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tcp: Revert "tcp: remove CA_ACK_SLOWPATH"

Browse source 
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 <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Florian Westphal 2017-08-30 19:24:57 +02:00 committed by David S. Miller
parent 0da93d2ebb
commit c1d2b4c3e2
3 changed files with 50 additions and 23 deletions
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5
include/net/tcp.h
View file

@ -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 */
};
/*

37
net/ipv4/tcp_input.c
View file

@ -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...
*/

31
net/ipv4/tcp_westwood.c
View file

@ -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)