linux/net/ipv4
Neal Cardwell 059217c18b tcp: fix quick-ack counting to count actual ACKs of new data
This commit fixes quick-ack counting so that it only considers that a
quick-ack has been provided if we are sending an ACK that newly
acknowledges data.

The code was erroneously using the number of data segments in outgoing
skbs when deciding how many quick-ack credits to remove. This logic
does not make sense, and could cause poor performance in
request-response workloads, like RPC traffic, where requests or
responses can be multi-segment skbs.

When a TCP connection decides to send N quick-acks, that is to
accelerate the cwnd growth of the congestion control module
controlling the remote endpoint of the TCP connection. That quick-ack
decision is purely about the incoming data and outgoing ACKs. It has
nothing to do with the outgoing data or the size of outgoing data.

And in particular, an ACK only serves the intended purpose of allowing
the remote congestion control to grow the congestion window quickly if
the ACK is ACKing or SACKing new data.

The fix is simple: only count packets as serving the goal of the
quickack mechanism if they are ACKing/SACKing new data. We can tell
whether this is the case by checking inet_csk_ack_scheduled(), since
we schedule an ACK exactly when we are ACKing/SACKing new data.

Fixes: fc6415bcb0 ("[TCP]: Fix quick-ack decrementing with TSO.")
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Yuchung Cheng <ycheng@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20231001151239.1866845-1-ncardwell.sw@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-10-04 15:34:18 -07:00
..
bpfilter net: Use umd_cleanup_helper() 2023-05-31 13:06:57 +02:00
netfilter inet: move inet->nodefrag to inet->inet_flags 2023-08-16 11:09:17 +01:00
af_inet.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-08-24 10:51:39 -07:00
ah4.c net: ipv4: Remove completion function scaffolding 2023-02-13 18:35:15 +08:00
arp.c neighbour: annotate lockless accesses to n->nud_state 2023-03-15 00:37:32 -07:00
bpf_tcp_ca.c bpf: Drop useless btf_vmlinux in bpf_tcp_ca 2023-07-18 17:31:10 -07:00
cipso_ipv4.c inet: move inet->is_icsk to inet->inet_flags 2023-08-16 11:09:17 +01:00
datagram.c ipv4: fix data-races around inet->inet_id 2023-08-20 11:40:49 +01:00
devinet.c net: ipv4: fix one memleak in __inet_del_ifa() 2023-09-08 08:02:17 +01:00
esp4_offload.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-06-22 18:40:38 -07:00
esp4.c net: ipv4: Use kfree_sensitive instead of kfree 2023-07-19 11:03:03 +01:00
fib_frontend.c ipv4: Fix incorrect table ID in IOCTL path 2023-03-16 17:26:31 -07:00
fib_lookup.h
fib_notifier.c
fib_rules.c
fib_semantics.c ipv4/fib: send notify when delete source address routes 2023-10-03 09:00:40 +02:00
fib_trie.c ipv4/fib: send notify when delete source address routes 2023-10-03 09:00:40 +02:00
fou_bpf.c bpf,fou: Add bpf_skb_{set,get}_fou_encap kfuncs 2023-04-12 16:40:39 -07:00
fou_core.c bpf,fou: Add bpf_skb_{set,get}_fou_encap kfuncs 2023-04-12 16:40:39 -07:00
fou_nl.c net: ynl: prefix uAPI header include with uapi/ 2023-05-26 10:30:14 +01:00
