645ca708f9
UDP sockets are hashed in a 128 slots hash table. This hash table is protected by *one* rwlock. This rwlock is readlocked each time an incoming UDP message is handled. This rwlock is writelocked each time a socket must be inserted in hash table (bind time), or deleted from this table (close time) This is not scalable on SMP machines : 1) Even in read mode, lock() and unlock() are atomic operations and must dirty a contended cache line, shared by all cpus. 2) A writer might be starved if many readers are 'in flight'. This can happen on a machine with some NIC receiving many UDP messages. User process can be delayed a long time at socket creation/dismantle time. This patch prepares RCU migration, by introducing 'struct udp_table and struct udp_hslot', and using one spinlock per chain, to reduce contention on central rwlock. Introducing one spinlock per chain reduces latencies, for port randomization on heavily loaded UDP servers. This also speedup bindings to specific ports. udp_lib_unhash() was uninlined, becoming to big. Some cleanups were done to ease review of following patch (RCUification of UDP Unicast lookups) Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
132 lines
3.1 KiB
C
132 lines
3.1 KiB
C
/*
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* UDPLITEv6 An implementation of the UDP-Lite protocol over IPv6.
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* See also net/ipv4/udplite.c
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*
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* Authors: Gerrit Renker <gerrit@erg.abdn.ac.uk>
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*
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* Changes:
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* Fixes:
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include "udp_impl.h"
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static int udplitev6_rcv(struct sk_buff *skb)
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{
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return __udp6_lib_rcv(skb, &udplite_table, IPPROTO_UDPLITE);
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}
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static void udplitev6_err(struct sk_buff *skb,
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struct inet6_skb_parm *opt,
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int type, int code, int offset, __be32 info)
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{
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__udp6_lib_err(skb, opt, type, code, offset, info, &udplite_table);
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}
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static struct inet6_protocol udplitev6_protocol = {
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.handler = udplitev6_rcv,
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.err_handler = udplitev6_err,
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.flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
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};
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struct proto udplitev6_prot = {
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.name = "UDPLITEv6",
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.owner = THIS_MODULE,
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.close = udp_lib_close,
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.connect = ip6_datagram_connect,
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.disconnect = udp_disconnect,
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.ioctl = udp_ioctl,
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.init = udplite_sk_init,
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.destroy = udpv6_destroy_sock,
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.setsockopt = udpv6_setsockopt,
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.getsockopt = udpv6_getsockopt,
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.sendmsg = udpv6_sendmsg,
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.recvmsg = udpv6_recvmsg,
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.backlog_rcv = udpv6_queue_rcv_skb,
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.hash = udp_lib_hash,
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.unhash = udp_lib_unhash,
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.get_port = udp_v6_get_port,
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.obj_size = sizeof(struct udp6_sock),
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.h.udp_table = &udplite_table,
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#ifdef CONFIG_COMPAT
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.compat_setsockopt = compat_udpv6_setsockopt,
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.compat_getsockopt = compat_udpv6_getsockopt,
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#endif
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};
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static struct inet_protosw udplite6_protosw = {
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.type = SOCK_DGRAM,
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.protocol = IPPROTO_UDPLITE,
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.prot = &udplitev6_prot,
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.ops = &inet6_dgram_ops,
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.capability = -1,
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.no_check = 0,
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.flags = INET_PROTOSW_PERMANENT,
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};
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int __init udplitev6_init(void)
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{
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int ret;
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ret = inet6_add_protocol(&udplitev6_protocol, IPPROTO_UDPLITE);
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if (ret)
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goto out;
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ret = inet6_register_protosw(&udplite6_protosw);
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if (ret)
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goto out_udplitev6_protocol;
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out:
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return ret;
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out_udplitev6_protocol:
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inet6_del_protocol(&udplitev6_protocol, IPPROTO_UDPLITE);
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goto out;
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}
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void udplitev6_exit(void)
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{
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inet6_unregister_protosw(&udplite6_protosw);
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inet6_del_protocol(&udplitev6_protocol, IPPROTO_UDPLITE);
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}
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#ifdef CONFIG_PROC_FS
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static struct udp_seq_afinfo udplite6_seq_afinfo = {
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.name = "udplite6",
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.family = AF_INET6,
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.udp_table = &udplite_table,
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.seq_fops = {
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.owner = THIS_MODULE,
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},
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.seq_ops = {
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.show = udp6_seq_show,
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},
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};
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static int udplite6_proc_init_net(struct net *net)
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{
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return udp_proc_register(net, &udplite6_seq_afinfo);
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}
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static void udplite6_proc_exit_net(struct net *net)
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{
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udp_proc_unregister(net, &udplite6_seq_afinfo);
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}
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static struct pernet_operations udplite6_net_ops = {
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.init = udplite6_proc_init_net,
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.exit = udplite6_proc_exit_net,
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};
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int __init udplite6_proc_init(void)
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{
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return register_pernet_subsys(&udplite6_net_ops);
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}
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void udplite6_proc_exit(void)
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{
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unregister_pernet_subsys(&udplite6_net_ops);
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}
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#endif
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