Commit 83f36f3f authored Aug 13, 2008 by David S. Miller

pkt_sched: Add queue stopped test back to qdisc_run().



Based upon a bug report by Andrew Gallatin on netdev
with subject "CPU utilization increased in 2.6.27rc"

In commit 37437bb2
("pkt_sched: Schedule qdiscs instead of netdev_queue.")
the test of the queue being stopped was erroneously
removed from qdisc_run().

When the TX queue of the device fills up, this omission
causes lots of extraneous useless work to be queued up
to softirq context, where we'll just return immediately
because the device is still stuffed up.

Signed-off-by: David S. Miller <davem@davemloft.net>

parent 5e0115e5

include/net/pkt_sched.h

+4 −1

Original line number	Diff line number	Diff line
		@@ -89,7 +89,10 @@ extern void __qdisc_run(struct Qdisc *q);

		static inline void qdisc_run(struct Qdisc *q)
		{
		if (!test_and_set_bit(__QDISC_STATE_RUNNING, &q->state))
		struct netdev_queue *txq = q->dev_queue;

		if (!netif_tx_queue_stopped(txq) &&
		!test_and_set_bit(__QDISC_STATE_RUNNING, &q->state))
		__qdisc_run(q);
		}

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