Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / net / ipv4 / tcp_scalable.c

diff --git a/kernel/net/ipv4/tcp_scalable.c b/kernel/net/ipv4/tcp_scalable.c
new file mode 100644 (file)
index 0000000..333bcb2
--- /dev/null
+++ b/kernel/net/ipv4/tcp_scalable.c
@@ -0,0 +1,62 @@
+/* Tom Kelly's Scalable TCP
+ *
+ * See http://www.deneholme.net/tom/scalable/
+ *
+ * John Heffner <jheffner@sc.edu>
+ */
+
+#include <linux/module.h>
+#include <net/tcp.h>
+
+/* These factors derived from the recommended values in the aer:
+ * .01 and and 7/8. We use 50 instead of 100 to account for
+ * delayed ack.
+ */
+#define TCP_SCALABLE_AI_CNT    50U
+#define TCP_SCALABLE_MD_SCALE  3
+
+static void tcp_scalable_cong_avoid(struct sock *sk, u32 ack, u32 acked)
+{
+       struct tcp_sock *tp = tcp_sk(sk);
+
+       if (!tcp_is_cwnd_limited(sk))
+               return;
+
+       if (tp->snd_cwnd <= tp->snd_ssthresh)
+               tcp_slow_start(tp, acked);
+       else
+               tcp_cong_avoid_ai(tp, min(tp->snd_cwnd, TCP_SCALABLE_AI_CNT),
+                                 1);
+}
+
+static u32 tcp_scalable_ssthresh(struct sock *sk)
+{
+       const struct tcp_sock *tp = tcp_sk(sk);
+
+       return max(tp->snd_cwnd - (tp->snd_cwnd>>TCP_SCALABLE_MD_SCALE), 2U);
+}
+
+static struct tcp_congestion_ops tcp_scalable __read_mostly = {
+       .ssthresh       = tcp_scalable_ssthresh,
+       .cong_avoid     = tcp_scalable_cong_avoid,
+
+       .owner          = THIS_MODULE,
+       .name           = "scalable",
+};
+
+static int __init tcp_scalable_register(void)
+{
+       return tcp_register_congestion_control(&tcp_scalable);
+}
+
+static void __exit tcp_scalable_unregister(void)
+{
+       tcp_unregister_congestion_control(&tcp_scalable);
+}
+
+module_init(tcp_scalable_register);
+module_exit(tcp_scalable_unregister);
+
+MODULE_AUTHOR("John Heffner");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Scalable TCP");