[PATCH] tcp: documents timewait refcnt tricks
[safe/jmp/linux-2.6] / net / ipv4 / tcp_yeah.c
index 81ef02c..a0f2403 100644 (file)
@@ -6,13 +6,14 @@
  *    http://wil.cs.caltech.edu/pfldnet2007/paper/YeAH_TCP.pdf
  *
  */
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/inet_diag.h>
 
-#include "tcp_yeah.h"
+#include <net/tcp.h>
 
-/* Default values of the Vegas variables, in fixed-point representation
- * with V_PARAM_SHIFT bits to the right of the binary point.
- */
-#define V_PARAM_SHIFT 1
+#include "tcp_vegas.h"
 
 #define TCP_YEAH_ALPHA       80 //lin number of packets queued at the bottleneck
 #define TCP_YEAH_GAMMA        1 //lin fraction of queue to be removed per rtt
 
 /* YeAH variables */
 struct yeah {
-       /* Vegas */
-       u32     beg_snd_nxt;    /* right edge during last RTT */
-       u32     beg_snd_una;    /* left edge  during last RTT */
-       u32     beg_snd_cwnd;   /* saves the size of the cwnd */
-       u8      doing_vegas_now;/* if true, do vegas for this RTT */
-       u16     cntRTT;         /* # of RTTs measured within last RTT */
-       u32     minRTT;         /* min of RTTs measured within last RTT (in usec) */
-       u32     baseRTT;        /* the min of all Vegas RTT measurements seen (in usec) */
+       struct vegas vegas;     /* must be first */
 
        /* YeAH */
        u32 lastQ;
@@ -64,7 +58,7 @@ static void tcp_yeah_init(struct sock *sk)
 }
 
 
-static void tcp_yeah_pkts_acked(struct sock *sk, u32 pkts_acked, ktime_t last)
+static void tcp_yeah_pkts_acked(struct sock *sk, u32 pkts_acked, s32 rtt_us)
 {
        const struct inet_connection_sock *icsk = inet_csk(sk);
        struct yeah *yeah = inet_csk_ca(sk);
@@ -72,11 +66,10 @@ static void tcp_yeah_pkts_acked(struct sock *sk, u32 pkts_acked, ktime_t last)
        if (icsk->icsk_ca_state == TCP_CA_Open)
                yeah->pkts_acked = pkts_acked;
 
-       tcp_vegas_pkts_acked(sk, pkts_acked, last);
+       tcp_vegas_pkts_acked(sk, pkts_acked, rtt_us);
 }
 
-static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack,
-                               u32 seq_rtt, u32 in_flight, int flag)
+static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack, u32 in_flight)
 {
        struct tcp_sock *tp = tcp_sk(sk);
        struct yeah *yeah = inet_csk_ca(sk);
@@ -84,12 +77,13 @@ static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack,
        if (!tcp_is_cwnd_limited(sk, in_flight))
                return;
 
-       if (tp->snd_cwnd <= tp->snd_ssthresh) {
+       if (tp->snd_cwnd <= tp->snd_ssthresh)
                tcp_slow_start(tp);
-       } else if (!yeah->doing_reno_now) {
+
+       else if (!yeah->doing_reno_now) {
                /* Scalable */
 
-               tp->snd_cwnd_cnt+=yeah->pkts_acked;
+               tp->snd_cwnd_cnt += yeah->pkts_acked;
                if (tp->snd_cwnd_cnt > min(tp->snd_cwnd, TCP_SCALABLE_AI_CNT)){
                        if (tp->snd_cwnd < tp->snd_cwnd_clamp)
                                tp->snd_cwnd++;
@@ -100,29 +94,22 @@ static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack,
 
        } else {
                /* Reno */
-
-               if (tp->snd_cwnd_cnt < tp->snd_cwnd)
-                       tp->snd_cwnd_cnt++;
-
-               if (tp->snd_cwnd_cnt >= tp->snd_cwnd) {
-                       tp->snd_cwnd++;
-                       tp->snd_cwnd_cnt = 0;
-               }
+               tcp_cong_avoid_ai(tp, tp->snd_cwnd);
        }
 
