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Message-ID: <20080918063036.27934.91273.stgit@localhost.localdomain>
Date: Wed, 17 Sep 2008 23:43:02 -0700
From: Alexander Duyck <alexander.h.duyck@...el.com>
To: netdev@...r.kernel.org
Cc: jarkao2@...il.com, herbert@...dor.apana.org.au, davem@...eloft.net,
kaber@...sh.net
Subject: [RFC PATCH] sched: only dequeue if packet can be queued to hardware
queue.
This this patch is mangled I appologize, this is my first try sending
a patch directly to netdev.
The patch below is my attempt to resolve the issue found with qdisc_run
only checking the state of queue zero before running. This approach
essentially makes the qdisc layer smart enough to do it's own check to
see if a hw queue is stopped instead of relying on other calls to check
beforehand.
I have been able to verify functionality for most qdiscs with the
exceptions of netem, red, sfq, and tbf. I am not familiar with the
operation of these qdiscs and so I am not certain how to avoid the high
drop rate I am currently seeing when using these qdiscs.
The main advantages of this patch can be seen using a netperf UDP_STREAM
test to a slow interface with multiple queues and a qdisc such as pfifo,
bfifo, or prio. For my testing I used an 82575 with 4 queues on a
system with 8 cpus. When any queue other than 0 was used in the old
method the cpu utilization for one core would go to 100%, using this new
approach the cpu utilization for all queues was at the same level queue
0 was with the old approach.
---
This patch changes the behavior of the sch->dequeue to only
dequeue a packet if the queue it is bound for is not currently
stopped. This functionality is provided via a new op called
smart_dequeue.
Signed-off-by: Alexander Duyck <alexander.h.duyck@...el.com>
---
include/net/pkt_sched.h | 5 --
include/net/sch_generic.h | 27 ++++++++++
net/sched/sch_atm.c | 22 ++++++++
net/sched/sch_blackhole.c | 1
net/sched/sch_cbq.c | 118 ++++++++++++++++++++++++++++++++++++++++++++-
net/sched/sch_dsmark.c | 47 ++++++++++++++++++
net/sched/sch_fifo.c | 2 +
net/sched/sch_generic.c | 30 +++++++++--
net/sched/sch_gred.c | 34 +++++++++++++
net/sched/sch_hfsc.c | 86 ++++++++++++++++++++++++++++++++-
net/sched/sch_htb.c | 82 ++++++++++++++++++++++++++++++-
net/sched/sch_multiq.c | 45 ++++++++++++++---
net/sched/sch_netem.c | 40 +++++++++++++++
net/sched/sch_prio.c | 23 +++++++++
net/sched/sch_red.c | 22 ++++++++
net/sched/sch_sfq.c | 46 ++++++++++++++++--
net/sched/sch_tbf.c | 66 +++++++++++++++++++++++++
net/sched/sch_teql.c | 49 ++++++++++++++++---
18 files changed, 706 insertions(+), 39 deletions(-)
diff --git a/include/net/pkt_sched.h b/include/net/pkt_sched.h
index b786a5b..4082f39 100644
--- a/include/net/pkt_sched.h
+++ b/include/net/pkt_sched.h
@@ -90,10 +90,7 @@ extern void __qdisc_run(struct Qdisc *q);
static inline void qdisc_run(struct Qdisc *q)
{
- struct netdev_queue *txq = q->dev_queue;
-
- if (!netif_tx_queue_stopped(txq) &&
- !test_and_set_bit(__QDISC_STATE_RUNNING, &q->state))
+ if (!test_and_set_bit(__QDISC_STATE_RUNNING, &q->state))
__qdisc_run(q);
}
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index e556962..4400a18 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -45,6 +45,7 @@ struct Qdisc
#define TCQ_F_BUILTIN 1
#define TCQ_F_THROTTLED 2
#define TCQ_F_INGRESS 4
+#define TCQ_F_STOPPED 8
int padded;
struct Qdisc_ops *ops;
struct qdisc_size_table *stab;
@@ -110,6 +111,7 @@ struct Qdisc_ops
int (*enqueue)(struct sk_buff *, struct Qdisc *);
struct sk_buff * (*dequeue)(struct Qdisc *);
+ struct sk_buff * (*smart_dequeue)(struct Qdisc *);
int (*requeue)(struct sk_buff *, struct Qdisc *);
unsigned int (*drop)(struct Qdisc *);
@@ -399,6 +401,31 @@ static inline int qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch)
return __qdisc_enqueue_tail(skb, sch, &sch->q);
}
+static inline struct sk_buff *__qdisc_smart_dequeue(struct Qdisc *sch,
+ struct sk_buff_head *list)
+{
+ struct sk_buff *skb = skb_peek(list);
+ struct netdev_queue *txq;
+
+ if (!skb)
+ return NULL;
+
+ txq = netdev_get_tx_queue(qdisc_dev(sch), skb_get_queue_mapping(skb));
+ if (netif_tx_queue_stopped(txq) || netif_tx_queue_frozen(txq)) {
+ sch->flags |= TCQ_F_STOPPED;
+ return NULL;
+ }
+ __skb_unlink(skb, list);
+ sch->qstats.backlog -= qdisc_pkt_len(skb);
+ sch->flags &= ~TCQ_F_STOPPED;
+ return skb;
+}
+
+static inline struct sk_buff *qdisc_smart_dequeue(struct Qdisc *sch)
+{
+ return __qdisc_smart_dequeue(sch, &sch->q);
