[TCP]: Congestion control API update.

Do some simple changes to make congestion control API faster/cleaner.
* use ktime_t rather than timeval
* merge rtt sampling into existing ack callback
  this means one indirect call versus two per ack.
* use flags bits to store options/settings

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

15 files changed, 65 insertions, 55 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 50f6f6a094c..2694cb3ca76 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1569,6 +1569,11 @@ static inline void __net_timestamp(struct sk_buff *skb)
         skb->tstamp = ktime_get_real();
 }
 
+static inline ktime_t net_timedelta(ktime_t t)
+{
+        return ktime_sub(ktime_get_real(), t);
+}
+
 
 extern __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len);
 extern __sum16 __skb_checksum_complete(struct sk_buff *skb);
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 43910fe3c44..a385797f160 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -629,9 +629,12 @@ enum tcp_ca_event {
 #define TCP_CA_MAX      128
 #define TCP_CA_BUF_MAX  (TCP_CA_NAME_MAX*TCP_CA_MAX)
 
+#define TCP_CONG_NON_RESTRICTED 0x1
+#define TCP_CONG_RTT_STAMP      0x2
+
 struct tcp_congestion_ops {
         struct list_head        list;
-        int     non_restricted;
+        unsigned long flags;
 
         /* initialize private data (optional) */
         void (*init)(struct sock *sk);
@@ -645,8 +648,6 @@ struct tcp_congestion_ops {
         /* do new cwnd calculation (required) */
         void (*cong_avoid)(struct sock *sk, u32 ack,
                            u32 rtt, u32 in_flight, int good_ack);
-        /* round trip time sample per acked packet (optional) */
-        void (*rtt_sample)(struct sock *sk, u32 usrtt);
         /* call before changing ca_state (optional) */
         void (*set_state)(struct sock *sk, u8 new_state);
         /* call when cwnd event occurs (optional) */
@@ -654,7 +655,7 @@ struct tcp_congestion_ops {
         /* new value of cwnd after loss (optional) */
         u32  (*undo_cwnd)(struct sock *sk);
         /* hook for packet ack accounting (optional) */
-        void (*pkts_acked)(struct sock *sk, u32 num_acked);
+        void (*pkts_acked)(struct sock *sk, u32 num_acked, ktime_t last);
         /* get info for inet_diag (optional) */
         void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb);
 
diff --git a/net/ipv4/tcp_bic.c b/net/ipv4/tcp_bic.c
index 5730333cd0a..281c9f91325 100644
--- a/net/ipv4/tcp_bic.c
+++ b/net/ipv4/tcp_bic.c
@@ -206,7 +206,7 @@ static void bictcp_state(struct sock *sk, u8 new_state)
 /* Track delayed acknowledgment ratio using sliding window
  * ratio = (15*ratio + sample) / 16
  */
-static void bictcp_acked(struct sock *sk, u32 cnt)
+static void bictcp_acked(struct sock *sk, u32 cnt, ktime_t last)
 {
         const struct inet_connection_sock *icsk = inet_csk(sk);
 
diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index ccd88407e0c..86b26539e54 100644
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -126,7 +126,7 @@ int tcp_set_default_congestion_control(const char *name)
 #endif
 
         if (ca) {
-                ca->non_restricted = 1; /* default is always allowed */
+                ca->flags |= TCP_CONG_NON_RESTRICTED;   /* default is always allowed */
                 list_move(&ca->list, &tcp_cong_list);
                 ret = 0;
         }
@@ -181,7 +181,7 @@ void tcp_get_allowed_congestion_control(char *buf, size_t maxlen)
         *buf = '\0';
         rcu_read_lock();
         list_for_each_entry_rcu(ca, &tcp_cong_list, list) {
-                if (!ca->non_restricted)
+                if (!(ca->flags & TCP_CONG_NON_RESTRICTED))
                         continue;
                 offs += snprintf(buf + offs, maxlen - offs,
                                  "%s%s",
@@ -212,16 +212,16 @@ int tcp_set_allowed_congestion_control(char *val)
                 }
         }
 
-        /* pass 2 clear */
+        /* pass 2 clear old values */
         list_for_each_entry_rcu(ca, &tcp_cong_list, list)
-                ca->non_restricted = 0;
+                ca->flags &= ~TCP_CONG_NON_RESTRICTED;
 
