diff options
Diffstat (limited to 'kernel/time')
| -rw-r--r-- | kernel/time/clocksource.c | 6 | ||||
| -rw-r--r-- | kernel/time/timekeeping.c | 235 |
2 files changed, 160 insertions, 81 deletions
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index f1508019bfb..f18c9a6bdcf 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -177,7 +177,8 @@ static void clocksource_watchdog(unsigned long data) 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(cs, &watchdog_list, wd_list) { @@ -196,7 +197,8 @@ static void clocksource_watchdog(unsigned long data) } /* Check the deviation from the watchdog clocksource. */ - cs_nsec = cyc2ns(cs, (csnow - cs->wd_last) & cs->mask); + 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); diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 325a9b63265..7af45cbf6b1 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -19,6 +19,65 @@ #include <linux/time.h> #include <linux/tick.h> +/* Structure holding internal timekeeping values. */ +struct timekeeper { + /* Current clocksource used for timekeeping. */ + struct clocksource *clock; + + /* 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; +}; + +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_orig/2; + do_div(tmp, clock->mult_orig); + 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_orig) >> clock->shift; + + timekeeper.xtime_nsec = 0; + + timekeeper.ntp_error = 0; +} /* * This read-write spinlock protects us from races in SMP while @@ -46,6 +105,11 @@ struct timespec xtime __attribute__ ((aligned (16))); struct timespec wall_to_monotonic __attribute__ ((aligned (16))); static unsigned long total_sleep_time; /* seconds */ +/* + * 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; @@ -56,42 +120,42 @@ 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, clock); + 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; + 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, clock->mult, clock->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_orig, clock->shift); + timespec_add_ns(&raw_time, nsec); } /** @@ -103,6 +167,7 @@ static void clocksource_forward_now(void) void getnstimeofday(struct timespec *ts) { cycle_t cycle_now, cycle_delta; + struct clocksource *clock; unsigned long seq; s64 nsecs; @@ -114,13 +179,15 @@ void getnstimeofday(struct timespec *ts) *ts = xtime; /* 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; /* convert to nanoseconds: */ - nsecs = cyc2ns(clock, cycle_delta); + nsecs = clocksource_cyc2ns(cycle_delta, clock->mult, + clock->shift); /* If arch requires, add in gettimeoffset() */ nsecs += arch_gettimeoffset(); @@ -135,6 +202,7 @@ EXPORT_SYMBOL(getnstimeofday); ktime_t ktime_get(void) { cycle_t cycle_now, cycle_delta; + struct clocksource *clock; unsigned int seq; s64 secs, nsecs; @@ -146,13 +214,15 @@ ktime_t ktime_get(void) nsecs = xtime.tv_nsec + wall_to_monotonic.tv_nsec; /* 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; /* convert to nanoseconds: */ - nsecs += cyc2ns(clock, cycle_delta); + nsecs += clocksource_cyc2ns(cycle_delta, clock->mult, + clock->shift); } while (read_seqretry(&xtime_lock, seq)); /* @@ -174,6 +244,7 @@ EXPORT_SYMBOL_GPL(ktime_get); void ktime_get_ts(struct timespec *ts) { cycle_t cycle_now, cycle_delta; + struct clocksource *clock; struct timespec tomono; unsigned int seq; s64 nsecs; @@ -186,13 +257,15 @@ void ktime_get_ts(struct timespec *ts) tomono = wall_to_monotonic; /* 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; /* convert to nanoseconds: */ - nsecs = cyc2ns(clock, cycle_delta); + nsecs = clocksource_cyc2ns(cycle_delta, clock->mult, + clock->shift); } while (read_seqretry(&xtime_lock, seq)); @@ -233,7 +306,7 @@ 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; @@ -243,10 +316,10 @@ 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); @@ -269,10 +342,10 @@ static void change_clocksource(void) new = clocksource_get_next(); - if (!new || clock == new) + if (!new || timekeeper.clock == new) return; - clocksource_forward_now(); + timekeeping_forward_now(); if (new->enable && !new->enable(new)) return; @@ -284,9 +357,9 @@ static void change_clocksource(void) */ new->mult_orig = new->mult; - new->raw_time = clock->raw_time; - old = clock; - clock = new; + old = timekeeper.clock; + timekeeper_setup_internals(new); + /* * Save