83f36f3f35
Based upon a bug report by Andrew Gallatin on netdev
with subject "CPU utilization increased in 2.6.27rc"
In commit 37437bb2e1
("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>
112 lines
3.1 KiB
C
112 lines
3.1 KiB
C
#ifndef __NET_PKT_SCHED_H
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#define __NET_PKT_SCHED_H
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#include <linux/jiffies.h>
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#include <linux/ktime.h>
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#include <net/sch_generic.h>
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struct qdisc_walker
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{
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int stop;
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int skip;
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int count;
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int (*fn)(struct Qdisc *, unsigned long cl, struct qdisc_walker *);
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};
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#define QDISC_ALIGNTO 32
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#define QDISC_ALIGN(len) (((len) + QDISC_ALIGNTO-1) & ~(QDISC_ALIGNTO-1))
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static inline void *qdisc_priv(struct Qdisc *q)
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{
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return (char *) q + QDISC_ALIGN(sizeof(struct Qdisc));
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}
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/*
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Timer resolution MUST BE < 10% of min_schedulable_packet_size/bandwidth
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Normal IP packet size ~ 512byte, hence:
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0.5Kbyte/1Mbyte/sec = 0.5msec, so that we need 50usec timer for
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10Mbit ethernet.
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10msec resolution -> <50Kbit/sec.
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The result: [34]86 is not good choice for QoS router :-(
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The things are not so bad, because we may use artifical
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clock evaluated by integration of network data flow
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in the most critical places.
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*/
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typedef u64 psched_time_t;
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typedef long psched_tdiff_t;
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/* Avoid doing 64 bit divide by 1000 */
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#define PSCHED_US2NS(x) ((s64)(x) << 10)
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#define PSCHED_NS2US(x) ((x) >> 10)
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#define PSCHED_TICKS_PER_SEC PSCHED_NS2US(NSEC_PER_SEC)
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#define PSCHED_PASTPERFECT 0
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static inline psched_time_t psched_get_time(void)
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{
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return PSCHED_NS2US(ktime_to_ns(ktime_get()));
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}
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static inline psched_tdiff_t
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psched_tdiff_bounded(psched_time_t tv1, psched_time_t tv2, psched_time_t bound)
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{
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return min(tv1 - tv2, bound);
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}
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struct qdisc_watchdog {
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struct hrtimer timer;
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struct Qdisc *qdisc;
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};
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extern void qdisc_watchdog_init(struct qdisc_watchdog *wd, struct Qdisc *qdisc);
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extern void qdisc_watchdog_schedule(struct qdisc_watchdog *wd,
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psched_time_t expires);
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extern void qdisc_watchdog_cancel(struct qdisc_watchdog *wd);
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extern struct Qdisc_ops pfifo_qdisc_ops;
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extern struct Qdisc_ops bfifo_qdisc_ops;
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extern int fifo_set_limit(struct Qdisc *q, unsigned int limit);
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extern struct Qdisc *fifo_create_dflt(struct Qdisc *sch, struct Qdisc_ops *ops,
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unsigned int limit);
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extern int register_qdisc(struct Qdisc_ops *qops);
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extern int unregister_qdisc(struct Qdisc_ops *qops);
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extern struct Qdisc *qdisc_lookup(struct net_device *dev, u32 handle);
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extern struct Qdisc *qdisc_lookup_class(struct net_device *dev, u32 handle);
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extern struct qdisc_rate_table *qdisc_get_rtab(struct tc_ratespec *r,
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struct nlattr *tab);
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extern void qdisc_put_rtab(struct qdisc_rate_table *tab);
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extern void qdisc_put_stab(struct qdisc_size_table *tab);
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extern void __qdisc_run(struct Qdisc *q);
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static inline void qdisc_run(struct Qdisc *q)
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{
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struct netdev_queue *txq = q->dev_queue;
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if (!netif_tx_queue_stopped(txq) &&
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!test_and_set_bit(__QDISC_STATE_RUNNING, &q->state))
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__qdisc_run(q);
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}
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extern int tc_classify_compat(struct sk_buff *skb, struct tcf_proto *tp,
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struct tcf_result *res);
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extern int tc_classify(struct sk_buff *skb, struct tcf_proto *tp,
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struct tcf_result *res);
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/* Calculate maximal size of packet seen by hard_start_xmit
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routine of this device.
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*/
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static inline unsigned psched_mtu(const struct net_device *dev)
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{
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return dev->mtu + dev->hard_header_len;
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}
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#endif
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