         /* pass 3 mark as allowed */
         while ((name = strsep(&val, " ")) && *name) {
                 ca = tcp_ca_find(name);
                 WARN_ON(!ca);
                 if (ca)
-                        ca->non_restricted = 1;
+                        ca->flags |= TCP_CONG_NON_RESTRICTED;
         }
 out:
         spin_unlock(&tcp_cong_list_lock);
@@ -256,7 +256,7 @@ int tcp_set_congestion_control(struct sock *sk, const char *name)
         if (!ca)
                 err = -ENOENT;
 
-        else if (!(ca->non_restricted || capable(CAP_NET_ADMIN)))
+        else if (!((ca->flags & TCP_CONG_NON_RESTRICTED) || capable(CAP_NET_ADMIN)))
                 err = -EPERM;
 
         else if (!try_module_get(ca->owner))
@@ -371,8 +371,8 @@ u32 tcp_reno_min_cwnd(const struct sock *sk)
 EXPORT_SYMBOL_GPL(tcp_reno_min_cwnd);
 
 struct tcp_congestion_ops tcp_reno = {
+        .flags          = TCP_CONG_NON_RESTRICTED,
         .name           = "reno",
-        .non_restricted = 1,
         .owner          = THIS_MODULE,
         .ssthresh       = tcp_reno_ssthresh,
         .cong_avoid     = tcp_reno_cong_avoid,
diff --git a/net/ipv4/tcp_cubic.c b/net/ipv4/tcp_cubic.c
index 296845be912..14224487b16 100644
--- a/net/ipv4/tcp_cubic.c
+++ b/net/ipv4/tcp_cubic.c
@@ -334,7 +334,7 @@ static void bictcp_state(struct sock *sk, u8 new_state)
 /* Track delayed acknowledgment ratio using sliding window
  * ratio = (15*ratio + sample) / 16
  */
-static void bictcp_acked(struct sock *sk, u32 cnt)
+static void bictcp_acked(struct sock *sk, u32 cnt, ktime_t last)
 {
         const struct inet_connection_sock *icsk = inet_csk(sk);
 
diff --git a/net/ipv4/tcp_htcp.c b/net/ipv4/tcp_htcp.c
index 1020eb48d8d..4ba4a7ae0a8 100644
--- a/net/ipv4/tcp_htcp.c
+++ b/net/ipv4/tcp_htcp.c
@@ -98,7 +98,7 @@ static inline void measure_rtt(struct sock *sk)
         }
 }
 
-static void measure_achieved_throughput(struct sock *sk, u32 pkts_acked)
+static void measure_achieved_throughput(struct sock *sk, u32 pkts_acked, ktime_t last)
 {
         const struct inet_connection_sock *icsk = inet_csk(sk);
         const struct tcp_sock *tp = tcp_sk(sk);
diff --git a/net/ipv4/tcp_illinois.c b/net/ipv4/tcp_illinois.c
index ae629860088..8e3165917f7 100644
--- a/net/ipv4/tcp_illinois.c
+++ b/net/ipv4/tcp_illinois.c
@@ -83,9 +83,14 @@ static void tcp_illinois_init(struct sock *sk)
 }
 
 /* Measure RTT for each ack. */
-static void tcp_illinois_rtt_sample(struct sock *sk, u32 rtt)
+static void tcp_illinois_acked(struct sock *sk, u32 pkts_acked, ktime_t last)
 {
         struct illinois *ca = inet_csk_ca(sk);
+        u32 rtt;
+
+        ca->acked = pkts_acked;
+
+        rtt = ktime_to_ns(net_timedelta(last)) / NSEC_PER_USEC;
 
         /* ignore bogus values, this prevents wraparound in alpha math */
         if (rtt > RTT_MAX)
@@ -103,13 +108,6 @@ static void tcp_illinois_rtt_sample(struct sock *sk, u32 rtt)
         ca->sum_rtt += rtt;
 }
 
