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tcp: consolidate congestion control undo functions

Browse Source 
Most TCP congestion controls are using identical logic to undo
cwnd except BBR. This patch consolidates these similar functions
to the one used currently by Reno and others.

Suggested-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Yuchung Cheng 2017-08-03 20:38:52 -07:00 committed by David S. Miller
parent 4faf783998
commit f1722a1be1
9 changed files with 9 additions and 103 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
net/ipv4/tcp_bic.c
View File

@ -49,7 +49,6 @@ MODULE_PARM_DESC(smooth_part, "log(B/(B*Smin))/log(B/(B-1))+B, # of RTT from Wma
struct bictcp {
u32 cnt; /* increase cwnd by 1 after ACKs */
u32 last_max_cwnd; /* last maximum snd_cwnd */
u32 loss_cwnd; /* congestion window at last loss */
u32 last_cwnd; /* the last snd_cwnd */
u32 last_time; /* time when updated last_cwnd */
u32 epoch_start; /* beginning of an epoch */
@ -72,7 +71,6 @@ static void bictcp_init(struct sock *sk)
struct bictcp *ca = inet_csk_ca(sk);
bictcp_reset(ca);
ca->loss_cwnd = 0;
if (initial_ssthresh)
tcp_sk(sk)->snd_ssthresh = initial_ssthresh;
@ -172,22 +170,12 @@ static u32 bictcp_recalc_ssthresh(struct sock *sk)
else
ca->last_max_cwnd = tp->snd_cwnd;
ca->loss_cwnd = tp->snd_cwnd;
if (tp->snd_cwnd <= low_window)
return max(tp->snd_cwnd >> 1U, 2U);
else
return max((tp->snd_cwnd * beta) / BICTCP_BETA_SCALE, 2U);
}
static u32 bictcp_undo_cwnd(struct sock *sk)
{
const struct tcp_sock *tp = tcp_sk(sk);
const struct bictcp *ca = inet_csk_ca(sk);
return max(tp->snd_cwnd, ca->loss_cwnd);
}
static void bictcp_state(struct sock *sk, u8 new_state)
{
if (new_state == TCP_CA_Loss)
@ -214,7 +202,7 @@ static struct tcp_congestion_ops bictcp __read_mostly = {
.ssthresh = bictcp_recalc_ssthresh,
.cong_avoid = bictcp_cong_avoid,
.set_state = bictcp_state,
.undo_cwnd = bictcp_undo_cwnd,
.undo_cwnd = tcp_reno_undo_cwnd,
.pkts_acked = bictcp_acked,
.owner = THIS_MODULE,
.name = "bic",

12
net/ipv4/tcp_cdg.c
View File

@ -85,7 +85,6 @@ struct cdg {
u8 state;
u8 delack;
u32 rtt_seq;
u32 undo_cwnd;
u32 shadow_wnd;
u16 backoff_cnt;
u16 sample_cnt;
@ -330,8 +329,6 @@ static u32 tcp_cdg_ssthresh(struct sock *sk)
struct cdg *ca = inet_csk_ca(sk);
struct tcp_sock *tp = tcp_sk(sk);
ca->undo_cwnd = tp->snd_cwnd;
if (ca->state == CDG_BACKOFF)
return max(2U, (tp->snd_cwnd * min(1024U, backoff_beta)) >> 10);
@ -344,13 +341,6 @@ static u32 tcp_cdg_ssthresh(struct sock *sk)
return max(2U, tp->snd_cwnd >> 1);
}
static u32 tcp_cdg_undo_cwnd(struct sock *sk)
{
struct cdg *ca = inet_csk_ca(sk);
return max(tcp_sk(sk)->snd_cwnd, ca->undo_cwnd);
}
static void tcp_cdg_cwnd_event(struct sock *sk, const enum tcp_ca_event ev)
{
struct cdg *ca = inet_csk_ca(sk);
@ -403,7 +393,7 @@ struct tcp_congestion_ops tcp_cdg __read_mostly = {
.cong_avoid = tcp_cdg_cong_avoid,
.cwnd_event = tcp_cdg_cwnd_event,
.pkts_acked = tcp_cdg_acked,
.undo_cwnd = tcp_cdg_undo_cwnd,
.undo_cwnd = tcp_reno_undo_cwnd,
.ssthresh = tcp_cdg_ssthresh,
.release = tcp_cdg_release,
.init = tcp_cdg_init,

