Revert "pkt_sched: Make default qdisc nonshared-multiqueue safe."
This reverts commit a0c80b80e0fb48129e4e9d6a9ede914f9ff1850d.
After discussions with Jamal and Herbert on netdev, we should
provide at least minimal prioritization at the qdisc level
even in multiqueue situations.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 09dead3..cb625b4 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -356,44 +356,99 @@
};
-static int fifo_fast_enqueue(struct sk_buff *skb, struct Qdisc* qdisc)
-{
- struct sk_buff_head *list = &qdisc->q;
+static const u8 prio2band[TC_PRIO_MAX+1] =
+ { 1, 2, 2, 2, 1, 2, 0, 0 , 1, 1, 1, 1, 1, 1, 1, 1 };
- if (skb_queue_len(list) < qdisc_dev(qdisc)->tx_queue_len)
+/* 3-band FIFO queue: old style, but should be a bit faster than
+ generic prio+fifo combination.
+ */
+
+#define PFIFO_FAST_BANDS 3
+
+static inline struct sk_buff_head *prio2list(struct sk_buff *skb,
+ struct Qdisc *qdisc)
+{
+ struct sk_buff_head *list = qdisc_priv(qdisc);
+ return list + prio2band[skb->priority & TC_PRIO_MAX];
+}
+
+static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc* qdisc)
+{
+ struct sk_buff_head *list = prio2list(skb, qdisc);
+
+ if (skb_queue_len(list) < qdisc_dev(qdisc)->tx_queue_len) {
+ qdisc->q.qlen++;
return __qdisc_enqueue_tail(skb, qdisc, list);
+ }
return qdisc_drop(skb, qdisc);
}
-static struct sk_buff *fifo_fast_dequeue(struct Qdisc* qdisc)
+static struct sk_buff *pfifo_fast_dequeue(struct Qdisc* qdisc)
{
- struct sk_buff_head *list = &qdisc->q;
+ int prio;
+ struct sk_buff_head *list = qdisc_priv(qdisc);
- if (!skb_queue_empty(list))
- return __qdisc_dequeue_head(qdisc, list);
+ for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
+ if (!skb_queue_empty(list + prio)) {
+ qdisc->q.qlen--;
+ return __qdisc_dequeue_head(qdisc, list + prio);
+ }
+ }
return NULL;
}
-static int fifo_fast_requeue(struct sk_buff *skb, struct Qdisc* qdisc)
+static int pfifo_fast_requeue(struct sk_buff *skb, struct Qdisc* qdisc)
{
- return __qdisc_requeue(skb, qdisc, &qdisc->q);
+ qdisc->q.qlen++;
+ return __qdisc_requeue(skb, qdisc, prio2list(skb, qdisc));
}
-static void fifo_fast_reset(struct Qdisc* qdisc)
+static void pfifo_fast_reset(struct Qdisc* qdisc)
{
- __qdisc_reset_queue(qdisc, &qdisc->q);
+ int prio;
+ struct sk_buff_head *list = qdisc_priv(qdisc);
+
+ for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
+ __qdisc_reset_queue(qdisc, list + prio);
+
qdisc->qstats.backlog = 0;
+ qdisc->q.qlen = 0;
}
-static struct Qdisc_ops fifo_fast_ops __read_mostly = {
- .id = "fifo_fast",
- .priv_size = 0,
- .enqueue = fifo_fast_enqueue,
- .dequeue = fifo_fast_dequeue,
- .requeue = fifo_fast_requeue,
- .reset = fifo_fast_reset,
+static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb)
+{
+ struct tc_prio_qopt opt = { .bands = PFIFO_FAST_BANDS };
+
+ memcpy(&opt.priomap, prio2band, TC_PRIO_MAX+1);
+ NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
+ return skb->len;
+
+nla_put_failure:
+ return -1;
+}
+
+static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt)
+{
+ int prio;
+ struct sk_buff_head *list = qdisc_priv(qdisc);
+
+ for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
+ skb_queue_head_init(list + prio);
+
+ return 0;
+}
+
+static struct Qdisc_ops pfifo_fast_ops __read_mostly = {
+ .id = "pfifo_fast",
+ .priv_size = PFIFO_FAST_BANDS * sizeof(struct sk_buff_head),
+ .enqueue = pfifo_fast_enqueue,
+ .dequeue = pfifo_fast_dequeue,
+ .requeue = pfifo_fast_requeue,
+ .init = pfifo_fast_init,
+ .reset = pfifo_fast_reset,
+ .dump = pfifo_fast_dump,
.owner = THIS_MODULE,
};
@@ -522,7 +577,7 @@
if (dev->tx_queue_len) {
qdisc = qdisc_create_dflt(dev, dev_queue,
- &fifo_fast_ops, TC_H_ROOT);
+ &pfifo_fast_ops, TC_H_ROOT);
if (!qdisc) {
printk(KERN_INFO "%s: activation failed\n", dev->name);
return;
@@ -550,9 +605,9 @@
int need_watchdog;
/* No queueing discipline is attached to device;
- * create default one i.e. fifo_fast for devices,
- * which need queueing and noqueue_qdisc for
- * virtual interfaces.
+ create default one i.e. pfifo_fast for devices,
+ which need queueing and noqueue_qdisc for
+ virtual interfaces
*/
if (dev_all_qdisc_sleeping_noop(dev))