Re: [RFC PATCH v4 1/5] irq: add tracepoint to softirq_raise

[Neil Horman <nhorman@tuxdriver.com>]

On Wed, Jul 28, 2010 at 03:29:05PM +0900, Koki Sanagi wrote:
> CHANGE-LOG since v3:
>   -change arguments of softirq tracepoint into original one.
> 
> From: Lai Jiangshan <laijs@cn.fujitsu.com>
> 
> Add a tracepoint for tracing when softirq action is raised.
> 
> It and the existed tracepoints complete softirq's tracepoints:
> softirq_raise, softirq_entry and softirq_exit.
> 
> And when this tracepoint is used in combination with
> the softirq_entry tracepoint we can determine
> the softirq raise latency.
> 
> Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
> Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
> Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
> 
Sorry its taken me awhile to get back to these, I've been on PTO
Acked-by: Neil Horman <nhorman@tuxdriver.com>

> [ factorize softirq events with DECLARE_EVENT_CLASS ]
> Signed-off-by: Koki Sanagi <sanagi.koki@jp.fujitsu.com>
> ---
>  include/linux/interrupt.h  |    8 +++++++-
>  include/trace/events/irq.h |   26 ++++++++++++++++++++++++--
>  2 files changed, 31 insertions(+), 3 deletions(-)
> 
> diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
> index c233113..5460db4 100644
> --- a/include/linux/interrupt.h
> +++ b/include/linux/interrupt.h
> @@ -18,6 +18,7 @@
>  #include <asm/atomic.h>
>  #include <asm/ptrace.h>
>  #include <asm/system.h>
> +#include <trace/events/irq.h>
>  
>  /*
>   * These correspond to the IORESOURCE_IRQ_* defines in
> @@ -402,7 +403,12 @@ asmlinkage void do_softirq(void);
>  asmlinkage void __do_softirq(void);
>  extern void open_softirq(int nr, void (*action)(struct softirq_action *));
>  extern void softirq_init(void);
> -#define __raise_softirq_irqoff(nr) do { or_softirq_pending(1UL << (nr)); } while (0)
> +static inline void __raise_softirq_irqoff(unsigned int nr)
> +{
> +	trace_softirq_raise((struct softirq_action *)&nr, NULL);
> +	or_softirq_pending(1UL << nr);
> +}
> +
>  extern void raise_softirq_irqoff(unsigned int nr);
>  extern void raise_softirq(unsigned int nr);
>  extern void wakeup_softirqd(void);
> diff --git a/include/trace/events/irq.h b/include/trace/events/irq.h
> index 0e4cfb6..3ddda02 100644
> --- a/include/trace/events/irq.h
> +++ b/include/trace/events/irq.h
> @@ -5,7 +5,9 @@
>  #define _TRACE_IRQ_H
>  
>  #include <linux/tracepoint.h>
> -#include <linux/interrupt.h>
> +
> +struct irqaction;
> +struct softirq_action;
>  
>  #define softirq_name(sirq) { sirq##_SOFTIRQ, #sirq }
>  #define show_softirq_name(val)				\
> @@ -93,7 +95,10 @@ DECLARE_EVENT_CLASS(softirq,
>  	),
>  
>  	TP_fast_assign(
> -		__entry->vec = (int)(h - vec);
> +		if (vec)
> +			__entry->vec = (int)(h - vec);
> +		else
> +			__entry->vec = *((int *)h);
>  	),
>  
>  	TP_printk("vec=%d [action=%s]", __entry->vec,
> @@ -136,6 +141,23 @@ DEFINE_EVENT(softirq, softirq_exit,
>  	TP_ARGS(h, vec)
>  );
>  
> +/**
> + * softirq_raise - called immediately when a softirq is raised
> + * @h: pointer to struct softirq_action
> + * @vec: pointer to first struct softirq_action in softirq_vec array
> + *
> + * The @h parameter contains a pointer to the softirq vector number which is
> + * raised. @vec is NULL and it means @h includes vector number not
> + * softirq_action. When used in combination with the softirq_entry tracepoint
> + * we can determine the softirq raise latency.
> + */
> +DEFINE_EVENT(softirq, softirq_raise,
> +
> +	TP_PROTO(struct softirq_action *h, struct softirq_action *vec),
> +
> +	TP_ARGS(h, vec)
> +);
> +
>  #endif /*  _TRACE_IRQ_H */
>  
>  /* This part must be outside protection */
> 
> --
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