Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
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kernel/time/timekeeping.c
+33
kernel/time/timekeeping.c
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#ifdef CONFIG_POSIX_AUX_CLOCKS
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static __init void tk_aux_setup(void);
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static void tk_aux_update_clocksource(void);
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#else
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static inline void tk_aux_setup(void) { }
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static inline void tk_aux_update_clocksource(void) { }
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#endif
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unsigned long timekeeper_lock_irqsave(void)
···
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timekeeping_update_from_shadow(&tk_core, TK_UPDATE_ALL);
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}
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tk_aux_update_clocksource();
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if (old) {
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if (old->disable)
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old->disable(old);
···
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#endif /* CONFIG_NTP_PPS */
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#ifdef CONFIG_POSIX_AUX_CLOCKS
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/*
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* Bitmap for the activated auxiliary timekeepers to allow lockless quick
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* checks in the hot paths without touching extra cache lines. If set, then
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* the state of the corresponding timekeeper has to be re-checked under
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* timekeeper::lock.
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*/
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static unsigned long aux_timekeepers;
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/* Invoked from timekeeping after a clocksource change */
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static void tk_aux_update_clocksource(void)
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{
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unsigned long active = READ_ONCE(aux_timekeepers);
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unsigned int id;
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for_each_set_bit(id, &active, BITS_PER_LONG) {
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struct tk_data *tkd = &timekeeper_data[id + TIMEKEEPER_AUX_FIRST];
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struct timekeeper *tks = &tkd->shadow_timekeeper;
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guard(raw_spinlock_irqsave)(&tkd->lock);
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if (!tks->clock_valid)
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continue;
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timekeeping_forward_now(tks);
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tk_setup_internals(tks, tk_core.timekeeper.tkr_mono.clock);
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timekeeping_update_from_shadow(tkd, TK_UPDATE_ALL);
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}
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}
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static __init void tk_aux_setup(void)
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{
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for (int i = TIMEKEEPER_AUX_FIRST; i <= TIMEKEEPER_AUX_LAST; i++)