linux/include/net
Neal Cardwell f4ce91ce12 tcp: fix tcp_cwnd_validate() to not forget is_cwnd_limited
This commit fixes a bug in the tracking of max_packets_out and
is_cwnd_limited. This bug can cause the connection to fail to remember
that is_cwnd_limited is true, causing the connection to fail to grow
cwnd when it should, causing throughput to be lower than it should be.

The following event sequence is an example that triggers the bug:

 (a) The connection is cwnd_limited, but packets_out is not at its
     peak due to TSO deferral deciding not to send another skb yet.
     In such cases the connection can advance max_packets_seq and set
     tp->is_cwnd_limited to true and max_packets_out to a small
     number.

(b) Then later in the round trip the connection is pacing-limited (not
     cwnd-limited), and packets_out is larger. In such cases the
     connection would raise max_packets_out to a bigger number but
     (unexpectedly) flip tp->is_cwnd_limited from true to false.

This commit fixes that bug.

One straightforward fix would be to separately track (a) the next
window after max_packets_out reaches a maximum, and (b) the next
window after tp->is_cwnd_limited is set to true. But this would
require consuming an extra u32 sequence number.

Instead, to save space we track only the most important
information. Specifically, we track the strongest available signal of
the degree to which the cwnd is fully utilized:

(1) If the connection is cwnd-limited then we remember that fact for
the current window.

(2) If the connection not cwnd-limited then we track the maximum
number of outstanding packets in the current window.

In particular, note that the new logic cannot trigger the buggy
(a)/(b) sequence above because with the new logic a condition where
tp->packets_out > tp->max_packets_out can only trigger an update of
tp->is_cwnd_limited if tp->is_cwnd_limited is false.

This first showed up in a testing of a BBRv2 dev branch, but this
buggy behavior highlighted a general issue with the
tcp_cwnd_validate() logic that can cause cwnd to fail to increase at
the proper rate for any TCP congestion control, including Reno or
CUBIC.

