linux/include/net/inet6_connection_sock.h
Eric Dumazet fa76ce7328 inet: get rid of central tcp/dccp listener timer
One of the major issue for TCP is the SYNACK rtx handling,
done by inet_csk_reqsk_queue_prune(), fired by the keepalive
timer of a TCP_LISTEN socket.

This function runs for awful long times, with socket lock held,
meaning that other cpus needing this lock have to spin for hundred of ms.

SYNACK are sent in huge bursts, likely to cause severe drops anyway.

This model was OK 15 years ago when memory was very tight.

We now can afford to have a timer per request sock.

Timer invocations no longer need to lock the listener,
and can be run from all cpus in parallel.

With following patch increasing somaxconn width to 32 bits,
I tested a listener with more than 4 million active request sockets,
and a steady SYNFLOOD of ~200,000 SYN per second.
Host was sending ~830,000 SYNACK per second.

This is ~100 times more what we could achieve before this patch.

Later, we will get rid of the listener hash and use ehash instead.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-20 12:40:25 -04:00

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1.4 KiB
C

/*
* NET Generic infrastructure for INET6 connection oriented protocols.
*
* Authors: Many people, see the TCPv6 sources
*
* From code originally in TCPv6
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifndef _INET6_CONNECTION_SOCK_H
#define _INET6_CONNECTION_SOCK_H
#include <linux/types.h>
struct in6_addr;
struct inet_bind_bucket;
struct request_sock;
struct sk_buff;
struct sock;
struct sockaddr;
int inet6_csk_bind_conflict(const struct sock *sk,
const struct inet_bind_bucket *tb, bool relax);
struct dst_entry *inet6_csk_route_req(struct sock *sk, struct flowi6 *fl6,
const struct request_sock *req);
struct request_sock *inet6_csk_search_req(struct sock *sk,
const __be16 rport,
const struct in6_addr *raddr,
const struct in6_addr *laddr,
const int iif);
void inet6_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
const unsigned long timeout);
void inet6_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr);
int inet6_csk_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl);
struct dst_entry *inet6_csk_update_pmtu(struct sock *sk, u32 mtu);
#endif /* _INET6_CONNECTION_SOCK_H */