fou_nl.h net: ynl: prefix uAPI header include with uapi/ 2023-05-26 10:30:14 +01:00
gre_demux.c
gre_offload.c net: move gso declarations and functions to their own files 2023-06-10 00:11:41 -07:00
icmp.c icmp: guard against too small mtu 2023-03-31 21:37:06 -07:00
igmp.c igmp: limit igmpv3_newpack() packet size to IP_MAX_MTU 2023-09-05 17:49:40 +01:00
inet_connection_sock.c tcp: annotate data-races around icsk->icsk_syn_retries 2023-07-20 12:34:18 -07:00
inet_diag.c inet: move inet->defer_connect to inet->inet_flags 2023-08-16 11:09:18 +01:00
inet_fragment.c net: dropreason: add SKB_DROP_REASON_FRAG_REASM_TIMEOUT 2022-10-31 20:14:27 -07:00
inet_hashtables.c tcp: Fix bind() regression for v4-mapped-v6 non-wildcard address. 2023-09-13 07:18:04 +01:00
inet_timewait_sock.c inet: move inet->transparent to inet->inet_flags 2023-08-16 11:09:17 +01:00
inetpeer.c inetpeer: Fix data-races around sysctl. 2022-07-08 12:10:33 +01:00
ip_forward.c net: ipv4, ipv6: fix IPSTATS_MIB_OUTOCTETS increment duplicated 2023-08-30 09:44:09 +01:00
ip_fragment.c networking: Update to register_net_sysctl_sz 2023-08-15 15:26:18 -07:00
ip_gre.c ipv4: ip_gre: fix return value check in erspan_xmit() 2023-07-19 12:27:09 +01:00
ip_input.c ipv4: ignore dst hint for multipath routes 2023-09-01 08:11:51 +01:00
ip_options.c
ip_output.c net: annotate data-races around sk->sk_tsflags 2023-09-01 07:27:33 +01:00
ip_sockglue.c net: annotate data-races around sk->sk_tsflags 2023-09-01 07:27:33 +01:00
ip_tunnel_core.c tunnels: fix kasan splat when generating ipv4 pmtu error 2023-08-04 18:24:52 -07:00
ip_tunnel.c bpf-next-for-netdev 2023-04-13 16:43:38 -07:00
ip_vti.c ip_vti: fix potential slab-use-after-free in decode_session6 2023-07-11 11:06:08 +02:00
ipcomp.c xfrm: ipcomp: add extack to ipcomp{4,6}_init_state 2022-09-29 07:18:00 +02:00
ipconfig.c net: ipconfig: move ic_nameservers_fallback into #ifdef block 2023-05-22 11:17:55 +01:00
ipip.c ipip,ip_tunnel,sit: Add FOU support for externally controlled ipip devices 2023-04-12 16:40:39 -07:00
ipmr_base.c ipmr: adopt rcu_read_lock() in mr_dump() 2022-06-24 11:34:38 +01:00
ipmr.c net: ipv4, ipv6: fix IPSTATS_MIB_OUTOCTETS increment duplicated 2023-08-30 09:44:09 +01:00
Kconfig tcp: configurable source port perturb table size 2022-11-16 13:02:04 +00:00
Makefile bpf,fou: Add bpf_skb_{set,get}_fou_encap kfuncs 2023-04-12 16:40:39 -07:00
metrics.c ipv4: prevent potential spectre v1 gadget in ip_metrics_convert() 2023-01-23 21:37:25 -08:00
netfilter.c
netlink.c
nexthop.c nexthop: Do not increment dump sentinel at the end of the dump 2023-08-15 18:54:53 -07:00
ping.c inet: move inet->recverr to inet->inet_flags 2023-08-16 11:09:17 +01:00
proc.c icmp: Add counters for rate limits 2023-01-26 10:52:18 +01:00
protocol.c
raw_diag.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-04-06 12:01:20 -07:00
raw.c inet: move inet->hdrincl to inet->inet_flags 2023-08-16 11:09:17 +01:00
route.c ipv4: Set offload_failed flag in fibmatch results 2023-10-04 11:39:36 -07:00
syncookies.c tcp: Set route scope properly in cookie_v4_check(). 2023-06-06 21:13:03 -07:00