+}
+
static inline struct sk_buff *__qdisc_dequeue_head(struct Qdisc *sch,
struct sk_buff_head *list)
{
diff --git a/net/sched/sch_atm.c b/net/sched/sch_atm.c
index 43d3725..91a40b2 100644
--- a/net/sched/sch_atm.c
+++ b/net/sched/sch_atm.c
@@ -516,12 +516,31 @@ static struct sk_buff *atm_tc_dequeue(struct Qdisc *sch)
pr_debug("atm_tc_dequeue(sch %p,[qdisc %p])\n", sch, p);
tasklet_schedule(&p->task);
- skb = p->link.q->dequeue(p->link.q);
+ skb = p->link.q->ops->dequeue(p->link.q);
if (skb)
sch->q.qlen--;
return skb;
}
+static struct sk_buff *atm_tc_smart_dequeue(struct Qdisc *sch)
+{
+ struct atm_qdisc_data *p = qdisc_priv(sch);
+ struct sk_buff *skb;
+
+ pr_debug("atm_tc_smart_dequeue(sch %p,[qdisc %p])\n", sch, p);
+ tasklet_schedule(&p->task);
+ skb = p->link.q->dequeue(p->link.q);
+ if (skb) {
+ sch->q.qlen--;
+ sch->flags &= ~TCQ_F_STOPPED;
+ } else {
+ if (p->link.q->flags & TCQ_F_STOPPED)
+ sch->flags |= TCQ_F_STOPPED;
+ }
+
+ return skb;
+}
+
static int atm_tc_requeue(struct sk_buff *skb, struct Qdisc *sch)
{
struct atm_qdisc_data *p = qdisc_priv(sch);
@@ -694,6 +713,7 @@ static struct Qdisc_ops atm_qdisc_ops __read_mostly = {
.priv_size = sizeof(struct atm_qdisc_data),
.enqueue = atm_tc_enqueue,
.dequeue = atm_tc_dequeue,
+ .smart_dequeue = atm_tc_smart_dequeue,
.requeue = atm_tc_requeue,
.drop = atm_tc_drop,
.init = atm_tc_init,
diff --git a/net/sched/sch_blackhole.c b/net/sched/sch_blackhole.c
index 507fb48..48e6909 100644
--- a/net/sched/sch_blackhole.c
+++ b/net/sched/sch_blackhole.c
@@ -33,6 +33,7 @@ static struct Qdisc_ops blackhole_qdisc_ops __read_mostly = {
.priv_size = 0,
.enqueue = blackhole_enqueue,
.dequeue = blackhole_dequeue,
+ .smart_dequeue = blackhole_dequeue,
.owner = THIS_MODULE,
};
diff --git a/net/sched/sch_cbq.c b/net/sched/sch_cbq.c
index 8b06fa9..5ec6040 100644
--- a/net/sched/sch_cbq.c
+++ b/net/sched/sch_cbq.c
@@ -851,7 +851,7 @@ cbq_under_limit(struct cbq_class *cl)
}
static __inline__ struct sk_buff *
-cbq_dequeue_prio(struct Qdisc *sch, int prio)
+cbq_dequeue_prio(struct Qdisc *sch, int prio, int *stopped)
{
struct cbq_sched_data *q = qdisc_priv(sch);
struct cbq_class *cl_tail, *cl_prev, *cl;
@@ -881,7 +881,10 @@ cbq_dequeue_prio(struct Qdisc *sch, int prio)
goto next_class;
}
- skb = cl->q->dequeue(cl->q);
+ if (stopped)
+ skb = cl->q->dequeue(cl->q);
+ else
+ skb = cl->q->ops->dequeue(cl->q);
/* Class did not give us any skb :-(
It could occur even if cl->q->q.qlen != 0
@@ -912,6 +915,11 @@ cbq_dequeue_prio(struct Qdisc *sch, int prio)
return skb;
skip_class:
+ if (stopped && (cl->q->flags & TCQ_F_STOPPED)) {
+ *stopped = true;
+ return NULL;
+ }
+
if (cl->q->q.qlen == 0 || prio != cl->cpriority) {
/* Class is empty or penalized.
Unlink it from active chain.
@@ -964,7 +972,7 @@ cbq_dequeue_1(struct Qdisc *sch)
while (activemask) {
int prio = ffz(~activemask);
activemask &= ~(1<<prio);
- skb = cbq_dequeue_prio(sch, prio);
+ skb = cbq_dequeue_prio(sch, prio, NULL);
if (skb)
return skb;
}
@@ -1048,6 +1056,109 @@ cbq_dequeue(struct Qdisc *sch)
return NULL;
}
+static __inline__ struct sk_buff *
+cbq_smart_dequeue_1(struct Qdisc *sch)
+{
+ struct cbq_sched_data *q = qdisc_priv(sch);
+ struct sk_buff *skb;
+ unsigned activemask;
+ int stopped = false;
+
+ activemask = q->activemask&0xFF;
+ while (activemask) {
+ int prio = ffz(~activemask);
+ activemask &= ~(1<<prio);
+ skb = cbq_dequeue_prio(sch, prio, &stopped);
+ if (skb)
+ return skb;
+ if (stopped) {
+ sch->flags |= TCQ_F_STOPPED;
+ break;
+ }
+ }
+ return NULL;
+}
+
+static struct sk_buff *
+cbq_smart_dequeue(struct Qdisc *sch)
+{
+ struct sk_buff *skb;
+ struct cbq_sched_data *q = qdisc_priv(sch);
+ psched_time_t now;
+ psched_tdiff_t incr;
+
+ now = psched_get_time();
+ incr = now - q->now_rt;
+
+ if (q->tx_class) {
+ psched_tdiff_t incr2;
+ /* Time integrator. We calculate EOS time
+ by adding expected packet transmission time.
+ If real time is greater, we warp artificial clock,
+ so that:
+
+ cbq_time = max(real_time, work);
+ */
+ incr2 = L2T(&q->link, q->tx_len);
+ q->now += incr2;
+ cbq_update(q);
+ incr -= incr2;
+ if (incr < 0)
+ incr = 0;
+ }
+ q->now += incr;
+ q->now_rt = now;
+
+ for (;;) {
+ q->wd_expires = 0;
+
+ skb = cbq_smart_dequeue_1(sch);
+ if (skb) {
+ sch->q.qlen--;
+ sch->flags &= ~(TCQ_F_THROTTLED | TCQ_F_STOPPED);
+ return skb;
+ }
+
+ if (sch->flags & TCQ_F_STOPPED)
+ return NULL;
+
+ /* All the classes are overlimit.
+
+ It is possible, if:
+
+ 1. Scheduler is empty.
