Re: [PATCH 3/3] add irq tracepoint documentation

From: Randy Dunlap
Date: Wed Apr 29 2009 - 15:10:58 EST


Jason Baron wrote:
> Document irqs for the newly created docbook.
>
> Signed-off-by: Jason Baron <jbaron@xxxxxxxxxx>
>
> ---
> Documentation/DocBook/tracepoint.tmpl | 5 +++
> include/trace/events/irq.h | 46 ++++++++++++++++++++++++++++++---
> 2 files changed, 47 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/DocBook/tracepoint.tmpl b/Documentation/DocBook/tracepoint.tmpl
> index 2639a8b..8b7fb48 100644
> --- a/Documentation/DocBook/tracepoint.tmpl
> +++ b/Documentation/DocBook/tracepoint.tmpl
> @@ -81,4 +81,9 @@
> </para>
> </chapter>
>
> + <chapter id="irq">
> + <title>IRQ</title>
> +!Iinclude/trace/events/irq.h
> + </chapter>
> +
> </book>
> diff --git a/include/trace/events/irq.h b/include/trace/events/irq.h
> index 7686864..bb5bbec 100644
> --- a/include/trace/events/irq.h
> +++ b/include/trace/events/irq.h
> @@ -7,8 +7,16 @@
> #undef TRACE_SYSTEM
> #define TRACE_SYSTEM irq
>
> -/*
> - * Tracepoint for entry of interrupt handler:
> +/**
> + * irq_handler_entry - called immediately before the irq action handler
> + * @irq: irq number
> + * @action: pointer to struct irqaction
> + *
> + * The struct irqaction pointed to by the 'action' parameter contains

Parameters are usually written as: @action
etc....

Otherwise looks good. Thanks.

Acked-by: Randy Dunlap <randy.dunlap@xxxxxxxxxx>


> + * various information about the handler, including the device name,
> + * action->name, and the device id, action->dev_id. When used in
> + * conjunction with the irq_handler_exit tracepoint, we can figure
> + * out irq handler latencies.
> */
> TRACE_EVENT(irq_handler_entry,
>
> @@ -29,8 +37,16 @@ TRACE_EVENT(irq_handler_entry,
> TP_printk("irq=%d handler=%s", __entry->irq, __get_str(name))
> );
>
> -/*
> - * Tracepoint for return of an interrupt handler:
> +/**
> + * irq_handler_exit - called immediately after the irq action handler returns
> + * @irq: irq number
> + * @action: pointer to struct irqaction
> + * @ret: return value
> + *
> + * If the 'ret' value is set to IRQ_HANDLED, then we know that the corresponding
> + * action->handler scuccessully handled this irq. Otherwise, the irq might be
> + * a shared irq line, or the irq was not handled successfully. Can be used in
> + * conjunction with the irq_handler_entry to understand irq handler latencies.
> */
> TRACE_EVENT(irq_handler_exit,
>
> @@ -52,6 +68,17 @@ TRACE_EVENT(irq_handler_exit,
> __entry->irq, __entry->ret ? "handled" : "unhandled")
> );
>
> +/**
> + * softirq_entry - called immediately before the softirq handler
> + * @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 struct softirq_action
> + * which has a pointer to the action handler that is called. By subtracting
> + * the 'vec' pointer from the 'h' pointer, we can determine the softirq
> + * number. Also, when used in combination with the softirq_exit tracepoint
> + * we can determine the softirq latency.
> + */
> TRACE_EVENT(softirq_entry,
>
> TP_PROTO(struct softirq_action *h, struct softirq_action *vec),
> @@ -71,6 +98,17 @@ TRACE_EVENT(softirq_entry,
> TP_printk("softirq=%d action=%s", __entry->vec, __get_str(name))
> );
>
> +/**
> + * softirq_exit - called immediately after the softirq handler returns
> + * @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 struct softirq_action
> + * that has handled the softirq. By subtracting the 'vec' pointer from
> + * the 'h' pointer, we can determine the softirq number. Also, when used in
> + * combination with the softirq_exit tracepoint we can determine the softirq
> + * latency.
> + */
> TRACE_EVENT(softirq_exit,
>
> TP_PROTO(struct softirq_action *h, struct softirq_action *vec),


--
~Randy
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