Commit 82506665 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

tcp: reorder tcp_congestion_ops for better cache locality 



Group all the often used fields in the first cache line,
to reduce cache line misses.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7f040aa3

include/net/tcp.h

+27 −15
Original line number Diff line number Diff line
@@ -1035,44 +1035,56 @@ struct rate_sample { 
};



struct tcp_congestion_ops {

	struct list_head	list;

	u32 key;

	u32 flags;



	/* initialize private data (optional) */

	void (*init)(struct sock *sk);

	/* cleanup private data  (optional) */

	void (*release)(struct sock *sk);

/* fast path fields are put first to fill one cache line */



	/* return slow start threshold (required) */

	u32 (*ssthresh)(struct sock *sk);



	/* do new cwnd calculation (required) */

	void (*cong_avoid)(struct sock *sk, u32 ack, u32 acked);



	/* call before changing ca_state (optional) */

	void (*set_state)(struct sock *sk, u8 new_state);



	/* call when cwnd event occurs (optional) */

	void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev);



	/* call when ack arrives (optional) */

	void (*in_ack_event)(struct sock *sk, u32 flags);

	/* new value of cwnd after loss (required) */

	u32  (*undo_cwnd)(struct sock *sk);



	/* hook for packet ack accounting (optional) */

	void (*pkts_acked)(struct sock *sk, const struct ack_sample *sample);



	/* override sysctl_tcp_min_tso_segs */

	u32 (*min_tso_segs)(struct sock *sk);

	/* returns the multiplier used in tcp_sndbuf_expand (optional) */

	u32 (*sndbuf_expand)(struct sock *sk);



	/* call when packets are delivered to update cwnd and pacing rate,

	 * after all the ca_state processing. (optional)

	 */

	void (*cong_control)(struct sock *sk, const struct rate_sample *rs);





	/* new value of cwnd after loss (required) */

	u32  (*undo_cwnd)(struct sock *sk);

	/* returns the multiplier used in tcp_sndbuf_expand (optional) */

	u32 (*sndbuf_expand)(struct sock *sk);



/* control/slow paths put last */

	/* get info for inet_diag (optional) */

	size_t (*get_info)(struct sock *sk, u32 ext, int *attr,

			   union tcp_cc_info *info);



	char 			name[TCP_CA_NAME_MAX];

	struct module		*owner;

};

	struct list_head	list;

	u32			key;

	u32			flags;



	/* initialize private data (optional) */

	void (*init)(struct sock *sk);

	/* cleanup private data  (optional) */

	void (*release)(struct sock *sk);

} ____cacheline_aligned_in_smp;



int tcp_register_congestion_control(struct tcp_congestion_ops *type);

void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);