sysctl_net_ipv4.c networking: Update to register_net_sysctl_sz 2023-08-15 15:26:18 -07:00
tcp_bbr.c bpf: Add __bpf_kfunc tag to all kfuncs 2023-02-02 00:25:14 +01:00
tcp_bic.c
tcp_bpf.c bpf, sockmap: Do not inc copied_seq when PEEK flag set 2023-09-29 17:05:00 +02:00
tcp_cdg.c Random number generator fixes for Linux 6.1-rc1. 2022-10-16 15:27:07 -07:00
tcp_cong.c net: Update an existing TCP congestion control algorithm. 2023-03-22 22:53:00 -07:00
tcp_cubic.c bpf: Add __bpf_kfunc tag to all kfuncs 2023-02-02 00:25:14 +01:00
tcp_dctcp.c bpf: Add __bpf_kfunc tag to all kfuncs 2023-02-02 00:25:14 +01:00
tcp_dctcp.h
tcp_diag.c tcp: Access &tcp_hashinfo via net. 2022-09-20 10:21:49 -07:00
tcp_fastopen.c inet: move inet->defer_connect to inet->inet_flags 2023-08-16 11:09:18 +01:00
tcp_highspeed.c
tcp_htcp.c
tcp_hybla.c
tcp_illinois.c
tcp_input.c inet: move inet->transparent to inet->inet_flags 2023-08-16 11:09:17 +01:00
tcp_ipv4.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-08-24 10:51:39 -07:00
tcp_lp.c
tcp_metrics.c tcp_metrics: hash table allocation cleanup 2023-08-04 15:33:39 -07:00
tcp_minisocks.c inet: move inet->transparent to inet->inet_flags 2023-08-16 11:09:17 +01:00
tcp_nv.c
tcp_offload.c net: move gso declarations and functions to their own files 2023-06-10 00:11:41 -07:00
tcp_output.c tcp: fix quick-ack counting to count actual ACKs of new data 2023-10-04 15:34:18 -07:00
tcp_plb.c prandom: remove prandom_u32_max() 2022-12-20 03:13:45 +01:00
tcp_rate.c
tcp_recovery.c tcp: preserve const qualifier in tcp_sk() 2023-03-18 12:23:34 +00:00
tcp_scalable.c
tcp_timer.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2023-08-18 12:44:56 -07:00
tcp_ulp.c net/ulp: use consistent error code when blocking ULP 2023-01-19 09:26:16 -08:00
tcp_vegas.c
tcp_vegas.h
tcp_veno.c
tcp_westwood.c
tcp_yeah.c
tcp.c bpf: tcp_read_skb needs to pop skb regardless of seq 2023-09-29 17:04:07 +02:00
tunnel4.c
udp_bpf.c bpf, sockmap: Fix an infinite loop error when len is 0 in tcp_bpf_recvmsg_parser() 2023-03-03 17:25:15 +01:00
udp_diag.c udp: Access &udp_table via net. 2022-11-16 09:43:35 +00:00
udp_impl.h sock: Remove ->sendpage*() in favour of sendmsg(MSG_SPLICE_PAGES) 2023-06-24 15:50:13 -07:00
udp_offload.c net: gro: fix misuse of CB in udp socket lookup 2023-07-29 17:10:27 +01:00
udp_tunnel_core.c inet: move inet->mc_loop to inet->inet_frags 2023-08-16 11:09:17 +01:00
udp_tunnel_nic.c udp_tunnel: Add checks for nla_nest_start() in __udp_tunnel_nic_dump_write() 2022-11-29 08:44:24 -08:00
udp_tunnel_stub.c
udp.c net: annotate data-races around sk->sk_forward_alloc 2023-09-01 07:27:33 +01:00
udplite.c sock: Remove ->sendpage*() in favour of sendmsg(MSG_SPLICE_PAGES) 2023-06-24 15:50:13 -07:00
xfrm4_input.c xfrm: fix inbound ipv4/udp/esp packets to UDPv6 dualstack sockets 2023-06-09 08:16:34 +02:00
xfrm4_output.c
xfrm4_policy.c sysctl-6.6-rc1 2023-08-29 17:39:15 -07:00
xfrm4_protocol.c
xfrm4_state.c
xfrm4_tunnel.c xfrm: tunnel: add extack to ipip_init_state, xfrm6_tunnel_init_state 2022-09-29 07:18:00 +02:00