+ 2. Toplevel cutoff inhibited borrowing.
+ 3. Root class is overlimit.
+
+ Reset 2d and 3d conditions and retry.
+
+ Note, that NS and cbq-2.0 are buggy, peeking
+ an arbitrary class is appropriate for ancestor-only
+ sharing, but not for toplevel algorithm.
+
+ Our version is better, but slower, because it requires
+ two passes, but it is unavoidable with top-level sharing.
+ */
+
+ if (q->toplevel == TC_CBQ_MAXLEVEL &&
+ q->link.undertime == PSCHED_PASTPERFECT)
+ break;
+
+ q->toplevel = TC_CBQ_MAXLEVEL;
+ q->link.undertime = PSCHED_PASTPERFECT;
+ }
+
+ /* No packets in scheduler or nobody wants to give them to us :-(
+ Sigh... start watchdog timer in the last case. */
+
+ if (sch->q.qlen) {
+ sch->qstats.overlimits++;
+ if (q->wd_expires)
+ qdisc_watchdog_schedule(&q->watchdog,
+ now + q->wd_expires);
+ }
+ return NULL;
+}
/* CBQ class maintanance routines */
static void cbq_adjust_levels(struct cbq_class *this)
@@ -2065,6 +2176,7 @@ static struct Qdisc_ops cbq_qdisc_ops __read_mostly = {
.priv_size = sizeof(struct cbq_sched_data),
.enqueue = cbq_enqueue,
.dequeue = cbq_dequeue,
+ .smart_dequeue = cbq_smart_dequeue,
.requeue = cbq_requeue,
.drop = cbq_drop,
.init = cbq_init,
diff --git a/net/sched/sch_dsmark.c b/net/sched/sch_dsmark.c
index edd1298..21da7af 100644
--- a/net/sched/sch_dsmark.c
+++ b/net/sched/sch_dsmark.c
@@ -313,6 +313,52 @@ static struct sk_buff *dsmark_dequeue(struct Qdisc *sch)
return skb;
}
+static struct sk_buff *dsmark_smart_dequeue(struct Qdisc *sch)
+{
+ struct dsmark_qdisc_data *p = qdisc_priv(sch);
+ struct sk_buff *skb;
+ u32 index;
+
+ pr_debug("dsmark_smart_dequeue(sch %p,[qdisc %p])\n", sch, p);
+
+ skb = p->q->dequeue(p->q);
+ if (skb == NULL) {
+ if (p->q->flags & TCQ_F_STOPPED)
+ sch->flags |= TCQ_F_STOPPED;
+ return NULL;
+ }
+
+ sch->q.qlen--;
+ sch->flags &= ~TCQ_F_STOPPED;
+
+ index = skb->tc_index & (p->indices - 1);
+ pr_debug("index %d->%d\n", skb->tc_index, index);
+
+ switch (skb->protocol) {
+ case __constant_htons(ETH_P_IP):
+ ipv4_change_dsfield(ip_hdr(skb), p->mask[index],
+ p->value[index]);
+ break;
+ case __constant_htons(ETH_P_IPV6):
+ ipv6_change_dsfield(ipv6_hdr(skb), p->mask[index],
+ p->value[index]);
+ break;
+ default:
+ /*
+ * Only complain if a change was actually attempted.
+ * This way, we can send non-IP traffic through dsmark
+ * and don't need yet another qdisc as a bypass.
+ */
+ if (p->mask[index] != 0xff || p->value[index])
+ printk(KERN_WARNING
+ "dsmark_smart_dequeue: unsupported protocol %d"
+ "\n", ntohs(skb->protocol));
+ break;
+ }
+
+ return skb;
+}
+
static int dsmark_requeue(struct sk_buff *skb, struct Qdisc *sch)
{
struct dsmark_qdisc_data *p = qdisc_priv(sch);
@@ -496,6 +542,7 @@ static struct Qdisc_ops dsmark_qdisc_ops __read_mostly = {
.priv_size = sizeof(struct dsmark_qdisc_data),
.enqueue = dsmark_enqueue,
.dequeue = dsmark_dequeue,
+ .smart_dequeue = dsmark_smart_dequeue,
.requeue = dsmark_requeue,
.drop = dsmark_drop,
.init = dsmark_init,
diff --git a/net/sched/sch_fifo.c b/net/sched/sch_fifo.c
index 23d258b..15f28f6 100644
--- a/net/sched/sch_fifo.c
+++ b/net/sched/sch_fifo.c
@@ -83,6 +83,7 @@ struct Qdisc_ops pfifo_qdisc_ops __read_mostly = {
.priv_size = sizeof(struct fifo_sched_data),
.enqueue = pfifo_enqueue,
.dequeue = qdisc_dequeue_head,
+ .smart_dequeue = qdisc_smart_dequeue,
.requeue = qdisc_requeue,
.drop = qdisc_queue_drop,
.init = fifo_init,
@@ -98,6 +99,7 @@ struct Qdisc_ops bfifo_qdisc_ops __read_mostly = {
.priv_size = sizeof(struct fifo_sched_data),
.enqueue = bfifo_enqueue,
.dequeue = qdisc_dequeue_head,
+ .smart_dequeue = qdisc_smart_dequeue,
.requeue = qdisc_requeue,
.drop = qdisc_queue_drop,
.init = fifo_init,
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index ec0a083..f32cb83 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -135,8 +135,7 @@ static inline int qdisc_restart(struct Qdisc *q)
txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
HARD_TX_LOCK(dev, txq, smp_processor_id());
- if (!netif_tx_queue_stopped(txq) &&
- !netif_tx_queue_frozen(txq))
+ if (!netif_tx_queue_stopped(txq) && !netif_tx_queue_frozen(txq))
ret = dev_hard_start_xmit(skb, dev, txq);
HARD_TX_UNLOCK(dev, txq);
@@ -163,10 +162,6 @@ static inline int qdisc_restart(struct Qdisc *q)
break;
}
- if (ret && (netif_tx_queue_stopped(txq) ||
- netif_tx_queue_frozen(txq)))
- ret = 0;
-
return ret;
