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>

4 files changed, 117 insertions, 95 deletions

diff --git a/include/net/red.h b/include/net/red.h
index ef715a16cce4..baab385a4736 100644
--- a/include/net/red.h
+++ b/include/net/red.h
@@ -137,7 +137,9 @@ struct red_parms {
         u8              Wlog;           /* log(W)               */
         u8              Plog;           /* random number bits   */
         u8              Stab[RED_STAB_SIZE];
+};
 
+struct red_vars {
         /* Variables */
         int             qcount;         /* Number of packets since last random
                                            number generation */
@@ -152,6 +154,16 @@ static inline u32 red_maxp(u8 Plog)
         return Plog < 32 ? (~0U >> Plog) : ~0U;
 }
 
+static inline void red_set_vars(struct red_vars *v)
+{
+        /* Reset average queue length, the value is strictly bound
+         * to the parameters below, reseting hurts a bit but leaving
+         * it might result in an unreasonable qavg for a while. --TGR
+         */
+        v->qavg         = 0;
+
+        v->qcount       = -1;
+}
 
 static inline void red_set_parms(struct red_parms *p,
                                  u32 qth_min, u32 qth_max, u8 Wlog, u8 Plog,
@@ -160,13 +172,6 @@ static inline void red_set_parms(struct red_parms *p,
         int delta = qth_max - qth_min;
         u32 max_p_delta;
 
-        /* Reset average queue length, the value is strictly bound
-         * to the parameters below, reseting hurts a bit but leaving
-         * it might result in an unreasonable qavg for a while. --TGR
-         */
-        p->qavg         = 0;
-
-        p->qcount       = -1;
         p->qth_min      = qth_min << Wlog;
         p->qth_max      = qth_max << Wlog;
         p->Wlog         = Wlog;
@@ -197,31 +202,32 @@ static inline void red_set_parms(struct red_parms *p,
         memcpy(p->Stab, stab, sizeof(p->Stab));
 }
 
-static inline int red_is_idling(const struct red_parms *p)
+static inline int red_is_idling(const struct red_vars *v)
 {
-        return p->qidlestart.tv64 != 0;
+        return v->qidlestart.tv64 != 0;
 }
 
-static inline void red_start_of_idle_period(struct red_parms *p)
+static inline void red_start_of_idle_period(struct red_vars *v)
 {
-        p->qidlestart = ktime_get();
+        v->qidlestart = ktime_get();
 }
 
-static inline void red_end_of_idle_period(struct red_parms *p)
+static inline void red_end_of_idle_period(struct red_vars *v)
 {
-        p->qidlestart.tv64 = 0;
+        v->qidlestart.tv64 = 0;
 }
 
-static inline void red_restart(struct red_parms *p)
+static inline void red_restart(struct red_vars *v)
 {
-        red_end_of_idle_period(p);
-        p->qavg = 0;
-        p->qcount = -1;
+        red_end_of_idle_period(v);
+        v->qavg = 0;
+        v->qcount = -1;
 }
 
-static inline unsigned long red_calc_qavg_from_idle_time(const struct red_parms *p)
+static inline unsigned long red_calc_qavg_from_idle_time(const struct red_parms *p,
+                                                         const struct red_vars *v)
 {
-        s64 delta = ktime_us_delta(ktime_get(), p->qidlestart);
+        s64 delta = ktime_us_delta(ktime_get(), v->qidlestart);
         long us_idle = min_t(s64, delta, p->Scell_max);
         int  shift;
 
@@ -248,7 +254,7 @@ static inline unsigned long red_calc_qavg_from_idle_time(const struct red_parms
         shift = p->Stab[(us_idle >> p->Scell_log) & RED_STAB_MASK];
 
         if (shift)
-                return p->qavg >> shift;
+                return v->qavg >> shift;
         else {
                 /* Approximate initial part of exponent with linear function:
                  *
@@ -257,16 +263,17 @@ static inline unsigned long red_calc_qavg_from_idle_time(const struct red_parms
                  * Seems, it is the best solution to
                  * problem of too coarse exponent tabulation.
                  */
-                us_idle = (p->qavg * (u64)us_idle) >> p->Scell_log;
+                us_idle = (v->qavg * (u64)us_idle) >> p->Scell_log;
 