-       /* The key players are v_beg_snd_una and v_beg_snd_nxt.
+       /* The key players are v_vegas.beg_snd_una and v_beg_snd_nxt.
         *
         * These are so named because they represent the approximate values
         * of snd_una and snd_nxt at the beginning of the current RTT. More
         * precisely, they represent the amount of data sent during the RTT.
         * At the end of the RTT, when we receive an ACK for v_beg_snd_nxt,
-        * we will calculate that (v_beg_snd_nxt - v_beg_snd_una) outstanding
+        * we will calculate that (v_beg_snd_nxt - v_vegas.beg_snd_una) outstanding
         * bytes of data have been ACKed during the course of the RTT, giving
         * an "actual" rate of:
         *
-        *     (v_beg_snd_nxt - v_beg_snd_una) / (rtt duration)
+        *     (v_beg_snd_nxt - v_vegas.beg_snd_una) / (rtt duration)
         *
-        * Unfortunately, v_beg_snd_una is not exactly equal to snd_una,
+        * Unfortunately, v_vegas.beg_snd_una is not exactly equal to snd_una,
         * because delayed ACKs can cover more than one segment, so they
         * don't line up yeahly with the boundaries of RTTs.
         *
@@ -132,7 +119,7 @@ static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack,
         * So we keep track of our cwnd separately, in v_beg_snd_cwnd.
         */
 
-       if (after(ack, yeah->beg_snd_nxt)) {
+       if (after(ack, yeah->vegas.beg_snd_nxt)) {
 
                /* We do the Vegas calculations only if we got enough RTT
                 * samples that we can be reasonably sure that we got
@@ -143,7 +130,7 @@ static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack,
                 * If  we have 3 samples, we should be OK.
                 */
 
-               if (yeah->cntRTT > 2) {
+               if (yeah->vegas.cntRTT > 2) {
                        u32 rtt, queue;
                        u64 bw;
 
@@ -158,20 +145,20 @@ static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack,
                         * of delayed ACKs, at the cost of noticing congestion
                         * a bit later.
                         */
-                       rtt = yeah->minRTT;
+                       rtt = yeah->vegas.minRTT;
 
                        /* Compute excess number of packets above bandwidth
                         * Avoid doing full 64 bit divide.
                         */
                        bw = tp->snd_cwnd;
-                       bw *= rtt - yeah->baseRTT;
+                       bw *= rtt - yeah->vegas.baseRTT;
                        do_div(bw, rtt);
                        queue = bw;
 
                        if (queue > TCP_YEAH_ALPHA ||
-                           rtt - yeah->baseRTT > (yeah->baseRTT / TCP_YEAH_PHY)) {
-                               if (queue > TCP_YEAH_ALPHA
-                                   && tp->snd_cwnd > yeah->reno_count) {
+                           rtt - yeah->vegas.baseRTT > (yeah->vegas.baseRTT / TCP_YEAH_PHY)) {
+                               if (queue > TCP_YEAH_ALPHA &&
+                                   tp->snd_cwnd > yeah->reno_count) {
                                        u32 reduction = min(queue / TCP_YEAH_GAMMA ,
                                                            tp->snd_cwnd >> TCP_YEAH_EPSILON);
 
@@ -208,13 +195,13 @@ static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack,
                /* Save the extent of the current window so we can use this
                 * at the end of the next RTT.
                 */
-               yeah->beg_snd_una  = yeah->beg_snd_nxt;
-               yeah->beg_snd_nxt  = tp->snd_nxt;
-               yeah->beg_snd_cwnd = tp->snd_cwnd;
+               yeah->vegas.beg_snd_una  = yeah->vegas.beg_snd_nxt;
+               yeah->vegas.beg_snd_nxt  = tp->snd_nxt;
+               yeah->vegas.beg_snd_cwnd = tp->snd_cwnd;
 
                /* Wipe the slate clean for the next RTT. */
-               yeah->cntRTT = 0;
-               yeah->minRTT = 0x7fffffff;
+               yeah->vegas.cntRTT = 0;
+               yeah->vegas.minRTT = 0x7fffffff;
        }
 }
 
@@ -230,7 +217,7 @@ static u32 tcp_yeah_ssthresh(struct sock *sk) {
 
                reduction = max( reduction, tp->snd_cwnd >> TCP_YEAH_DELTA);
        } else
-               reduction = max(tp->snd_cwnd>>1,2U);
+               reduction = max(tp->snd_cwnd>>1, 2U);
 
        yeah->fast_count = 0;
        yeah->reno_count = max(yeah->reno_count>>1, 2U);