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SubjectRe: [PATCH -tip] x86,trace: Add rcu_irq_enter/exit() in smp_trace_reschedule_interrupt()
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On Fri, 2013-06-28 at 15:13 +0000, Seiji Aguchi wrote:

> OK.
> So, ack_APIC_irq() and irq_enter() are needed.
> It can be shared with smp_call_function() and smp_call_function_single() like this.
> I will update the patch.
>
> arch/x86/kernel/smp.c | 23 ++++++++++++-----------
> 1 files changed, 12 insertions(+), 11 deletions(-)
>
> diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
> index f4fe0b8..732b618 100644
> --- a/arch/x86/kernel/smp.c
> +++ b/arch/x86/kernel/smp.c
> @@ -265,23 +265,24 @@ void smp_reschedule_interrupt(struct pt_regs *regs)
> */
> }
>
> -void smp_trace_reschedule_interrupt(struct pt_regs *regs)
> +static inline void smp_entering_irq(void)
> {
> ack_APIC_irq();
> + irq_enter();
> +}
> +
> +void smp_trace_reschedule_interrupt(struct pt_regs *regs)
> +{

Sure, but we should probably add a comment here to why
smp_trace_reschedule_interrupt() is different than
smp_reschedule_interrupt().

/*
* Need to call irq_enter() before calling the trace point.
* __smp_reschedule_interrupt() calls irq_enter/exit() too (in
* scheduler_ipi(). This is OK, since those functions are allowed
* to nest.
*/

-- Steve

> + smp_entering_irq();
> trace_reschedule_entry(RESCHEDULE_VECTOR);
> __smp_reschedule_interrupt();
> trace_reschedule_exit(RESCHEDULE_VECTOR);
> + exiting_irq();
> /*
> * KVM uses this interrupt to force a cpu out of guest mode
> */
> }
>
> -static inline void call_function_entering_irq(void)
> -{
> - ack_APIC_irq();
> - irq_enter();
> -}
> -
> static inline void __smp_call_function_interrupt(void)
> {
> generic_smp_call_function_interrupt();
> @@ -290,14 +291,14 @@ static inline void __smp_call_function_interrupt(void)
>
> void smp_call_function_interrupt(struct pt_regs *regs)
> {
> - call_function_entering_irq();
> + smp_entering_irq();
> __smp_call_function_interrupt();
> exiting_irq();
> }
>
> void smp_trace_call_function_interrupt(struct pt_regs *regs)
> {
> - call_function_entering_irq();
> + smp_entering_irq();
> trace_call_function_entry(CALL_FUNCTION_VECTOR);
> __smp_call_function_interrupt();
> trace_call_function_exit(CALL_FUNCTION_VECTOR);
> @@ -312,14 +313,14 @@ static inline void __smp_call_function_single_interrupt(void)
>
> void smp_call_function_single_interrupt(struct pt_regs *regs)
> {
> - call_function_entering_irq();
> + smp_entering_irq();
> __smp_call_function_single_interrupt();
> exiting_irq();
> }
>
> void smp_trace_call_function_single_interrupt(struct pt_regs *regs)
> {
> - call_function_entering_irq();
> + smp_entering_irq();
> trace_call_function_single_entry(CALL_FUNCTION_SINGLE_VECTOR);
> __smp_call_function_single_interrupt();
> trace_call_function_single_exit(CALL_FUNCTION_SINGLE_VECTOR);




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