespec_add_ns(&timekeeper.raw_time, nsec);
+ timespec_add_ns(&tk->raw_time, nsec);
}
/**
@@ -287,7 +286,7 @@
seq = read_seqbegin(&timekeeper.lock);
ts->tv_sec = timekeeper.xtime_sec;
- ts->tv_nsec = timekeeping_get_ns();
+ ts->tv_nsec = timekeeping_get_ns(&timekeeper);
} while (read_seqretry(&timekeeper.lock, seq));
@@ -306,7 +305,7 @@
seq = read_seqbegin(&timekeeper.lock);
secs = timekeeper.xtime_sec +
timekeeper.wall_to_monotonic.tv_sec;
- nsecs = timekeeping_get_ns() +
+ nsecs = timekeeping_get_ns(&timekeeper) +
timekeeper.wall_to_monotonic.tv_nsec;
} while (read_seqretry(&timekeeper.lock, seq));
@@ -336,7 +335,7 @@
do {
seq = read_seqbegin(&timekeeper.lock);
ts->tv_sec = timekeeper.xtime_sec;
- ts->tv_nsec = timekeeping_get_ns();
+ ts->tv_nsec = timekeeping_get_ns(&timekeeper);
tomono = timekeeper.wall_to_monotonic;
} while (read_seqretry(&timekeeper.lock, seq));
@@ -371,8 +370,8 @@
ts_real->tv_sec = timekeeper.xtime_sec;
ts_real->tv_nsec = 0;
- nsecs_raw = timekeeping_get_ns_raw();
- nsecs_real = timekeeping_get_ns();
+ nsecs_raw = timekeeping_get_ns_raw(&timekeeper);
+ nsecs_real = timekeeping_get_ns(&timekeeper);
} while (read_seqretry(&timekeeper.lock, seq));
@@ -415,7 +414,7 @@
write_seqlock_irqsave(&timekeeper.lock, flags);
- timekeeping_forward_now();
+ timekeeping_forward_now(&timekeeper);
xt = tk_xtime(&timekeeper);
ts_delta.tv_sec = tv->tv_sec - xt.tv_sec;
@@ -426,7 +425,7 @@
tk_set_xtime(&timekeeper, tv);
- timekeeping_update(true);
+ timekeeping_update(&timekeeper, true);
write_sequnlock_irqrestore(&timekeeper.lock, flags);
@@ -453,14 +452,14 @@
write_seqlock_irqsave(&timekeeper.lock, flags);
- timekeeping_forward_now();
+ timekeeping_forward_now(&timekeeper);
tk_xtime_add(&timekeeper, ts);
timekeeper.wall_to_monotonic =
timespec_sub(timekeeper.wall_to_monotonic, *ts);
- timekeeping_update(true);
+ timekeeping_update(&timekeeper, true);
write_sequnlock_irqrestore(&timekeeper.lock, flags);
@@ -485,14 +484,14 @@
write_seqlock_irqsave(&timekeeper.lock, flags);
- timekeeping_forward_now();
+ timekeeping_forward_now(&timekeeper);
if (!new->enable || new->enable(new) == 0) {
old = timekeeper.clock;
- timekeeper_setup_internals(new);
+ tk_setup_internals(&timekeeper, new);
if (old->disable)
old->disable(old);
}
- timekeeping_update(true);
+ timekeeping_update(&timekeeper, true);
write_sequnlock_irqrestore(&timekeeper.lock, flags);
@@ -542,7 +541,7 @@
do {
seq = read_seqbegin(&timekeeper.lock);
- nsecs = timekeeping_get_ns_raw();
+ nsecs = timekeeping_get_ns_raw(&timekeeper);
*ts = timekeeper.raw_time;
} while (read_seqretry(&timekeeper.lock, seq));
@@ -638,7 +637,7 @@
clock = clocksource_default_clock();
if (clock->enable)
clock->enable(clock);
- timekeeper_setup_internals(clock);
+ tk_setup_internals(&timekeeper, clock);
tk_set_xtime(&timekeeper, &now);
timekeeper.raw_time.tv_sec = 0;
@@ -648,7 +647,7 @@
set_normalized_timespec(&timekeeper.wall_to_monotonic,
-boot.tv_sec, -boot.tv_nsec);
- update_rt_offset();
+ update_rt_offset(&timekeeper);
timekeeper.total_sleep_time.tv_sec = 0;
timekeeper.total_sleep_time.tv_nsec = 0;
write_sequnlock_irqrestore(&timekeeper.lock, flags);
@@ -670,7 +669,8 @@
* Takes a timespec offset measuring a suspend interval and properly
* adds the sleep offset to the timekeeping variables.
