Le Thu, Jan 04, 2024 at 05:25:08PM +0100, Uladzislau Rezki (Sony) a écrit :
> Add an rcu_sr_normal() trace event. It takes three arguments
> first one is the name of RCU flavour, second one is a user id
> which triggeres synchronize_rcu_normal() and last one is an
> event.
>
> There are two traces in the synchronize_rcu_normal(). On entry,
> when a new request is registered and on exit point when request
> is completed.
>
> Please note, CONFIG_RCU_TRACE=y is required to activate traces.
>
> Signed-off-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
> ---
> include/trace/events/rcu.h | 27 +++++++++++++++++++++++++++
> kernel/rcu/tree.c | 7 ++++++-
> 2 files changed, 33 insertions(+), 1 deletion(-)
>
> diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h
> index 2ef9c719772a..31b3e0d3e65f 100644
> --- a/include/trace/events/rcu.h
> +++ b/include/trace/events/rcu.h
> @@ -707,6 +707,33 @@ TRACE_EVENT_RCU(rcu_invoke_kfree_bulk_callback,
> __entry->rcuname, __entry->p, __entry->nr_records)
> );
>
> +/*
> + * Tracepoint for a normal synchronize_rcu() states. The first argument
> + * is the RCU flavor, the second argument is a pointer to rcu_head the
> + * last one is an event.
> + */
> +TRACE_EVENT_RCU(rcu_sr_normal,
Can we call this "synchronize_rcu" instead? So people really know what it's
about.
Then should the need arise, we can still add "synchronize_rcu_expedited" trace
events later.
Thanks.
> +
> + TP_PROTO(const char *rcuname, struct rcu_head *rhp, const char *srevent),
> +
> + TP_ARGS(rcuname, rhp, srevent),
> +
> + TP_STRUCT__entry(
> + __field(const char *, rcuname)
> + __field(void *, rhp)
> + __field(const char *, srevent)
> + ),
> +
> + TP_fast_assign(
> + __entry->rcuname = rcuname;
> + __entry->rhp = rhp;
> + __entry->srevent = srevent;
> + ),
> +
> + TP_printk("%s rhp=0x%p event=%s",
> + __entry->rcuname, __entry->rhp, __entry->srevent)
> +);
> +
> /*
> * Tracepoint for exiting rcu_do_batch after RCU callbacks have been
> * invoked. The first argument is the name of the RCU flavor,
> diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> index b756c40e4960..7d2ed89efcb3 100644
> --- a/kernel/rcu/tree.c
> +++ b/kernel/rcu/tree.c
> @@ -3672,9 +3672,11 @@ static void synchronize_rcu_normal(void)
> {
> struct rcu_synchronize rs;
>
> + trace_rcu_sr_normal(rcu_state.name, &rs.head, TPS("request"));
> +
> if (!READ_ONCE(rcu_normal_wake_from_gp)) {
> wait_rcu_gp(call_rcu_hurry);
> - return;
> + goto trace_complete_out;
> }
>
> init_rcu_head_on_stack(&rs.head);
> @@ -3695,6 +3697,9 @@ static void synchronize_rcu_normal(void)
> /* Now we can wait. */
> wait_for_completion(&rs.completion);
> destroy_rcu_head_on_stack(&rs.head);
> +
> +trace_complete_out:
> + trace_rcu_sr_normal(rcu_state.name, &rs.head, TPS("complete"));
> }
>
> /**
> --
> 2.39.2
>
