net_sched: red: split red_parms into parms and vars

This patch splits the red_parms structure into two components.

One holding the RED 'constant' parameters, and one containing the
variables.

This permits a size reduction of GRED qdisc, and is a preliminary step
to add an optional RED unit to SFQ.

SFQRED will have a single red_parms structure shared by all flows, and a
private red_vars per flow.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Dave Taht <dave.taht@gmail.com>
CC: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 62 insertions, 52 deletions

diff --git a/net/sched/sch_choke.c b/net/sched/sch_choke.c
index bef00ac..e465064 100644
--- a/net/sched/sch_choke.c
+++ b/net/sched/sch_choke.c
@@ -57,6 +57,7 @@ struct choke_sched_data {
 	struct red_parms parms;
 
 /* Variables */
+	struct red_vars  vars;
 	struct tcf_proto *filter_list;
 	struct {
 		u32	prob_drop;	/* Early probability drops */
@@ -265,7 +266,7 @@ static bool choke_match_random(const struct choke_sched_data *q,
 static int choke_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 {
 	struct choke_sched_data *q = qdisc_priv(sch);
-	struct red_parms *p = &q->parms;
+	const struct red_parms *p = &q->parms;
 	int ret = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
 
 	if (q->filter_list) {
@@ -276,13 +277,13 @@ static int choke_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 
 	choke_skb_cb(skb)->keys_valid = 0;
 	/* Compute average queue usage (see RED) */
-	p->qavg = red_calc_qavg(p, sch->q.qlen);
-	if (red_is_idling(p))
-		red_end_of_idle_period(p);
+	q->vars.qavg = red_calc_qavg(p, &q->vars, sch->q.qlen);
+	if (red_is_idling(&q->vars))
+		red_end_of_idle_period(&q->vars);
 
 	/* Is queue small? */
-	if (p->qavg <= p->qth_min)
-		p->qcount = -1;
+	if (q->vars.qavg <= p->qth_min)
+		q->vars.qcount = -1;
 	else {
 		unsigned int idx;
 
@@ -294,8 +295,8 @@ static int choke_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 		}
 
 		/* Queue is large, always mark/drop */
-		if (p->qavg > p->qth_max) {
-			p->qcount = -1;
+		if (q->vars.qavg > p->qth_max) {
+			q->vars.qcount = -1;
 
 			sch->qstats.overlimits++;
 			if (use_harddrop(q) || !use_ecn(q) ||
@@ -305,10 +306,10 @@ static int choke_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 			}
 
 			q->stats.forced_mark++;
-		} else if (++p->qcount) {
-			if (red_mark_probability(p, p->qavg)) {
-				p->qcount = 0;
-				p->qR = red_random(p);
+		} else if (++q->vars.qcount) {
+			if (red_mark_probability(p, &q->vars, q->vars.qavg)) {
+				q->vars.qcount = 0;
+				q->vars.qR = red_random(p);
 
 				sch->qstats.overlimits++;
 				if (!use_ecn(q) || !INET_ECN_set_ce(skb)) {
@@ -319,7 +320,7 @@ static int choke_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 				q->stats.prob_mark++;
 			}
 		} else
-			p->qR = red_random(p);
+			q->vars.qR = red_random(p);
 	}
 
 	/* Admit new packet */
@@ -353,8 +354,8 @@ static struct sk_buff *choke_dequeue(struct Qdisc *sch)
 	struct sk_buff *skb;
 
 	if (q->head == q->tail) {
-		if (!red_is_idling(&q->parms))
-			red_start_of_idle_period(&q->parms);
+		if (!red_is_idling(&q->vars))
+			red_start_of_idle_period(&q->vars);
 		return NULL;
 	}
 
@@ -377,8 +378,8 @@ static unsigned int choke_drop(struct Qdisc *sch)
 	if (len > 0)
 		q->stats.other++;
 	else {
-		if (!red_is_idling(&q->parms))
-			red_start_of_idle_period(&q->parms);
+		if (!red_is_idling(&q->vars))
+			red_start_of_idle_period(&q->vars);
 	}
 
 	return len;
@@ -388,7 +389,7 @@ static void choke_reset(struct Qdisc *sch)
 {
 	struct choke_sched_data *q = qdisc_priv(sch);
 