13
net/ipv4/tcp_cubic.c
View File

@ -83,7 +83,6 @@ MODULE_PARM_DESC(hystart_ack_delta, "spacing between ack's indicating train (mse
struct bictcp {
u32 cnt; /* increase cwnd by 1 after ACKs */
u32 last_max_cwnd; /* last maximum snd_cwnd */
u32 loss_cwnd; /* congestion window at last loss */
u32 last_cwnd; /* the last snd_cwnd */
u32 last_time; /* time when updated last_cwnd */
u32 bic_origin_point;/* origin point of bic function */
@ -142,7 +141,6 @@ static void bictcp_init(struct sock *sk)
struct bictcp *ca = inet_csk_ca(sk);
bictcp_reset(ca);
ca->loss_cwnd = 0;
if (hystart)
bictcp_hystart_reset(sk);
@ -366,18 +364,9 @@ static u32 bictcp_recalc_ssthresh(struct sock *sk)
else
ca->last_max_cwnd = tp->snd_cwnd;
ca->loss_cwnd = tp->snd_cwnd;
return max((tp->snd_cwnd * beta) / BICTCP_BETA_SCALE, 2U);
}
static u32 bictcp_undo_cwnd(struct sock *sk)
{
struct bictcp *ca = inet_csk_ca(sk);
return max(tcp_sk(sk)->snd_cwnd, ca->loss_cwnd);
}
static void bictcp_state(struct sock *sk, u8 new_state)
{
if (new_state == TCP_CA_Loss) {
@ -470,7 +459,7 @@ static struct tcp_congestion_ops cubictcp __read_mostly = {
.ssthresh = bictcp_recalc_ssthresh,
.cong_avoid = bictcp_cong_avoid,
.set_state = bictcp_state,
.undo_cwnd = bictcp_undo_cwnd,
.undo_cwnd = tcp_reno_undo_cwnd,
.cwnd_event = bictcp_cwnd_event,
.pkts_acked = bictcp_acked,
.owner = THIS_MODULE,

11
net/ipv4/tcp_highspeed.c
View File

@ -94,7 +94,6 @@ static const struct hstcp_aimd_val {
struct hstcp {
u32 ai;
u32 loss_cwnd;
};
static void hstcp_init(struct sock *sk)
@ -153,22 +152,14 @@ static u32 hstcp_ssthresh(struct sock *sk)
const struct tcp_sock *tp = tcp_sk(sk);
struct hstcp *ca = inet_csk_ca(sk);
ca->loss_cwnd = tp->snd_cwnd;
/* Do multiplicative decrease */
return max(tp->snd_cwnd - ((tp->snd_cwnd * hstcp_aimd_vals[ca->ai].md) >> 8), 2U);
}
static u32 hstcp_cwnd_undo(struct sock *sk)
{
const struct hstcp *ca = inet_csk_ca(sk);
return max(tcp_sk(sk)->snd_cwnd, ca->loss_cwnd);
}
static struct tcp_congestion_ops tcp_highspeed __read_mostly = {
.init = hstcp_init,
.ssthresh = hstcp_ssthresh,
.undo_cwnd = hstcp_cwnd_undo,
.undo_cwnd = tcp_reno_undo_cwnd,
.cong_avoid = hstcp_cong_avoid,
.owner = THIS_MODULE,

