forked from mirrors/linux
f1722a1be1
Most TCP congestion controls are using identical logic to undo cwnd except BBR. This patch consolidates these similar functions to the one used currently by Reno and others. Suggested-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
63 lines
1.4 KiB
C
63 lines
1.4 KiB
C
/* Tom Kelly's Scalable TCP
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*
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* See http://www.deneholme.net/tom/scalable/
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*
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* John Heffner <jheffner@sc.edu>
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*/
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#include <linux/module.h>
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#include <net/tcp.h>
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/* These factors derived from the recommended values in the aer:
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* .01 and and 7/8. We use 50 instead of 100 to account for
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* delayed ack.
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*/
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#define TCP_SCALABLE_AI_CNT 50U
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#define TCP_SCALABLE_MD_SCALE 3
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static void tcp_scalable_cong_avoid(struct sock *sk, u32 ack, u32 acked)
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{
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struct tcp_sock *tp = tcp_sk(sk);
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if (!tcp_is_cwnd_limited(sk))
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return;
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if (tcp_in_slow_start(tp))
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tcp_slow_start(tp, acked);
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else
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tcp_cong_avoid_ai(tp, min(tp->snd_cwnd, TCP_SCALABLE_AI_CNT),
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1);
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}
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static u32 tcp_scalable_ssthresh(struct sock *sk)
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{
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const struct tcp_sock *tp = tcp_sk(sk);
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return max(tp->snd_cwnd - (tp->snd_cwnd>>TCP_SCALABLE_MD_SCALE), 2U);
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}
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static struct tcp_congestion_ops tcp_scalable __read_mostly = {
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.ssthresh = tcp_scalable_ssthresh,
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.undo_cwnd = tcp_reno_undo_cwnd,
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.cong_avoid = tcp_scalable_cong_avoid,
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.owner = THIS_MODULE,
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.name = "scalable",
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};
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static int __init tcp_scalable_register(void)
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{
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return tcp_register_congestion_control(&tcp_scalable);
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}
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static void __exit tcp_scalable_unregister(void)
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{
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tcp_unregister_congestion_control(&tcp_scalable);
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}
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module_init(tcp_scalable_register);
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module_exit(tcp_scalable_unregister);
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MODULE_AUTHOR("John Heffner");
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Scalable TCP");
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