Commit 079096f1 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

tcp/dccp: install syn_recv requests into ehash table 



In this patch, we insert request sockets into TCP/DCCP
regular ehash table (where ESTABLISHED and TIMEWAIT sockets
are) instead of using the per listener hash table.

ACK packets find SYN_RECV pseudo sockets without having
to find and lock the listener.

In nominal conditions, this halves pressure on listener lock.

Note that this will allow for SO_REUSEPORT refinements,
so that we can select a listener using cpu/numa affinities instead
of the prior 'consistent hash', since only SYN packets will
apply this selection logic.

We will shrink listen_sock in the following patch to ease
code review.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Ying Cai <ycai@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2feda341

include/net/inet_connection_sock.h

+0 −4
Original line number Diff line number Diff line
@@ -258,10 +258,6 @@ inet_csk_rto_backoff(const struct inet_connection_sock *icsk, 


struct sock *inet_csk_accept(struct sock *sk, int flags, int *err);



struct request_sock *inet_csk_search_req(struct sock *sk,

					 const __be16 rport,

					 const __be32 raddr,

					 const __be32 laddr);

int inet_csk_bind_conflict(const struct sock *sk,

			   const struct inet_bind_bucket *tb, bool relax);

int inet_csk_get_port(struct sock *sk, unsigned short snum);

include/net/inet_hashtables.h

+1 −0
Original line number Diff line number Diff line
@@ -205,6 +205,7 @@ void inet_put_port(struct sock *sk); 


void inet_hashinfo_init(struct inet_hashinfo *h);



int inet_ehash_insert(struct sock *sk, struct sock *osk);

void __inet_hash_nolisten(struct sock *sk, struct sock *osk);

void __inet_hash(struct sock *sk, struct sock *osk);

void inet_hash(struct sock *sk);

include/net/request_sock.h

+0 −4
Original line number Diff line number Diff line
@@ -266,8 +266,4 @@ static inline int reqsk_queue_is_full(const struct request_sock_queue *queue) 
	return reqsk_queue_len(queue) >> queue->listen_opt->max_qlen_log;

}



void reqsk_queue_hash_req(struct request_sock_queue *queue,

			  u32 hash, struct request_sock *req,

			  unsigned long timeout);



#endif /* _REQUEST_SOCK_H */

include/net/tcp.h

+0 −3
Original line number Diff line number Diff line
@@ -1618,7 +1618,6 @@ static inline bool tcp_stream_is_thin(struct tcp_sock *tp) 
/* /proc */

enum tcp_seq_states {

	TCP_SEQ_STATE_LISTENING,

	TCP_SEQ_STATE_OPENREQ,

	TCP_SEQ_STATE_ESTABLISHED,

};
@@ -1717,8 +1716,6 @@ struct tcp_request_sock_ops { 
	int (*send_synack)(const struct sock *sk, struct dst_entry *dst,

			   struct flowi *fl, struct request_sock *req,

			   u16 queue_mapping, struct tcp_fastopen_cookie *foc);

	void (*queue_hash_add)(struct sock *sk, struct request_sock *req,

			       const unsigned long timeout);

};



#ifdef CONFIG_SYN_COOKIES

net/core/request_sock.c

+1 −27
Original line number Diff line number Diff line
@@ -99,35 +99,9 @@ static inline struct listen_sock *reqsk_queue_yank_listen_sk( 


void reqsk_queue_destroy(struct request_sock_queue *queue)

{

	/* make all the listen_opt local to us */

	struct listen_sock *lopt = reqsk_queue_yank_listen_sk(queue);



	if (reqsk_queue_len(queue) != 0) {

		unsigned int i;



		for (i = 0; i < lopt->nr_table_entries; i++) {

			struct request_sock *req;



			spin_lock_bh(&queue->syn_wait_lock);

			while ((req = lopt->syn_table[i]) != NULL) {

				lopt->syn_table[i] = req->dl_next;

				/* Because of following del_timer_sync(),

				 * we must release the spinlock here

				 * or risk a dead lock.

				 */

				spin_unlock_bh(&queue->syn_wait_lock);

				atomic_dec(&queue->qlen);

				if (del_timer_sync(&req->rsk_timer))

					reqsk_put(req);

				reqsk_put(req);

				spin_lock_bh(&queue->syn_wait_lock);

			}

			spin_unlock_bh(&queue->syn_wait_lock);

		}

	}



	if (WARN_ON(reqsk_queue_len(queue) != 0))

		pr_err("qlen %u\n", reqsk_queue_len(queue));

	/* cleaning is done by req timers */

	kvfree(lopt);

}

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