-	red_restart(&q->parms);
+	red_restart(&q->vars);
 }
 
 static const struct nla_policy choke_policy[TCA_CHOKE_MAX + 1] = {
@@ -482,9 +483,10 @@ static int choke_change(struct Qdisc *sch, struct nlattr *opt)
 		      ctl->Plog, ctl->Scell_log,
 		      nla_data(tb[TCA_CHOKE_STAB]),
 		      max_P);
+	red_set_vars(&q->vars);
 
 	if (q->head == q->tail)
-		red_end_of_idle_period(&q->parms);
+		red_end_of_idle_period(&q->vars);
 
 	sch_tree_unlock(sch);
 	choke_free(old);
diff --git a/net/sched/sch_gred.c b/net/sched/sch_gred.c
index 53204de..0b15236 100644
--- a/net/sched/sch_gred.c
+++ b/net/sched/sch_gred.c
@@ -41,6 +41,7 @@ struct gred_sched_data {
 	u8		prio;		/* the prio of this vq */
 
 	struct red_parms parms;
+	struct red_vars  vars;
 	struct red_stats stats;
 };
 
@@ -55,7 +56,7 @@ struct gred_sched {
 	u32		red_flags;
 	u32 		DPs;
 	u32 		def;
-	struct red_parms wred_set;
+	struct red_vars wred_set;
 };
 
 static inline int gred_wred_mode(struct gred_sched *table)
@@ -125,17 +126,17 @@ static inline u16 tc_index_to_dp(struct sk_buff *skb)
 	return skb->tc_index & GRED_VQ_MASK;
 }
 
-static inline void gred_load_wred_set(struct gred_sched *table,
+static inline void gred_load_wred_set(const struct gred_sched *table,
 				      struct gred_sched_data *q)
 {
-	q->parms.qavg = table->wred_set.qavg;
-	q->parms.qidlestart = table->wred_set.qidlestart;
+	q->vars.qavg = table->wred_set.qavg;
+	q->vars.qidlestart = table->wred_set.qidlestart;
 }
 
 static inline void gred_store_wred_set(struct gred_sched *table,
 				       struct gred_sched_data *q)
 {
-	table->wred_set.qavg = q->parms.qavg;
+	table->wred_set.qavg = q->vars.qavg;
 }
 
 static inline int gred_use_ecn(struct gred_sched *t)
@@ -170,7 +171,7 @@ static int gred_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 				goto drop;
 		}
 
-		/* fix tc_index? --could be controvesial but needed for
+		/* fix tc_index? --could be controversial but needed for
 		   requeueing */
 		skb->tc_index = (skb->tc_index & ~GRED_VQ_MASK) | dp;
 	}
@@ -181,8 +182,8 @@ static int gred_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 
 		for (i = 0; i < t->DPs; i++) {
 			if (t->tab[i] && t->tab[i]->prio < q->prio &&
-			    !red_is_idling(&t->tab[i]->parms))
-				qavg += t->tab[i]->parms.qavg;
+			    !red_is_idling(&t->tab[i]->vars))
+				qavg += t->tab[i]->vars.qavg;
 		}
 
 	}
@@ -193,15 +194,17 @@ static int gred_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 	if (gred_wred_mode(t))
 		gred_load_wred_set(t, q);
 
-	q->parms.qavg = red_calc_qavg(&q->parms, gred_backlog(t, q, sch));
+	q->vars.qavg = red_calc_qavg(&q->parms,
+				     &q->vars,
+				     gred_backlog(t, q, sch));
 
-	if (red_is_idling(&q->parms))
-		red_end_of_idle_period(&q->parms);
+	if (red_is_idling(&q->vars))
+		red_end_of_idle_period(&q->vars);
 
 	if (gred_wred_mode(t))
 		gred_store_wred_set(t, q);
 
-	switch (red_action(&q->parms, q->parms.qavg + qavg)) {
+	switch (red_action(&q->parms, &q->vars, q->vars.qavg + qavg)) {
 	case RED_DONT_MARK:
 		break;
 
@@ -260,7 +263,7 @@ static struct sk_buff *gred_dequeue(struct Qdisc *sch)
 			q->backlog -= qdisc_pkt_len(skb);
 
 			if (!q->backlog && !gred_wred_mode(t))
-				red_start_of_idle_period(&q->parms);
+				red_start_of_idle_period(&q->vars);
 		}
 
 		return skb;
@@ -293,7 +296,7 @@ static unsigned int gred_drop(struct Qdisc *sch)
 			q->stats.other++;
 
 			if (!q->backlog && !gred_wred_mode(t))
-				red_start_of_idle_period(&q->parms);
+				red_start_of_idle_period(&q->vars);
 		}
 
 		qdisc_drop(skb, sch);
@@ -320,7 +323,7 @@ static void gred_reset(struct Qdisc *sch)
 		if (!q)
 			continue;
 
-		red_restart(&q->parms);
+		red_restart(&q->vars);
 		q->backlog = 0;
 	}
 }
@@ -398,12 +401,12 @@ static inline int gred_change_vq(struct Qdisc *sch, int dp,
 	q->limit = ctl->limit;
 
 	if (q->backlog == 0)
-		red_end_of_idle_period(&q->parms);
+		red_end_of_idle_period(&q->vars);
 
 	red_set_parms(&q->parms,
 		      ctl->qth_min, ctl->qth_max, ctl->Wlog, ctl->Plog,
 		      ctl->Scell_log, stab, max_P);
-
+	red_set_vars(&q->vars);
 	return 0;
 }
 
