diff options
Diffstat (limited to 'kernel/time/timekeeping.c')
-rw-r--r-- | kernel/time/timekeeping.c | 94 |
1 files changed, 25 insertions, 69 deletions
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 929846b8b45a..1e67d076f195 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -682,19 +682,20 @@ static void timekeeping_update_from_shadow(struct tk_data *tkd, unsigned int act } /** - * timekeeping_forward - update clock to given cycle now value + * timekeeping_forward_now - update clock to the current time * @tk: Pointer to the timekeeper to update - * @cycle_now: Current clocksource read value * * 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 timekeeping_forward(struct timekeeper *tk, u64 cycle_now) +static void timekeeping_forward_now(struct timekeeper *tk) { - u64 delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last, tk->tkr_mono.mask, - tk->tkr_mono.clock->max_raw_delta); + u64 cycle_now, delta; + cycle_now = tk_clock_read(&tk->tkr_mono); + delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last, tk->tkr_mono.mask, + tk->tkr_mono.clock->max_raw_delta); tk->tkr_mono.cycle_last = cycle_now; tk->tkr_raw.cycle_last = cycle_now; @@ -710,21 +711,6 @@ static void timekeeping_forward(struct timekeeper *tk, u64 cycle_now) } /** - * timekeeping_forward_now - update clock to the current time - * @tk: Pointer to the timekeeper to update - * - * 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 timekeeping_forward_now(struct timekeeper *tk) -{ - u64 cycle_now = tk_clock_read(&tk->tkr_mono); - - timekeeping_forward(tk, cycle_now); -} - -/** * ktime_get_real_ts64 - Returns the time of day in a timespec64. * @ts: pointer to the timespec to be set * @@ -2165,54 +2151,6 @@ static u64 logarithmic_accumulation(struct timekeeper *tk, u64 offset, return offset; } -static u64 timekeeping_accumulate(struct timekeeper *tk, u64 offset, - enum timekeeping_adv_mode mode, - unsigned int *clock_set) -{ - int shift = 0, maxshift; - - /* - * TK_ADV_FREQ indicates that adjtimex(2) directly set the - * frequency or the tick length. - * - * Accumulate the offset, so that the new multiplier starts from - * now. This is required as otherwise for offsets, which are - * smaller than tk::cycle_interval, timekeeping_adjust() could set - * xtime_nsec backwards, which subsequently causes time going - * backwards in the coarse time getters. But even for the case - * where offset is greater than tk::cycle_interval the periodic - * accumulation does not have much value. - * - * Also reset tk::ntp_error as it does not make sense to keep the - * old accumulated error around in this case. - */ - if (mode == TK_ADV_FREQ) { - timekeeping_forward(tk, tk->tkr_mono.cycle_last + offset); - tk->ntp_error = 0; - return 0; - } - - /* - * With NO_HZ we may have to accumulate many cycle_intervals - * (think "ticks") worth of time at once. To do this efficiently, - * we calculate the largest doubling multiple of cycle_intervals - * that is smaller than the offset. We then accumulate that - * chunk in one go, and then try to consume the next smaller - * doubled multiple. - */ - shift = ilog2(offset) - ilog2(tk->cycle_interval); - shift = max(0, shift); - /* Bound shift to one less than what overflows tick_length */ - maxshift = (64 - (ilog2(ntp_tick_length()) + 1)) - 1; - shift = min(shift, maxshift); - while (offset >= tk->cycle_interval) { - offset = logarithmic_accumulation(tk, offset, shift, clock_set); - if (offset < tk->cycle_interval << shift) - shift--; - } - return offset; -} - /* * timekeeping_advance - Updates the timekeeper to the current time and * current NTP tick length @@ -2222,6 +2160,7 @@ static bool timekeeping_advance(enum timekeeping_adv_mode mode) struct timekeeper *tk = &tk_core.shadow_timekeeper; struct timekeeper *real_tk = &tk_core.timekeeper; unsigned int clock_set = 0; + int shift = 0, maxshift; u64 offset; guard(raw_spinlock_irqsave)(&tk_core.lock); @@ -2238,7 +2177,24 @@ static bool timekeeping_advance(enum timekeeping_adv_mode mode) if (offset < real_tk->cycle_interval && mode == TK_ADV_TICK) return false; - offset = timekeeping_accumulate(tk, offset, mode, &clock_set); + /* + * With NO_HZ we may have to accumulate many cycle_intervals + * (think "ticks") worth of time at once. To do this efficiently, + * we calculate the largest doubling multiple of cycle_intervals + * that is smaller than the offset. We then accumulate that + * chunk in one go, and then try to consume the next smaller + * doubled multiple. + */ + shift = ilog2(offset) - ilog2(tk->cycle_interval); + shift = max(0, shift); + /* Bound shift to one less than what overflows tick_length */ + maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1; + shift = min(shift, maxshift); + while (offset >= tk->cycle_interval) { + offset = logarithmic_accumulation(tk, offset, shift, &clock_set); + if (offset < tk->cycle_interval<<shift) + shift--; + } /* Adjust the multiplier to correct NTP error */ timekeeping_adjust(tk, offset); |