x86_64: disable srat when numa emulation succeeds
[wrt350n-kernel.git] / net / sched / sch_generic.c
blobc81649cf0b9ecc62316205286eb6149e869b910b
1 /*
2 * net/sched/sch_generic.c Generic packet scheduler routines.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 * Jamal Hadi Salim, <hadi@cyberus.ca> 990601
11 * - Ingress support
14 #include <linux/bitops.h>
15 #include <linux/module.h>
16 #include <linux/types.h>
17 #include <linux/kernel.h>
18 #include <linux/sched.h>
19 #include <linux/string.h>
20 #include <linux/errno.h>
21 #include <linux/netdevice.h>
22 #include <linux/skbuff.h>
23 #include <linux/rtnetlink.h>
24 #include <linux/init.h>
25 #include <linux/rcupdate.h>
26 #include <linux/list.h>
27 #include <net/pkt_sched.h>
29 /* Main transmission queue. */
31 /* Modifications to data participating in scheduling must be protected with
32 * dev->queue_lock spinlock.
34 * The idea is the following:
35 * - enqueue, dequeue are serialized via top level device
36 * spinlock dev->queue_lock.
37 * - ingress filtering is serialized via top level device
38 * spinlock dev->ingress_lock.
39 * - updates to tree and tree walking are only done under the rtnl mutex.
42 void qdisc_lock_tree(struct net_device *dev)
44 spin_lock_bh(&dev->queue_lock);
45 spin_lock(&dev->ingress_lock);
48 void qdisc_unlock_tree(struct net_device *dev)
50 spin_unlock(&dev->ingress_lock);
51 spin_unlock_bh(&dev->queue_lock);
54 static inline int qdisc_qlen(struct Qdisc *q)
56 return q->q.qlen;
59 static inline int dev_requeue_skb(struct sk_buff *skb, struct net_device *dev,
60 struct Qdisc *q)
62 if (unlikely(skb->next))
63 dev->gso_skb = skb;
64 else
65 q->ops->requeue(skb, q);
67 netif_schedule(dev);
68 return 0;
71 static inline struct sk_buff *dev_dequeue_skb(struct net_device *dev,
72 struct Qdisc *q)
74 struct sk_buff *skb;
76 if ((skb = dev->gso_skb))
77 dev->gso_skb = NULL;
78 else
79 skb = q->dequeue(q);
81 return skb;
84 static inline int handle_dev_cpu_collision(struct sk_buff *skb,
85 struct net_device *dev,
86 struct Qdisc *q)
88 int ret;
90 if (unlikely(dev->xmit_lock_owner == smp_processor_id())) {
92 * Same CPU holding the lock. It may be a transient
93 * configuration error, when hard_start_xmit() recurses. We
94 * detect it by checking xmit owner and drop the packet when
95 * deadloop is detected. Return OK to try the next skb.
97 kfree_skb(skb);
98 if (net_ratelimit())
99 printk(KERN_WARNING "Dead loop on netdevice %s, "
100 "fix it urgently!\n", dev->name);
101 ret = qdisc_qlen(q);
102 } else {
104 * Another cpu is holding lock, requeue & delay xmits for
105 * some time.
107 __get_cpu_var(netdev_rx_stat).cpu_collision++;
108 ret = dev_requeue_skb(skb, dev, q);
111 return ret;
115 * NOTE: Called under dev->queue_lock with locally disabled BH.
117 * __LINK_STATE_QDISC_RUNNING guarantees only one CPU can process this
118 * device at a time. dev->queue_lock serializes queue accesses for
119 * this device AND dev->qdisc pointer itself.
121 * netif_tx_lock serializes accesses to device driver.
123 * dev->queue_lock and netif_tx_lock are mutually exclusive,
124 * if one is grabbed, another must be free.
126 * Note, that this procedure can be called by a watchdog timer
128 * Returns to the caller:
129 * 0 - queue is empty or throttled.
130 * >0 - queue is not empty.
133 static inline int qdisc_restart(struct net_device *dev)
135 struct Qdisc *q = dev->qdisc;
136 struct sk_buff *skb;
137 unsigned lockless;
138 int ret;
140 /* Dequeue packet */
141 if (unlikely((skb = dev_dequeue_skb(dev, q)) == NULL))
142 return 0;
145 * When the driver has LLTX set, it does its own locking in
146 * start_xmit. These checks are worth it because even uncongested
147 * locks can be quite expensive. The driver can do a trylock, as
148 * is being done here; in case of lock contention it should return
149 * NETDEV_TX_LOCKED and the packet will be requeued.
