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-rw-r--r--include/net/pkt_sched.h3
-rw-r--r--include/net/sch_generic.h15
-rw-r--r--net/core/dev.c48
-rw-r--r--net/sched/sch_generic.c93
4 files changed, 108 insertions, 51 deletions
diff --git a/include/net/pkt_sched.h b/include/net/pkt_sched.h
index 82a3191375f..f911ec7598e 100644
--- a/include/net/pkt_sched.h
+++ b/include/net/pkt_sched.h
@@ -87,6 +87,9 @@ extern struct qdisc_rate_table *qdisc_get_rtab(struct tc_ratespec *r,
extern void qdisc_put_rtab(struct qdisc_rate_table *tab);
extern void qdisc_put_stab(struct qdisc_size_table *tab);
extern void qdisc_warn_nonwc(char *txt, struct Qdisc *qdisc);
+extern int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
+ struct net_device *dev, struct netdev_queue *txq,
+ spinlock_t *root_lock);
extern void __qdisc_run(struct Qdisc *q);
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index 964ffa0d881..84b3fc2aef0 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_CAN_BYPASS 8
#define TCQ_F_WARN_NONWC (1 << 16)
int padded;
struct Qdisc_ops *ops;
@@ -182,6 +183,11 @@ struct qdisc_skb_cb {
char data[];
};
+static inline int qdisc_qlen(struct Qdisc *q)
+{
+ return q->q.qlen;
+}
+
static inline struct qdisc_skb_cb *qdisc_skb_cb(struct sk_buff *skb)
{
return (struct qdisc_skb_cb *)skb->cb;
@@ -387,13 +393,18 @@ static inline int qdisc_enqueue_root(struct sk_buff *skb, struct Qdisc *sch)
return qdisc_enqueue(skb, sch) & NET_XMIT_MASK;
}
+static inline void __qdisc_update_bstats(struct Qdisc *sch, unsigned int len)
+{
+ sch->bstats.bytes += len;
+ sch->bstats.packets++;
+}
+
static inline int __qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch,
struct sk_buff_head *list)
{
__skb_queue_tail(list, skb);
sch->qstats.backlog += qdisc_pkt_len(skb);
- sch->bstats.bytes += qdisc_pkt_len(skb);
- sch->bstats.packets++;
+ __qdisc_update_bstats(sch, qdisc_pkt_len(skb));
return NET_XMIT_SUCCESS;
}
diff --git a/net/core/dev.c b/net/core/dev.c
index f01a9c41f11..a0bc087616a 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1786,6 +1786,40 @@ static struct netdev_queue *dev_pick_tx(struct net_device *dev,
return netdev_get_tx_queue(dev, queue_index);
}
+static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q,
+ struct net_device *dev,
+ struct netdev_queue *txq)
+{
+ spinlock_t *root_lock = qdisc_lock(q);
+ int rc;
+
+ spin_lock(root_lock);
+ if (unlikely(test_bit(__QDISC_STATE_DEACTIVATED, &q->state))) {
+ kfree_skb(skb);
+ rc = NET_XMIT_DROP;
+ } else if ((q->flags & TCQ_F_CAN_BYPASS) && !qdisc_qlen(q) &&
+ !test_and_set_bit(__QDISC_STATE_RUNNING, &q->state)) {
+ /*
+ * This is a work-conserving queue; there are no old skbs
+ * waiting to be sent out; and the qdisc is not running -
+ * xmit the skb directly.
+ */
+ __qdisc_update_bstats(q, skb->len);
+ if (sch_direct_xmit(skb, q, dev, txq, root_lock))
+ __qdisc_run(q);
+ else
+ clear_bit(__QDISC_STATE_RUNNING, &q->state);
+
+ rc = NET_XMIT_SUCCESS;
+ } else {
+ rc = qdisc_enqueue_root(skb, q);
+ qdisc_run(q);
+ }
+ spin_unlock(root_lock);
+
+ return rc;
+}
+
/**
* dev_queue_xmit - transmit a buffer
* @skb: buffer to transmit
@@ -1859,19 +1893,7 @@ gso:
skb->tc_verd = SET_TC_AT(skb->tc_verd,AT_EGRESS);
#endif
if (q->enqueue) {
- spinlock_t *root_lock = qdisc_lock(q);
-
- spin_lock(root_lock);
-
- if (unlikely(test_bit(__QDISC_STATE_DEACTIVATED, &q->state))) {
- kfree_skb(skb);
- rc = NET_XMIT_DROP;
- } else {
- rc = qdisc_enqueue_root(skb, q);
- qdisc_run(q);
- }
- spin_unlock(root_lock);
-
+ rc = __dev_xmit_skb(skb, q, dev, txq);
goto out;
}
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 27d03816ec3..693df7ae33d 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -37,15 +37,11 @@
* - updates to tree and tree walking are only done under the rtnl mutex.
