2016-12-30 0:45 GMT+08:00 Frederic Weisbecker <[email protected]>: > When clock_event_device::set_state_oneshot_stopped() is not implemented, > hrtimer_cancel() can't stop the clock when there is no more timer in > the queue. So the ghost of the freshly cancelled hrtimer haunts us back > later with an extra interrupt: > > <idle>-0 [002] d..2 2248.557659: hrtimer_cancel: > hrtimer=ffff88021fa92d80 > <idle>-0 [002] d.h1 2249.303659: local_timer_entry: vector=239 > > So let's implement this missing callback for the lapic clock. This > consist in calling its set_state_shutdown() callback. There don't seem > to be a lighter way to stop the clock. Simply writing 0 to APIC_TMICT > won't be enough to stop the clock and avoid the extra interrupt, as > opposed to what is specified in the specs. We must also mask the > timer interrupt in the device. > > Cc: Thomas Gleixner <[email protected]> > Cc: Borislav Petkov <[email protected]> > Cc: Ingo Molnar <[email protected]> > Cc: Wanpeng Li <[email protected]> > Cc: Viresh Kumar <[email protected]> > Signed-off-by: Frederic Weisbecker <[email protected]> > ---
Reviewed-by: Wanpeng Li <[email protected]> > arch/x86/kernel/apic/apic.c | 25 +++++++++++++------------ > 1 file changed, 13 insertions(+), 12 deletions(-) > > diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c > index 5b7e43e..a8e90db 100644 > --- a/arch/x86/kernel/apic/apic.c > +++ b/arch/x86/kernel/apic/apic.c > @@ -529,18 +529,19 @@ static void lapic_timer_broadcast(const struct cpumask > *mask) > * The local apic timer can be used for any function which is CPU local. > */ > static struct clock_event_device lapic_clockevent = { > - .name = "lapic", > - .features = CLOCK_EVT_FEAT_PERIODIC | > - CLOCK_EVT_FEAT_ONESHOT | > CLOCK_EVT_FEAT_C3STOP > - | CLOCK_EVT_FEAT_DUMMY, > - .shift = 32, > - .set_state_shutdown = lapic_timer_shutdown, > - .set_state_periodic = lapic_timer_set_periodic, > - .set_state_oneshot = lapic_timer_set_oneshot, > - .set_next_event = lapic_next_event, > - .broadcast = lapic_timer_broadcast, > - .rating = 100, > - .irq = -1, > + .name = "lapic", > + .features = CLOCK_EVT_FEAT_PERIODIC | > + CLOCK_EVT_FEAT_ONESHOT | > CLOCK_EVT_FEAT_C3STOP > + | CLOCK_EVT_FEAT_DUMMY, > + .shift = 32, > + .set_state_shutdown = lapic_timer_shutdown, > + .set_state_periodic = lapic_timer_set_periodic, > + .set_state_oneshot = lapic_timer_set_oneshot, > + .set_state_oneshot_stopped = lapic_timer_shutdown, > + .set_next_event = lapic_next_event, > + .broadcast = lapic_timer_broadcast, > + .rating = 100, > + .irq = -1, > }; > static DEFINE_PER_CPU(struct clock_event_device, lapic_events); > > -- > 2.7.4 >
