[PATCH v9 21/32] timers: Split next timer interrupt logic

Anna-Maria Behnsen
2023-12-01T09:28:34Z

Logic for getting next timer interrupt (no matter of recalculated or
already stored in base->next_expiry) is split into a separate function
"next_timer_interrupt()" to make it available for new call sites.

No functional change.

Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
---
v9: Adapt to the fix for empty timer bases.
---
kernel/time/timer.c | 32 +++++++++++++++++++-------------
1 file changed, 19 insertions(+), 13 deletions(-)

diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index b14d84f1fe50..eda4972ca862 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1951,12 +1951,29 @@ static u64 cmp_next_hrtimer_event(u64 basem, u64 expires)
return DIV_ROUND_UP_ULL(nextevt, TICK_NSEC) * TICK_NSEC;
}

+static unsigned long next_timer_interrupt(struct timer_base *base,
+ unsigned long basej)
+{
+ if (base->next_expiry_recalc)
+ next_expiry_recalc(base);
+
+ /*
+ * Move next_expiry for the empty base into the future to prevent a
+ * unnecessary raise of the timer softirq when the next_expiry value
+ * will be reached even if there is no timer pending.
+ */
+ if (!base->timers_pending)
+ base->next_expiry = basej + NEXT_TIMER_MAX_DELTA;
+
+ return base->next_expiry;
+}
+
static inline u64 __get_next_timer_interrupt(unsigned long basej, u64 basem,
bool *idle)
{
struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]);
- unsigned long nextevt = basej + NEXT_TIMER_MAX_DELTA;
u64 expires = KTIME_MAX;
+ unsigned long nextevt;

/*
* Pretend that there is no timer pending if the cpu is offline.
@@ -1969,24 +1986,13 @@ static inline u64 __get_next_timer_interrupt(unsigned long basej, u64 basem,
}

raw_spin_lock(&base->lock);
- if (base->next_expiry_recalc)
- next_expiry_recalc(base);
+ nextevt = next_timer_interrupt(base, basej);

if (base->timers_pending) {
- nextevt = base->next_expiry;
-
/* If we missed a tick already, force 0 delta */
if (time_before(nextevt, basej))
nextevt = basej;
expires = basem + (u64)(nextevt - basej) * TICK_NSEC;
- } else {
- /*
- * Move next_expiry for the empty base into the future to
- * prevent a unnecessary raise of the timer softirq when the
- * next_expiry value will be reached even if there is no timer
- * pending.
- */
- base->next_expiry = nextevt;
}

/*
--
2.39.2