diff options
| author | Anna-Maria Behnsen <anna-maria@linutronix.de> | 2024-02-21 10:05:39 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2024-02-22 17:52:31 +0100 |
| commit | 21927fc89e5feebc1f7cbf50bb58b81d776a62b4 (patch) | |
| tree | 3ff9a9fc8f26b65ff254201eda60b6f3ba643a6f /kernel/time | |
| parent | 83a665dc99a7b0721fa1e02fb60d2a1789ccd371 (diff) | |
timers: Retrieve next expiry of pinned/non-pinned timers separately
For the conversion of the NOHZ timer placement to a pull at expiry time
model it's required to have separate expiry times for the pinned and the
non-pinned (movable) timers. Therefore struct timer_events is introduced.
No functional change
Originally-by: Richard Cochran (linutronix GmbH) <richardcochran@gmail.com>
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20240221090548.36600-12-anna-maria@linutronix.de
Diffstat (limited to 'kernel/time')
| -rw-r--r-- | kernel/time/timer.c | 35 |
1 files changed, 31 insertions, 4 deletions
diff --git a/kernel/time/timer.c b/kernel/time/timer.c index aabd13675723..38becd2facee 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -266,6 +266,11 @@ struct timer_base { static DEFINE_PER_CPU(struct timer_base, timer_bases[NR_BASES]); +struct timer_events { + u64 local; + u64 global; +}; + #ifdef CONFIG_NO_HZ_COMMON static DEFINE_STATIC_KEY_FALSE(timers_nohz_active); @@ -2031,10 +2036,11 @@ static unsigned long next_timer_interrupt(struct timer_base *base, static inline u64 __get_next_timer_interrupt(unsigned long basej, u64 basem, bool *idle) { + struct timer_events tevt = { .local = KTIME_MAX, .global = KTIME_MAX }; unsigned long nextevt, nextevt_local, nextevt_global; struct timer_base *base_local, *base_global; - u64 expires = KTIME_MAX; bool local_first; + u64 expires; /* * Pretend that there is no timer pending if the cpu is offline. @@ -2043,7 +2049,7 @@ static inline u64 __get_next_timer_interrupt(unsigned long basej, u64 basem, if (cpu_is_offline(smp_processor_id())) { if (idle) *idle = true; - return expires; + return tevt.local; } base_local = this_cpu_ptr(&timer_bases[BASE_LOCAL]); @@ -2059,14 +2065,33 @@ static inline u64 __get_next_timer_interrupt(unsigned long basej, u64 basem, nextevt = local_first ? nextevt_local : nextevt_global; - if (base_local->timers_pending || base_global->timers_pending) { + /* + * If the @nextevt is at max. one tick away, use @nextevt and store + * it in the local expiry value. The next global event is irrelevant in + * this case and can be left as KTIME_MAX. + */ + if (time_before_eq(nextevt, basej + 1)) { /* If we missed a tick already, force 0 delta */ if (time_before(nextevt, basej)) nextevt = basej; - expires = basem + (u64)(nextevt - basej) * TICK_NSEC; + tevt.local = basem + (u64)(nextevt - basej) * TICK_NSEC; + goto forward; } /* + * Update tevt.* values: + * + * If the local queue expires first, then the global event can be + * ignored. If the global queue is empty, nothing to do either. + */ + if (!local_first && base_global->timers_pending) + tevt.global = basem + (u64)(nextevt_global - basej) * TICK_NSEC; + + if (base_local->timers_pending) + tevt.local = basem + (u64)(nextevt_local - basej) * TICK_NSEC; + +forward: + /* * We have a fresh next event. Check whether we can forward the * base. */ @@ -2096,6 +2121,8 @@ static inline u64 __get_next_timer_interrupt(unsigned long basej, u64 basem, raw_spin_unlock(&base_global->lock); raw_spin_unlock(&base_local->lock); + expires = min_t(u64, tevt.local, tevt.global); + return cmp_next_hrtimer_event(basem, expires); } |