}
@@ -313,6 +308,7 @@ struct Qdisc_ops noop_qdisc_ops __read_mostly = {
.priv_size = 0,
.enqueue = noop_enqueue,
.dequeue = noop_dequeue,
+ .smart_dequeue = noop_dequeue,
.requeue = noop_requeue,
.owner = THIS_MODULE,
};
@@ -337,6 +333,7 @@ static struct Qdisc_ops noqueue_qdisc_ops __read_mostly = {
.priv_size = 0,
.enqueue = noop_enqueue,
.dequeue = noop_dequeue,
+ .smart_dequeue = noop_dequeue,
.requeue = noop_requeue,
.owner = THIS_MODULE,
};
@@ -400,6 +397,24 @@ static struct sk_buff *pfifo_fast_dequeue(struct Qdisc* qdisc)
return NULL;
}
+static struct sk_buff *pfifo_fast_smart_dequeue(struct Qdisc* qdisc)
+{
+ int prio;
+ struct sk_buff_head *list = qdisc_priv(qdisc);
+ struct sk_buff *skb;
+
+ for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
+ if (!skb_queue_empty(list + prio)) {
+ skb = __qdisc_smart_dequeue(qdisc, list + prio);
+ if (skb != NULL)
+ qdisc->q.qlen--;
+ return skb;
+ }
+ }
+
+ return NULL;
+}
+
static int pfifo_fast_requeue(struct sk_buff *skb, struct Qdisc* qdisc)
{
qdisc->q.qlen++;
@@ -446,6 +461,7 @@ static struct Qdisc_ops pfifo_fast_ops __read_mostly = {
.priv_size = PFIFO_FAST_BANDS * sizeof(struct sk_buff_head),
.enqueue = pfifo_fast_enqueue,
.dequeue = pfifo_fast_dequeue,
+ .smart_dequeue = pfifo_fast_smart_dequeue,
.requeue = pfifo_fast_requeue,
.init = pfifo_fast_init,
.reset = pfifo_fast_reset,
@@ -475,7 +491,7 @@ struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
skb_queue_head_init(&sch->q);
sch->ops = ops;
sch->enqueue = ops->enqueue;
- sch->dequeue = ops->dequeue;
+ sch->dequeue = ops->smart_dequeue;
sch->dev_queue = dev_queue;
dev_hold(qdisc_dev(sch));
atomic_set(&sch->refcnt, 1);
diff --git a/net/sched/sch_gred.c b/net/sched/sch_gred.c
index c1ad6b8..5d1654f 100644
--- a/net/sched/sch_gred.c
+++ b/net/sched/sch_gred.c
@@ -292,6 +292,39 @@ static struct sk_buff *gred_dequeue(struct Qdisc* sch)
return NULL;
}
+static struct sk_buff *gred_smart_dequeue(struct Qdisc* sch)
+{
+ struct sk_buff *skb;
+ struct gred_sched *t = qdisc_priv(sch);
+
+ skb = qdisc_smart_dequeue(sch);
+
+ if (skb) {
+ struct gred_sched_data *q;
+ u16 dp = tc_index_to_dp(skb);
+
+ if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
+ if (net_ratelimit())
+ printk(KERN_WARNING "GRED: Unable to relocate "
+ "VQ 0x%x after dequeue, screwing up "
+ "backlog.\n", tc_index_to_dp(skb));
+ } else {
+ q->backlog -= qdisc_pkt_len(skb);
+
+ if (!q->backlog && !gred_wred_mode(t))
+ red_start_of_idle_period(&q->parms);
+ }
+
+ return skb;
+ }
+
+ if (!(sch->flags & TCQ_F_STOPPED) && gred_wred_mode(t) &&
+ !red_is_idling(&t->wred_set))
+ red_start_of_idle_period(&t->wred_set);
+
+ return NULL;
+}
+
static unsigned int gred_drop(struct Qdisc* sch)
{
struct sk_buff *skb;
@@ -602,6 +635,7 @@ static struct Qdisc_ops gred_qdisc_ops __read_mostly = {
.priv_size = sizeof(struct gred_sched),
.enqueue = gred_enqueue,
.dequeue = gred_dequeue,
+ .smart_dequeue = gred_smart_dequeue,
.requeue = gred_requeue,
.drop = gred_drop,
.init = gred_init,
diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
index c1e77da..2060250 100644
--- a/net/sched/sch_hfsc.c
+++ b/net/sched/sch_hfsc.c
@@ -889,7 +889,7 @@ qdisc_peek_len(struct Qdisc *sch)
struct sk_buff *skb;
unsigned int len;
- skb = sch->dequeue(sch);
+ skb = sch->ops->dequeue(sch);
if (skb == NULL) {
if (net_ratelimit())
printk("qdisc_peek_len: non work-conserving qdisc ?\n");
@@ -1642,7 +1642,7 @@ hfsc_dequeue(struct Qdisc *sch)
}
}
- skb = cl->qdisc->dequeue(cl->qdisc);
+ skb = cl->qdisc->ops->dequeue(cl->qdisc);
if (skb == NULL) {
if (net_ratelimit())
printk("HFSC: Non-work-conserving qdisc ?\n");
@@ -1674,6 +1674,87 @@ hfsc_dequeue(struct Qdisc *sch)
return skb;
}
+static struct sk_buff *
+hfsc_smart_dequeue(struct Qdisc *sch)
+{
+ struct hfsc_sched *q = qdisc_priv(sch);
+ struct hfsc_class *cl;
+ struct sk_buff *skb;
+ u64 cur_time;
+ unsigned int next_len;
+ int realtime = 0;
+
+ if (sch->q.qlen == 0)
+ return NULL;
+ skb = skb_peek(&q->requeue);
+ if (skb) {
+ struct netdev_queue *txq;
+ txq = netdev_get_tx_queue(qdisc_dev(sch),
+ skb_get_queue_mapping(skb));
+ if (netif_tx_queue_stopped(txq) ||
+ netif_tx_queue_frozen(txq)) {
+ sch->flags |= TCQ_F_STOPPED;
+ return NULL;
+ }
+ __skb_unlink(skb, &q->requeue);
+ goto out;
+ }
+
+ cur_time = psched_get_time();
+
+ /*
+ * if there are eligible classes, use real-time criteria.
