net_sched: move TCQ_F_THROTTLED flag

In commit 371121057607e (net: QDISC_STATE_RUNNING dont need atomic bit
ops) I moved QDISC_STATE_RUNNING flag to __state container, located in
the cache line containing qdisc lock and often dirtied fields.

I now move TCQ_F_THROTTLED bit too, so that we let first cache line read
mostly, and shared by all cpus. This should speedup HTB/CBQ for example.

Not using test_bit()/__clear_bit()/__test_and_set_bit allows to use an
"unsigned int" for __state container, reducing by 8 bytes Qdisc size.

Introduce helpers to hide implementation details.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Patrick McHardy <kaber@trash.net>
CC: Jesper Dangaard Brouer <hawk@diku.dk>
CC: Jarek Poplawski <jarkao2@gmail.com>
CC: Jamal Hadi Salim <hadi@cyberus.ca>
CC: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

7 files changed, 39 insertions, 21 deletions

diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index e9eee99d8b1..f6345f55041 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -31,7 +31,8 @@ enum qdisc_state_t {
  * following bits are only changed while qdisc lock is held
  */
 enum qdisc___state_t {
-        __QDISC___STATE_RUNNING,
+        __QDISC___STATE_RUNNING = 1,
+        __QDISC___STATE_THROTTLED = 2,
 };
 
 struct qdisc_size_table {
@@ -46,10 +47,9 @@ struct Qdisc {
         struct sk_buff *        (*dequeue)(struct Qdisc *dev);
         unsigned                flags;
 #define TCQ_F_BUILTIN           1
-#define TCQ_F_THROTTLED         2
-#define TCQ_F_INGRESS           4
-#define TCQ_F_CAN_BYPASS        8
-#define TCQ_F_MQROOT            16
+#define TCQ_F_INGRESS           2
+#define TCQ_F_CAN_BYPASS        4
+#define TCQ_F_MQROOT            8
 #define TCQ_F_WARN_NONWC        (1 << 16)
         int                     padded;
         struct Qdisc_ops        *ops;
@@ -78,25 +78,43 @@ struct Qdisc {
         unsigned long           state;
         struct sk_buff_head     q;
         struct gnet_stats_basic_packed bstats;
-        unsigned long           __state;
+        unsigned int            __state;
         struct gnet_stats_queue qstats;
         struct rcu_head         rcu_head;
         spinlock_t              busylock;
 };
 
-static inline bool qdisc_is_running(struct Qdisc *qdisc)
+static inline bool qdisc_is_running(const struct Qdisc *qdisc)
 {
-        return test_bit(__QDISC___STATE_RUNNING, &qdisc->__state);
+        return (qdisc->__state & __QDISC___STATE_RUNNING) ? true : false;
 }
 
 static inline bool qdisc_run_begin(struct Qdisc *qdisc)
 {
-        return !__test_and_set_bit(__QDISC___STATE_RUNNING, &qdisc->__state);
+        if (qdisc_is_running(qdisc))
+                return false;
+        qdisc->__state |= __QDISC___STATE_RUNNING;
+        return true;
 }
 
 static inline void qdisc_run_end(struct Qdisc *qdisc)
 {
-        __clear_bit(__QDISC___STATE_RUNNING, &qdisc->__state);
+        qdisc->__state &= ~__QDISC___STATE_RUNNING;
+}
+
+static inline bool qdisc_is_throttled(const struct Qdisc *qdisc)
+{
+        return (qdisc->__state & __QDISC___STATE_THROTTLED) ? true : false;
+}
+
+static inline void qdisc_throttled(struct Qdisc *qdisc)
+{
+        qdisc->__state |= __QDISC___STATE_THROTTLED;
+}
+
+static inline void qdisc_unthrottled(struct Qdisc *qdisc)
+{
+        qdisc->__state &= ~__QDISC___STATE_THROTTLED;
 }
 
 struct Qdisc_class_ops {
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 36ac0ec81ce..374fcbef80e 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -473,7 +473,7 @@ static enum hrtimer_restart qdisc_watchdog(struct hrtimer *timer)
         struct qdisc_watchdog *wd = container_of(timer, struct qdisc_watchdog,
                                                  timer);
 
-        wd->qdisc->flags &= ~TCQ_F_THROTTLED;
+        qdisc_unthrottled(wd->qdisc);
         __netif_schedule(qdisc_root(wd->qdisc));
 
         return HRTIMER_NORESTART;
@@ -495,7 +495,7 @@ void qdisc_watchdog_schedule(struct qdisc_watchdog *wd, psched_time_t expires)
                      &qdisc_root_sleeping(wd->qdisc)->state))
                 return;
 