-                if (us_idle < (p->qavg >> 1))
-                        return p->qavg - us_idle;
+                if (us_idle < (v->qavg >> 1))
+                        return v->qavg - us_idle;
                 else
-                        return p->qavg >> 1;
+                        return v->qavg >> 1;
         }
 }
 
 static inline unsigned long red_calc_qavg_no_idle_time(const struct red_parms *p,
+                                                       const struct red_vars *v,
                                                        unsigned int backlog)
 {
         /*
@@ -278,16 +285,17 @@ static inline unsigned long red_calc_qavg_no_idle_time(const struct red_parms *p
          *
          * --ANK (980924)
          */
-        return p->qavg + (backlog - (p->qavg >> p->Wlog));
+        return v->qavg + (backlog - (v->qavg >> p->Wlog));
 }
 
 static inline unsigned long red_calc_qavg(const struct red_parms *p,
+                                          const struct red_vars *v,
                                           unsigned int backlog)
 {
-        if (!red_is_idling(p))
-                return red_calc_qavg_no_idle_time(p, backlog);
+        if (!red_is_idling(v))
+                return red_calc_qavg_no_idle_time(p, v, backlog);
         else
-                return red_calc_qavg_from_idle_time(p);
+                return red_calc_qavg_from_idle_time(p, v);
 }
 
 
@@ -296,7 +304,9 @@ static inline u32 red_random(const struct red_parms *p)
         return reciprocal_divide(net_random(), p->max_P_reciprocal);
 }
 
-static inline int red_mark_probability(const struct red_parms *p, unsigned long qavg)
+static inline int red_mark_probability(const struct red_parms *p,
+                                       const struct red_vars *v,
+                                       unsigned long qavg)
 {
         /* The formula used below causes questions.
 
@@ -314,7 +324,7 @@ static inline int red_mark_probability(const struct red_parms *p, unsigned long
 
            Any questions? --ANK (980924)
          */
-        return !(((qavg - p->qth_min) >> p->Wlog) * p->qcount < p->qR);
+        return !(((qavg - p->qth_min) >> p->Wlog) * v->qcount < v->qR);
 }
 
 enum {
@@ -323,7 +333,7 @@ enum {
         RED_ABOVE_MAX_TRESH,
 };
 
-static inline int red_cmp_thresh(struct red_parms *p, unsigned long qavg)
+static inline int red_cmp_thresh(const struct red_parms *p, unsigned long qavg)
 {
         if (qavg < p->qth_min)
                 return RED_BELOW_MIN_THRESH;
@@ -339,27 +349,29 @@ enum {
         RED_HARD_MARK,
 };
 
-static inline int red_action(struct red_parms *p, unsigned long qavg)
+static inline int red_action(const struct red_parms *p,
+                             struct red_vars *v,
+                             unsigned long qavg)
 {
         switch (red_cmp_thresh(p, qavg)) {
                 case RED_BELOW_MIN_THRESH:
-                        p->qcount = -1;
+                        v->qcount = -1;
                         return RED_DONT_MARK;
 
                 case RED_BETWEEN_TRESH:
-                        if (++p->qcount) {
-                                if (red_mark_probability(p, qavg)) {
-                                        p->qcount = 0;
-                                        p->qR = red_random(p);
+                        if (++v->qcount) {
+                                if (red_mark_probability(p, v, qavg)) {
+                                        v->qcount = 0;
+                                        v->qR = red_random(p);
                                         return RED_PROB_MARK;
                                 }
                         } else
-                                p->qR = red_random(p);
+                                v->qR = red_random(p);
 
                         return RED_DONT_MARK;
 
                 case RED_ABOVE_MAX_TRESH:
-                        p->qcount = -1;
+                        v->qcount = -1;
                         return RED_HARD_MARK;
         }
 
@@ -367,14 +379,14 @@ static inline int red_action(struct red_parms *p, unsigned long qavg)
         return RED_DONT_MARK;
 }
 
-static inline void red_adaptative_algo(struct red_parms *p)
+static inline void red_adaptative_algo(struct red_parms *p, struct red_vars *v)
 {
         unsigned long qavg;
         u32 max_p_delta;
 
-        qavg = p->qavg;
-        if (red_is_idling(p))
-                qavg = red_calc_qavg_from_idle_time(p);
+        qavg = v->qavg;
+        if (red_is_idling(v))
+                qavg = red_calc_qavg_from_idle_time(p, v);
 
         /* p->qavg is fixed point number with point at Wlog */
         qavg >>= p->Wlog;
diff --git a/net/sched/sch_choke.c b/net/sched/sch_choke.c
index bef00acb8bd2..e465064d39a3 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 53204de71c39..0b15236be7b6 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 ce2256a17d7e..a5cc3012cf42 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);
 }