linux/net/ipv4
Eric Dumazet c9c3321257 tcp: add tcp_add_backlog()
When TCP operates in lossy environments (between 1 and 10 % packet
losses), many SACK blocks can be exchanged, and I noticed we could
drop them on busy senders, if these SACK blocks have to be queued
into the socket backlog.

While the main cause is the poor performance of RACK/SACK processing,
we can try to avoid these drops of valuable information that can lead to
spurious timeouts and retransmits.

Cause of the drops is the skb->truesize overestimation caused by :

- drivers allocating ~2048 (or more) bytes as a fragment to hold an
  Ethernet frame.

- various pskb_may_pull() calls bringing the headers into skb->head
  might have pulled all the frame content, but skb->truesize could
  not be lowered, as the stack has no idea of each fragment truesize.

The backlog drops are also more visible on bidirectional flows, since
their sk_rmem_alloc can be quite big.

Let's add some room for the backlog, as only the socket owner
can selectively take action to lower memory needs, like collapsing
receive queues or partial ofo pruning.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-08-29 00:20:24 -04:00
..
netfilter netfilter: x_tables: speed up jump target validation 2016-07-18 21:35:23 +02:00
af_inet.c tcp: Set read_sock and peek_len proto_ops 2016-08-28 23:32:41 -04:00
ah4.c
arp.c net: rename NET_{ADD|INC}_STATS_BH() 2016-04-27 22:48:24 -04:00
cipso_ipv4.c Merge branch 'stable-4.8' of git://git.infradead.org/users/pcmoore/selinux into next 2016-07-07 10:15:34 +10:00
datagram.c
devinet.c ipv4: do not abuse GFP_ATOMIC in inet_netconf_notify_devconf() 2016-07-09 18:12:25 -04:00
esp4.c esp: Fix ESN generation under UDP encapsulation 2016-06-23 11:52:00 -04:00
fib_frontend.c net: Remove fib_local variable 2016-08-09 14:57:39 -07:00
fib_lookup.h
fib_rules.c net: Add l3mdev rule 2016-06-08 11:36:02 -07:00
fib_semantics.c net: ipv4: fix sparse error in fib_good_nh() 2016-08-19 17:07:30 -07:00
fib_trie.c ipv4: panic in leaf_walk_rcu due to stale node pointer 2016-08-06 00:10:05 -04:00
fou.c gue: Implement direction IP encapsulation 2016-06-07 23:51:14 -07:00
gre_demux.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-06-30 05:03:36 -04:00
gre_offload.c gso: Remove arbitrary checks for unsupported GSO 2016-05-20 18:03:15 -04:00
icmp.c net: icmp: rename ICMPMSGIN_INC_STATS_BH() 2016-04-27 22:48:23 -04:00
igmp.c net/multicast: should not send source list records when have filter mode change 2016-08-08 16:04:39 -07:00
inet_connection_sock.c timers, net/ipv4/inet: Initialize connection request timers as pinned 2016-07-07 10:35:06 +02:00
inet_diag.c net: diag: allow socket bytecode filters to match socket marks 2016-08-24 21:57:20 -07:00
inet_fragment.c net: disable fragment reassembly if high_thresh is zero 2016-06-05 22:56:42 -04:00
inet_hashtables.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-05-04 00:52:29 -04:00
inet_timewait_sock.c timers, net/ipv4/inet: Initialize connection request timers as pinned 2016-07-07 10:35:06 +02:00
inetpeer.c
ip_forward.c net/ipv4: Introduce IPSKB_FRAG_SEGS bit to inet_skb_parm.flags 2016-07-19 16:40:22 -07:00
ip_fragment.c net: rename IP_INC_STATS_BH() 2016-04-27 22:48:23 -04:00
ip_gre.c gre: set inner_protocol on xmit 2016-08-15 13:37:12 -07:00
ip_input.c net: original ingress device index in PKTINFO 2016-05-11 19:31:40 -04:00
ip_options.c net: ipv4: Convert IP network timestamps to be y2038 safe 2016-03-01 17:18:44 -05:00
ip_output.c net/ipv4: Introduce IPSKB_FRAG_SEGS bit to inet_skb_parm.flags 2016-07-19 16:40:22 -07:00
ip_sockglue.c sock: propagate __sock_cmsg_send() error 2016-05-16 13:46:23 -04:00
ip_tunnel_core.c net: ip_finish_output_gso: If skb_gso_network_seglen exceeds MTU, allow segmentation for local udp tunneled skbs 2016-07-19 16:40:22 -07:00
