2024-12-10 00:17:37 +03:00
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From 024469ad0aec82573e1aa8f3dde55aeac4c35aee Mon Sep 17 00:00:00 2001
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2024-10-29 05:12:06 +03:00
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From: Jianfeng Wang <jfwang@google.com>
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Date: Tue, 16 Jun 2020 17:41:19 +0000
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Subject: [PATCH 13/19] net-tcp_bbr: v2: inform CC module of losses repaired by
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TLP probe
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Before this commit, when there is a packet loss that creates a sequence
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hole that is filled by a TLP loss probe, then tcp_process_tlp_ack()
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only informs the congestion control (CC) module via a back-to-back entry
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and exit of CWR. But some congestion control modules (e.g. BBR) do not
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respond to CWR events.
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This commit adds a new CA event with which the core TCP stack notifies
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the CC module when a loss is repaired by a TLP. This will allow CC
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modules that do not use the CWR mechanism to have a custom handler for
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such TLP recoveries.
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Effort: net-tcp_bbr
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Change-Id: Ieba72332b401b329bff5a641d2b2043a3fb8f632
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Signed-off-by: Alexandre Frade <kernel@xanmod.org>
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---
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include/net/tcp.h | 1 +
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net/ipv4/tcp_input.c | 1 +
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2 files changed, 2 insertions(+)
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--- a/include/net/tcp.h
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+++ b/include/net/tcp.h
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2024-12-10 00:17:37 +03:00
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@@ -1098,6 +1098,7 @@ enum tcp_ca_event {
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2024-10-29 05:12:06 +03:00
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CA_EVENT_LOSS, /* loss timeout */
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CA_EVENT_ECN_NO_CE, /* ECT set, but not CE marked */
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CA_EVENT_ECN_IS_CE, /* received CE marked IP packet */
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+ CA_EVENT_TLP_RECOVERY, /* a lost segment was repaired by TLP probe */
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};
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/* Information about inbound ACK, passed to cong_ops->in_ack_event() */
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--- a/net/ipv4/tcp_input.c
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+++ b/net/ipv4/tcp_input.c
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@@ -3859,6 +3859,7 @@ static void tcp_process_tlp_ack(struct s
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/* ACK advances: there was a loss, so reduce cwnd. Reset
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* tlp_high_seq in tcp_init_cwnd_reduction()
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*/
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+ tcp_ca_event(sk, CA_EVENT_TLP_RECOVERY);
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tcp_init_cwnd_reduction(sk);
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tcp_set_ca_state(sk, TCP_CA_CWR);
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tcp_end_cwnd_reduction(sk);
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