+ * find the class with the minimum deadline among
+ * the eligible classes.
+ */
+ cl = eltree_get_mindl(q, cur_time);
+ if (cl != NULL) {
+ realtime = 1;
+ } else {
+ /*
+ * use link-sharing criteria
+ * get the class with the minimum vt in the hierarchy
+ */
+ cl = vttree_get_minvt(&q->root, cur_time);
+ if (cl == NULL) {
+ sch->qstats.overlimits++;
+ hfsc_schedule_watchdog(sch);
+ return NULL;
+ }
+ }
+
+ skb = cl->qdisc->dequeue(cl->qdisc);
+ if (skb == NULL) {
+ if (net_ratelimit())
+ printk("HFSC: Non-work-conserving qdisc ?\n");
+ return NULL;
+ }
+
+ update_vf(cl, qdisc_pkt_len(skb), cur_time);
+ if (realtime)
+ cl->cl_cumul += qdisc_pkt_len(skb);
+
+ if (cl->qdisc->q.qlen != 0) {
+ if (cl->cl_flags & HFSC_RSC) {
+ /* update ed */
+ next_len = qdisc_peek_len(cl->qdisc);
+ if (realtime)
+ update_ed(cl, next_len);
+ else
+ update_d(cl, next_len);
+ }
+ } else {
+ /* the class becomes passive */
+ set_passive(cl);
+ }
+
+ out:
+ sch->flags &= ~(TCQ_F_THROTTLED | TCQ_F_STOPPED);
+ sch->q.qlen--;
+
+ return skb;
+}
+
static int
hfsc_requeue(struct sk_buff *skb, struct Qdisc *sch)
{
@@ -1735,6 +1816,7 @@ static struct Qdisc_ops hfsc_qdisc_ops __read_mostly = {
.dump = hfsc_dump_qdisc,
.enqueue = hfsc_enqueue,
.dequeue = hfsc_dequeue,
+ .smart_dequeue = hfsc_smart_dequeue,
.requeue = hfsc_requeue,
.drop = hfsc_drop,
.cl_ops = &hfsc_class_ops,
diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index d14f020..4da1a85 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -803,7 +803,7 @@ static struct htb_class *htb_lookup_leaf(struct rb_root *tree, int prio,
/* dequeues packet at given priority and level; call only if
you are sure that there is active class at prio/level */
static struct sk_buff *htb_dequeue_tree(struct htb_sched *q, int prio,
- int level)
+ int level, int *stopped)
{
struct sk_buff *skb = NULL;
struct htb_class *cl, *start;
@@ -840,9 +840,17 @@ next:
goto next;
}
- skb = cl->un.leaf.q->dequeue(cl->un.leaf.q);
+ if (stopped)
+ skb = cl->un.leaf.q->dequeue(cl->un.leaf.q);
+ else
+ skb = cl->un.leaf.q->ops->dequeue(cl->un.leaf.q);
+
if (likely(skb != NULL))
break;
+ if (stopped && (cl->un.leaf.q->flags & TCQ_F_STOPPED)) {
+ *stopped = true;
+ break;
+ }
if (!cl->warned) {
printk(KERN_WARNING
"htb: class %X isn't work conserving ?!\n",
@@ -915,7 +923,7 @@ static struct sk_buff *htb_dequeue(struct Qdisc *sch)
while (m != (int)(-1)) {
int prio = ffz(m);
m |= 1 << prio;
- skb = htb_dequeue_tree(q, prio, level);
+ skb = htb_dequeue_tree(q, prio, level, NULL);
if (likely(skb != NULL)) {
sch->q.qlen--;
sch->flags &= ~TCQ_F_THROTTLED;
@@ -929,6 +937,73 @@ fin:
return skb;
}
+static struct sk_buff *htb_smart_dequeue(struct Qdisc *sch)
+{
+ struct sk_buff *skb = NULL;
+ struct htb_sched *q = qdisc_priv(sch);
+ int level, stopped = false;
+ psched_time_t next_event;
+
+ /* try to dequeue direct packets as high prio (!) to minimize cpu work */
+ skb = skb_peek(&q->direct_queue);
+ if (skb) {
+ struct netdev_queue *txq;
+ txq = netdev_get_tx_queue(qdisc_dev(sch),
+ skb_get_queue_mapping(skb));
+ if (netif_tx_queue_stopped(txq) ||
+ netif_tx_queue_frozen(txq)) {
+ sch->flags |= TCQ_F_STOPPED;
+ return NULL;
+ }
+ __skb_unlink(skb, &q->direct_queue);
+ sch->flags &= ~(TCQ_F_THROTTLED | TCQ_F_STOPPED);
+ sch->q.qlen--;
+ return skb;
+ }
+
+ if (!sch->q.qlen)
+ goto fin;
+ q->now = psched_get_time();
+
+ next_event = q->now + 5 * PSCHED_TICKS_PER_SEC;
+ q->nwc_hit = 0;
+ for (level = 0; level < TC_HTB_MAXDEPTH; level++) {
+ /* common case optimization - skip event handler quickly */
+ int m;
+ psched_time_t event;
+
+ if (q->now >= q->near_ev_cache[level]) {
+ event = htb_do_events(q, level);
+ if (!event)
+ event = q->now + PSCHED_TICKS_PER_SEC;
+ q->near_ev_cache[level] = event;
+ } else
+ event = q->near_ev_cache[level];
+
+ if (event && next_event > event)
+ next_event = event;
+
+ m = ~q->row_mask[level];
+ while (m != (int)(-1)) {
+ int prio = ffz(m);
+ m |= 1 << prio;
+ skb = htb_dequeue_tree(q, prio, level, &stopped);
+ if (likely(skb != NULL)) {
+ sch->q.qlen--;
+ sch->flags &= ~(TCQ_F_THROTTLED |
+ TCQ_F_STOPPED);
+ goto fin;
+ }
+ if (stopped)
+ goto fin;
+ }
+ }
+ sch->qstats.overlimits++;
+ qdisc_watchdog_schedule(&q->watchdog, next_event);
+fin:
+ return skb;
+}
+
/* try to drop from each class (by prio) until one succeed */
static unsigned int htb_drop(struct Qdisc *sch)
{
@@ -1565,6 +1640,7 @@ static struct Qdisc_ops htb_qdisc_ops __read_mostly = {
.priv_size = sizeof(struct htb_sched),
