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Date: Fri, 10 Jun 2016 16:41:39 -0700
From: Eric Dumazet <edumazet@...gle.com>
To: "David S . Miller" <davem@...emloft.net>
Cc: netdev <netdev@...r.kernel.org>,
Eric Dumazet <edumazet@...gle.com>,
Eric Dumazet <eric.dumazet@...il.com>
Subject: [PATCH net-next 4/4] net_sched: remove generic throttled management
__QDISC_STATE_THROTTLED bit manipulation is rather expensive
for HTB and few others.
I already removed it for sch_fq in commit f2600cf02b5b
("net: sched: avoid costly atomic operation in fq_dequeue()")
and so far nobody complained.
When one ore more packets are stuck in one or more throttled
HTB class, a htb dequeue() performs two atomic operations
to clear/set __QDISC_STATE_THROTTLED bit, while root qdisc
lock is held.
Removing this pair of atomic operations bring me a 8 % performance
increase on 200 TCP_RR tests, in presence of throttled classes.
This patch has no side effect, since nothing actually uses
disc_is_throttled() anymore.
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
include/net/pkt_sched.h | 4 ++--
include/net/sch_generic.h | 16 ----------------
net/sched/sch_api.c | 7 +------
net/sched/sch_cbq.c | 2 --
net/sched/sch_fq.c | 3 +--
net/sched/sch_hfsc.c | 1 -
net/sched/sch_htb.c | 3 +--
net/sched/sch_netem.c | 1 -
net/sched/sch_tbf.c | 4 +---
9 files changed, 6 insertions(+), 35 deletions(-)
diff --git a/include/net/pkt_sched.h b/include/net/pkt_sched.h
index fea53f4d92ca..7caa99b482c6 100644
--- a/include/net/pkt_sched.h
+++ b/include/net/pkt_sched.h
@@ -67,12 +67,12 @@ struct qdisc_watchdog {
};
void qdisc_watchdog_init(struct qdisc_watchdog *wd, struct Qdisc *qdisc);
-void qdisc_watchdog_schedule_ns(struct qdisc_watchdog *wd, u64 expires, bool throttle);
+void qdisc_watchdog_schedule_ns(struct qdisc_watchdog *wd, u64 expires);
static inline void qdisc_watchdog_schedule(struct qdisc_watchdog *wd,
psched_time_t expires)
{
- qdisc_watchdog_schedule_ns(wd, PSCHED_TICKS2NS(expires), true);
+ qdisc_watchdog_schedule_ns(wd, PSCHED_TICKS2NS(expires));
}
void qdisc_watchdog_cancel(struct qdisc_watchdog *wd);
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index 9f3581980c15..9a0d177884c6 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -26,7 +26,6 @@ struct qdisc_rate_table {
enum qdisc_state_t {
__QDISC_STATE_SCHED,
__QDISC_STATE_DEACTIVATED,
- __QDISC_STATE_THROTTLED,
};
struct qdisc_size_table {
@@ -125,21 +124,6 @@ static inline int qdisc_avail_bulklimit(const struct netdev_queue *txq)
#endif
}
-static inline bool qdisc_is_throttled(const struct Qdisc *qdisc)
-{
- return test_bit(__QDISC_STATE_THROTTLED, &qdisc->state) ? true : false;
-}
-
-static inline void qdisc_throttled(struct Qdisc *qdisc)
-{
- set_bit(__QDISC_STATE_THROTTLED, &qdisc->state);
-}
-
-static inline void qdisc_unthrottled(struct Qdisc *qdisc)
-{
- clear_bit(__QDISC_STATE_THROTTLED, &qdisc->state);
-}
-
struct Qdisc_class_ops {
/* Child qdisc manipulation */
struct netdev_queue * (*select_queue)(struct Qdisc *, struct tcmsg *);
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index d4a8bbfcc953..401eda6de682 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -583,7 +583,6 @@ static enum hrtimer_restart qdisc_watchdog(struct hrtimer *timer)
timer);
rcu_read_lock();
- qdisc_unthrottled(wd->qdisc);
__netif_schedule(qdisc_root(wd->qdisc));
rcu_read_unlock();
