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    SubjectRe: [patch 11/41] x86/irqwork: Get rid of duplicated tracing interrupt code
    On Fri, 25 Aug 2017 12:31:14 +0200
    Thomas Gleixner <tglx@linutronix.de> wrote:


    > --- a/arch/x86/kernel/irq_work.c
    > +++ b/arch/x86/kernel/irq_work.c
    > @@ -11,24 +11,12 @@
    > #include <asm/trace/irq_vectors.h>
    > #include <linux/interrupt.h>
    >
    > -static inline void __smp_irq_work_interrupt(void)
    > -{
    > - inc_irq_stat(apic_irq_work_irqs);
    > - irq_work_run();
    > -}
    > -
    > __visible void __irq_entry smp_irq_work_interrupt(struct pt_regs *regs)
    > {
    > ipi_entering_ack_irq();
    > - __smp_irq_work_interrupt();
    > - exiting_irq();
    > -}
    > -
    > -__visible void __irq_entry smp_trace_irq_work_interrupt(struct pt_regs *regs)
    > -{
    > - ipi_entering_ack_irq();
    > + inc_irq_stat(apic_irq_work_irqs);
    > trace_irq_work_entry(IRQ_WORK_VECTOR);
    > - __smp_irq_work_interrupt();

    This changes from what we use to have:

    Original:

    ipi_entering_ack_irq();
    trace_irq_work_entry(IRQ_WORK_VECTOR);
    inc_irq_stat(apic_irq_work_irqs);
    irq_work_run();

    Patched:

    ipi_entering_ack_irq();
    inc_irq_stat(apic_irq_work_irqs);
    trace_irq_work_entry(IRQ_WORK_VECTOR);
    irq_work_run();

    Is there a reason for the swap? It's not mentioned in the change log.

    Also, tracepoints can issue new irq works. I don't think that would be
    a problem here, as interrupts are disabled in this path. Just wanted to
    point it out.

    -- Steve


    > + irq_work_run();
    > trace_irq_work_exit(IRQ_WORK_VECTOR);
    > exiting_irq();
    > }
    >

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