@@ -563,12 +566,12 @@ static int gred_dump(struct Qdisc *sch, struct sk_buff *skb)
 		opt.bytesin	= q->bytesin;
 
 		if (gred_wred_mode(table)) {
-			q->parms.qidlestart =
-				table->tab[table->def]->parms.qidlestart;
-			q->parms.qavg = table->tab[table->def]->parms.qavg;
+			q->vars.qidlestart =
+				table->tab[table->def]->vars.qidlestart;
+			q->vars.qavg = table->tab[table->def]->vars.qavg;
 		}
 
-		opt.qave = red_calc_qavg(&q->parms, q->parms.qavg);
+		opt.qave = red_calc_qavg(&q->parms, &q->vars, q->vars.qavg);
 
 append_opt:
 		if (nla_append(skb, sizeof(opt), &opt) < 0)
diff --git a/net/sched/sch_red.c b/net/sched/sch_red.c
index ce2256a..a5cc301 100644
--- a/net/sched/sch_red.c
+++ b/net/sched/sch_red.c
@@ -41,6 +41,7 @@ struct red_sched_data {
 	unsigned char		flags;
 	struct timer_list	adapt_timer;
 	struct red_parms	parms;
+	struct red_vars		vars;
 	struct red_stats	stats;
 	struct Qdisc		*qdisc;
 };
@@ -61,12 +62,14 @@ static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 	struct Qdisc *child = q->qdisc;
 	int ret;
 
-	q->parms.qavg = red_calc_qavg(&q->parms, child->qstats.backlog);
+	q->vars.qavg = red_calc_qavg(&q->parms,
+				     &q->vars,
+				     child->qstats.backlog);
 
-	if (red_is_idling(&q->parms))
-		red_end_of_idle_period(&q->parms);
+	if (red_is_idling(&q->vars))
+		red_end_of_idle_period(&q->vars);
 
-	switch (red_action(&q->parms, q->parms.qavg)) {
+	switch (red_action(&q->parms, &q->vars, q->vars.qavg)) {
 	case RED_DONT_MARK:
 		break;
 
@@ -117,8 +120,8 @@ static struct sk_buff *red_dequeue(struct Qdisc *sch)
 		qdisc_bstats_update(sch, skb);
 		sch->q.qlen--;
 	} else {
-		if (!red_is_idling(&q->parms))
-			red_start_of_idle_period(&q->parms);
+		if (!red_is_idling(&q->vars))
+			red_start_of_idle_period(&q->vars);
 	}
 	return skb;
 }
@@ -144,8 +147,8 @@ static unsigned int red_drop(struct Qdisc *sch)
 		return len;
 	}
 
-	if (!red_is_idling(&q->parms))
-		red_start_of_idle_period(&q->parms);
+	if (!red_is_idling(&q->vars))
+		red_start_of_idle_period(&q->vars);
 
 	return 0;
 }
@@ -156,7 +159,7 @@ static void red_reset(struct Qdisc *sch)
 
 	qdisc_reset(q->qdisc);
 	sch->q.qlen = 0;
-	red_restart(&q->parms);
+	red_restart(&q->vars);
 }
 
 static void red_destroy(struct Qdisc *sch)
@@ -212,17 +215,19 @@ static int red_change(struct Qdisc *sch, struct nlattr *opt)
 		q->qdisc = child;
 	}
 
-	red_set_parms(&q->parms, ctl->qth_min, ctl->qth_max, ctl->Wlog,
+	red_set_parms(&q->parms,
+		      ctl->qth_min, ctl->qth_max, ctl->Wlog,
 		      ctl->Plog, ctl->Scell_log,
 		      nla_data(tb[TCA_RED_STAB]),
 		      max_P);
+	red_set_vars(&q->vars);
 
 	del_timer(&q->adapt_timer);
 	if (ctl->flags & TC_RED_ADAPTATIVE)
 		mod_timer(&q->adapt_timer, jiffies + HZ/2);
 
 	if (!q->qdisc->q.qlen)
-		red_start_of_idle_period(&q->parms);
+		red_start_of_idle_period(&q->vars);
 
 	sch_tree_unlock(sch);
 	return 0;
@@ -235,7 +240,7 @@ static inline void red_adaptative_timer(unsigned long arg)
 	spinlock_t *root_lock = qdisc_lock(qdisc_root_sleeping(sch));
 
 	spin_lock(root_lock);
-	red_adaptative_algo(&q->parms);
+	red_adaptative_algo(&q->parms, &q->vars);
 	mod_timer(&q->adapt_timer, jiffies + HZ/2);
 	spin_unlock(root_lock);
 }