On 29-12-16, 17:45, Frederic Weisbecker wrote: > 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]> > --- > arch/x86/kernel/apic/apic.c | 25 +++++++++++++------------ > 1 file changed, 13 insertions(+), 12 deletions(-)
I didn't try updating anything other than the ARM subsystem as I was afraid of getting crushed by Thomas :) Though, I do remember from one of the email (from Thomas), where he mentioned that disabling the timer on some platforms may have bigger penalties. Perhaps its fast enough for apic.. Reviewed-by: Viresh Kumar <[email protected]> -- viresh