Fixes: ca8a226343 ("tcp: make cwnd-limited checks measurement-based, and gentler")
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Kevin(Yudong) Yang <yyd@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-09-30 12:37:45 +01:00
..
9p 9p: Add client parameter to p9_req_put() 2022-07-09 14:38:35 +09:00
bluetooth Bluetooth: Fix HCIGETDEVINFO regression 2022-09-09 12:25:18 -07:00
caif net: remove the caif_hsi driver 2021-07-01 13:19:48 -07:00
iucv net/af_iucv: Use struct_group() to zero struct iucv_sock region 2021-11-19 11:52:25 +00:00
netfilter netfilter: remove nf_conntrack_helper sysctl and modparam toggles 2022-08-31 12:12:32 +02:00
netns Merge git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf 2022-09-02 19:38:25 -07:00
nfc NFC: add NCI_UNREG flag to eliminate the race 2021-11-17 20:17:05 -08:00
phonet net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
sctp net: remove noblock parameter from recvmsg() entities 2022-04-12 15:00:25 +02:00
tc_act Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-05-12 16:15:30 -07:00
6lowpan.h
act_api.h net/sched: act_api: Add extack to offload_act_setup() callback 2022-04-08 13:45:43 +01:00
addrconf.h ipv6/addrconf: fix a null-ptr-deref bug for ip6_ptr 2022-07-28 10:42:44 -07:00
af_ieee802154.h
af_rxrpc.h rxrpc: Remove rxrpc_get_reply_time() which is no longer used 2022-09-01 11:44:13 +01:00
af_unix.h af_unix: Remove unix_table_locks. 2022-06-22 12:59:43 +01:00
af_vsock.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
ah.h
amt.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
arp.h ipv4: Invalidate neighbour for broadcast address upon address addition 2022-02-21 11:44:30 +00:00
atmclip.h
ax25.h ax25: fix incorrect dev_tracker usage 2022-07-28 22:06:15 -07:00
ax88796.h ax88796: Fix some typo in a comment 2022-08-09 22:14:02 -07:00
bareudp.h bareudp: Move definition of struct bareudp_conf to bareudp.c 2021-12-13 12:34:09 +00:00
bond_3ad.h net: bonding: Share lacpdu_mcast_addr definition 2022-09-16 14:34:01 +01:00
bond_alb.h bonding: make tx_rebalance_counter an atomic 2021-12-03 14:16:48 +00:00
bond_options.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
bonding.h net: bonding: Share lacpdu_mcast_addr definition 2022-09-16 14:34:01 +01:00
bpf_sk_storage.h bpf: struct sock is declared twice in bpf_sk_storage header 2021-03-26 17:43:55 +01:00
busy_poll.h net: Fix a data-race around sysctl_net_busy_poll. 2022-08-24 13:46:58 +01:00
calipso.h
cfg80211-wext.h
cfg80211.h wifi: nl80211: add MLO link ID to the NL80211_CMD_FRAME TX API 2022-07-22 14:28:33 +02:00
cfg802154.h net: wrap the wireless pointers in struct net_device in an ifdef 2022-05-22 21:51:54 +01:00
checksum.h powerpc/net: Implement powerpc specific csum_shift() to remove branch 2022-03-11 10:57:22 +00:00
cipso_ipv4.h
cls_cgroup.h
codel_impl.h codel: remove unnecessary sock.h include 2021-12-22 15:03:47 -08:00
codel_qdisc.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
codel.h codel: remove unnecessary pkt_sched.h include 2021-12-22 15:03:51 -08:00
compat.h net: copy from user before calling __get_compat_msghdr 2022-07-24 18:39:17 -06:00
datalink.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
dcbevent.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
dcbnl.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
devlink.h devlink: introduce framework for selftests 2022-07-28 21:56:53 -07:00
dn_dev.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
dn_fib.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
dn_neigh.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
dn_nsp.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
dn_route.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
dn.h decnet: constify dev_addr passing 2021-10-13 09:40:46 -07:00
dropreason.h net: skb: export skb drop reaons to user by TRACE_DEFINE_ENUM 2022-09-07 15:28:08 +01:00
dsa.h net: dsa: tag_ksz: add tag handling for Microchip LAN937x 2022-07-02 16:34:05 +01:00
dsfield.h
dst_cache.h wireguard: device: reset peer src endpoint when netns exits 2021-11-29 19:50:45 -08:00
dst_metadata.h net: fix a memleak when uncloning an skb dst and its metadata 2022-02-09 11:41:47 +00:00
dst_ops.h
dst.h net: dst: add net device refcount tracking to dst_entry 2021-12-06 16:05:10 -08:00
erspan.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
esp.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
espintcp.h
ethoc.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
failover.h net: failover: add net device refcount tracker 2021-12-06 16:06:02 -08:00
fib_notifier.h
fib_rules.h fib: expand fib_rule_policy 2021-12-16 07:18:35 -08:00
firewire.h firewire: net: Make use of get_unaligned_be48(), put_unaligned_be48() 2022-07-28 22:21:54 -07:00
flow_dissector.h flow_dissector: Add PPPoE dissectors 2022-07-26 09:49:12 -07:00
flow_offload.h flow_offload: Introduce flow_match_pppoe 2022-07-26 10:49:27 -07:00
