From c1d2b4c3e204e602c97680335d082b8d012d08cd Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Wed, 30 Aug 2017 19:24:57 +0200 Subject: [PATCH] tcp: Revert "tcp: remove CA_ACK_SLOWPATH" This change was a followup to the header prediction removal, so first revert this as a prerequisite to back out hp removal. Signed-off-by: Florian Westphal Signed-off-by: David S. Miller --- include/net/tcp.h | 5 +++-- net/ipv4/tcp_input.c | 37 ++++++++++++++++++++----------------- net/ipv4/tcp_westwood.c | 31 +++++++++++++++++++++++++++---- 3 files changed, 50 insertions(+), 23 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index c614ff135b66..c546d13ffbca 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -910,8 +910,9 @@ enum tcp_ca_event { /* Information about inbound ACK, passed to cong_ops->in_ack_event() */ enum tcp_ca_ack_event_flags { - CA_ACK_WIN_UPDATE = (1 << 0), /* ACK updated window */ - CA_ACK_ECE = (1 << 1), /* ECE bit is set on ack */ + CA_ACK_SLOWPATH = (1 << 0), /* In slow path processing */ + CA_ACK_WIN_UPDATE = (1 << 1), /* ACK updated window */ + CA_ACK_ECE = (1 << 2), /* ECE bit is set on ack */ }; /* diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 7616cd76f6f6..a0e436366d31 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3552,7 +3552,6 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag) u32 lost = tp->lost; int acked = 0; /* Number of packets newly acked */ int rexmit = REXMIT_NONE; /* Flag to (re)transmit to recover losses */ - u32 ack_ev_flags = 0; sack_state.first_sackt = 0; sack_state.rate = &rs; @@ -3593,27 +3592,31 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag) if (flag & FLAG_UPDATE_TS_RECENT) tcp_replace_ts_recent(tp, TCP_SKB_CB(skb)->seq); - if (ack_seq != TCP_SKB_CB(skb)->end_seq) - flag |= FLAG_DATA; - else - NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPPUREACKS); + { + u32 ack_ev_flags = CA_ACK_SLOWPATH; - flag |= tcp_ack_update_window(sk, skb, ack, ack_seq); + if (ack_seq != TCP_SKB_CB(skb)->end_seq) + flag |= FLAG_DATA; + else + NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPPUREACKS); - if (TCP_SKB_CB(skb)->sacked) - flag |= tcp_sacktag_write_queue(sk, skb, prior_snd_una, - &sack_state); + flag |= tcp_ack_update_window(sk, skb, ack, ack_seq); - if (tcp_ecn_rcv_ecn_echo(tp, tcp_hdr(skb))) { - flag |= FLAG_ECE; - ack_ev_flags = CA_ACK_ECE; + if (TCP_SKB_CB(skb)->sacked) + flag |= tcp_sacktag_write_queue(sk, skb, prior_snd_una, + &sack_state); + + if (tcp_ecn_rcv_ecn_echo(tp, tcp_hdr(skb))) { + flag |= FLAG_ECE; + ack_ev_flags |= CA_ACK_ECE; + } + + if (flag & FLAG_WIN_UPDATE) + ack_ev_flags |= CA_ACK_WIN_UPDATE; + + tcp_in_ack_event(sk, ack_ev_flags); } - if (flag & FLAG_WIN_UPDATE) - ack_ev_flags |= CA_ACK_WIN_UPDATE; - - tcp_in_ack_event(sk, ack_ev_flags); - /* We passed data and got it acked, remove any soft error * log. Something worked... */ diff --git a/net/ipv4/tcp_westwood.c b/net/ipv4/tcp_westwood.c index e5de84310949..bec9cafbe3f9 100644 --- a/net/ipv4/tcp_westwood.c +++ b/net/ipv4/tcp_westwood.c @@ -153,6 +153,24 @@ static inline void update_rtt_min(struct westwood *w) w->rtt_min = min(w->rtt, w->rtt_min); } +/* + * @westwood_fast_bw + * It is called when we are in fast path. In particular it is called when + * header prediction is successful. In such case in fact update is + * straight forward and doesn't need any particular care. + */ +static inline void westwood_fast_bw(struct sock *sk) +{ + const struct tcp_sock *tp = tcp_sk(sk); + struct westwood *w = inet_csk_ca(sk); + + westwood_update_window(sk); + + w->bk += tp->snd_una - w->snd_una; + w->snd_una = tp->snd_una; + update_rtt_min(w); +} + /* * @westwood_acked_count * This function evaluates cumul_ack for evaluating bk in case of @@ -205,12 +223,17 @@ static u32 tcp_westwood_bw_rttmin(const struct sock *sk) static void tcp_westwood_ack(struct sock *sk, u32 ack_flags) { - struct westwood *w = inet_csk_ca(sk); + if (ack_flags & CA_ACK_SLOWPATH) { + struct westwood *w = inet_csk_ca(sk); - westwood_update_window(sk); - w->bk += westwood_acked_count(sk); + westwood_update_window(sk); + w->bk += westwood_acked_count(sk); - update_rtt_min(w); + update_rtt_min(w); + return; + } + + westwood_fast_bw(sk); } static void tcp_westwood_event(struct sock *sk, enum tcp_ca_event event)