| Message ID | 1299566250-10516-2-git-send-email-benh@kernel.crashing.org (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Headers | show |
On Tue, 2011-03-08 at 17:37 +1100, Benjamin Herrenschmidt wrote: > With some implementations, it is possible that a timer interrupt > occurs every few seconds on an offline CPU. In this case, just > re-arm the decrementer and return immediately > > Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> > --- > arch/powerpc/kernel/time.c | 15 +++++++++++---- > 1 files changed, 11 insertions(+), 4 deletions(-) > > diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c > index 09d31db..ecebc7c 100644 > --- a/arch/powerpc/kernel/time.c > +++ b/arch/powerpc/kernel/time.c > @@ -577,14 +577,21 @@ void timer_interrupt(struct pt_regs * regs) > struct clock_event_device *evt = &decrementer->event; > u64 now; > > + /* Ensure a positive value is written to the decrementer, or else > + * some CPUs will continuue to take decrementer exceptions ^ Seeing as you're moving it anyway, and maybe a full-stop. cheers
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index 09d31db..ecebc7c 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -577,14 +577,21 @@ void timer_interrupt(struct pt_regs * regs) struct clock_event_device *evt = &decrementer->event; u64 now; + /* Ensure a positive value is written to the decrementer, or else + * some CPUs will continuue to take decrementer exceptions + */ + set_dec(DECREMENTER_MAX); + + /* Some implementations of hotplug will get timer interrupts while + * offline, just ignore these + */ + if (!cpu_online(smp_processor_id())) + return; + trace_timer_interrupt_entry(regs); __get_cpu_var(irq_stat).timer_irqs++; - /* Ensure a positive value is written to the decrementer, or else - * some CPUs will continuue to take decrementer exceptions */ - set_dec(DECREMENTER_MAX); - #if defined(CONFIG_PPC32) && defined(CONFIG_PMAC) if (atomic_read(&ppc_n_lost_interrupts) != 0) do_IRQ(regs);
With some implementations, it is possible that a timer interrupt occurs every few seconds on an offline CPU. In this case, just re-arm the decrementer and return immediately Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- arch/powerpc/kernel/time.c | 15 +++++++++++---- 1 files changed, 11 insertions(+), 4 deletions(-)