flow.h net: Add l3mdev index to flow struct and avoid oif reset for port devices 2022-03-15 20:20:02 -07:00
fou.h
fq_impl.h net/fq_impl: Use the bitmap API to allocate bitmaps 2022-07-11 19:49:38 -07:00
fq.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
garp.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
gen_stats.h net: sched: Remove Qdisc::running sequence counter 2021-10-18 12:54:41 +01:00
genetlink.h net: add missing kdoc for struct genl_multicast_group::flags 2022-08-11 09:26:04 -07:00
geneve.h
gre.h ip_gre: add csum offload support for gre header 2021-01-29 20:39:14 -08:00
gro_cells.h
gro.h net: Fix a data-race around gro_normal_batch. 2022-08-24 13:46:58 +01:00
gtp.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
gue.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
hwbm.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
icmp.h ipv6: ICMPV6: add response to ICMPV6 RFC 8335 PROBE messages 2021-06-28 14:29:45 -07:00
ieee80211_radiotap.h ieee80211: radiotap: fix -Wcast-qual warnings 2022-02-04 16:25:21 +01:00
ieee802154_netdev.h net/ieee802154: fix uninit value bug in dgram_sendmsg 2022-09-16 10:53:55 +01:00
if_inet6.h ipv6: fix locking issues with loops over idev->addr_list 2022-04-06 22:09:39 -07:00
ife.h
ila.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
inet6_connection_sock.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
inet6_hashtables.h net: allow unbound socket for packets in VRF when tcp_l3mdev_accept set 2022-07-29 11:58:54 +01:00
inet_common.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
inet_connection_sock.h Revert "tcp: change pingpong threshold to 3" 2022-07-22 15:09:10 -07:00
inet_dscp.h ipv6: Define dscp_t and stop taking ECN bits into account in fib6-rules 2022-02-07 20:12:45 -08:00
inet_ecn.h net: add skb_get_dsfield() helper 2021-10-15 11:33:08 +01:00
inet_frag.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
inet_hashtables.h net: allow unbound socket for packets in VRF when tcp_l3mdev_accept set 2022-07-29 11:58:54 +01:00
inet_sock.h net: allow unbound socket for packets in VRF when tcp_l3mdev_accept set 2022-07-29 11:58:54 +01:00
inet_timewait_sock.h Revert "tcp/dccp: get rid of inet_twsk_purge()" 2022-05-13 12:24:12 +01:00
inetpeer.h
ioam6.h treewide: Replace zero-length arrays with flexible-array members 2022-02-17 07:00:39 -06:00
ip6_checksum.h net: move gro definitions to include/net/gro.h 2021-11-16 13:16:54 +00:00
ip6_fib.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-02-17 11:44:20 -08:00
ip6_route.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
ip6_tunnel.h ip_gre, ip6_gre: Fix race condition on o_seqno in collect_md mode 2022-04-25 11:40:45 +01:00
ip_fib.h ipv4: Use dscp_t in struct fib_entry_notifier_info 2022-04-11 17:37:50 -07:00
ip_tunnels.h ip_tunnel: Respect tunnel key's "flow_flags" in IP tunnels 2022-08-18 21:18:28 +02:00
ip_vs.h ipvs: add sysctl_run_estimation to support disable estimation 2021-10-07 19:52:58 +02:00
ip.h ip: Fix data-races around sysctl_ip_prot_sock. 2022-07-20 10:14:49 +01:00
ipcomp.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
ipconfig.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
ipv6_frag.h net: don't include ndisc.h from ipv6.h 2022-02-04 14:15:11 -08:00
ipv6_stubs.h net: ipv6: add fib6_nh_release_dsts stub 2021-11-22 15:44:49 +00:00
ipv6.h ipv6: Fix signed integer overflow in __ip6_append_data 2022-06-08 10:56:43 -07:00
iw_handler.h
kcm.h
l3mdev.h
lag.h
lapb.h net: lapb: Make "lapb_t1timer_running" able to detect an already running timer 2021-03-23 14:14:50 -07:00
lib80211.h
llc_c_ac.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
llc_c_ev.h
llc_c_st.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
llc_conn.h llc: add net device refcount tracker 2021-12-07 20:44:59 -08:00
llc_if.h llc/snap: constify dev_addr passing 2021-10-13 09:40:46 -07:00
llc_pdu.h net: llc: fix skb_over_panic 2021-07-27 13:05:56 +01:00
llc_s_ac.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
llc_s_ev.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
llc_s_st.h add missing includes and forward declarations to networking includes under linux/ 2022-07-28 11:29:36 +02:00
llc_sap.h
llc.h llc: fix out-of-bound array index in llc_sk_dev_hash() 2021-11-07 19:25:29 +00:00
lwtunnel.h netfilter: add netfilter hooks to SRv6 data plane 2021-08-30 01:51:36 +02:00
mac80211.h wifi: mac80211: add macros to loop over active links 2022-07-22 14:28:47 +02:00
mac802154.h net: mac802154: Create an error helper for asynchronous offloading errors 2022-04-25 20:51:12 +02:00
macsec.h net: macsec: fix the length used to copy the key for offloading 2021-06-24 12:41:12 -07:00
mctp.h mctp: Use output netdev to allocate skb headroom 2022-04-01 12:04:15 +01:00
mctpdevice.h mctp: Pass flow data & flow release events to drivers 2021-10-29 13:23:51 +01:00