-/* Capture count of packets covered by ack, to adjust for delayed acks */
-static void tcp_illinois_acked(struct sock *sk, u32 pkts_acked)
-{
-        struct illinois *ca = inet_csk_ca(sk);
-        ca->acked = pkts_acked;
-}
-
 /* Maximum queuing delay */
 static inline u32 max_delay(const struct illinois *ca)
 {
@@ -325,12 +323,12 @@ static void tcp_illinois_info(struct sock *sk, u32 ext,
 }
 
 static struct tcp_congestion_ops tcp_illinois = {
+        .flags          = TCP_CONG_RTT_STAMP,
         .init           = tcp_illinois_init,
         .ssthresh       = tcp_illinois_ssthresh,
         .min_cwnd       = tcp_reno_min_cwnd,
         .cong_avoid     = tcp_illinois_cong_avoid,
         .set_state      = tcp_illinois_state,
-        .rtt_sample     = tcp_illinois_rtt_sample,
         .get_info       = tcp_illinois_info,
         .pkts_acked     = tcp_illinois_acked,
 
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 63338939078..051f0f815f1 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2402,14 +2402,6 @@ static int tcp_tso_acked(struct sock *sk, struct sk_buff *skb,
         return acked;
 }
 
-static u32 tcp_usrtt(struct timeval *tv)
-{
-        struct timeval now;
-
-        do_gettimeofday(&now);
-        return (now.tv_sec - tv->tv_sec) * 1000000 + (now.tv_usec - tv->tv_usec);
-}
-
 /* Remove acknowledged frames from the retransmission queue. */
 static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
 {
@@ -2420,9 +2412,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
         int acked = 0;
         __s32 seq_rtt = -1;
         u32 pkts_acked = 0;
-        void (*rtt_sample)(struct sock *sk, u32 usrtt)
-                = icsk->icsk_ca_ops->rtt_sample;
-        struct timeval tv = { .tv_sec = 0, .tv_usec = 0 };
+        ktime_t last_ackt = ktime_set(0,0);
 
         while ((skb = tcp_write_queue_head(sk)) &&
                skb != tcp_send_head(sk)) {
@@ -2471,7 +2461,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
                                 seq_rtt = -1;
                         } else if (seq_rtt < 0) {
                                 seq_rtt = now - scb->when;
-                                skb_get_timestamp(skb, &tv);
+                                last_ackt = skb->tstamp;
                         }
                         if (sacked & TCPCB_SACKED_ACKED)
                                 tp->sacked_out -= tcp_skb_pcount(skb);
@@ -2484,7 +2474,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
                         }
                 } else if (seq_rtt < 0) {
                         seq_rtt = now - scb->when;
-                        skb_get_timestamp(skb, &tv);
+                        last_ackt = skb->tstamp;
                 }
                 tcp_dec_pcount_approx(&tp->fackets_out, skb);
                 tcp_packets_out_dec(tp, skb);
@@ -2494,13 +2484,14 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
         }
 
         if (acked&FLAG_ACKED) {
+                const struct tcp_congestion_ops *ca_ops
+                        = inet_csk(sk)->icsk_ca_ops;
+
                 tcp_ack_update_rtt(sk, acked, seq_rtt);
                 tcp_ack_packets_out(sk);
-                if (rtt_sample && !(acked & FLAG_RETRANS_DATA_ACKED))
-                        (*rtt_sample)(sk, tcp_usrtt(&tv));
 
-                if (icsk->icsk_ca_ops->pkts_acked)
-                        icsk->icsk_ca_ops->pkts_acked(sk, pkts_acked);
+                if (ca_ops->pkts_acked)
+                        ca_ops->pkts_acked(sk, pkts_acked, last_ackt);
         }
 
 #if FASTRETRANS_DEBUG > 0
diff --git a/net/ipv4/tcp_lp.c b/net/ipv4/tcp_lp.c
index f0ebaf0e21c..b4e062ab24a 100644
--- a/net/ipv4/tcp_lp.c
+++ b/net/ipv4/tcp_lp.c
@@ -218,7 +218,7 @@ static u32 tcp_lp_owd_calculator(struct sock *sk)
  *   3. calc smoothed OWD (SOWD).
  * Most ideas come from the original TCP-LP implementation.
  */
-static void tcp_lp_rtt_sample(struct sock *sk, u32 usrtt)
+static void tcp_lp_rtt_sample(struct sock *sk, u32 rtt)
 {
         struct lp *lp = inet_csk_ca(sk);
         s64 mowd = tcp_lp_owd_calculator(sk);
@@ -261,11 +261,13 @@ static void tcp_lp_rtt_sample(struct sock *sk, u32 usrtt)
  * newReno in increase case.
  * We work it out by following the idea from TCP-LP's paper directly
  */
-static void tcp_lp_pkts_acked(struct sock *sk, u32 num_acked)
+static void tcp_lp_pkts_acked(struct sock *sk, u32 num_acked, ktime_t last)
 {
         struct tcp_sock *tp = tcp_sk(sk);
         struct lp *lp = inet_csk_ca(sk);
 