151 lockless = (dev->features & NETIF_F_LLTX);
153 if (!lockless && !netif_tx_trylock(dev)) {
154 /* Another CPU grabbed the driver tx lock */
155 return handle_dev_cpu_collision(skb, dev, q);
158 /* And release queue */
159 spin_unlock(&dev->queue_lock);
161 ret = dev_hard_start_xmit(skb, dev);
163 if (!lockless)
164 netif_tx_unlock(dev);
166 spin_lock(&dev->queue_lock);
167 q = dev->qdisc;
169 switch (ret) {
170 case NETDEV_TX_OK:
171 /* Driver sent out skb successfully */
172 ret = qdisc_qlen(q);
173 break;
175 case NETDEV_TX_LOCKED:
176 /* Driver try lock failed */
177 ret = handle_dev_cpu_collision(skb, dev, q);
178 break;
180 default:
181 /* Driver returned NETDEV_TX_BUSY - requeue skb */
182 if (unlikely (ret != NETDEV_TX_BUSY && net_ratelimit()))
183 printk(KERN_WARNING "BUG %s code %d qlen %d\n",
184 dev->name, ret, q->q.qlen);
186 ret = dev_requeue_skb(skb, dev, q);
187 break;
190 return ret;
193 void __qdisc_run(struct net_device *dev)
195 do {
196 if (!qdisc_restart(dev))
197 break;
198 } while (!netif_queue_stopped(dev));
200 clear_bit(__LINK_STATE_QDISC_RUNNING, &dev->state);
203 static void dev_watchdog(unsigned long arg)
205 struct net_device *dev = (struct net_device *)arg;
207 netif_tx_lock(dev);
208 if (dev->qdisc != &noop_qdisc) {
209 if (netif_device_present(dev) &&
210 netif_running(dev) &&
211 netif_carrier_ok(dev)) {
212 if (netif_queue_stopped(dev) &&
213 time_after(jiffies, dev->trans_start + dev->watchdog_timeo)) {
215 printk(KERN_INFO "NETDEV WATCHDOG: %s: transmit timed out\n",
216 dev->name);
217 dev->tx_timeout(dev);
219 if (!mod_timer(&dev->watchdog_timer, round_jiffies(jiffies + dev->watchdog_timeo)))
220 dev_hold(dev);
223 netif_tx_unlock(dev);
225 dev_put(dev);
228 static void dev_watchdog_init(struct net_device *dev)
230 init_timer(&dev->watchdog_timer);
231 dev->watchdog_timer.data = (unsigned long)dev;
232 dev->watchdog_timer.function = dev_watchdog;
235 void __netdev_watchdog_up(struct net_device *dev)
237 if (dev->tx_timeout) {
238 if (dev->watchdog_timeo <= 0)
239 dev->watchdog_timeo = 5*HZ;
240 if (!mod_timer(&dev->watchdog_timer,
241 round_jiffies(jiffies + dev->watchdog_timeo)))
242 dev_hold(dev);
246 static void dev_watchdog_up(struct net_device *dev)
248 __netdev_watchdog_up(dev);
251 static void dev_watchdog_down(struct net_device *dev)
253 netif_tx_lock_bh(dev);
254 if (del_timer(&dev->watchdog_timer))
255 dev_put(dev);
256 netif_tx_unlock_bh(dev);
259 void netif_carrier_on(struct net_device *dev)
261 if (test_and_clear_bit(__LINK_STATE_NOCARRIER, &dev->state))
262 linkwatch_fire_event(dev);
263 if (netif_running(dev))
264 __netdev_watchdog_up(dev);
267 void netif_carrier_off(struct net_device *dev)
269 if (!test_and_set_bit(__LINK_STATE_NOCARRIER, &dev->state))
270 linkwatch_fire_event(dev);
273 /* "NOOP" scheduler: the best scheduler, recommended for all interfaces
274 under all circumstances. It is difficult to invent anything faster or
275 cheaper.
