Re: [PATCH] tcp: Add tracepoint for tcp_set_ca_state

[Denis Kirjanov <dkirjanov@suse.de>]

3/30/22 16:01, jackygam2001 пишет:
> The congestion status of a tcp flow may be updated since there
> is congestion between tcp sender and receiver. It makes sense for
> adding tracepoint for congestion status update function to evaluate
> the performance of network and congestion algorithm.
> 
> Link: https://github.com/iovisor/bcc/pull/3899
> 
> Signed-off-by: jackygam2001 <jacky_gam_2001@163.com>
Please use net-next prefix and use your real name in SOB

> ---
>   include/net/tcp.h          | 12 +++---------
>   include/trace/events/tcp.h | 45 +++++++++++++++++++++++++++++++++++++++++++++
>   net/ipv4/tcp_cong.c        | 12 ++++++++++++
>   3 files changed, 60 insertions(+), 9 deletions(-)
> 
> diff --git a/include/net/tcp.h b/include/net/tcp.h
> index 70ca4a5e330a..9a3786f33798 100644
> --- a/include/net/tcp.h
> +++ b/include/net/tcp.h
> @@ -1139,15 +1139,6 @@ static inline bool tcp_ca_needs_ecn(const struct sock *sk)
>   	return icsk->icsk_ca_ops->flags & TCP_CONG_NEEDS_ECN;
>   }
>   
> -static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state)
> -{
> -	struct inet_connection_sock *icsk = inet_csk(sk);
> -
> -	if (icsk->icsk_ca_ops->set_state)
> -		icsk->icsk_ca_ops->set_state(sk, ca_state);
> -	icsk->icsk_ca_state = ca_state;
> -}
> -
>   static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
>   {
>   	const struct inet_connection_sock *icsk = inet_csk(sk);
> @@ -1156,6 +1147,9 @@ static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event)
>   		icsk->icsk_ca_ops->cwnd_event(sk, event);
>   }
>   
> +/* From tcp_cong.c */
> +void tcp_set_ca_state(struct sock *sk, const u8 ca_state);
> +
>   /* From tcp_rate.c */
>   void tcp_rate_skb_sent(struct sock *sk, struct sk_buff *skb);
>   void tcp_rate_skb_delivered(struct sock *sk, struct sk_buff *skb,
> diff --git a/include/trace/events/tcp.h b/include/trace/events/tcp.h
> index 521059d8dc0a..69a68b01c1de 100644
> --- a/include/trace/events/tcp.h
> +++ b/include/trace/events/tcp.h
> @@ -371,6 +371,51 @@ DEFINE_EVENT(tcp_event_skb, tcp_bad_csum,
>   	TP_ARGS(skb)
>   );
>   
> +TRACE_EVENT(tcp_cong_state_set,
> +
> +	TP_PROTO(struct sock *sk, const u8 ca_state),
> +
> +	TP_ARGS(sk, ca_state),
> +
> +	TP_STRUCT__entry(
> +		__field(const void *, skaddr)
> +		__field(__u16, sport)
> +		__field(__u16, dport)
> +		__array(__u8, saddr, 4)
> +		__array(__u8, daddr, 4)
> +		__array(__u8, saddr_v6, 16)
> +		__array(__u8, daddr_v6, 16)
> +		__field(__u8, cong_state)
> +	),
> +
> +	TP_fast_assign(
> +		struct inet_sock *inet = inet_sk(sk);
> +		__be32 *p32;
> +
> +		__entry->skaddr = sk;
> +
> +		__entry->sport = ntohs(inet->inet_sport);
> +		__entry->dport = ntohs(inet->inet_dport);
> +
> +		p32 = (__be32 *) __entry->saddr;
> +		*p32 = inet->inet_saddr;
> +
> +		p32 = (__be32 *) __entry->daddr;
> +		*p32 =  inet->inet_daddr;
> +
> +		TP_STORE_ADDRS(__entry, inet->inet_saddr, inet->inet_daddr,
> +			   sk->sk_v6_rcv_saddr, sk->sk_v6_daddr);
> +
> +		__entry->cong_state = ca_state;
> +	),
> +
> +	TP_printk("sport=%hu dport=%hu saddr=%pI4 daddr=%pI4 saddrv6=%pI6c daddrv6=%pI6c cong_state=%u",
> +		  __entry->sport, __entry->dport,
> +		  __entry->saddr, __entry->daddr,
> +		  __entry->saddr_v6, __entry->daddr_v6,
> +		  __entry->cong_state)
> +);
> +
>   #endif /* _TRACE_TCP_H */
>   
>   /* This part must be outside protection */
> diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
> index dc95572163df..98b48bdb8be7 100644
> --- a/net/ipv4/tcp_cong.c
> +++ b/net/ipv4/tcp_cong.c
> @@ -16,6 +16,7 @@
>   #include <linux/gfp.h>
>   #include <linux/jhash.h>
>   #include <net/tcp.h>
> +#include <trace/events/tcp.h>
>   
>   static DEFINE_SPINLOCK(tcp_cong_list_lock);
>   static LIST_HEAD(tcp_cong_list);
> @@ -33,6 +34,17 @@ struct tcp_congestion_ops *tcp_ca_find(const char *name)
>   	return NULL;
>   }
>   
> +void tcp_set_ca_state(struct sock *sk, const u8 ca_state)
> +{
> +	struct inet_connection_sock *icsk = inet_csk(sk);
> +
> +	trace_tcp_cong_state_set(sk, ca_state);
> +
> +	if (icsk->icsk_ca_ops->set_state)
> +		icsk->icsk_ca_ops->set_state(sk, ca_state);
> +	icsk->icsk_ca_state = ca_state;
> +}
> +
>   /* Must be called with rcu lock held */
>   static struct tcp_congestion_ops *tcp_ca_find_autoload(struct net *net,
>   						       const char *name)