11
net/ipv4/tcp_illinois.c
View File

@ -48,7 +48,6 @@ struct illinois {
u32 end_seq; /* right edge of current RTT */
u32 alpha; /* Additive increase */
u32 beta; /* Muliplicative decrease */
u32 loss_cwnd; /* cwnd on loss */
u16 acked; /* # packets acked by current ACK */
u8 rtt_above; /* average rtt has gone above threshold */
u8 rtt_low; /* # of rtts measurements below threshold */
@ -297,18 +296,10 @@ static u32 tcp_illinois_ssthresh(struct sock *sk)
struct tcp_sock *tp = tcp_sk(sk);
struct illinois *ca = inet_csk_ca(sk);
ca->loss_cwnd = tp->snd_cwnd;
/* Multiplicative decrease */
return max(tp->snd_cwnd - ((tp->snd_cwnd * ca->beta) >> BETA_SHIFT), 2U);
}
static u32 tcp_illinois_cwnd_undo(struct sock *sk)
{
const struct illinois *ca = inet_csk_ca(sk);
return max(tcp_sk(sk)->snd_cwnd, ca->loss_cwnd);
}
/* Extract info for Tcp socket info provided via netlink. */
static size_t tcp_illinois_info(struct sock *sk, u32 ext, int *attr,
union tcp_cc_info *info)
@ -336,7 +327,7 @@ static size_t tcp_illinois_info(struct sock *sk, u32 ext, int *attr,
static struct tcp_congestion_ops tcp_illinois __read_mostly = {
.init = tcp_illinois_init,
.ssthresh = tcp_illinois_ssthresh,
.undo_cwnd = tcp_illinois_cwnd_undo,
.undo_cwnd = tcp_reno_undo_cwnd,
.cong_avoid = tcp_illinois_cong_avoid,
.set_state = tcp_illinois_state,
.get_info = tcp_illinois_info,

13
net/ipv4/tcp_nv.c
View File

@ -86,7 +86,6 @@ struct tcpnv {
* < 0 => less than 1 packet/RTT */
u8 available8;
u16 available16;
u32 loss_cwnd; /* cwnd at last loss */
u8 nv_allow_cwnd_growth:1, /* whether cwnd can grow */
nv_reset:1, /* whether to reset values */
nv_catchup:1; /* whether we are growing because
@ -121,7 +120,6 @@ static inline void tcpnv_reset(struct tcpnv *ca, struct sock *sk)
struct tcp_sock *tp = tcp_sk(sk);
ca->nv_reset = 0;
ca->loss_cwnd = 0;
ca->nv_no_cong_cnt = 0;
ca->nv_rtt_cnt = 0;
ca->nv_last_rtt = 0;
@ -177,19 +175,10 @@ static void tcpnv_cong_avoid(struct sock *sk, u32 ack, u32 acked)
static u32 tcpnv_recalc_ssthresh(struct sock *sk)
{
const struct tcp_sock *tp = tcp_sk(sk);
struct tcpnv *ca = inet_csk_ca(sk);
ca->loss_cwnd = tp->snd_cwnd;
return max((tp->snd_cwnd * nv_loss_dec_factor) >> 10, 2U);
}
static u32 tcpnv_undo_cwnd(struct sock *sk)
{
struct tcpnv *ca = inet_csk_ca(sk);
return max(tcp_sk(sk)->snd_cwnd, ca->loss_cwnd);
}
static void tcpnv_state(struct sock *sk, u8 new_state)
{
struct tcpnv *ca = inet_csk_ca(sk);
@ -446,7 +435,7 @@ static struct tcp_congestion_ops tcpnv __read_mostly = {
.ssthresh = tcpnv_recalc_ssthresh,
.cong_avoid = tcpnv_cong_avoid,
.set_state = tcpnv_state,
.undo_cwnd = tcpnv_undo_cwnd,
.undo_cwnd = tcp_reno_undo_cwnd,
.pkts_acked = tcpnv_acked,
.get_info = tcpnv_get_info,

