The following commit has been merged into the timers/core branch of tip:
Commit-ID: 7a35bf2a6a871cd0252cd371d741e7d070b53af9
Gitweb: https://git.kernel.org/tip/7a35bf2a6a871cd0252cd371d741e7d070b53af9
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Tue, 17 Nov 2020 14:19:47 +01:00
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Thu, 19 Nov 2020 10:48:29 +01:00
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@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20201117132006.565663056@xxxxxxxxxxxxx
---
kernel/time/tick-sched.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index ca9191c..306adeb 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()
|