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authorThomas Gleixner <tglx@linutronix.de>2020-11-17 16:19:47 +0300
committerThomas Gleixner <tglx@linutronix.de>2020-11-19 12:48:29 +0300
commit7a35bf2a6a871cd0252cd371d741e7d070b53af9 (patch)
treeca12023fb7277cff6826cdd3f29bfbaa87c4ab1c /kernel/time/tick-sched.c
parent94ad2e3cedb82af034f6d97c58022f162b669f9b (diff)
downloadlinux-7a35bf2a6a871cd0252cd371d741e7d070b53af9.tar.xz
tick/sched: Optimize tick_do_update_jiffies64() further
Now that it's clear that there is always one tick to account, simplify the calculations some more. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201117132006.565663056@linutronix.de
Diffstat (limited to 'kernel/time/tick-sched.c')
-rw-r--r--kernel/time/tick-sched.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index ca9191ced4b5..306adeb6ce4c 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -55,7 +55,7 @@ static ktime_t last_jiffies_update;
*/
static void tick_do_update_jiffies64(ktime_t now)
{
- unsigned long ticks = 0;
+ unsigned long ticks = 1;
ktime_t delta;
/*
@@ -93,20 +93,21 @@ static void tick_do_update_jiffies64(ktime_t now)
write_seqcount_begin(&jiffies_seq);
- last_jiffies_update = ktime_add(last_jiffies_update, tick_period);
-
delta = ktime_sub(now, tick_next_period);
if (unlikely(delta >= tick_period)) {
/* Slow path for long idle sleep times */
s64 incr = ktime_to_ns(tick_period);
- ticks = ktime_divns(delta, incr);
+ ticks += ktime_divns(delta, incr);
last_jiffies_update = ktime_add_ns(last_jiffies_update,
incr * ticks);
+ } else {
+ last_jiffies_update = ktime_add(last_jiffies_update,
+ tick_period);
}
- do_timer(++ticks);
+ do_timer(ticks);
/*
* Keep the tick_next_period variable up to date. WRITE_ONCE()