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

From: "Jiayuan Chen" <[email-masked]>
Date: Wed, 09 Apr 2025 16:40:55 +0000

April 10, 2025 at 24:11, "Steven Rostedt" <[email-masked]> wrote:

> 
> On Wed, 9 Apr 2025 18:29:33 +0800
> 
> Jiayuan Chen <[email-masked]> 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
>
Using an enum is indeed more appropriate in TRACE.

Thank you for the suggestion.