@@ -598,15 +597,12 @@ void qdisc_watchdog_init(struct qdisc_watchdog *wd, struct Qdisc *qdisc)
}
EXPORT_SYMBOL(qdisc_watchdog_init);
-void qdisc_watchdog_schedule_ns(struct qdisc_watchdog *wd, u64 expires, bool throttle)
+void qdisc_watchdog_schedule_ns(struct qdisc_watchdog *wd, u64 expires)
{
if (test_bit(__QDISC_STATE_DEACTIVATED,
&qdisc_root_sleeping(wd->qdisc)->state))
return;
- if (throttle)
- qdisc_throttled(wd->qdisc);
-
if (wd->last_expires == expires)
return;
@@ -620,7 +616,6 @@ EXPORT_SYMBOL(qdisc_watchdog_schedule_ns);
void qdisc_watchdog_cancel(struct qdisc_watchdog *wd)
{
hrtimer_cancel(&wd->timer);
- qdisc_unthrottled(wd->qdisc);
}
EXPORT_SYMBOL(qdisc_watchdog_cancel);
diff --git a/net/sched/sch_cbq.c b/net/sched/sch_cbq.c
index 6e61f9aa8783..a29fd811d7b9 100644
--- a/net/sched/sch_cbq.c
+++ b/net/sched/sch_cbq.c
@@ -513,7 +513,6 @@ static enum hrtimer_restart cbq_undelay(struct hrtimer *timer)
hrtimer_start(&q->delay_timer, time, HRTIMER_MODE_ABS_PINNED);
}
- qdisc_unthrottled(sch);
__netif_schedule(qdisc_root(sch));
return HRTIMER_NORESTART;
}
@@ -819,7 +818,6 @@ cbq_dequeue(struct Qdisc *sch)
if (skb) {
qdisc_bstats_update(sch, skb);
sch->q.qlen--;
- qdisc_unthrottled(sch);
return skb;
}
diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c
index 3c6a47d66a04..f49c81e91acd 100644
--- a/net/sched/sch_fq.c
+++ b/net/sched/sch_fq.c
@@ -445,8 +445,7 @@ begin:
if (!head->first) {
if (q->time_next_delayed_flow != ~0ULL)
qdisc_watchdog_schedule_ns(&q->watchdog,
- q->time_next_delayed_flow,
- false);
+ q->time_next_delayed_flow);
return NULL;
}
}
diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
index eb3d3f5aba80..bd08c363a26d 100644
--- a/net/sched/sch_hfsc.c
+++ b/net/sched/sch_hfsc.c
@@ -1664,7 +1664,6 @@ hfsc_dequeue(struct Qdisc *sch)
set_passive(cl);
}
- qdisc_unthrottled(sch);
qdisc_bstats_update(sch, skb);
qdisc_qstats_backlog_dec(sch, skb);
sch->q.qlen--;
diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index b74d06668ab4..07dcd2933f01 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -889,7 +889,6 @@ static struct sk_buff *htb_dequeue(struct Qdisc *sch)
if (skb != NULL) {
ok:
qdisc_bstats_update(sch, skb);
- qdisc_unthrottled(sch);
qdisc_qstats_backlog_dec(sch, skb);
sch->q.qlen--;
return skb;
@@ -929,7 +928,7 @@ ok:
}
qdisc_qstats_overlimit(sch);
if (likely(next_event > q->now))
- qdisc_watchdog_schedule_ns(&q->watchdog, next_event, true);
+ qdisc_watchdog_schedule_ns(&q->watchdog, next_event);
else
schedule_work(&q->work);
fin:
diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index 2dbe732ca135..876df13c745a 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -587,7 +587,6 @@ tfifo_dequeue:
if (skb) {
qdisc_qstats_backlog_dec(sch, skb);
deliver:
- qdisc_unthrottled(sch);
qdisc_bstats_update(sch, skb);
return skb;
}
diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
index 7fa3d6e1291c..c12df84d1078 100644
--- a/net/sched/sch_tbf.c
+++ b/net/sched/sch_tbf.c
@@ -254,14 +254,12 @@ static struct sk_buff *tbf_dequeue(struct Qdisc *sch)
q->ptokens = ptoks;
qdisc_qstats_backlog_dec(sch, skb);
sch->q.qlen--;
- qdisc_unthrottled(sch);
qdisc_bstats_update(sch, skb);
return skb;
}
qdisc_watchdog_schedule_ns(&q->watchdog,
- now + max_t(long, -toks, -ptoks),
- true);
+ now + max_t(long, -toks, -ptoks));
/* Maybe we have a shorter packet in the queue,
which can be sent now. It sounds cool,
--
2.8.0.rc3.226.g39d4020
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