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SubjectRe: [RESEND PATCH 1/2] perf, cpu hotplug: Run CPU_STARTING notifiers with irqs disabled
On Tue, Oct 16, 2012 at 01:28:10PM +0530, Srivatsa S. Bhat wrote:
> The CPU_STARTING notifiers are supposed to be run with irqs disabled. But the
> perf_cpu_notifier() macro invokes them without doing that. Fix it.

Color me confused... Isn't perf_event_task_tick() invoked only
from scheduler_tick(), which always has interrupts disabled?

Or are you needing to invoke it from somewhere else?

Thanx, Paul

> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
> ---
>
> include/linux/perf_event.h | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
> index 2e90235..0647805 100644
> --- a/include/linux/perf_event.h
> +++ b/include/linux/perf_event.h
> @@ -803,10 +803,13 @@ static inline void perf_event_task_tick(void) { }
> do { \
> static struct notifier_block fn##_nb __cpuinitdata = \
> { .notifier_call = fn, .priority = CPU_PRI_PERF }; \
> + unsigned long flags; \
> fn(&fn##_nb, (unsigned long)CPU_UP_PREPARE, \
> (void *)(unsigned long)smp_processor_id()); \
> + local_irq_save(flags); \
> fn(&fn##_nb, (unsigned long)CPU_STARTING, \
> (void *)(unsigned long)smp_processor_id()); \
> + local_irq_restore(flags); \
> fn(&fn##_nb, (unsigned long)CPU_ONLINE, \
> (void *)(unsigned long)smp_processor_id()); \
> register_cpu_notifier(&fn##_nb); \
>



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