+        tcp_lp_rtt_sample(sk,  ktime_to_ns(net_timedelta(last)) / NSEC_PER_USEC);
+
         /* calc inference */
         if (tcp_time_stamp > tp->rx_opt.rcv_tsecr)
                 lp->inference = 3 * (tcp_time_stamp - tp->rx_opt.rcv_tsecr);
@@ -312,11 +314,11 @@ static void tcp_lp_pkts_acked(struct sock *sk, u32 num_acked)
 }
 
 static struct tcp_congestion_ops tcp_lp = {
+        .flags = TCP_CONG_RTT_STAMP,
         .init = tcp_lp_init,
         .ssthresh = tcp_reno_ssthresh,
         .cong_avoid = tcp_lp_cong_avoid,
         .min_cwnd = tcp_reno_min_cwnd,
-        .rtt_sample = tcp_lp_rtt_sample,
         .pkts_acked = tcp_lp_pkts_acked,
 
         .owner = THIS_MODULE,
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 3a60aea744a..e70a6840cb6 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -409,7 +409,7 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
         /* If congestion control is doing timestamping, we must
          * take such a timestamp before we potentially clone/copy.
          */
-        if (icsk->icsk_ca_ops->rtt_sample)
+        if (icsk->icsk_ca_ops->flags & TCP_CONG_RTT_STAMP)
                 __net_timestamp(skb);
 
         if (likely(clone_it)) {
diff --git a/net/ipv4/tcp_vegas.c b/net/ipv4/tcp_vegas.c
index 87e72bef6d0..f4104eeb5f2 100644
--- a/net/ipv4/tcp_vegas.c
+++ b/net/ipv4/tcp_vegas.c
@@ -120,10 +120,13 @@ static void tcp_vegas_init(struct sock *sk)
  *   o min-filter RTT samples from a much longer window (forever for now)
  *     to find the propagation delay (baseRTT)
  */
-static void tcp_vegas_rtt_calc(struct sock *sk, u32 usrtt)
+static void tcp_vegas_pkts_acked(struct sock *sk, u32 cnt, ktime_t last)
 {
         struct vegas *vegas = inet_csk_ca(sk);
-        u32 vrtt = usrtt + 1; /* Never allow zero rtt or baseRTT */
+        u32 vrtt;
+
+        /* Never allow zero rtt or baseRTT */
+        vrtt = (ktime_to_ns(net_timedelta(last)) / NSEC_PER_USEC) + 1;
 
         /* Filter to find propagation delay: */
         if (vrtt < vegas->baseRTT)
@@ -353,11 +356,12 @@ static void tcp_vegas_get_info(struct sock *sk, u32 ext,
 }
 
 static struct tcp_congestion_ops tcp_vegas = {
+        .flags          = TCP_CONG_RTT_STAMP,
         .init           = tcp_vegas_init,
         .ssthresh       = tcp_reno_ssthresh,
         .cong_avoid     = tcp_vegas_cong_avoid,
         .min_cwnd       = tcp_reno_min_cwnd,
-        .rtt_sample     = tcp_vegas_rtt_calc,
+        .pkts_acked     = tcp_vegas_pkts_acked,
         .set_state      = tcp_vegas_state,
         .cwnd_event     = tcp_vegas_cwnd_event,
         .get_info       = tcp_vegas_get_info,
diff --git a/net/ipv4/tcp_veno.c b/net/ipv4/tcp_veno.c
index ce57bf302f6..0b50d0607a0 100644
--- a/net/ipv4/tcp_veno.c
+++ b/net/ipv4/tcp_veno.c
@@ -69,10 +69,13 @@ static void tcp_veno_init(struct sock *sk)
 }
 
 /* Do rtt sampling needed for Veno. */
-static void tcp_veno_rtt_calc(struct sock *sk, u32 usrtt)
+static void tcp_veno_pkts_acked(struct sock *sk, u32 cnt, ktime_t last)
 {
         struct veno *veno = inet_csk_ca(sk);
-        u32 vrtt = usrtt + 1;   /* Never allow zero rtt or basertt */
+        u32 vrtt;
+
+        /* Never allow zero rtt or baseRTT */
+        vrtt = (ktime_to_ns(net_timedelta(last)) / NSEC_PER_USEC) + 1;
 
