[v11,14/20] timers: Restructure internal locking
Commit Message
From: "Richard Cochran (linutronix GmbH)" <richardcochran@gmail.com>
Move the locking out from __run_timers() to the call sites, so the
protected section can be extended at the call site. Preparatory patch for
changing the NOHZ timer placement to a pull at expiry time model.
No functional change.
Signed-off-by: Richard Cochran (linutronix GmbH) <richardcochran@gmail.com>
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
---
kernel/time/timer.c | 31 +++++++++++++++++++++----------
1 file changed, 21 insertions(+), 10 deletions(-)
@@ -2238,11 +2238,7 @@ static inline void __run_timers(struct timer_base *base)
struct hlist_head heads[LVL_DEPTH];
int levels;
- if (time_before(jiffies, base->next_expiry))
- return;
-
- timer_base_lock_expiry(base);
- raw_spin_lock_irq(&base->lock);
+ lockdep_assert_held(&base->lock);
while (time_after_eq(jiffies, base->clk) &&
time_after_eq(jiffies, base->next_expiry)) {
@@ -2266,21 +2262,36 @@ static inline void __run_timers(struct timer_base *base)
while (levels--)
expire_timers(base, heads + levels);
}
+}
+
+static void __run_timer_base(struct timer_base *base)
+{
+ if (time_before(jiffies, base->next_expiry))
+ return;
+
+ timer_base_lock_expiry(base);
+ raw_spin_lock_irq(&base->lock);
+ __run_timers(base);
raw_spin_unlock_irq(&base->lock);
timer_base_unlock_expiry(base);
}
+static void run_timer_base(int index)
+{
+ struct timer_base *base = this_cpu_ptr(&timer_bases[index]);
+
+ __run_timer_base(base);
+}
+
/*
* This function runs timers and the timer-tq in bottom half context.
*/
static __latent_entropy void run_timer_softirq(struct softirq_action *h)
{
- struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_LOCAL]);
-
- __run_timers(base);
+ run_timer_base(BASE_LOCAL);
if (IS_ENABLED(CONFIG_NO_HZ_COMMON)) {
- __run_timers(this_cpu_ptr(&timer_bases[BASE_GLOBAL]));
- __run_timers(this_cpu_ptr(&timer_bases[BASE_DEF]));
+ run_timer_base(BASE_GLOBAL);
+ run_timer_base(BASE_DEF);
}
}