16
net/ipv4/tcp_scalable.c
View File

@ -15,10 +15,6 @@
#define TCP_SCALABLE_AI_CNT 50U
#define TCP_SCALABLE_MD_SCALE 3
struct scalable {
u32 loss_cwnd;
};
static void tcp_scalable_cong_avoid(struct sock *sk, u32 ack, u32 acked)
{
struct tcp_sock *tp = tcp_sk(sk);
@ -36,23 +32,13 @@ static void tcp_scalable_cong_avoid(struct sock *sk, u32 ack, u32 acked)
static u32 tcp_scalable_ssthresh(struct sock *sk)
{
const struct tcp_sock *tp = tcp_sk(sk);
struct scalable *ca = inet_csk_ca(sk);
ca->loss_cwnd = tp->snd_cwnd;
return max(tp->snd_cwnd - (tp->snd_cwnd>>TCP_SCALABLE_MD_SCALE), 2U);
}
static u32 tcp_scalable_cwnd_undo(struct sock *sk)
{
const struct scalable *ca = inet_csk_ca(sk);
return max(tcp_sk(sk)->snd_cwnd, ca->loss_cwnd);
}
static struct tcp_congestion_ops tcp_scalable __read_mostly = {
.ssthresh = tcp_scalable_ssthresh,
.undo_cwnd = tcp_scalable_cwnd_undo,
.undo_cwnd = tcp_reno_undo_cwnd,
.cong_avoid = tcp_scalable_cong_avoid,
.owner = THIS_MODULE,

11
net/ipv4/tcp_veno.c
View File

@ -30,7 +30,6 @@ struct veno {
u32 basertt; /* the min of all Veno rtt measurements seen (in usec) */
u32 inc; /* decide whether to increase cwnd */
u32 diff; /* calculate the diff rate */
u32 loss_cwnd; /* cwnd when loss occured */
};
/* There are several situations when we must "re-start" Veno:
@ -194,7 +193,6 @@ static u32 tcp_veno_ssthresh(struct sock *sk)
const struct tcp_sock *tp = tcp_sk(sk);
struct veno *veno = inet_csk_ca(sk);
veno->loss_cwnd = tp->snd_cwnd;
if (veno->diff < beta)
/* in "non-congestive state", cut cwnd by 1/5 */
return max(tp->snd_cwnd * 4 / 5, 2U);
@ -203,17 +201,10 @@ static u32 tcp_veno_ssthresh(struct sock *sk)
return max(tp->snd_cwnd >> 1U, 2U);
}
static u32 tcp_veno_cwnd_undo(struct sock *sk)
{
const struct veno *veno = inet_csk_ca(sk);
return max(tcp_sk(sk)->snd_cwnd, veno->loss_cwnd);
}
static struct tcp_congestion_ops tcp_veno __read_mostly = {
.init = tcp_veno_init,
.ssthresh = tcp_veno_ssthresh,
.undo_cwnd = tcp_veno_cwnd_undo,
.undo_cwnd = tcp_reno_undo_cwnd,
.cong_avoid = tcp_veno_cong_avoid,
.pkts_acked = tcp_veno_pkts_acked,
.set_state = tcp_veno_state,

11
net/ipv4/tcp_yeah.c
View File

@ -37,7 +37,6 @@ struct yeah {
u32 fast_count;
u32 pkts_acked;
u32 loss_cwnd;
};
static void tcp_yeah_init(struct sock *sk)
@ -220,22 +219,14 @@ static u32 tcp_yeah_ssthresh(struct sock *sk)
yeah->fast_count = 0;
yeah->reno_count = max(yeah->reno_count>>1, 2U);
yeah->loss_cwnd = tp->snd_cwnd;
return max_t(int, tp->snd_cwnd - reduction, 2);
}
static u32 tcp_yeah_cwnd_undo(struct sock *sk)
{
const struct yeah *yeah = inet_csk_ca(sk);
return max(tcp_sk(sk)->snd_cwnd, yeah->loss_cwnd);
}
static struct tcp_congestion_ops tcp_yeah __read_mostly = {
.init = tcp_yeah_init,
.ssthresh = tcp_yeah_ssthresh,
.undo_cwnd = tcp_yeah_cwnd_undo,
.undo_cwnd = tcp_reno_undo_cwnd,
.cong_avoid = tcp_yeah_cong_avoid,
.set_state = tcp_vegas_state,
.cwnd_event = tcp_vegas_cwnd_event,