.enqueue = htb_enqueue,
.dequeue = htb_dequeue,
+ .smart_dequeue = htb_smart_dequeue,
.requeue = htb_requeue,
.drop = htb_drop,
.init = htb_init,
diff --git a/net/sched/sch_multiq.c b/net/sched/sch_multiq.c
index 7f4dbf0..e201171 100644
--- a/net/sched/sch_multiq.c
+++ b/net/sched/sch_multiq.c
@@ -142,15 +142,45 @@ static struct sk_buff *multiq_dequeue(struct Qdisc *sch)
/* Check that target subqueue is available before
* pulling an skb to avoid excessive requeues
*/
- if (!__netif_subqueue_stopped(qdisc_dev(sch), q->curband)) {
- qdisc = q->queues[q->curband];
- skb = qdisc->dequeue(qdisc);
- if (skb) {
- sch->q.qlen--;
- return skb;
- }
+ qdisc = q->queues[q->curband];
+ skb = qdisc->ops->dequeue(qdisc);
+ if (skb) {
+ sch->q.qlen--;
+ return skb;
+ }
+ }
+ return NULL;
+
+}
+
+static struct sk_buff *multiq_smart_dequeue(struct Qdisc *sch)
+{
+ struct multiq_sched_data *q = qdisc_priv(sch);
+ struct Qdisc *qdisc;
+ struct sk_buff *skb;
+ int band, stopped = 0;
+
+ for (band = 0; band < q->bands; band++) {
+ /* cycle through bands to ensure fairness */
+ q->curband++;
+ if (q->curband >= q->bands)
+ q->curband = 0;
+
+ /* Check that target subqueue is available before
+ * pulling an skb to avoid excessive requeues
+ */
+ qdisc = q->queues[q->curband];
+ skb = qdisc->dequeue(qdisc);
+ if (skb) {
+ sch->q.qlen--;
+ sch->flags &= ~TCQ_F_STOPPED;
+ return skb;
}
+ if (qdisc->flags & TCQ_F_STOPPED)
+ stopped++;
}
+ if (stopped)
+ sch->flags |= TCQ_F_STOPPED;
return NULL;
}
@@ -448,6 +478,7 @@ static struct Qdisc_ops multiq_qdisc_ops __read_mostly = {
.priv_size = sizeof(struct multiq_sched_data),
.enqueue = multiq_enqueue,
.dequeue = multiq_dequeue,
+ .smart_dequeue = multiq_smart_dequeue,
.requeue = multiq_requeue,
.drop = multiq_drop,
.init = multiq_init,
diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index a119599..47dfe8e 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -283,7 +283,7 @@ static struct sk_buff *netem_dequeue(struct Qdisc *sch)
if (sch->flags & TCQ_F_THROTTLED)
return NULL;
- skb = q->qdisc->dequeue(q->qdisc);
+ skb = q->qdisc->ops->dequeue(q->qdisc);
if (skb) {
const struct netem_skb_cb *cb = netem_skb_cb(skb);
psched_time_t now = psched_get_time();
@@ -308,6 +308,42 @@ static struct sk_buff *netem_dequeue(struct Qdisc *sch)
return NULL;
}
+static struct sk_buff *netem_smart_dequeue(struct Qdisc *sch)
+{
+ struct netem_sched_data *q = qdisc_priv(sch);
+ struct sk_buff *skb;
+
+ smp_mb();
+ if (sch->flags & TCQ_F_THROTTLED)
+ return NULL;
+
+ skb = q->qdisc->dequeue(q->qdisc);
+ if (skb) {
+ const struct netem_skb_cb *cb = netem_skb_cb(skb);
+ psched_time_t now = psched_get_time();
+
+ /* if more time remaining? */
+ if (cb->time_to_send <= now) {
+ pr_debug("netem_dequeue: return skb=%p\n", skb);
+ sch->q.qlen--;
+ sch->flags &= ~TCQ_F_STOPPED;
+ return skb;
+ }
+
+ if (unlikely(q->qdisc->ops->requeue(skb, q->qdisc) != NET_XMIT_SUCCESS)) {
+ qdisc_tree_decrease_qlen(q->qdisc, 1);
+ sch->qstats.drops++;
+ printk(KERN_ERR "netem: %s could not requeue\n",
+ q->qdisc->ops->id);
+ }
+
+ qdisc_watchdog_schedule(&q->watchdog, cb->time_to_send);
+ } else if (q->qdisc->flags & TCQ_F_STOPPED) {
+ sch->flags |= TCQ_F_STOPPED;
+ }
+
+ return NULL;
+}
static void netem_reset(struct Qdisc *sch)
{
struct netem_sched_data *q = qdisc_priv(sch);
@@ -541,6 +577,7 @@ static struct Qdisc_ops tfifo_qdisc_ops __read_mostly = {
.priv_size = sizeof(struct fifo_sched_data),
.enqueue = tfifo_enqueue,
.dequeue = qdisc_dequeue_head,
+ .smart_dequeue = qdisc_smart_dequeue,
.requeue = qdisc_requeue,
.drop = qdisc_queue_drop,
.init = tfifo_init,
@@ -716,6 +753,7 @@ static struct Qdisc_ops netem_qdisc_ops __read_mostly = {
.priv_size = sizeof(struct netem_sched_data),
.enqueue = netem_enqueue,
.dequeue = netem_dequeue,
+ .smart_dequeue = netem_smart_dequeue,
.requeue = netem_requeue,
.drop = netem_drop,
.init = netem_init,
diff --git a/net/sched/sch_prio.c b/net/sched/sch_prio.c
index 504a78c..f085dbe 100644
--- a/net/sched/sch_prio.c
+++ b/net/sched/sch_prio.c
@@ -128,11 +128,33 @@ static struct sk_buff *prio_dequeue(struct Qdisc* sch)
for (prio = 0; prio < q->bands; prio++) {
struct Qdisc *qdisc = q->queues[prio];
+ struct sk_buff *skb = qdisc->ops->dequeue(qdisc);
+ if (skb) {
+ sch->q.qlen--;
+ return skb;
+ }
+ }
+ return NULL;
+
+}
+
+static struct sk_buff *prio_smart_dequeue(struct Qdisc* sch)
+{
+ struct prio_sched_data *q = qdisc_priv(sch);
+ int prio;
+
