On Thu, Sep 7, 2023 at 12:14 AM Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
>
> Increase misses stats in case bpf array execution is skipped
> because of recursion check in trace_call_bpf.
>
> Adding bpf_prog_inc_misses_counters that increase misses
> counts for all bpf programs in bpf_prog_array.
>
> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Reviewed-and-tested-by: Song Liu <song@xxxxxxxxxx>
> ---
> include/linux/bpf.h | 16 ++++++++++++++++
> kernel/trace/bpf_trace.c | 3 +++
> 2 files changed, 19 insertions(+)
>
> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> index 87eeb3a46a1d..abc18d6f2f2e 100644
> --- a/include/linux/bpf.h
> +++ b/include/linux/bpf.h
> @@ -2911,6 +2911,22 @@ static inline int sock_map_bpf_prog_query(const union bpf_attr *attr,
> #endif /* CONFIG_BPF_SYSCALL */
> #endif /* CONFIG_NET && CONFIG_BPF_SYSCALL */
>
> +static __always_inline void
> +bpf_prog_inc_misses_counters(const struct bpf_prog_array *array)
> +{
> + const struct bpf_prog_array_item *item;
> + struct bpf_prog *prog;
> +
> + if (unlikely(!array))
> + return;
> +
> + item = &array->items[0];
> + while ((prog = READ_ONCE(item->prog))) {
> + bpf_prog_inc_misses_counter(prog);
> + item++;
> + }
> +}
> +
> #if defined(CONFIG_INET) && defined(CONFIG_BPF_SYSCALL)
> void bpf_sk_reuseport_detach(struct sock *sk);
> int bpf_fd_reuseport_array_lookup_elem(struct bpf_map *map, void *key,
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index a9d8634b503c..44f399b19af1 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -117,6 +117,9 @@ unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx)
> * and don't send kprobe event into ring-buffer,
> * so return zero here
> */
> + rcu_read_lock();
> + bpf_prog_inc_misses_counters(rcu_dereference(call->prog_array));
> + rcu_read_unlock();
> ret = 0;
> goto out;
> }
> --
> 2.41.0
>
>