ip_tunnel.c net: ipv4: Add ability to have GRE ignore DF bit in IPv4 payloads 2016-06-15 21:39:59 -07:00
ip_vti.c vti: flush x-netns xfrm cache when vti interface is removed 2016-08-09 12:57:49 -07:00
ipcomp.c
ipconfig.c net: ipconfig: Fix NULL pointer dereference on RARP/BOOTP/DHCP timeout 2016-08-22 21:04:41 -07:00
ipip.c ipip: support MPLS over IPv4 2016-07-09 17:45:56 -04:00
ipmr.c net: ipmr/ip6mr: update lastuse on entry change 2016-07-26 15:18:31 -07:00
Kconfig tcp: add NV congestion control 2016-06-10 23:07:49 -07:00
Makefile tcp: add NV congestion control 2016-06-10 23:07:49 -07:00
netfilter.c
ping.c sock: enable timestamping using control messages 2016-04-04 15:50:30 -04:00
proc.c tcp: md5: add LINUX_MIB_TCPMD5FAILURE counter 2016-08-25 16:43:11 -07:00
protocol.c
raw.c sock: enable timestamping using control messages 2016-04-04 15:50:30 -04:00
route.c net: l3mdev: Allow send on enslaved interface 2016-05-09 22:33:52 -04:00
syncookies.c net: rename NET_{ADD|INC}_STATS_BH() 2016-04-27 22:48:24 -04:00
sysctl_net_ipv4.c ipv4: Fix non-initialized TTL when CONFIG_SYSCTL=n 2016-05-23 14:32:06 -07:00
tcp_bic.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_cdg.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_cong.c
tcp_cubic.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_dctcp.c tcp: return sizeof tcp_dctcp_info in dctcp_get_info() 2016-06-14 23:46:30 -07:00
tcp_diag.c net: diag: Support destroying TCP sockets. 2015-12-15 23:26:52 -05:00
tcp_fastopen.c tcp: do not assume TCP code is non preemptible 2016-05-02 17:02:25 -04:00
tcp_highspeed.c
tcp_htcp.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_hybla.c
tcp_illinois.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_input.c tcp: refine tcp_prune_ofo_queue() to not drop all packets 2016-08-18 23:36:07 -07:00
tcp_ipv4.c tcp: add tcp_add_backlog() 2016-08-29 00:20:24 -04:00
tcp_lp.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_metrics.c libnl: nla_put_msecs(): align on a 64-bit area 2016-04-23 20:13:24 -04:00
tcp_minisocks.c tcp: do not assume TCP code is non preemptible 2016-05-02 17:02:25 -04:00
tcp_nv.c tcp: add NV congestion control 2016-06-10 23:07:49 -07:00
tcp_offload.c gso: Remove arbitrary checks for unsupported GSO 2016-05-20 18:03:15 -04:00
tcp_output.c tcp: defer sacked assignment 2016-08-18 23:27:27 -07:00
tcp_probe.c net: ipv4: tcp_probe: Replace timespec with timespec64 2016-03-01 17:18:44 -05:00
tcp_recovery.c tcp: do not assume TCP code is non preemptible 2016-05-02 17:02:25 -04:00
tcp_scalable.c
tcp_timer.c tcp_timer.c: Add kernel-doc function descriptions 2016-07-15 23:18:14 -07:00
tcp_vegas.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_vegas.h tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_veno.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_westwood.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_yeah.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp.c tcp: Set read_sock and peek_len proto_ops 2016-08-28 23:32:41 -04:00
tunnel4.c tunnels: correct conditional build of MPLS and IPv6 2016-07-11 13:27:06 -07:00
udp_diag.c net: diag: support SOCK_DESTROY for UDP sockets 2016-08-23 23:12:27 -07:00
udp_impl.h
udp_offload.c gso: Remove arbitrary checks for unsupported GSO 2016-05-20 18:03:15 -04:00
udp_tunnel.c net: Remove deprecated tunnel specific UDP offload functions 2016-06-17 20:23:32 -07:00
udp.c udp: get rid of sk_prot_clear_portaddr_nulls() 2016-08-23 23:25:29 -07:00
udplite.c udp: get rid of sk_prot_clear_portaddr_nulls() 2016-08-23 23:25:29 -07:00
xfrm4_input.c
xfrm4_mode_beet.c
xfrm4_mode_transport.c
xfrm4_mode_tunnel.c
xfrm4_output.c
xfrm4_policy.c net: xfrm: fix old-style declaration 2016-06-16 22:06:30 -07:00
xfrm4_protocol.c
xfrm4_state.c
xfrm4_tunnel.c