Re: [v6 PATCH] block: introduce block_rq_error tracepoint

[Yang Shi]

On Fri, Feb 4, 2022 at 12:35 AM Chaitanya Kulkarni
<chaitanyak@xxxxxxxxxx> wrote:
>
> Yang,
>
> > Question 1 :- What prevents us from using the same format for
> > both blk_rq_complete() and blk_rq_error() ?
> >
> > Question 2 :- assuming that blk_rq_complete() and blk_rq_error()
> > are using same format why can't we :-
> >
> > declare DECLARE_EVENT_CLASS(blk_rq_completion....)
> > and use that class for blk_rq_complete() and blk_rq_error() ?
> >
> > since if I remember correctly we need to define a event class
> > instead of duplicating a tracepoint with similar reporting.
>
> What I meant is following compile tested patch (although it will
> need to split into a prep patch in order to post it) :-

Thank you so much. I will prepare the new patches. I assume you prefer
a prep patch which converts trace event to event class, then add
block_rq_err event.

>
> diff --git a/include/trace/events/block.h b/include/trace/events/block.h
> index 27170e40e8c9..7f4dfbdf12a6 100644
> --- a/include/trace/events/block.h
> +++ b/include/trace/events/block.h
> @@ -100,19 +100,7 @@ TRACE_EVENT(block_rq_requeue,
>                    __entry->nr_sector, 0)
>   );
>
> -/**
> - * block_rq_complete - block IO operation completed by device driver
> - * @rq: block operations request
> - * @error: status code
> - * @nr_bytes: number of completed bytes
> - *
> - * The block_rq_complete tracepoint event indicates that some portion
> - * of operation request has been completed by the device driver.  If
> - * the @rq->bio is %NULL, then there is absolutely no additional work to
> - * do for the request. If @rq->bio is non-NULL then there is
> - * additional work required to complete the request.
> - */
> -TRACE_EVENT(block_rq_complete,
> +DECLARE_EVENT_CLASS(block_rq_completion,
>
>          TP_PROTO(struct request *rq, blk_status_t error, unsigned int
> nr_bytes),
>
> @@ -144,6 +132,41 @@ TRACE_EVENT(block_rq_complete,
>                    __entry->nr_sector, __entry->error)
>   );
>
> +/**
> + * block_rq_complete - block IO operation completed by device driver
> + * @rq: block operations request
> + * @error: status code
> + * @nr_bytes: number of completed bytes
> + *
> + * The block_rq_complete tracepoint event indicates that some portion
> + * of operation request has been completed by the device driver.  If
> + * the @rq->bio is %NULL, then there is absolutely no additional work to
> + * do for the request. If @rq->bio is non-NULL then there is
> + * additional work required to complete the request.
> + */
> +DEFINE_EVENT(block_rq_completion, block_rq_complete,
> +
> +       TP_PROTO(struct request *rq, blk_status_t error, unsigned int
> nr_bytes),
> +
> +       TP_ARGS(rq, error, nr_bytes)
> +);
> +
> +/**
> + * block_rq_error - block IO operation error reported by device driver
> + * @rq: block operations request
> + * @error: status code
> + * @nr_bytes: number of completed bytes
> + *
> + * The block_rq_error tracepoint event indicates that some portion
> + * of operation request has failed as reported by the device driver.
> + */
> +DEFINE_EVENT(block_rq_completion, block_rq_error,
> +
> +       TP_PROTO(struct request *rq, blk_status_t error, unsigned int
> nr_bytes),
> +
> +       TP_ARGS(rq, error, nr_bytes)
> +);
> +
>   DECLARE_EVENT_CLASS(block_rq,
>
>          TP_PROTO(struct request *rq),
> >
> > -ck
> >
> >
>