mult_orig in mult so that the value can be restored * regardless if ->enable() updates the value of mult or not. @@ -295,22 +368,10 @@ static void change_clocksource(void) if (old->disable) old->disable(old); - clock->cycle_last = clock->read(clock); - clock->error = 0; - clock->xtime_nsec = 0; - clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH); - tick_clock_notify(); - - /* - * 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); - */ } #else /* GENERIC_TIME */ -static inline void clocksource_forward_now(void) { } +static inline void timekeeping_forward_now(void) { } static inline void change_clocksource(void) { } /** @@ -380,20 +441,23 @@ void getrawmonotonic(struct timespec *ts) unsigned long seq; s64 nsecs; cycle_t cycle_now, cycle_delta; + struct clocksource *clock; do { seq = read_seqbegin(&xtime_lock); /* 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; /* convert to nanoseconds: */ - nsecs = ((s64)cycle_delta * clock->mult_orig) >> clock->shift; + nsecs = clocksource_cyc2ns(cycle_delta, clock->mult_orig, + clock->shift); - *ts = clock->raw_time; + *ts = raw_time; } while (read_seqretry(&xtime_lock, seq)); @@ -413,7 +477,7 @@ 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)); @@ -439,6 +503,7 @@ 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(); @@ -451,11 +516,13 @@ void __init timekeeping_init(void) clock->enable(clock); /* set mult_orig on enable */ clock->mult_orig = clock->mult; - clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH); - clock->cycle_last = clock->read(clock); + + timekeeper_setup_internals(clock); xtime.tv_sec = sec; xtime.tv_nsec = 0; + raw_time.tv_sec = 0; + raw_time.tv_nsec = 0; set_normalized_timespec(&wall_to_monotonic, -xtime.tv_sec, -xtime.tv_nsec); update_xtime_cache(0); @@ -492,8 +559,8 @@ static int timekeeping_resume(struct sys_device *dev) } update_xtime_cache(0); /* re-base the last cycle value */ - clock->cycle_last = clock->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); @@ -514,7 +581,7 @@ static int timekeeping_suspend(struct sys_device *dev, pm_message_t state) timekeeping_suspend_time = read_persistent_clock(); write_seqlock_irqsave(&xtime_lock, flags); - clocksource_forward_now(); + timekeeping_forward_now(); timekeeping_suspended = 1; write_sequnlock_irqrestore(&xtime_lock, flags); @@ -549,7 +616,7 @@ 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; @@ -565,7 +632,7 @@ 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; @@ -574,8 +641,9 @@ 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 >> + (NTP_SCALE_SHIFT - timekeeper.clock->shift + 1); + tick_error -= timekeeper.xtime_interval >> 1; error = ((error - tick_error) >> look_ahead) + tick_error; /* Finally calculate the adjustment shift value. */ @@ -600,18 +668,19 @@ 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 >> + (NTP_SCALE_SHIFT - timekeeper.clock->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)) { @@ -619,15 +688,15 @@ 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.clock->mult += adj; + timekeeper.xtime_interval += interval; + timekeeper.xtime_nsec -= offset; + timekeeper.ntp_error -= (interval - offset) << + (NTP_SCALE_SHIFT - timekeeper.clock->shift); } /** @@ -637,53 +706,59 @@ static void clocksource_adjust(s64 offset) */ void update_wall_time(void) { + struct clocksource *clock; cycle_t offset; + s64 nsecs; /* Make sure we're fully resumed: */ if (unlikely(timekeeping_suspended)) return; + clock = timekeeper.clock; #ifdef CONFIG_GENERIC_TIME 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 << clock->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 << clock->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 << + (NTP_SCALE_SHIFT - clock->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. * @@ -695,24 +770,26 @@ 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 << (NTP_SCALE_SHIFT - clock->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 >> clock->shift) + 1; + timekeeper.xtime_nsec -= (s64)xtime.tv_nsec << clock->shift; + timekeeper.ntp_error += timekeeper.xtime_nsec << + (NTP_SCALE_SHIFT - clock->shift); - update_xtime_cache(cyc2ns(clock, offset)); + nsecs = clocksource_cyc2ns(offset, clock->mult, clock->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); } /** |