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Commit 9121c777 authored by Stephen Hemminger's avatar Stephen Hemminger Committed by David S. Miller
Browse files

[TCP]: cleanup of htcp (resend)



Minor non-invasive cleanups:
 * white space around operators and line wrapping
 * use const
 * use __read_mostly

Signed-off-by: default avatarStephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 59758f44
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+37 −28
Original line number Original line Diff line number Diff line
@@ -14,18 +14,19 @@
#define BETA_MIN	(1<<6)	/* 0.5 with shift << 7 */
#define BETA_MIN	(1<<6)	/* 0.5 with shift << 7 */
#define BETA_MAX	102	/* 0.8 with shift << 7 */
#define BETA_MAX	102	/* 0.8 with shift << 7 */


static int use_rtt_scaling = 1;
static int use_rtt_scaling __read_mostly = 1;
module_param(use_rtt_scaling, int, 0644);
module_param(use_rtt_scaling, int, 0644);
MODULE_PARM_DESC(use_rtt_scaling, "turn on/off RTT scaling");
MODULE_PARM_DESC(use_rtt_scaling, "turn on/off RTT scaling");


static int use_bandwidth_switch = 1;
static int use_bandwidth_switch __read_mostly = 1;
module_param(use_bandwidth_switch, int, 0644);
module_param(use_bandwidth_switch, int, 0644);
MODULE_PARM_DESC(use_bandwidth_switch, "turn on/off bandwidth switcher");
MODULE_PARM_DESC(use_bandwidth_switch, "turn on/off bandwidth switcher");


struct htcp {
struct htcp {
	u32	alpha;		/* Fixed point arith, << 7 */
	u32	alpha;		/* Fixed point arith, << 7 */
	u8	beta;           /* Fixed point arith, << 7 */
	u8	beta;           /* Fixed point arith, << 7 */
	u8	modeswitch;     /* Delay modeswitch until we had at least one congestion event */
	u8	modeswitch;	/* Delay modeswitch
				   until we had at least one congestion event */
	u16	pkts_acked;
	u16	pkts_acked;
	u32	packetcount;
	u32	packetcount;
	u32	minRTT;
	u32	minRTT;
@@ -44,12 +45,12 @@ struct htcp {
	u32	lasttime;
	u32	lasttime;
};
};


static inline u32 htcp_cong_time(struct htcp *ca)
static inline u32 htcp_cong_time(const struct htcp *ca)
{
{
	return jiffies - ca->last_cong;
	return jiffies - ca->last_cong;
}
}


static inline u32 htcp_ccount(struct htcp *ca)
static inline u32 htcp_ccount(const struct htcp *ca)
{
{
	return htcp_cong_time(ca) / ca->minRTT;
	return htcp_cong_time(ca) / ca->minRTT;
}
}
@@ -67,9 +68,11 @@ static u32 htcp_cwnd_undo(struct sock *sk)
{
{
	const struct tcp_sock *tp = tcp_sk(sk);
	const struct tcp_sock *tp = tcp_sk(sk);
	struct htcp *ca = inet_csk_ca(sk);
	struct htcp *ca = inet_csk_ca(sk);

	ca->last_cong = ca->undo_last_cong;
	ca->last_cong = ca->undo_last_cong;
	ca->maxRTT = ca->undo_maxRTT;
	ca->maxRTT = ca->undo_maxRTT;
	ca->old_maxB = ca->undo_old_maxB;
	ca->old_maxB = ca->undo_old_maxB;

	return max(tp->snd_cwnd, (tp->snd_ssthresh << 7) / ca->beta);
	return max(tp->snd_cwnd, (tp->snd_ssthresh << 7) / ca->beta);
}
}


@@ -85,10 +88,12 @@ static inline void measure_rtt(struct sock *sk)
		ca->minRTT = srtt;
		ca->minRTT = srtt;


