linux/net/ipv6
Eric Dumazet ca6fb06518 tcp: attach SYNACK messages to request sockets instead of listener
If a listen backlog is very big (to avoid syncookies), then
the listener sk->sk_wmem_alloc is the main source of false
sharing, as we need to touch it twice per SYNACK re-transmit
and TX completion.

(One SYN packet takes listener lock once, but up to 6 SYNACK
are generated)

By attaching the skb to the request socket, we remove this
source of contention.

Tested:

 listen(fd, 10485760); // single listener (no SO_REUSEPORT)
 16 RX/TX queue NIC
 Sustain a SYNFLOOD attack of ~320,000 SYN per second,
 Sending ~1,400,000 SYNACK per second.
 Perf profiles now show listener spinlock being next bottleneck.

    20.29%  [kernel]  [k] queued_spin_lock_slowpath
    10.06%  [kernel]  [k] __inet_lookup_established
     5.12%  [kernel]  [k] reqsk_timer_handler
     3.22%  [kernel]  [k] get_next_timer_interrupt
     3.00%  [kernel]  [k] tcp_make_synack
     2.77%  [kernel]  [k] ipt_do_table
     2.70%  [kernel]  [k] run_timer_softirq
     2.50%  [kernel]  [k] ip_finish_output
     2.04%  [kernel]  [k] cascade