         /* Filter to find propagation delay: */
         if (vrtt < veno->basertt)
@@ -199,10 +202,11 @@ static u32 tcp_veno_ssthresh(struct sock *sk)
 }
 
 static struct tcp_congestion_ops tcp_veno = {
+        .flags          = TCP_CONG_RTT_STAMP,
         .init           = tcp_veno_init,
         .ssthresh       = tcp_veno_ssthresh,
         .cong_avoid     = tcp_veno_cong_avoid,
-        .rtt_sample     = tcp_veno_rtt_calc,
+        .pkts_acked     = tcp_veno_pkts_acked,
         .set_state      = tcp_veno_state,
         .cwnd_event     = tcp_veno_cwnd_event,
 
diff --git a/net/ipv4/tcp_westwood.c b/net/ipv4/tcp_westwood.c
index ae1026a6772..e61e09dd513 100644
--- a/net/ipv4/tcp_westwood.c
+++ b/net/ipv4/tcp_westwood.c
@@ -100,7 +100,7 @@ static void westwood_filter(struct westwood *w, u32 delta)
  * Called after processing group of packets.
  * but all westwood needs is the last sample of srtt.
  */
-static void tcp_westwood_pkts_acked(struct sock *sk, u32 cnt)
+static void tcp_westwood_pkts_acked(struct sock *sk, u32 cnt, ktime_t last)
 {
         struct westwood *w = inet_csk_ca(sk);
         if (cnt > 0)
diff --git a/net/ipv4/tcp_yeah.c b/net/ipv4/tcp_yeah.c
index 46dd1bee583..81ef02c1649 100644
--- a/net/ipv4/tcp_yeah.c
+++ b/net/ipv4/tcp_yeah.c
@@ -64,13 +64,15 @@ static void tcp_yeah_init(struct sock *sk)
 }
 
 
-static void tcp_yeah_pkts_acked(struct sock *sk, u32 pkts_acked)
+static void tcp_yeah_pkts_acked(struct sock *sk, u32 pkts_acked, ktime_t last)
 {
         const struct inet_connection_sock *icsk = inet_csk(sk);
         struct yeah *yeah = inet_csk_ca(sk);
 
         if (icsk->icsk_ca_state == TCP_CA_Open)
                 yeah->pkts_acked = pkts_acked;
+
+        tcp_vegas_pkts_acked(sk, pkts_acked, last);
 }
 
 static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack,
@@ -237,11 +239,11 @@ static u32 tcp_yeah_ssthresh(struct sock *sk) {
 }
 
 static struct tcp_congestion_ops tcp_yeah = {
+        .flags          = TCP_CONG_RTT_STAMP,
         .init           = tcp_yeah_init,
         .ssthresh       = tcp_yeah_ssthresh,
         .cong_avoid     = tcp_yeah_cong_avoid,
         .min_cwnd       = tcp_reno_min_cwnd,
-        .rtt_sample     = tcp_vegas_rtt_calc,
         .set_state      = tcp_vegas_state,
         .cwnd_event     = tcp_vegas_cwnd_event,
         .get_info       = tcp_vegas_get_info,
diff --git a/net/ipv4/tcp_yeah.h b/net/ipv4/tcp_yeah.h
index a62d82038fd..33ad5385c18 100644
--- a/net/ipv4/tcp_yeah.h
+++ b/net/ipv4/tcp_yeah.h
@@ -81,10 +81,13 @@ static void tcp_vegas_state(struct sock *sk, u8 ca_state)
  *   o min-filter RTT samples from a much longer window (forever for now)
  *     to find the propagation delay (baseRTT)
  */
-static void tcp_vegas_rtt_calc(struct sock *sk, u32 usrtt)
+static void tcp_vegas_pkts_acked(struct sock *sk, u32 cnt, ktime_t last)
 {
         struct vegas *vegas = inet_csk_ca(sk);
-        u32 vrtt = usrtt + 1; /* Never allow zero rtt or baseRTT */
+        u32 vrtt;
+
+        /* Never allow zero rtt or baseRTT */
+        vrtt = (ktime_to_ns(net_timedelta(last)) / NSEC_PER_USEC) + 1;
 
         /* Filter to find propagation delay: */
         if (vrtt < vegas->baseRTT)