[PATCH 04/12] timer: Move trigger_dyntick_cpu() to enqueue_timer()

From: Frederic Weisbecker
Date: Fri Jul 17 2020 - 10:06:44 EST


Consolidate the code by calling trigger_dyntick_cpu() from
enqueue_timer() instead of calling it from all its callers.

Tested-by: Juri Lelli <juri.lelli@xxxxxxxxxx>
Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Anna-Maria Behnsen <anna-maria@xxxxxxxxxxxxx>
Cc: Juri Lelli <juri.lelli@xxxxxxxxxx>
---
kernel/time/timer.c | 61 +++++++++++++++++++--------------------------
1 file changed, 25 insertions(+), 36 deletions(-)

diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index a7a3cf737411..2af08a169564 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -533,30 +533,6 @@ static int calc_wheel_index(unsigned long expires, unsigned long clk,
return idx;
}

-/*
- * Enqueue the timer into the hash bucket, mark it pending in
- * the bitmap and store the index in the timer flags.
- */
-static void enqueue_timer(struct timer_base *base, struct timer_list *timer,
- unsigned int idx)
-{
- hlist_add_head(&timer->entry, base->vectors + idx);
- __set_bit(idx, base->pending_map);
- timer_set_idx(timer, idx);
-
- trace_timer_start(timer, timer->expires, timer->flags);
-}
-
-static void
-__internal_add_timer(struct timer_base *base, struct timer_list *timer,
- unsigned long *bucket_expiry)
-{
- unsigned int idx;
-
- idx = calc_wheel_index(timer->expires, base->clk, bucket_expiry);
- enqueue_timer(base, timer, idx);
-}
-
static void
trigger_dyntick_cpu(struct timer_base *base, struct timer_list *timer,
unsigned long bucket_expiry)
@@ -598,15 +574,31 @@ trigger_dyntick_cpu(struct timer_base *base, struct timer_list *timer,
wake_up_nohz_cpu(base->cpu);
}

-static void
-internal_add_timer(struct timer_base *base, struct timer_list *timer)
+/*
+ * Enqueue the timer into the hash bucket, mark it pending in
+ * the bitmap, store the index in the timer flags then wake up
+ * the target CPU if needed.
+ */
+static void enqueue_timer(struct timer_base *base, struct timer_list *timer,
+ unsigned int idx, unsigned long bucket_expiry)
{
- unsigned long bucket_expiry;
+ hlist_add_head(&timer->entry, base->vectors + idx);
+ __set_bit(idx, base->pending_map);
+ timer_set_idx(timer, idx);

- __internal_add_timer(base, timer, &bucket_expiry);
+ trace_timer_start(timer, timer->expires, timer->flags);
trigger_dyntick_cpu(base, timer, bucket_expiry);
}

+static void internal_add_timer(struct timer_base *base, struct timer_list *timer)
+{
+ unsigned long bucket_expiry;
+ unsigned int idx;
+
+ idx = calc_wheel_index(timer->expires, base->clk, &bucket_expiry);
+ enqueue_timer(base, timer, idx, bucket_expiry);
+}
+
#ifdef CONFIG_DEBUG_OBJECTS_TIMERS

static struct debug_obj_descr timer_debug_descr;
@@ -1057,16 +1049,13 @@ __mod_timer(struct timer_list *timer, unsigned long expires, unsigned int option
/*
* If 'idx' was calculated above and the base time did not advance
* between calculating 'idx' and possibly switching the base, only
- * enqueue_timer() and trigger_dyntick_cpu() is required. Otherwise
- * we need to (re)calculate the wheel index via
- * internal_add_timer().
+ * enqueue_timer() is required. Otherwise we need to (re)calculate
+ * the wheel index via internal_add_timer().
*/
- if (idx != UINT_MAX && clk == base->clk) {
- enqueue_timer(base, timer, idx);
- trigger_dyntick_cpu(base, timer, bucket_expiry);
- } else {
+ if (idx != UINT_MAX && clk == base->clk)
+ enqueue_timer(base, timer, idx, bucket_expiry);
+ else
internal_add_timer(base, timer);
- }

out_unlock:
raw_spin_unlock_irqrestore(&base->lock, flags);
--
2.26.2