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-10-03 04:32:43 -07:00
..
netfilter ipv6: Pass struct net into ip6_route_me_harder 2015-09-29 20:21:32 +02:00
addrconf.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-09-26 16:08:27 -07:00
addrconf_core.c ipv6: change ipv6_stub_impl.ipv6_dst_lookup to take net argument 2015-07-31 15:21:30 -07:00
addrlabel.c netlink: implement nla_put_in_addr and nla_put_in6_addr 2015-03-31 13:58:35 -04:00
af_inet6.c ipv6: Disable flowlabel state ranges by default 2015-07-31 17:07:11 -07:00
ah6.c ah6: fix error return code 2015-08-25 13:37:31 -07:00
anycast.c ipv6: coding style: comparison for equality with NULL 2015-03-31 13:51:54 -04:00
datagram.c ipv6: constify ip6_xmit() sock argument 2015-09-25 13:00:38 -07:00
esp6.c esp6: Switch to new AEAD interface 2015-05-28 11:23:20 +08:00
exthdrs.c ipv6: use flag instead of u16 for hop in inet6_skb_parm 2015-07-09 15:06:59 -07:00
exthdrs_core.c ipv6: coding style: comparison for equality with NULL 2015-03-31 13:51:54 -04:00
exthdrs_offload.c ipv6: fix exthdrs offload registration in out_rt path 2015-09-02 15:31:00 -07:00
fib6_rules.c net: ipv6: use common fib_default_rule_pref 2015-09-09 14:19:50 -07:00
icmp.c ipv6: change ipv6_stub_impl.ipv6_dst_lookup to take net argument 2015-07-31 15:21:30 -07:00
ila.c ila: Precompute checksum difference for translations 2015-08-24 10:34:40 -07:00
inet6_connection_sock.c tcp/dccp: install syn_recv requests into ehash table 2015-10-03 04:32:41 -07:00
inet6_hashtables.c inet: inet_twsk_deschedule factorization 2015-07-09 15:12:20 -07:00
ip6_checksum.c udp: Generic functions to set checksum 2014-06-04 22:46:38 -07:00
ip6_fib.c ipv6: include NLM_F_REPLACE in route replace notifications 2015-09-17 15:00:27 -07:00
ip6_flowlabel.c ipv6: Flow label state ranges 2015-05-03 21:58:01 -04:00
ip6_gre.c ip6_gre: Reduce log level in ip6gre_err() to debug 2015-09-24 15:28:43 -07:00
ip6_icmp.c ipv6: White-space cleansing : Line Layouts 2014-08-24 22:37:52 -07:00
ip6_input.c netfilter: Pass net into okfn 2015-09-17 17:18:37 -07:00
ip6_offload.c Revert "sit: Add gro callbacks to sit_offload" 2015-07-20 16:52:28 -07:00
ip6_offload.h
ip6_output.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-09-26 16:08:27 -07:00
ip6_tunnel.c ip6_tunnel: Reduce log level in ip6_tnl_err() to debug 2015-09-24 16:08:37 -07:00
ip6_udp_tunnel.c vxlan: do not receive IPv4 packets on IPv6 socket 2015-08-29 13:07:54 -07:00
ip6_vti.c net: Merge dst_output and dst_output_sk 2015-09-17 17:18:32 -07:00
ip6mr.c netfilter: Pass net into okfn 2015-09-17 17:18:37 -07:00
ipcomp6.c ipv6: White-space cleansing : Structure layouts 2014-08-24 22:37:52 -07:00
ipv6_sockglue.c ipv6: coding style: comparison for equality with NULL 2015-03-31 13:51:54 -04:00
Kconfig net: Identifier Locator Addressing module 2015-08-17 21:33:06 -07:00
Makefile net: Identifier Locator Addressing module 2015-08-17 21:33:06 -07:00
mcast.c netfilter: Pass net into okfn 2015-09-17 17:18:37 -07:00
mcast_snoop.c net: fix wrong skb_get() usage / crash in IGMP/MLD parsing code 2015-08-13 17:08:39 -07:00
mip6.c net: Convert LIMIT_NETDEBUG to net_dbg_ratelimited 2014-11-11 14:10:31 -05:00
ndisc.c ipv6: remove unused neigh parameter from ndisc functions 2015-09-24 12:26:08 -07:00
netfilter.c ipv6: Pass struct net into ip6_route_me_harder 2015-09-29 20:21:32 +02:00
output_core.c netfilter: Pass net into okfn 2015-09-17 17:18:37 -07:00
ping.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-03-09 23:38:02 -04:00
proc.c udp: Increment UDP_MIB_IGNOREDMULTI for arriving unmatched multicasts 2014-11-07 15:45:50 -05:00
protocol.c net: Export inet_offloads and inet6_offloads 2014-09-19 17:15:31 -04:00
raw.c netfilter: Pass net into okfn 2015-09-17 17:18:37 -07:00
reassembly.c inet: frags: remove INET_FRAG_EVICTED and use list_evictor for the test 2015-07-26 21:00:15 -07:00
route.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-10-02 07:21:25 -07:00
sit.c ip_gre: Add support to collect tunnel metadata. 2015-08-10 14:03:54 -07:00
syncookies.c tcp: cookie_init_sequence() cleanups 2015-09-29 16:53:09 -07:00
sysctl_net_ipv6.c ipv6: Implement different admin modes for automatic flow labels 2015-07-31 17:07:11 -07:00
tcp_ipv6.c tcp: attach SYNACK messages to request sockets instead of listener 2015-10-03 04:32:43 -07:00
tcpv6_offload.c tcp: cleanup static functions 2015-02-28 16:56:51 -05:00
tunnel6.c ipv6: White-space cleansing : gaps between function and symbol export 2014-08-24 22:37:52 -07:00
udp.c ipv6: trivial whitespace fix 2015-08-17 14:34:48 -07:00
udp_impl.h net: Remove iocb argument from sendmsg and recvmsg 2015-03-02 13:06:31 -05:00
udp_offload.c ipv6: hash net ptr into fragmentation bucket selection 2015-03-25 14:07:04 -04:00
udplite.c net: Eliminate no_check from protosw 2014-05-23 16:28:53 -04:00
xfrm6_input.c netfilter: Pass struct net into the netfilter hooks 2015-09-17 17:18:37 -07:00
xfrm6_mode_beet.c xfrm: simplify xfrm_address_t use 2015-03-31 13:58:35 -04:00
xfrm6_mode_ro.c ipv4/ipv6: Fix FSF address in file headers 2013-12-06 12:37:56 -05:00
xfrm6_mode_transport.c
xfrm6_mode_tunnel.c xfrm6: Fix IPv6 ECN decapsulation 2015-08-11 12:41:34 +02:00
xfrm6_output.c netfilter: Add blank lines in callers of netfilter hooks 2015-09-17 17:18:37 -07:00
xfrm6_policy.c net: Replace vrf_master_ifindex{, _rcu} with l3mdev equivalents 2015-09-29 20:40:33 -07:00
xfrm6_protocol.c xfrm6: Properly handle unsupported protocols 2014-05-06 07:08:38 +02:00
xfrm6_state.c ipv6: White-space cleansing : Line Layouts 2014-08-24 22:37:52 -07:00
xfrm6_tunnel.c ipv6: White-space cleansing : gaps between function and symbol export 2014-08-24 22:37:52 -07:00