Re: [PATCH bpf-next v1] bpf, sockmap: Introduce tracing capability for sockmap

[Steven Rostedt]

On Wed,  9 Apr 2025 18:29:33 +0800
Jiayuan Chen <jiayuan.chen@xxxxxxxxx> wrote:

> +#define trace_sockmap_skmsg_redirect(sk, prog, msg, act)	\
> +	trace_sockmap_redirect((sk), "msg", (prog), (msg)->sg.size, (act))
> +
> +#define trace_sockmap_skb_redirect(sk, prog, skb, act)		\
> +	trace_sockmap_redirect((sk), "skb", (prog), (skb)->len, (act))
> +
> +TRACE_EVENT(sockmap_redirect,
> +	    TP_PROTO(const struct sock *sk, const char *type,
> +		     const struct bpf_prog *prog, int length, int act),
> +	    TP_ARGS(sk, type, prog, length, act),
> +
> +	TP_STRUCT__entry(
> +		__field(const void *, sk)
> +		__field(const char *, type)

On 64bit, const char * is 8 bytes, and you are pointing it to a string of
size 4 bytes (3 chars and '\0'). Why not just make it a constant string, or
better yet, an enum?

-- Steve


> +		__field(__u16, family)
> +		__field(__u16, protocol)
> +		__field(int, prog_id)
> +		__field(int, length)
> +		__field(int, act)
> +	),
> +
> +	TP_fast_assign(
> +		__entry->sk		= sk;
> +		__entry->type		= type;
> +		__entry->family		= sk->sk_family;
> +		__entry->protocol	= sk->sk_protocol;
> +		__entry->prog_id	= prog->aux->id;
> +		__entry->length		= length;
> +		__entry->act		= act;
> +	),
> +