Add the rt linux 4.1.3-rt3 as base

Import the rt linux 4.1.3-rt3 as OPNFV kvm base.

It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:

commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date:   Sat Jul 25 12:13:34 2015 +0200

    Prepare v4.1.3-rt3

    Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.

Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>

1 files changed, 185 insertions, 0 deletions

diff --git a/kernel/net/ipv4/tcp_highspeed.c b/kernel/net/ipv4/tcp_highspeed.c
new file mode 100644
index 000000000..882c08aae
--- /dev/null
+++ b/kernel/net/ipv4/tcp_highspeed.c
@@ -0,0 +1,185 @@
+/*
+ * Sally Floyd's High Speed TCP (RFC 3649) congestion control
+ *
+ * See http://www.icir.org/floyd/hstcp.html
+ *
+ * John Heffner <jheffner@psc.edu>
+ */
+
+#include <linux/module.h>
+#include <net/tcp.h>
+
+/* From AIMD tables from RFC 3649 appendix B,
+ * with fixed-point MD scaled <<8.
+ */
+static const struct hstcp_aimd_val {
+	unsigned int cwnd;
+	unsigned int md;
+} hstcp_aimd_vals[] = {
+	{     38,  128, /*  0.50 */ },
+	{    118,  112, /*  0.44 */ },
+	{    221,  104, /*  0.41 */ },
+	{    347,   98, /*  0.38 */ },
+	{    495,   93, /*  0.37 */ },
+	{    663,   89, /*  0.35 */ },
+	{    851,   86, /*  0.34 */ },
+	{   1058,   83, /*  0.33 */ },
+	{   1284,   81, /*  0.32 */ },
+	{   1529,   78, /*  0.31 */ },
+	{   1793,   76, /*  0.30 */ },
+	{   2076,   74, /*  0.29 */ },
+	{   2378,   72, /*  0.28 */ },
+	{   2699,   71, /*  0.28 */ },
+	{   3039,   69, /*  0.27 */ },
+	{   3399,   68, /*  0.27 */ },
+	{   3778,   66, /*  0.26 */ },
+	{   4177,   65, /*  0.26 */ },
+	{   4596,   64, /*  0.25 */ },
+	{   5036,   62, /*  0.25 */ },
+	{   5497,   61, /*  0.24 */ },
+	{   5979,   60, /*  0.24 */ },
+	{   6483,   59, /*  0.23 */ },
+	{   7009,   58, /*  0.23 */ },
+	{   7558,   57, /*  0.22 */ },
+	{   8130,   56, /*  0.22 */ },
+	{   8726,   55, /*  0.22 */ },
+	{   9346,   54, /*  0.21 */ },
+	{   9991,   53, /*  0.21 */ },
+	{  10661,   52, /*  0.21 */ },
+	{  11358,   52, /*  0.20 */ },
+	{  12082,   51, /*  0.20 */ },
+	{  12834,   50, /*  0.20 */ },
+	{  13614,   49, /*  0.19 */ },
+	{  14424,   48, /*  0.19 */ },
+	{  15265,   48, /*  0.19 */ },
+	{  16137,   47, /*  0.19 */ },
+	{  17042,   46, /*  0.18 */ },
+	{  17981,   45, /*  0.18 */ },
+	{  18955,   45, /*  0.18 */ },
+	{  19965,   44, /*  0.17 */ },
+	{  21013,   43, /*  0.17 */ },
+	{  22101,   43, /*  0.17 */ },
+	{  23230,   42, /*  0.17 */ },
+	{  24402,   41, /*  0.16 */ },
+	{  25618,   41, /*  0.16 */ },
+	{  26881,   40, /*  0.16 */ },
+	{  28193,   39, /*  0.16 */ },
+	{  29557,   39, /*  0.15 */ },
+	{  30975,   38, /*  0.15 */ },
+	{  32450,   38, /*  0.15 */ },
+	{  33986,   37, /*  0.15 */ },
+	{  35586,   36, /*  0.14 */ },
+	{  37253,   36, /*  0.14 */ },
+	{  38992,   35, /*  0.14 */ },
+	{  40808,   35, /*  0.14 */ },
+	{  42707,   34, /*  0.13 */ },
