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timers: Split out forward timer base functionality

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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>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20231201092654.34614-10-anna-maria@linutronix.de
This commit is contained in:
Anna-Maria Behnsen 2023-12-01 10:26:31 +01:00 committed by Thomas Gleixner
parent 8a2c9c7e78
commit 1e490484aa
1 changed files with 10 additions and 6 deletions
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16
kernel/time/timer.c
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@ -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