diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2025-06-25 20:38:29 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2025-06-27 20:13:12 +0200 |
| commit | 9f7729480a2c771bbe49b7eab034a8eaa5e27bfb (patch) | |
| tree | 0f97310e395e1389bfc4c18f28b1052c5d7e16f6 | |
| parent | 180d8b4ce91fe0cf7a9cb236bb01f14587ba4bf0 (diff) | |
timekeeping: Update auxiliary timekeepers on clocksource change
Propagate a system clocksource change to the auxiliary timekeepers so that
they can pick up the new clocksource.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <jstultz@google.com>
Link: https://lore.kernel.org/all/20250625183757.803890875@linutronix.de
| -rw-r--r-- | kernel/time/timekeeping.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 7d3693a72a01..ee9757018341 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -119,8 +119,10 @@ static struct tk_fast tk_fast_raw ____cacheline_aligned = { #ifdef CONFIG_POSIX_AUX_CLOCKS static __init void tk_aux_setup(void); +static void tk_aux_update_clocksource(void); #else static inline void tk_aux_setup(void) { } +static inline void tk_aux_update_clocksource(void) { } #endif unsigned long timekeeper_lock_irqsave(void) @@ -1548,6 +1550,8 @@ static int change_clocksource(void *data) timekeeping_update_from_shadow(&tk_core, TK_UPDATE_ALL); } + tk_aux_update_clocksource(); + if (old) { if (old->disable) old->disable(old); @@ -2651,6 +2655,35 @@ EXPORT_SYMBOL(hardpps); #endif /* CONFIG_NTP_PPS */ #ifdef CONFIG_POSIX_AUX_CLOCKS + +/* + * Bitmap for the activated auxiliary timekeepers to allow lockless quick + * checks in the hot paths without touching extra cache lines. If set, then + * the state of the corresponding timekeeper has to be re-checked under + * timekeeper::lock. + */ +static unsigned long aux_timekeepers; + +/* Invoked from timekeeping after a clocksource change */ +static void tk_aux_update_clocksource(void) +{ + unsigned long active = READ_ONCE(aux_timekeepers); + unsigned int id; + + for_each_set_bit(id, &active, BITS_PER_LONG) { + struct tk_data *tkd = &timekeeper_data[id + TIMEKEEPER_AUX_FIRST]; + struct timekeeper *tks = &tkd->shadow_timekeeper; + + guard(raw_spinlock_irqsave)(&tkd->lock); + if (!tks->clock_valid) + continue; + + timekeeping_forward_now(tks); + tk_setup_internals(tks, tk_core.timekeeper.tkr_mono.clock); + timekeeping_update_from_shadow(tkd, TK_UPDATE_ALL); + } +} + static __init void tk_aux_setup(void) { for (int i = TIMEKEEPER_AUX_FIRST; i <= TIMEKEEPER_AUX_LAST; i++) |