+ for (prio = 0; prio < q->bands; prio++) {
+ struct Qdisc *qdisc = q->queues[prio];
struct sk_buff *skb = qdisc->dequeue(qdisc);
if (skb) {
sch->q.qlen--;
+ sch->flags &= ~TCQ_F_STOPPED;
return skb;
}
+ if (qdisc->flags & TCQ_F_STOPPED) {
+ sch->flags |= TCQ_F_STOPPED;
+ return NULL;
+ }
}
return NULL;
@@ -421,6 +443,7 @@ static struct Qdisc_ops prio_qdisc_ops __read_mostly = {
.priv_size = sizeof(struct prio_sched_data),
.enqueue = prio_enqueue,
.dequeue = prio_dequeue,
+ .smart_dequeue = prio_smart_dequeue,
.requeue = prio_requeue,
.drop = prio_drop,
.init = prio_init,
diff --git a/net/sched/sch_red.c b/net/sched/sch_red.c
index 5da0583..b8247cb 100644
--- a/net/sched/sch_red.c
+++ b/net/sched/sch_red.c
@@ -131,7 +131,7 @@ static struct sk_buff * red_dequeue(struct Qdisc* sch)
struct red_sched_data *q = qdisc_priv(sch);
struct Qdisc *child = q->qdisc;
- skb = child->dequeue(child);
+ skb = child->ops->dequeue(child);
if (skb)
sch->q.qlen--;
else if (!red_is_idling(&q->parms))
@@ -140,6 +140,25 @@ static struct sk_buff * red_dequeue(struct Qdisc* sch)
return skb;
}
+static struct sk_buff * red_smart_dequeue(struct Qdisc* sch)
+{
+ struct sk_buff *skb;
+ struct red_sched_data *q = qdisc_priv(sch);
+ struct Qdisc *child = q->qdisc;
+
+ skb = child->dequeue(child);
+ if (skb) {
+ sch->q.qlen--;
+ sch->flags &= ~TCQ_F_STOPPED;
+ } else {
+ if (child->flags & TCQ_F_STOPPED)
+ sch->flags |= TCQ_F_STOPPED;
+ else if (!red_is_idling(&q->parms))
+ red_start_of_idle_period(&q->parms);
+ }
+
+ return skb;
+}
static unsigned int red_drop(struct Qdisc* sch)
{
struct red_sched_data *q = qdisc_priv(sch);
@@ -361,6 +380,7 @@ static struct Qdisc_ops red_qdisc_ops __read_mostly = {
.cl_ops = &red_class_ops,
.enqueue = red_enqueue,
.dequeue = red_dequeue,
+ .smart_dequeue = red_smart_dequeue,
.requeue = red_requeue,
.drop = red_drop,
.init = red_init,
diff --git a/net/sched/sch_sfq.c b/net/sched/sch_sfq.c
index 6e041d1..2a7ba8e 100644
--- a/net/sched/sch_sfq.c
+++ b/net/sched/sch_sfq.c
@@ -391,9 +391,6 @@ sfq_requeue(struct sk_buff *skb, struct Qdisc *sch)
return NET_XMIT_CN;
}
-
-
-
static struct sk_buff *
sfq_dequeue(struct Qdisc *sch)
{
@@ -431,6 +428,48 @@ sfq_dequeue(struct Qdisc *sch)
return skb;
}
+static struct sk_buff *
+sfq_smart_dequeue(struct Qdisc *sch)
+{
+ struct sfq_sched_data *q = qdisc_priv(sch);
+ struct sk_buff *skb;
+ sfq_index a, old_a;
+ struct netdev_queue *txq;
+
+ /* No active slots */
+ if (q->tail == SFQ_DEPTH)
+ return NULL;
+
+ a = old_a = q->next[q->tail];
+
+ /* Grab packet */
+ skb = __qdisc_smart_dequeue(sch, &q->qs[a]);
+
+ if (!skb && (sch->flags & TCQ_F_STOPPED))
+ return NULL;
+
+ sfq_dec(q, a);
+ sch->q.qlen--;
+
+ /* Is the slot empty? */
+ if (q->qs[a].qlen == 0) {
+ q->ht[q->hash[a]] = SFQ_DEPTH;
+ a = q->next[a];
+ if (a == old_a) {
+ q->tail = SFQ_DEPTH;
+ return skb;
+ }
+ q->next[q->tail] = a;
+ q->allot[a] += q->quantum;
+ } else if ((q->allot[a] -= qdisc_pkt_len(skb)) <= 0) {
+ q->tail = a;
+ a = q->next[a];
+ q->allot[a] += q->quantum;
+ }
+ sch->flags &= ~TCQ_F_STOPPED;
+ return skb;
+}
+
static void
sfq_reset(struct Qdisc *sch)
{
@@ -624,6 +663,7 @@ static struct Qdisc_ops sfq_qdisc_ops __read_mostly = {
.priv_size = sizeof(struct sfq_sched_data),
.enqueue = sfq_enqueue,
.dequeue = sfq_dequeue,
+ .smart_dequeue = sfq_smart_dequeue,
.requeue = sfq_requeue,
.drop = sfq_drop,
.init = sfq_init,
diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
index 94c6159..f65204c 100644
--- a/net/sched/sch_tbf.c
+++ b/net/sched/sch_tbf.c
@@ -169,6 +169,67 @@ static struct sk_buff *tbf_dequeue(struct Qdisc* sch)
struct tbf_sched_data *q = qdisc_priv(sch);
struct sk_buff *skb;
+ skb = q->qdisc->ops->dequeue(q->qdisc);
+
+ if (skb) {
+ psched_time_t now;
+ long toks;
+ long ptoks = 0;
+ unsigned int len = qdisc_pkt_len(skb);
+
+ now = psched_get_time();
+ toks = psched_tdiff_bounded(now, q->t_c, q->buffer);
+
+ if (q->P_tab) {
+ ptoks = toks + q->ptokens;
+ if (ptoks > (long)q->mtu)
+ ptoks = q->mtu;
+ ptoks -= L2T_P(q, len);
+ }
+ toks += q->tokens;
+ if (toks > (long)q->buffer)
+ toks = q->buffer;
+ toks -= L2T(q, len);
+
+ if ((toks|ptoks) >= 0) {
+ q->t_c = now;
+ q->tokens = toks;
+ q->ptokens = ptoks;
+ sch->q.qlen--;
+ sch->flags &= ~TCQ_F_THROTTLED;
+ return skb;
+ }
+
+ qdisc_watchdog_schedule(&q->watchdog,
+ now + max_t(long, -toks, -ptoks));
+
+ /* Maybe we have a shorter packet in the queue,
+ which can be sent now. It sounds cool,
+ but, however, this is wrong in principle.