mip6.h
mld.h mld: add new workqueues for process mld events 2021-03-26 15:14:56 -07:00
mpls_iptunnel.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
mpls.h
mptcp.h mptcp, btf: Add struct mptcp_sock definition when CONFIG_MPTCP is disabled 2022-08-08 15:30:45 +02:00
mrp.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
ncsi.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
ndisc.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-03-03 11:55:12 -08:00
neighbour.h neighbour: make proxy_queue.qlen limit per-device 2022-08-15 11:25:09 +01:00
net_debug.h net: add CONFIG_DEBUG_NET 2022-05-11 12:43:10 +01:00
net_failover.h
net_namespace.h netfilter: nf_flow_table: count pending offload workqueue tasks 2022-07-11 16:25:14 +02:00
net_ratelimit.h
net_trackers.h net: add networking namespace refcount tracker 2021-12-10 06:38:26 -08:00
netevent.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
netlabel.h
netlink.h net: netlink: add the case when nlh is NULL 2021-07-27 11:43:50 +01:00
netprio_cgroup.h
netrom.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
nexthop.h net: ipv4: Fix rtnexthop len when RTA_FLOW is present 2021-09-24 14:07:10 +01:00
nl802154.h net: ieee802154: handle iftypes as u32 2021-11-16 18:02:46 +01:00
nsh.h
p8022.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
page_pool.h net: page_pool: introduce ethtool stats 2022-04-15 10:43:47 +01:00
pie.h
ping.h net: remove noblock parameter from recvmsg() entities 2022-04-12 15:00:25 +02:00
pkt_cls.h net/sched: remove return value of unregister_tcf_proto_ops 2022-07-13 14:46:59 +01:00
pkt_sched.h net: sched: provide shim definitions for taprio_offload_{get,free} 2022-07-05 17:50:38 -07:00
pptp.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
protocol.h tcp/udp: Make early_demux back namespacified. 2022-07-15 18:50:35 -07:00
psample.h psample: Add a fwd declaration for skbuff 2021-08-09 15:34:21 -07:00
psnap.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
raw.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-07-14 15:27:35 -07:00
rawv6.h raw: convert raw sockets to RCU 2022-06-19 10:00:02 +01:00
red.h sch_red: fix off-by-one checks in red_check_params() 2021-03-25 17:40:43 -07:00
regulatory.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
request_sock.h tcp: Use BPF timeout setting for SYN ACK RTO 2022-02-02 14:45:18 +00:00
rose.h net: rose: add netdev ref tracker to 'struct rose_sock' 2022-08-01 11:59:23 -07:00
route.h Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next 2022-07-25 13:25:39 +01:00
rpl.h
rsi_91x.h
rtnetlink.h net: rtnetlink: add bulk delete support flag 2022-04-13 12:46:26 +01:00
rtnh.h
sch_generic.h net/sched: remove qdisc_root_lock() helper 2022-07-19 17:14:55 -07:00
scm.h
secure_seq.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
seg6_hmac.h
seg6_local.h
seg6.h udp6: Use Segment Routing Header for dest address if present 2022-01-04 12:17:35 +00:00
selftests.h net: selftest: fix build issue if INET is disabled 2021-04-28 14:06:45 -07:00
slhc_vj.h
smc.h net/smc: Pass on DMBE bit mask in IRQ handler 2022-07-27 13:24:42 +01:00
snmp.h
sock_reuseport.h tcp: Add reuseport_migrate_sock() to select a new listener. 2021-06-15 18:01:05 +02:00
sock.h net: Fix suspicious RCU usage in bpf_sk_reuseport_detach() 2022-08-17 16:42:59 -07:00
Space.h wan: remove sbni/granch driver 2021-08-03 13:05:26 +01:00
stp.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
strparser.h tls: rx: remove the message decrypted tracking 2022-07-18 11:24:10 +01:00
switchdev.h net: switchdev: add reminder near struct switchdev_notifier_fdb_info 2022-06-29 20:37:36 -07:00
tcp_states.h
tcp.h tcp: fix tcp_cwnd_validate() to not forget is_cwnd_limited 2022-09-30 12:37:45 +01:00
timewait_sock.h
tipc.h
tls_toe.h
tls.h net/tls: Use RCU API to access tls_ctx->netdev 2022-08-10 22:58:43 -07:00
transp_v6.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
tso.h
tun_proto.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
udp_tunnel.h rxrpc: Fix ICMP/ICMP6 error handling 2022-09-01 11:42:12 +01:00
udp.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-07-21 13:03:39 -07:00
udplite.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
vsock_addr.h
vxlan.h drivers: vxlan: vnifilter: per vni stats 2022-03-01 08:38:02 +00:00
wext.h
x25.h
x25device.h
xdp_priv.h net: add missing includes and forward declarations under net/ 2022-07-22 12:53:22 +01:00
xdp_sock_drv.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-08-03 09:04:55 +02:00
xdp_sock.h net: Don't include filter.h from net/sock.h 2021-12-29 08:48:14 -08:00
xdp.h net: veth: Account total xdp_frame len running ndo_xdp_xmit 2022-03-17 20:33:52 +01:00
xfrm.h Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next 2022-07-25 13:25:39 +01:00
xsk_buff_pool.h xsk: Fix possible crash when multiple sockets are created 2022-04-26 16:19:54 +02:00