Re: [PATCH v3 net-next 2/5] net: tracepoint: replace tcp_set_state tracepoint with inet_sock_set_state tracepoint

[Brendan Gregg]

On Tue, Dec 19, 2017 at 7:12 PM, Yafang Shao <laoar.shao@xxxxxxxxx> wrote:
> As sk_state is a common field for struct sock, so the state
> transition tracepoint should not be a TCP specific feature.
> Currently it traces all AF_INET state transition, so I rename this
> tracepoint to inet_sock_set_state tracepoint with some minor changes and move it
> into trace/events/sock.h.

The tcp:tcp_set_state probe is tcp_set_state(), so it's only going to
fire for TCP sessions. It's not broken, and we could add a
sctp:sctp_set_state as well. Replacing tcp:tcp_set_state with
inet_sk_set_state is feeling like we might be baking too much
implementation detail into the tracepoint API.

If we must have inet_sk_set_state, then must we also delete tcp:tcp_set_state?

Brendan


> We dont need to create a file named trace/events/inet_sock.h for this one single
> tracepoint.
>
> Two helpers are introduced to trace sk_state transition
>     - void inet_sk_state_store(struct sock *sk, int newstate);
>     - void inet_sk_set_state(struct sock *sk, int state);
> As trace header should not be included in other header files,
> so they are defined in sock.c.
>
> The protocol such as SCTP maybe compiled as a ko, hence export
> inet_sk_set_state().
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