#define PFIFO_FAST_BANDS 3
-static inline struct sk_buff_head *prio2list(struct sk_buff *skb,
- struct Qdisc *qdisc)
+/*
+ * Private data for a pfifo_fast scheduler containing:
+ * - queues for the three band
+ * - bitmap indicating which of the bands contain skbs
+ */
+struct pfifo_fast_priv {
+ u32 bitmap;
+ struct sk_buff_head q[PFIFO_FAST_BANDS];
+};
+
+/*
+ * Convert a bitmap to the first band number where an skb is queued, where:
+ * bitmap=0 means there are no skbs on any band.
+ * bitmap=1 means there is an skb on band 0.
+ * bitmap=7 means there are skbs on all 3 bands, etc.
+ */
+static const int bitmap2band[] = {-1, 0, 1, 0, 2, 0, 1, 0};
+
+static inline struct sk_buff_head *band2list(struct pfifo_fast_priv *priv,
+ int band)
{
- struct sk_buff_head *list = qdisc_priv(qdisc);
- return list + prio2band[skb->priority & TC_PRIO_MAX];
+ return priv->q + band;
}
static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc* qdisc)
{
- struct sk_buff_head *list = prio2list(skb, qdisc);
+ if (skb_queue_len(&qdisc->q) < qdisc_dev(qdisc)->tx_queue_len) {
+ int band = prio2band[skb->priority & TC_PRIO_MAX];
+ struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
+ struct sk_buff_head *list = band2list(priv, band);
- if (skb_queue_len(list) < qdisc_dev(qdisc)->tx_queue_len) {
+ priv->bitmap |= (1 << band);
qdisc->q.qlen++;
return __qdisc_enqueue_tail(skb, qdisc, list);
}
static struct sk_buff *pfifo_fast_dequeue(struct Qdisc* qdisc)
{
- int prio;
- struct sk_buff_head *list = qdisc_priv(qdisc);
+ struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
+ int band = bitmap2band[priv->bitmap];
- for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
- if (!skb_queue_empty(list + prio)) {
- qdisc->q.qlen--;
- return __qdisc_dequeue_head(qdisc, list + prio);
- }
+ if (likely(band >= 0)) {
+ struct sk_buff_head *list = band2list(priv, band);
+ struct sk_buff *skb = __qdisc_dequeue_head(qdisc, list);
+
+ qdisc->q.qlen--;
+ if (skb_queue_empty(list))
+ priv->bitmap &= ~(1 << band);
+
+ return skb;
}
return NULL;
static struct sk_buff *pfifo_fast_peek(struct Qdisc* qdisc)
{
- int prio;
- struct sk_buff_head *list = qdisc_priv(qdisc);
+ struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
+ int band = bitmap2band[priv->bitmap];
+
+ if (band >= 0) {
+ struct sk_buff_head *list = band2list(priv, band);
- for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
- if (!skb_queue_empty(list + prio))
- return skb_peek(list + prio);
+ return skb_peek(list);
}
return NULL;
static void pfifo_fast_reset(struct Qdisc* qdisc)
{
int prio;
- struct sk_buff_head *list = qdisc_priv(qdisc);
+ struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
- __qdisc_reset_queue(qdisc, list + prio);
+ __qdisc_reset_queue(qdisc, band2list(priv, prio));
+ priv->bitmap = 0;
qdisc->qstats.backlog = 0;
qdisc->q.qlen = 0;
}
static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt)
{
int prio;
- struct sk_buff_head *list = qdisc_priv(qdisc);
+ struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
- skb_queue_head_init(list + prio);
+ skb_queue_head_init(band2list(priv, prio));
return 0;
}
-static struct Qdisc_ops pfifo_fast_ops __read_mostly = {
+struct Qdisc_ops pfifo_fast_ops __read_mostly = {
.id = "pfifo_fast",
- .priv_size = PFIFO_FAST_BANDS * sizeof(struct sk_buff_head),
+ .priv_size = sizeof(struct pfifo_fast_priv),
.enqueue = pfifo_fast_enqueue,
.dequeue = pfifo_fast_dequeue,
.peek = pfifo_fast_peek,
}
EXPORT_SYMBOL(qdisc_destroy);
-static bool dev_all_qdisc_sleeping_noop(struct net_device *dev)
+/* Attach toplevel qdisc to device queue. */
+struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
+ struct Qdisc *qdisc)
{
- unsigned int i;
+ struct Qdisc *oqdisc = dev_queue->qdisc_sleeping;
+ spinlock_t *root_lock;
- for (i = 0; i < dev->num_tx_queues; i++) {
- struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
+ root_lock = qdisc_lock(oqdisc);
+ spin_lock_bh(root_lock);
- if (txq->qdisc_sleeping != &noop_qdisc)
- return false;
- }
- return true;
+ /* Prune old scheduler */
+ if (oqdisc && atomic_read(&oqdisc->refcnt) <= 1)
+ qdisc_reset(oqdisc);
+
+ /* ... and graft new one */
+ if (qdisc == NULL)
+ qdisc = &noop_qdisc;
+ dev_queue->qdisc_sleeping = qdisc;
+ rcu_assign_pointer(dev_queue->qdisc, &noop_qdisc);
+
+ spin_unlock_bh(root_lock);
+
+ return oqdisc;
}
static void attach_one_default_qdisc(struct net_device *dev,
dev_queue->qdisc_sleeping = qdisc;
}
+static void attach_default_qdiscs(struct net_device *dev)
+{
+ struct netdev_queue *txq;
+ struct Qdisc *qdisc;
+
+ txq = netdev_get_tx_queue(dev, 0);
+
+ if (!netif_is_multiqueue(dev) || dev->tx_queue_len == 0) {
+ netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
+ dev->qdisc = txq->qdisc_sleeping;
+ atomic_inc(&dev->qdisc->refcnt);
+ } else {
+ qdisc = qdisc_create_dflt(dev, txq, &mq_qdisc_ops, TC_H_ROOT);
+ if (qdisc) {
+ qdisc->ops->attach(qdisc);
+ dev->qdisc = qdisc;
+ }
+ }
+}
+
static void transition_one_qdisc(struct net_device *dev,
struct netdev_queue *dev_queue,
void *_need_watchdog)
virtual interfaces
*/
- if (dev_all_qdisc_sleeping_noop(dev))
- netdev_for_each_tx_queue(dev, attach_one_default_qdisc, NULL);
+ if (dev->qdisc == &noop_qdisc)
+ attach_default_qdiscs(dev);
if (!netif_carrier_ok(dev))
/* Delay activation until next carrier-on event */
void dev_init_scheduler(struct net_device *dev)
{
+ dev->qdisc = &noop_qdisc;
netdev_for_each_tx_queue(dev, dev_init_scheduler_queue, &noop_qdisc);
dev_init_scheduler_queue(dev, &dev->rx_queue, &noop_qdisc);
{
netdev_for_each_tx_queue(dev, shutdown_scheduler_queue, &noop_qdisc);
shutdown_scheduler_queue(dev, &dev->rx_queue, &noop_qdisc);
+ qdisc_destroy(dev->qdisc);
+ dev->qdisc = &noop_qdisc;
+
WARN_ON(timer_pending(&dev->watchdog_timer));
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff