On Sun, Aug 13, 2023 at 03:16:19AM +0000, Joel Fernandes (Google) wrote: > From: Nicholas Piggin <npiggin@xxxxxxxxx> > > [ Upstream commit 5417ddc1cf1f5c8cba31ab217cf57ada7ab6ea88 ] I have the wrong SHA here, it should be: 62c1256d544747b38e77ca9b5bfe3a26f9592576 If you don't mind correcting it, please go ahead. Or I can resend the patch in the future. thanks, - Joel > > 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@xxxxxxxxx> > Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > Link: https://lore.kernel.org/r/20220422141446.915024-1-npiggin@xxxxxxxxx > Signed-off-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx> > --- > kernel/time/tick-sched.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c > index 7701c720dc1f..5786e2794ae1 100644 > --- a/kernel/time/tick-sched.c > +++ b/kernel/time/tick-sched.c > @@ -950,6 +950,8 @@ 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; > } > > @@ -1356,9 +1358,15 @@ 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); > -- > 2.41.0.640.ga95def55d0-goog >
