[PATCH v7 17/21] timer: Check if timers base is handled already

Anna-Maria Behnsen
2023-05-24T07:08:25Z

Due to the conversion of the NOHZ timer placement to a pull at expiry
time model, the per CPU timer bases with non pinned timers are no
longer handled only by the local CPU. In case a remote CPU already
expires the non pinned timers base of the local cpu, nothing more
needs to be done by the local CPU. A check at the begin of the expire
timers routine is required, because timer base lock is dropped before
executing the timer callback function.

This is a preparatory work, but has no functional impact right now.

Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
---
v6: Drop double negation
---
kernel/time/timer.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 20106dad531a..c2d66fd4638f 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -2204,6 +2204,9 @@ static inline void __run_timers(struct timer_base *base)

lockdep_assert_held(&base->lock);

+ if (base->running_timer)
+ return;
+
while (time_after_eq(jiffies, base->clk) &&
time_after_eq(jiffies, base->next_expiry)) {
levels = collect_expired_timers(base, heads);
--
2.30.2