*/
-static void __timekeeping_inject_sleeptime(struct timespec *delta)
+static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
+ struct timespec *delta)
{
if (!timespec_valid(delta)) {
printk(KERN_WARNING "__timekeeping_inject_sleeptime: Invalid "
@@ -678,10 +678,9 @@
return;
}
- tk_xtime_add(&timekeeper, delta);
- timekeeper.wall_to_monotonic =
- timespec_sub(timekeeper.wall_to_monotonic, *delta);
- update_sleep_time(timespec_add(timekeeper.total_sleep_time, *delta));
+ tk_xtime_add(tk, delta);
+ tk->wall_to_monotonic = timespec_sub(tk->wall_to_monotonic, *delta);
+ update_sleep_time(timespec_add(tk->total_sleep_time, *delta));
}
@@ -707,11 +706,11 @@
write_seqlock_irqsave(&timekeeper.lock, flags);
- timekeeping_forward_now();
+ timekeeping_forward_now(&timekeeper);
- __timekeeping_inject_sleeptime(delta);
+ __timekeeping_inject_sleeptime(&timekeeper, delta);
- timekeeping_update(true);
+ timekeeping_update(&timekeeper, true);
write_sequnlock_irqrestore(&timekeeper.lock, flags);
@@ -740,7 +739,7 @@
if (timespec_compare(&ts, &timekeeping_suspend_time) > 0) {
ts = timespec_sub(ts, timekeeping_suspend_time);
- __timekeeping_inject_sleeptime(&ts);
+ __timekeeping_inject_sleeptime(&timekeeper, &ts);
}
/* re-base the last cycle value */
timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock);
@@ -765,7 +764,7 @@
read_persistent_clock(&timekeeping_suspend_time);
write_seqlock_irqsave(&timekeeper.lock, flags);
- timekeeping_forward_now();
+ timekeeping_forward_now(&timekeeper);
timekeeping_suspended = 1;
/*
@@ -813,7 +812,8 @@
* If the error is already larger, we look ahead even further
* to compensate for late or lost adjustments.
*/
-static __always_inline int timekeeping_bigadjust(s64 error, s64 *interval,
+static __always_inline int timekeeping_bigadjust(struct timekeeper *tk,
+ s64 error, s64 *interval,
s64 *offset)
{
s64 tick_error, i;
@@ -829,7 +829,7 @@
* 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 = timekeeper.ntp_error >> (NTP_SCALE_SHIFT + 22 - 2 * SHIFT_HZ);
+ error2 = tk->ntp_error >> (NTP_SCALE_SHIFT + 22 - 2 * SHIFT_HZ);
error2 = abs(error2);
for (look_ahead = 0; error2 > 0; look_ahead++)
error2 >>= 2;
@@ -838,8 +838,8 @@
* Now calculate the error in (1 << look_ahead) ticks, but first
* remove the single look ahead already included in the error.
*/
- tick_error = ntp_tick_length() >> (timekeeper.ntp_error_shift + 1);
- tick_error -= timekeeper.xtime_interval >> 1;
+ tick_error = ntp_tick_length() >> (tk->ntp_error_shift + 1);
+ tick_error -= tk->xtime_interval >> 1;
error = ((error - tick_error) >> look_ahead) + tick_error;
/* Finally calculate the adjustment shift value. */
@@ -864,9 +864,9 @@
* this is optimized for the most common adjustments of -1,0,1,
* for other values we can do a bit more work.
*/
-static void timekeeping_adjust(s64 offset)
+static void timekeeping_adjust(struct timekeeper *tk, s64 offset)
{
- s64 error, interval = timekeeper.cycle_interval;
+ s64 error, interval = tk->cycle_interval;
int adj;
/*
@@ -882,7 +882,7 @@
*
* Note: It does not "save" on aggravation when reading the code.
*/
- error = timekeeper.ntp_error >> (timekeeper.ntp_error_shift - 1);
+ error = tk->ntp_error >> (tk->ntp_error_shift - 1);
if (error > interval) {
/*
* We now divide error by 4(via shift), which checks if
@@ -904,7 +904,8 @@
if (likely(error <= interval))
adj = 1;
else
- adj = timekeeping_bigadjust(error, &interval, &offset);
+ adj = timekeeping_bigadjust(tk, error, &interval,
+ &offset);
} else if (error < -interval) {
/* See comment above, this is just switched for the negative */
error >>= 2;
@@ -913,18 +914,17 @@
interval = -interval;
offset = -offset;
} else
- adj = timekeeping_bigadjust(error, &interval, &offset);
- } else /* No adjustment needed */
+ adj = timekeeping_bigadjust(tk, error, &interval,
+ &offset);
+ } else
return;
- if (unlikely(timekeeper.clock->maxadj &&
- (timekeeper.mult + adj >
- timekeeper.clock->mult + timekeeper.clock->maxadj))) {
+ if (unlikely(tk->clock->maxadj &&
+ (tk->mult + adj > tk->clock->mult + tk->clock->maxadj))) {
printk_once(KERN_WARNING
"Adjusting %s more than 11%% (%ld vs %ld)\n",
- timekeeper.clock->name, (long)timekeeper.mult + adj,
- (long)timekeeper.clock->mult +
- timekeeper.clock->maxadj);
+ tk->clock->name, (long)tk->mult + adj,
+ (long)tk->clock->mult + tk->clock->maxadj);
}
/*
* So the following can be confusing.