-        wd->qdisc->flags |= TCQ_F_THROTTLED;
+        qdisc_throttled(wd->qdisc);
         time = ktime_set(0, 0);
         time = ktime_add_ns(time, PSCHED_TICKS2NS(expires));
         hrtimer_start(&wd->timer, time, HRTIMER_MODE_ABS);
@@ -505,7 +505,7 @@ EXPORT_SYMBOL(qdisc_watchdog_schedule);
 void qdisc_watchdog_cancel(struct qdisc_watchdog *wd)
 {
         hrtimer_cancel(&wd->timer);
-        wd->qdisc->flags &= ~TCQ_F_THROTTLED;
+        qdisc_unthrottled(wd->qdisc);
 }
 EXPORT_SYMBOL(qdisc_watchdog_cancel);
 
diff --git a/net/sched/sch_cbq.c b/net/sched/sch_cbq.c
index 4aaf44c95c5..25ed522b289 100644
--- a/net/sched/sch_cbq.c
+++ b/net/sched/sch_cbq.c
@@ -351,7 +351,7 @@ cbq_mark_toplevel(struct cbq_sched_data *q, struct cbq_class *cl)
 {
         int toplevel = q->toplevel;
 
-        if (toplevel > cl->level && !(cl->q->flags & TCQ_F_THROTTLED)) {
+        if (toplevel > cl->level && !(qdisc_is_throttled(cl->q))) {
                 psched_time_t now;
                 psched_tdiff_t incr;
 
@@ -625,7 +625,7 @@ static enum hrtimer_restart cbq_undelay(struct hrtimer *timer)
                 hrtimer_start(&q->delay_timer, time, HRTIMER_MODE_ABS);
         }
 
-        sch->flags &= ~TCQ_F_THROTTLED;
+        qdisc_unthrottled(sch);
         __netif_schedule(qdisc_root(sch));
         return HRTIMER_NORESTART;
 }
@@ -974,7 +974,7 @@ cbq_dequeue(struct Qdisc *sch)
                 skb = cbq_dequeue_1(sch);
                 if (skb) {
                         sch->q.qlen--;
-                        sch->flags &= ~TCQ_F_THROTTLED;
+                        qdisc_unthrottled(sch);
                         return skb;
                 }
 
diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
index dea4009615f..b632d925191 100644
--- a/net/sched/sch_hfsc.c
+++ b/net/sched/sch_hfsc.c
@@ -1664,7 +1664,7 @@ hfsc_dequeue(struct Qdisc *sch)
                 set_passive(cl);
         }
 
-        sch->flags &= ~TCQ_F_THROTTLED;
+        qdisc_unthrottled(sch);
         sch->q.qlen--;
 
         return skb;
diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 3e86fd3a1b7..39db75cd8c1 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -865,7 +865,7 @@ static struct sk_buff *htb_dequeue(struct Qdisc *sch)
         /* try to dequeue direct packets as high prio (!) to minimize cpu work */
         skb = __skb_dequeue(&q->direct_queue);
         if (skb != NULL) {
-                sch->flags &= ~TCQ_F_THROTTLED;
+                qdisc_unthrottled(sch);
                 sch->q.qlen--;
                 return skb;
         }
@@ -901,7 +901,7 @@ static struct sk_buff *htb_dequeue(struct Qdisc *sch)
                         skb = htb_dequeue_tree(q, prio, level);
                         if (likely(skb != NULL)) {
                                 sch->q.qlen--;
-                                sch->flags &= ~TCQ_F_THROTTLED;
+                                qdisc_unthrottled(sch);
                                 goto fin;
                         }
                 }
diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index c2bbbe60d54..c26ef3614f7 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -266,7 +266,7 @@ static struct sk_buff *netem_dequeue(struct Qdisc *sch)
         struct netem_sched_data *q = qdisc_priv(sch);
         struct sk_buff *skb;
 
-        if (sch->flags & TCQ_F_THROTTLED)
+        if (qdisc_is_throttled(sch))
                 return NULL;
 
         skb = q->qdisc->ops->peek(q->qdisc);
diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
index 475edfb69c2..86c01669697 100644
--- a/net/sched/sch_tbf.c
+++ b/net/sched/sch_tbf.c
@@ -185,7 +185,7 @@ static struct sk_buff *tbf_dequeue(struct Qdisc *sch)
                         q->tokens = toks;
                         q->ptokens = ptoks;
                         sch->q.qlen--;
-                        sch->flags &= ~TCQ_F_THROTTLED;
+                        qdisc_unthrottled(sch);
                         return skb;
                 }