linux-kernel - Re: [patch 13/41] x86/smp: Remove pointless duplicated interrupt code

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Date:   Fri, 25 Aug 2017 14:24:39 -0400
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>, Peter Anvin <hpa@...or.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Andy Lutomirski <luto@...nel.org>,
        Borislav Petkov <bp@...en8.de>
Subject: Re: [patch 13/41] x86/smp: Remove pointless duplicated interrupt
 code

On Fri, 25 Aug 2017 12:31:16 +0200
Thomas Gleixner <tglx@...utronix.de> wrote:

> -static inline void __smp_call_function_interrupt(void)
> -{
> -	generic_smp_call_function_interrupt();
> -	inc_irq_stat(irq_call_count);

Interesting. The origin code calls the
generic_smp_call_function_interrupt() and then calls inc_irq_stat().
Not sure it matters, but just stating this because...

>  }
>  
>  __visible void __irq_entry smp_call_function_interrupt(struct pt_regs *regs)
>  {
>  	ipi_entering_ack_irq();
> -	__smp_call_function_interrupt();
> -	exiting_irq();
> -}
> -
> -__visible void __irq_entry
> -smp_trace_call_function_interrupt(struct pt_regs *regs)
> -{
> -	ipi_entering_ack_irq();
>  	trace_call_function_entry(CALL_FUNCTION_VECTOR);
> -	__smp_call_function_interrupt();
> -	trace_call_function_exit(CALL_FUNCTION_VECTOR);
> -	exiting_irq();
> -}
> -
> -static inline void __smp_call_function_single_interrupt(void)
> -{
> -	generic_smp_call_function_single_interrupt();
>  	inc_irq_stat(irq_call_count);
> -}
> -
> -__visible void __irq_entry
> -smp_call_function_single_interrupt(struct pt_regs *regs)
> -{
> -	ipi_entering_ack_irq();
> -	__smp_call_function_single_interrupt();
> +	generic_smp_call_function_interrupt();

here and

> +	trace_call_function_exit(CALL_FUNCTION_VECTOR);
>  	exiting_irq();
>  }
>  
> -__visible void __irq_entry
> -smp_trace_call_function_single_interrupt(struct pt_regs *regs)
> +__visible void __irq_entry smp_call_function_single_interrupt(struct pt_regs *r)
>  {
>  	ipi_entering_ack_irq();
>  	trace_call_function_single_entry(CALL_FUNCTION_SINGLE_VECTOR);
> -	__smp_call_function_single_interrupt();
> +	inc_irq_stat(irq_call_count);
> +	generic_smp_call_function_single_interrupt();

here, you reverse it.

Should at least be mentioned in the change log.

-- Steve

>  	trace_call_function_single_exit(CALL_FUNCTION_SINGLE_VECTOR);
>  	exiting_irq();
>  }
>