+ We MUST NOT reorder packets under these circumstances.
+
+ Really, if we split the flow into independent
+ subflows, it would be a very good solution.
+ This is the main idea of all FQ algorithms
+ (cf. CSZ, HPFQ, HFSC)
+ */
+
+ if (q->qdisc->ops->requeue(skb, q->qdisc) != NET_XMIT_SUCCESS) {
+ /* When requeue fails skb is dropped */
+ qdisc_tree_decrease_qlen(q->qdisc, 1);
+ sch->qstats.drops++;
+ }
+
+ sch->qstats.overlimits++;
+ }
+ return NULL;
+}
+
+static struct sk_buff *tbf_smart_dequeue(struct Qdisc* sch)
+{
+ struct tbf_sched_data *q = qdisc_priv(sch);
+ struct sk_buff *skb;
+
skb = q->qdisc->dequeue(q->qdisc);
if (skb) {
@@ -179,6 +240,7 @@ static struct sk_buff *tbf_dequeue(struct Qdisc* sch)
now = psched_get_time();
toks = psched_tdiff_bounded(now, q->t_c, q->buffer);
+ sch->flags &= ~TCQ_F_STOPPED;
if (q->P_tab) {
ptoks = toks + q->ptokens;
@@ -221,7 +283,10 @@ static struct sk_buff *tbf_dequeue(struct Qdisc* sch)
}
sch->qstats.overlimits++;
+ } else if (q->qdisc->flags & TCQ_F_STOPPED) {
+ sch->flags |= TCQ_F_STOPPED;
}
+
return NULL;
}
@@ -469,6 +534,7 @@ static struct Qdisc_ops tbf_qdisc_ops __read_mostly = {
.priv_size = sizeof(struct tbf_sched_data),
.enqueue = tbf_enqueue,
.dequeue = tbf_dequeue,
+ .smart_dequeue = tbf_smart_dequeue,
.requeue = tbf_requeue,
.drop = tbf_drop,
.init = tbf_init,
diff --git a/net/sched/sch_teql.c b/net/sched/sch_teql.c
index d35ef05..fecb3f8 100644
--- a/net/sched/sch_teql.c
+++ b/net/sched/sch_teql.c
@@ -123,6 +123,40 @@ teql_dequeue(struct Qdisc* sch)
return skb;
}
+static struct sk_buff *
+teql_smart_dequeue(struct Qdisc* sch)
+{
+ struct teql_sched_data *dat = qdisc_priv(sch);
+ struct netdev_queue *dat_queue;
+ struct sk_buff *skb;
+ struct netdev_queue *txq;
+
+ skb = skb_peek(&dat->q);
+ if (skb) {
+ txq = netdev_get_tx_queue(qdisc_dev(sch),
+ skb_get_queue_mapping(skb));
+ if (netif_tx_queue_stopped(txq) ||
+ netif_tx_queue_frozen(txq)) {
+ sch->flags |= TCQ_F_STOPPED;
+ return NULL;
+ }
+ __skb_unlink(skb, &dat->q);
+ }
+ dat_queue = netdev_get_tx_queue(dat->m->dev, 0);
+ if (skb == NULL) {
+ struct net_device *m = qdisc_dev(dat_queue->qdisc);
+ if (m) {
+ dat->m->slaves = sch;
+ netif_wake_queue(m);
+ }
+ } else {
+ sch->flags &= ~TCQ_F_STOPPED;
+ }
+ sch->q.qlen = dat->q.qlen + dat_queue->qdisc->q.qlen;
+
+ return skb;
+}
+
static __inline__ void
teql_neigh_release(struct neighbour *n)
{
@@ -431,13 +465,14 @@ static __init void teql_master_setup(struct net_device *dev)
master->dev = dev;
ops->priv_size = sizeof(struct teql_sched_data);
- ops->enqueue = teql_enqueue;
- ops->dequeue = teql_dequeue;
- ops->requeue = teql_requeue;
- ops->init = teql_qdisc_init;
- ops->reset = teql_reset;
- ops->destroy = teql_destroy;
- ops->owner = THIS_MODULE;
+ ops->enqueue = teql_enqueue;
+ ops->dequeue = teql_dequeue;
+ ops->smart_dequeue = teql_smart_dequeue;
+ ops->requeue = teql_requeue;
+ ops->init = teql_qdisc_init;
+ ops->reset = teql_reset;
+ ops->destroy = teql_destroy;
+ ops->owner = THIS_MODULE;
dev->open = teql_master_open;
dev->hard_start_xmit = teql_master_xmit;
--
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