On Mon, Oct 12, 2020 at 6:59 AM Steven Rostedt <rost...@goodmis.org> wrote:
>
> On Sat, 10 Oct 2020 11:03:22 -0700
> Rob Clark <robdcl...@gmail.com> wrote:
>
> > /**
> > + * sched_kthread_work_execute_start - called immediately before the work
> > callback
> > + * @work: pointer to struct kthread_work
> > + *
> > + * Allows to track kthread work execution.
> > + */
> > +TRACE_EVENT(sched_kthread_work_execute_start,
> > +
> > + TP_PROTO(struct kthread_work *work),
> > +
> > + TP_ARGS(work),
> > +
> > + TP_STRUCT__entry(
> > + __field( void *, work )
> > + __field( void *, function)
> > + ),
> > +
> > + TP_fast_assign(
> > + __entry->work = work;
> > + __entry->function = work->func;
> > + ),
> > +
> > + TP_printk("work struct %p: function %ps", __entry->work,
> > __entry->function)
> > +);
> > +
> > +/**
> > + * sched_kthread_work_execute_end - called immediately after the work
> > callback
> > + * @work: pointer to struct work_struct
> > + * @function: pointer to worker function
> > + *
> > + * Allows to track workqueue execution.
> > + */
> > +TRACE_EVENT(sched_kthread_work_execute_end,
> > +
> > + TP_PROTO(struct kthread_work *work, kthread_work_func_t function),
> > +
> > + TP_ARGS(work, function),
> > +
> > + TP_STRUCT__entry(
> > + __field( void *, work )
> > + __field( void *, function)
> > + ),
> > +
> > + TP_fast_assign(
> > + __entry->work = work;
> > + __entry->function = function;
> > + ),
> > +
> > + TP_printk("work struct %p: function %ps", __entry->work,
> > __entry->function)
> > +);
> > +
>
>
> Please combine the above into:
>
> DECLARE_EVENT_CLASS(sched_kthread_work_execute_template,
>
> TP_PROTO(struct kthread_work *work),
>
> TP_ARGS(work),
>
> TP_STRUCT__entry(
> __field( void *, work )
> __field( void *, function)
> ),
>
> TP_fast_assign(
> __entry->work = work;
> __entry->function = work->func;
> ),
>
> TP_printk("work struct %p: function %ps", __entry->work,
> __entry->function)
> );
>
> DEFINE_EVENT(sched_kthread_work_execute_template,
> sched_kthread_work_execute_start,
> TP_PROTO(struct kthread_work *work),
> TP_ARGS(work));
>
> DEFINE_EVENT(sched_kthread_work_execute_template,
> sched_kthread_work_execute_end,
> TP_PROTO(struct kthread_work *work),
> TP_ARGS(work));
>
> As events are cheap, classes are expensive (size wise), and a TRACE_EVENT()
> is really just a CLASS and EVENT for a single instance.
I think we cannot quite do this, because we should not rely on being
able to dereference work after it finishes. Although I suppose I
could just define it to explicitly pass the fxn ptr to both
tracepoints..
BR,
-R