@@ -975,11 +975,10 @@
*
* XXX - TODO: Doc ntp_error calculation.
*/
- timekeeper.mult += adj;
- timekeeper.xtime_interval += interval;
- timekeeper.xtime_nsec -= offset;
- timekeeper.ntp_error -= (interval - offset) <<
- timekeeper.ntp_error_shift;
+ tk->mult += adj;
+ tk->xtime_interval += interval;
+ tk->xtime_nsec -= offset;
+ tk->ntp_error -= (interval - offset) << tk->ntp_error_shift;
/*
* It may be possible that when we entered this function, xtime_nsec
@@ -995,10 +994,10 @@
* We'll correct this error next time through this function, when
* xtime_nsec is not as small.
*/
- 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;
+ if (unlikely((s64)tk->xtime_nsec < 0)) {
+ s64 neg = -(s64)tk->xtime_nsec;
+ tk->xtime_nsec = 0;
+ tk->ntp_error += neg << tk->ntp_error_shift;
}
}
@@ -1042,37 +1041,36 @@
*
* Returns the unconsumed cycles.
*/
-static cycle_t logarithmic_accumulation(cycle_t offset, u32 shift)
+static cycle_t logarithmic_accumulation(struct timekeeper *tk, cycle_t offset,
+ u32 shift)
{
u64 raw_nsecs;
- /* If the offset is smaller than a shifted interval, do nothing */
- if (offset < timekeeper.cycle_interval<<shift)
+ /* If the offset is smaller then a shifted interval, do nothing */
+ if (offset < tk->cycle_interval<<shift)
return offset;
/* Accumulate one shifted interval */
- offset -= timekeeper.cycle_interval << shift;
- timekeeper.clock->cycle_last += timekeeper.cycle_interval << shift;
+ offset -= tk->cycle_interval << shift;
+ tk->clock->cycle_last += tk->cycle_interval << shift;
- timekeeper.xtime_nsec += timekeeper.xtime_interval << shift;
-
- accumulate_nsecs_to_secs(&timekeeper);
+ tk->xtime_nsec += tk->xtime_interval << shift;
+ accumulate_nsecs_to_secs(tk);
/* Accumulate raw time */
- raw_nsecs = timekeeper.raw_interval << shift;
- raw_nsecs += timekeeper.raw_time.tv_nsec;
+ raw_nsecs = tk->raw_interval << shift;
+ raw_nsecs += tk->raw_time.tv_nsec;
if (raw_nsecs >= NSEC_PER_SEC) {
u64 raw_secs = raw_nsecs;
raw_nsecs = do_div(raw_secs, NSEC_PER_SEC);
- timekeeper.raw_time.tv_sec += raw_secs;
+ tk->raw_time.tv_sec += raw_secs;
}
- timekeeper.raw_time.tv_nsec = raw_nsecs;
+ tk->raw_time.tv_nsec = raw_nsecs;
/* Accumulate error between NTP and clock interval */
- timekeeper.ntp_error += ntp_tick_length() << shift;
- timekeeper.ntp_error -=
- (timekeeper.xtime_interval + timekeeper.xtime_remainder) <<
- (timekeeper.ntp_error_shift + shift);
+ tk->ntp_error += ntp_tick_length() << shift;
+ tk->ntp_error -= (tk->xtime_interval + tk->xtime_remainder) <<
+ (tk->ntp_error_shift + shift);
return offset;
}
@@ -1118,13 +1116,13 @@
maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1;
shift = min(shift, maxshift);
while (offset >= timekeeper.cycle_interval) {
- offset = logarithmic_accumulation(offset, shift);
+ offset = logarithmic_accumulation(&timekeeper, offset, shift);
if(offset < timekeeper.cycle_interval<<shift)
shift--;
}
/* correct the clock when NTP error is too big */
- timekeeping_adjust(offset);
+ timekeeping_adjust(&timekeeper, offset);
/*
@@ -1147,7 +1145,7 @@
*/
accumulate_nsecs_to_secs(&timekeeper);
- timekeeping_update(false);
+ timekeeping_update(&timekeeper, false);
out:
write_sequnlock_irqrestore(&timekeeper.lock, flags);
@@ -1198,7 +1196,7 @@
do {
seq = read_seqbegin(&timekeeper.lock);
ts->tv_sec = timekeeper.xtime_sec;
- ts->tv_nsec = timekeeping_get_ns();
+ ts->tv_nsec = timekeeping_get_ns(&timekeeper);
tomono = timekeeper.wall_to_monotonic;
sleep = timekeeper.total_sleep_time;
@@ -1330,7 +1328,7 @@
seq = read_seqbegin(&timekeeper.lock);
secs = timekeeper.xtime_sec;
- nsecs = timekeeping_get_ns();
+ nsecs = timekeeping_get_ns(&timekeeper);
*offs_real = timekeeper.offs_real;
*offs_boot = timekeeper.offs_boot;