	/* max RTT */
	/* max RTT */
	if (icsk->icsk_ca_state == TCP_CA_Open && tp->snd_ssthresh < 0xFFFF && htcp_ccount(ca) > 3) {
	if (icsk->icsk_ca_state == TCP_CA_Open
	    && tp->snd_ssthresh < 0xFFFF && htcp_ccount(ca) > 3) {
		if (ca->maxRTT < ca->minRTT)
		if (ca->maxRTT < ca->minRTT)
			ca->maxRTT = ca->minRTT;
			ca->maxRTT = ca->minRTT;
		if (ca->maxRTT < srtt && srtt <= ca->maxRTT+msecs_to_jiffies(20))
		if (ca->maxRTT < srtt
		    && srtt <= ca->maxRTT + msecs_to_jiffies(20))
			ca->maxRTT = srtt;
			ca->maxRTT = srtt;
	}
	}
}
}
@@ -120,6 +125,7 @@ static void measure_achieved_throughput(struct sock *sk, u32 pkts_acked)
	    && now - ca->lasttime >= ca->minRTT
	    && now - ca->lasttime >= ca->minRTT
	    && ca->minRTT > 0) {
	    && ca->minRTT > 0) {
		__u32 cur_Bi = ca->packetcount * HZ / (now - ca->lasttime);
		__u32 cur_Bi = ca->packetcount * HZ / (now - ca->lasttime);

		if (htcp_ccount(ca) <= 3) {
		if (htcp_ccount(ca) <= 3) {
			/* just after backoff */
			/* just after backoff */
			ca->minB = ca->maxB = ca->Bi = cur_Bi;
			ca->minB = ca->maxB = ca->Bi = cur_Bi;
@@ -174,7 +180,9 @@ static inline void htcp_alpha_update(struct htcp *ca)


	if (use_rtt_scaling && minRTT) {
	if (use_rtt_scaling && minRTT) {
		u32 scale = (HZ << 3) / (10 * minRTT);
		u32 scale = (HZ << 3) / (10 * minRTT);
		scale = min(max(scale, 1U<<2), 10U<<3); /* clamping ratio to interval [0.5,10]<<3 */

		/* clamping ratio to interval [0.5,10]<<3 */
		scale = min(max(scale, 1U << 2), 10U << 3);
		factor = (factor << 3) / scale;
		factor = (factor << 3) / scale;
		if (!factor)
		if (!factor)
			factor = 1;
			factor = 1;
@@ -185,7 +193,8 @@ static inline void htcp_alpha_update(struct htcp *ca)
		ca->alpha = ALPHA_BASE;
		ca->alpha = ALPHA_BASE;
}
}


/* After we have the rtt data to calculate beta, we'd still prefer to wait one
/*
 * After we have the rtt data to calculate beta, we'd still prefer to wait one
 * rtt before we adjust our beta to ensure we are working from a consistent
 * rtt before we adjust our beta to ensure we are working from a consistent
 * data.
 * data.
 *
 *
@@ -202,7 +211,7 @@ static void htcp_param_update(struct sock *sk)
	htcp_beta_update(ca, minRTT, maxRTT);
	htcp_beta_update(ca, minRTT, maxRTT);
	htcp_alpha_update(ca);
	htcp_alpha_update(ca);


	/* add slowly fading memory for maxRTT to accommodate routing changes etc */
	/* add slowly fading memory for maxRTT to accommodate routing changes */
	if (minRTT > 0 && maxRTT > minRTT)
	if (minRTT > 0 && maxRTT > minRTT)
		ca->maxRTT = minRTT + ((maxRTT - minRTT) * 95) / 100;
		ca->maxRTT = minRTT + ((maxRTT - minRTT) * 95) / 100;
}
}
@@ -211,6 +220,7 @@ static u32 htcp_recalc_ssthresh(struct sock *sk)
{
{
	const struct tcp_sock *tp = tcp_sk(sk);
	const struct tcp_sock *tp = tcp_sk(sk);
	const struct htcp *ca = inet_csk_ca(sk);
	const struct htcp *ca = inet_csk_ca(sk);

	htcp_param_update(sk);
	htcp_param_update(sk);
	return max((tp->snd_cwnd * ca->beta) >> 7, 2U);
	return max((tp->snd_cwnd * ca->beta) >> 7, 2U);
}
}
@@ -227,7 +237,6 @@ static void htcp_cong_avoid(struct sock *sk, u32 ack, u32 rtt,
	if (tp->snd_cwnd <= tp->snd_ssthresh)
	if (tp->snd_cwnd <= tp->snd_ssthresh)
		tcp_slow_start(tp);
		tcp_slow_start(tp);
	else {
	else {

		measure_rtt(sk);
		measure_rtt(sk);


		/* In dangerous area, increase slowly.
		/* In dangerous area, increase slowly.