From ea08eeccae9297f7aabd2ef7f0c2517ac4549acc Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:18:26 +0000
Subject: [PATCH] write in 30M
---
kernel/net/ipv4/tcp_input.c | 32 +++++++++++++++++++++++++-------
1 files changed, 25 insertions(+), 7 deletions(-)
diff --git a/kernel/net/ipv4/tcp_input.c b/kernel/net/ipv4/tcp_input.c
index 4a3926c..46836e4 100644
--- a/kernel/net/ipv4/tcp_input.c
+++ b/kernel/net/ipv4/tcp_input.c
@@ -243,6 +243,19 @@
if (unlikely(len > icsk->icsk_ack.rcv_mss +
MAX_TCP_OPTION_SPACE))
tcp_gro_dev_warn(sk, skb, len);
+ /* If the skb has a len of exactly 1*MSS and has the PSH bit
+ * set then it is likely the end of an application write. So
+ * more data may not be arriving soon, and yet the data sender
+ * may be waiting for an ACK if cwnd-bound or using TX zero
+ * copy. So we set ICSK_ACK_PUSHED here so that
+ * tcp_cleanup_rbuf() will send an ACK immediately if the app
+ * reads all of the data and is not ping-pong. If len > MSS
+ * then this logic does not matter (and does not hurt) because
+ * tcp_cleanup_rbuf() will always ACK immediately if the app
+ * reads data and there is more than an MSS of unACKed data.
+ */
+ if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_PSH)
+ icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
} else {
/* Otherwise, we make more careful check taking into account,
* that SACKs block is variable.
@@ -287,7 +300,7 @@
icsk->icsk_ack.quick = quickacks;
}
-void tcp_enter_quickack_mode(struct sock *sk, unsigned int max_quickacks)
+static void tcp_enter_quickack_mode(struct sock *sk, unsigned int max_quickacks)
{
struct inet_connection_sock *icsk = inet_csk(sk);
@@ -295,7 +308,6 @@
inet_csk_exit_pingpong_mode(sk);
icsk->icsk_ack.ato = TCP_ATO_MIN;
}
-EXPORT_SYMBOL(tcp_enter_quickack_mode);
/* Send ACKs quickly, if "quick" count is not exhausted
* and the session is not interactive.
@@ -3561,8 +3573,11 @@
static bool __tcp_oow_rate_limited(struct net *net, int mib_idx,
u32 *last_oow_ack_time)
{
- if (*last_oow_ack_time) {
- s32 elapsed = (s32)(tcp_jiffies32 - *last_oow_ack_time);
+ /* Paired with the WRITE_ONCE() in this function. */
+ u32 val = READ_ONCE(*last_oow_ack_time);
+
+ if (val) {
+ s32 elapsed = (s32)(tcp_jiffies32 - val);
if (0 <= elapsed &&
elapsed < READ_ONCE(net->ipv4.sysctl_tcp_invalid_ratelimit)) {
@@ -3571,7 +3586,10 @@
}
}
- *last_oow_ack_time = tcp_jiffies32;
+ /* Paired with the prior READ_ONCE() and with itself,
+ * as we might be lockless.
+ */
+ WRITE_ONCE(*last_oow_ack_time, tcp_jiffies32);
return false; /* not rate-limited: go ahead, send dupack now! */
}
@@ -4324,7 +4342,7 @@
inet_csk_schedule_ack(sk);
- sk->sk_shutdown |= RCV_SHUTDOWN;
+ WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | RCV_SHUTDOWN);
sock_set_flag(sk, SOCK_DONE);
switch (sk->sk_state) {
@@ -6506,7 +6524,7 @@
break;
tcp_set_state(sk, TCP_FIN_WAIT2);
- sk->sk_shutdown |= SEND_SHUTDOWN;
+ WRITE_ONCE(sk->sk_shutdown, sk->sk_shutdown | SEND_SHUTDOWN);
sk_dst_confirm(sk);
--
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