[PATCH v9 09/32] timers: Split out forward timer base functionality

Anna-Maria Behnsen
2023-12-01T09:27:42Z

Forwarding timer base is done when the next expiry value is calculated and
when a new timer is enqueued. When the next expiry value is calculated the
jiffies value is already available and does not need to be reread a second
time.

Splitting out the forward timer base functionality to make it executable
via both contextes - those where jiffies are already known and those, where
jiffies need to be read.

No functional change.

Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
---
kernel/time/timer.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 66bac56909ba..e289cbd84e8c 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -939,30 +939,34 @@ get_target_base(struct timer_base *base, unsigned tflags)
return get_timer_this_cpu_base(tflags);
}

-static inline void forward_timer_base(struct timer_base *base)
+static inline void __forward_timer_base(struct timer_base *base,
+ unsigned long basej)
{
- unsigned long jnow = READ_ONCE(jiffies);
-
/*
* Check whether we can forward the base. We can only do that when
* @basej is past base->clk otherwise we might rewind base->clk.
*/
- if (time_before_eq(jnow, base->clk))
+ if (time_before_eq(basej, base->clk))
return;

/*
* If the next expiry value is > jiffies, then we fast forward to
* jiffies otherwise we forward to the next expiry value.
*/
- if (time_after(base->next_expiry, jnow)) {
- base->clk = jnow;
+ if (time_after(base->next_expiry, basej)) {
+ base->clk = basej;
} else {
if (WARN_ON_ONCE(time_before(base->next_expiry, base->clk)))
return;
base->clk = base->next_expiry;
}
+
}

+static inline void forward_timer_base(struct timer_base *base)
+{
+ __forward_timer_base(base, READ_ONCE(jiffies));
+}

/*
* We are using hashed locking: Holding per_cpu(timer_bases[x]).lock means
--
2.39.2