+	{  44694,   33, /*  0.13 */ },
+	{  46776,   33, /*  0.13 */ },
+	{  48961,   32, /*  0.13 */ },
+	{  51258,   32, /*  0.13 */ },
+	{  53677,   31, /*  0.12 */ },
+	{  56230,   30, /*  0.12 */ },
+	{  58932,   30, /*  0.12 */ },
+	{  61799,   29, /*  0.12 */ },
+	{  64851,   28, /*  0.11 */ },
+	{  68113,   28, /*  0.11 */ },
+	{  71617,   27, /*  0.11 */ },
+	{  75401,   26, /*  0.10 */ },
+	{  79517,   26, /*  0.10 */ },
+	{  84035,   25, /*  0.10 */ },
+	{  89053,   24, /*  0.10 */ },
+};
+
+#define HSTCP_AIMD_MAX	ARRAY_SIZE(hstcp_aimd_vals)
+
+struct hstcp {
+	u32	ai;
+};
+
+static void hstcp_init(struct sock *sk)
+{
+	struct tcp_sock *tp = tcp_sk(sk);
+	struct hstcp *ca = inet_csk_ca(sk);
+
+	ca->ai = 0;
+
+	/* Ensure the MD arithmetic works.  This is somewhat pedantic,
+	 * since I don't think we will see a cwnd this large. :) */
+	tp->snd_cwnd_clamp = min_t(u32, tp->snd_cwnd_clamp, 0xffffffff/128);
+}
+
+static void hstcp_cong_avoid(struct sock *sk, u32 ack, u32 acked)
+{
+	struct tcp_sock *tp = tcp_sk(sk);
+	struct hstcp *ca = inet_csk_ca(sk);
+
+	if (!tcp_is_cwnd_limited(sk))
+		return;
+
+	if (tp->snd_cwnd <= tp->snd_ssthresh)
+		tcp_slow_start(tp, acked);
+	else {
+		/* Update AIMD parameters.
+		 *
+		 * We want to guarantee that:
+		 *     hstcp_aimd_vals[ca->ai-1].cwnd <
+		 *     snd_cwnd <=
+		 *     hstcp_aimd_vals[ca->ai].cwnd
+		 */
+		if (tp->snd_cwnd > hstcp_aimd_vals[ca->ai].cwnd) {
+			while (tp->snd_cwnd > hstcp_aimd_vals[ca->ai].cwnd &&
+			       ca->ai < HSTCP_AIMD_MAX - 1)
+				ca->ai++;
+		} else if (ca->ai && tp->snd_cwnd <= hstcp_aimd_vals[ca->ai-1].cwnd) {
+			while (ca->ai && tp->snd_cwnd <= hstcp_aimd_vals[ca->ai-1].cwnd)
+				ca->ai--;
+		}
+
+		/* Do additive increase */
+		if (tp->snd_cwnd < tp->snd_cwnd_clamp) {
+			/* cwnd = cwnd + a(w) / cwnd */
+			tp->snd_cwnd_cnt += ca->ai + 1;
+			if (tp->snd_cwnd_cnt >= tp->snd_cwnd) {
+				tp->snd_cwnd_cnt -= tp->snd_cwnd;
+				tp->snd_cwnd++;
+			}
+		}
+	}
+}
+
+static u32 hstcp_ssthresh(struct sock *sk)
+{
+	const struct tcp_sock *tp = tcp_sk(sk);
+	const struct hstcp *ca = inet_csk_ca(sk);
+
+	/* Do multiplicative decrease */
+	return max(tp->snd_cwnd - ((tp->snd_cwnd * hstcp_aimd_vals[ca->ai].md) >> 8), 2U);
+}
+
+
+static struct tcp_congestion_ops tcp_highspeed __read_mostly = {
+	.init		= hstcp_init,
+	.ssthresh	= hstcp_ssthresh,
+	.cong_avoid	= hstcp_cong_avoid,
+
+	.owner		= THIS_MODULE,
+	.name		= "highspeed"
+};
+
+static int __init hstcp_register(void)
+{
+	BUILD_BUG_ON(sizeof(struct hstcp) > ICSK_CA_PRIV_SIZE);
+	return tcp_register_congestion_control(&tcp_highspeed);
+}
+
+static void __exit hstcp_unregister(void)
+{
+	tcp_unregister_congestion_control(&tcp_highspeed);
+}
+
+module_init(hstcp_register);
+module_exit(hstcp_unregister);
+
+MODULE_AUTHOR("John Heffner");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("High Speed TCP");