*/
-static inline int qdisc_qlen(struct Qdisc *q)
-{
- return q->q.qlen;
-}
-
static inline int dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q)
{
q->gso_skb = skb;
q->qstats.requeues++;
+ q->q.qlen++; /* it's still part of the queue */
__netif_schedule(q);
return 0;
@@ -61,9 +57,11 @@ static inline struct sk_buff *dequeue_skb(struct Qdisc *q)
/* check the reason of requeuing without tx lock first */
txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
- if (!netif_tx_queue_stopped(txq) && !netif_tx_queue_frozen(txq))
+ if (!netif_tx_queue_stopped(txq) &&
+ !netif_tx_queue_frozen(txq)) {
q->gso_skb = NULL;
- else
+ q->q.qlen--;
+ } else
skb = NULL;
} else {
skb = q->dequeue(q);
@@ -103,44 +101,23 @@ static inline int handle_dev_cpu_collision(struct sk_buff *skb,
}
/*
- * NOTE: Called under qdisc_lock(q) with locally disabled BH.
- *
- * __QDISC_STATE_RUNNING guarantees only one CPU can process
- * this qdisc at a time. qdisc_lock(q) serializes queue accesses for
- * this queue.
- *
- * netif_tx_lock serializes accesses to device driver.
- *
- * qdisc_lock(q) and netif_tx_lock are mutually exclusive,
- * if one is grabbed, another must be free.
- *
- * Note, that this procedure can be called by a watchdog timer
+ * Transmit one skb, and handle the return status as required. Holding the
+ * __QDISC_STATE_RUNNING bit guarantees that only one CPU can execute this
+ * function.
*
* Returns to the caller:
* 0 - queue is empty or throttled.
* >0 - queue is not empty.
- *
*/
-static inline int qdisc_restart(struct Qdisc *q)
+int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
+ struct net_device *dev, struct netdev_queue *txq,
+ spinlock_t *root_lock)
{
- struct netdev_queue *txq;
int ret = NETDEV_TX_BUSY;
- struct net_device *dev;
- spinlock_t *root_lock;
- struct sk_buff *skb;
-
- /* Dequeue packet */
- if (unlikely((skb = dequeue_skb(q)) == NULL))
- return 0;
-
- root_lock = qdisc_lock(q);
/* And release qdisc */
spin_unlock(root_lock);
- dev = qdisc_dev(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))
@@ -177,6 +154,44 @@ static inline int qdisc_restart(struct Qdisc *q)
return ret;
}
+/*
+ * NOTE: Called under qdisc_lock(q) with locally disabled BH.
+ *
+ * __QDISC_STATE_RUNNING guarantees only one CPU can process
+ * this qdisc at a time. qdisc_lock(q) serializes queue accesses for
+ * this queue.
+ *
+ * netif_tx_lock serializes accesses to device driver.
+ *
+ * qdisc_lock(q) and netif_tx_lock are mutually exclusive,
+ * if one is grabbed, another must be free.
+ *
+ * Note, that this procedure can be called by a watchdog timer
+ *
+ * Returns to the caller:
+ * 0 - queue is empty or throttled.
+ * >0 - queue is not empty.
+ *
+ */
+static inline int qdisc_restart(struct Qdisc *q)
+{
+ struct netdev_queue *txq;
+ struct net_device *dev;
+ spinlock_t *root_lock;
+ struct sk_buff *skb;
+
+ /* Dequeue packet */
+ skb = dequeue_skb(q);
+ if (unlikely(!skb))
+ return 0;
+
+ root_lock = qdisc_lock(q);
+ dev = qdisc_dev(q);
+ txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
+
+ return sch_direct_xmit(skb, q, dev, txq, root_lock);
+}
+
void __qdisc_run(struct Qdisc *q)
{
unsigned long start_time = jiffies;
@@ -547,8 +562,11 @@ void qdisc_reset(struct Qdisc *qdisc)
if (ops->reset)
ops->reset(qdisc);
- kfree_skb(qdisc->gso_skb);
- qdisc->gso_skb = NULL;
+ if (qdisc->gso_skb) {
+ kfree_skb(qdisc->gso_skb);
+ qdisc->gso_skb = NULL;
+ qdisc->q.qlen = 0;
+ }
}
EXPORT_SYMBOL(qdisc_reset);
@@ -605,6 +623,9 @@ static void attach_one_default_qdisc(struct net_device *dev,
printk(KERN_INFO "%s: activation failed\n", dev->name);
return;
}
+
+ /* Can by-pass the queue discipline for default qdisc */
+ qdisc->flags |= TCQ_F_CAN_BYPASS;
} else {
qdisc = &noqueue_qdisc;
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-13 07:19:02 +0000