diff options
| author | Nicholas Piggin | 2022-04-23 00:14:46 +1000 |
|---|---|---|
| committer | Thomas Gleixner | 2022-04-25 14:45:22 +0200 |
| commit | 62c1256d544747b38e77ca9b5bfe3a26f9592576 (patch) | |
| tree | 76b7ac3839b9382128b1a0b69eee7f527d95c77b | |
| parent | ce8abf340e40e1126bfcb9e7679b3d6b524ae3e0 (diff) | |
timers/nohz: Switch to ONESHOT_STOPPED in the low-res handler when the tick is stopped
When tick_nohz_stop_tick() stops the tick and high resolution timers are
disabled, then the clock event device is not put into ONESHOT_STOPPED
mode. This can lead to spurious timer interrupts with some clock event
device drivers that don't shut down entirely after firing.
Eliminate these by putting the device into ONESHOT_STOPPED mode at points
where it is not being reprogrammed. When there are no timers active, then
tick_program_event() with KTIME_MAX can be used to stop the device. When
there is a timer active, the device can be stopped at the next tick (any
new timer added by timers will reprogram the tick).
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20220422141446.915024-1-npiggin@gmail.com
| -rw-r--r-- | kernel/time/tick-sched.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 2d76c91b85de..b1b105db31eb 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -928,6 +928,8 @@ static void tick_nohz_stop_tick(struct tick_sched *ts, int cpu) if (unlikely(expires == KTIME_MAX)) { if (ts->nohz_mode == NOHZ_MODE_HIGHRES) hrtimer_cancel(&ts->sched_timer); + else + tick_program_event(KTIME_MAX, 1); return; } @@ -1364,9 +1366,15 @@ static void tick_nohz_handler(struct clock_event_device *dev) tick_sched_do_timer(ts, now); tick_sched_handle(ts, regs); - /* No need to reprogram if we are running tickless */ - if (unlikely(ts->tick_stopped)) + if (unlikely(ts->tick_stopped)) { + /* + * The clockevent device is not reprogrammed, so change the + * clock event device to ONESHOT_STOPPED to avoid spurious + * interrupts on devices which might not be truly one shot. + */ + tick_program_event(KTIME_MAX, 1); return; + } hrtimer_forward(&ts->sched_timer, now, TICK_NSEC); tick_program_event(hrtimer_get_expires(&ts->sched_timer), 1); |