278 static int noop_enqueue(struct sk_buff *skb, struct Qdisc * qdisc)
280 kfree_skb(skb);
281 return NET_XMIT_CN;
284 static struct sk_buff *noop_dequeue(struct Qdisc * qdisc)
286 return NULL;
289 static int noop_requeue(struct sk_buff *skb, struct Qdisc* qdisc)
291 if (net_ratelimit())
292 printk(KERN_DEBUG "%s deferred output. It is buggy.\n",
293 skb->dev->name);
294 kfree_skb(skb);
295 return NET_XMIT_CN;
298 struct Qdisc_ops noop_qdisc_ops = {
299 .id = "noop",
300 .priv_size = 0,
301 .enqueue = noop_enqueue,
302 .dequeue = noop_dequeue,
303 .requeue = noop_requeue,
304 .owner = THIS_MODULE,
307 struct Qdisc noop_qdisc = {
308 .enqueue = noop_enqueue,
309 .dequeue = noop_dequeue,
310 .flags = TCQ_F_BUILTIN,
311 .ops = &noop_qdisc_ops,
312 .list = LIST_HEAD_INIT(noop_qdisc.list),
315 static struct Qdisc_ops noqueue_qdisc_ops = {
316 .id = "noqueue",
317 .priv_size = 0,
318 .enqueue = noop_enqueue,
319 .dequeue = noop_dequeue,
320 .requeue = noop_requeue,
321 .owner = THIS_MODULE,
324 static struct Qdisc noqueue_qdisc = {
325 .enqueue = NULL,
326 .dequeue = noop_dequeue,
327 .flags = TCQ_F_BUILTIN,
328 .ops = &noqueue_qdisc_ops,
329 .list = LIST_HEAD_INIT(noqueue_qdisc.list),
333 static const u8 prio2band[TC_PRIO_MAX+1] =
334 { 1, 2, 2, 2, 1, 2, 0, 0 , 1, 1, 1, 1, 1, 1, 1, 1 };
336 /* 3-band FIFO queue: old style, but should be a bit faster than
337 generic prio+fifo combination.
340 #define PFIFO_FAST_BANDS 3
342 static inline struct sk_buff_head *prio2list(struct sk_buff *skb,
343 struct Qdisc *qdisc)
345 struct sk_buff_head *list = qdisc_priv(qdisc);
346 return list + prio2band[skb->priority & TC_PRIO_MAX];
349 static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc* qdisc)
351 struct sk_buff_head *list = prio2list(skb, qdisc);
353 if (skb_queue_len(list) < qdisc->dev->tx_queue_len) {
354 qdisc->q.qlen++;
355 return __qdisc_enqueue_tail(skb, qdisc, list);
358 return qdisc_drop(skb, qdisc);
361 static struct sk_buff *pfifo_fast_dequeue(struct Qdisc* qdisc)
363 int prio;
364 struct sk_buff_head *list = qdisc_priv(qdisc);
366 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
367 if (!skb_queue_empty(list + prio)) {
368 qdisc->q.qlen--;
369 return __qdisc_dequeue_head(qdisc, list + prio);
373 return NULL;
376 static int pfifo_fast_requeue(struct sk_buff *skb, struct Qdisc* qdisc)
378 qdisc->q.qlen++;
379 return __qdisc_requeue(skb, qdisc, prio2list(skb, qdisc));
382 static void pfifo_fast_reset(struct Qdisc* qdisc)
384 int prio;
385 struct sk_buff_head *list = qdisc_priv(qdisc);
387 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
388 __qdisc_reset_queue(qdisc, list + prio);
390 qdisc->qstats.backlog = 0;
391 qdisc->q.qlen = 0;
394 static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb)
396 struct tc_prio_qopt opt = { .bands = PFIFO_FAST_BANDS };
398 memcpy(&opt.priomap, prio2band, TC_PRIO_MAX+1);
399 RTA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
400 return skb->len;
402 rtattr_failure:
403 return -1;
406 static int pfifo_fast_init(struct Qdisc *qdisc, struct rtattr *opt)
408 int prio;
409 struct sk_buff_head *list = qdisc_priv(qdisc);
411 for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
412 skb_queue_head_init(list + prio);
414 return 0;
417 static struct Qdisc_ops pfifo_fast_ops = {
418 .id = "pfifo_fast",
419 .priv_size = PFIFO_FAST_BANDS * sizeof(struct sk_buff_head),
420 .enqueue = pfifo_fast_enqueue,
421 .dequeue = pfifo_fast_dequeue,
422 .requeue = pfifo_fast_requeue,
423 .init = pfifo_fast_init,
424 .reset = pfifo_fast_reset,
425 .dump = pfifo_fast_dump,
426 .owner = THIS_MODULE,
429 struct Qdisc *qdisc_alloc(struct net_device *dev, struct Qdisc_ops *ops)
431 void *p;
432 struct Qdisc *sch;
433 unsigned int size;
434 int err = -ENOBUFS;
436 /* ensure that the Qdisc and the private data are 32-byte aligned */
437 size = QDISC_ALIGN(sizeof(*sch));
438 size += ops->priv_size + (QDISC_ALIGNTO - 1);
440 p = kzalloc(size, GFP_KERNEL);
441 if (!p)
442 goto errout;
443 sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p);
444 sch->padded = (char *) sch - (char *) p;
446 INIT_LIST_HEAD(&sch->list);
447 skb_queue_head_init(&sch->q);
448 sch->ops = ops;
449 sch->enqueue = ops->enqueue;
450 sch->dequeue = ops->dequeue;
451 sch->dev = dev;
452 dev_hold(dev);
453 atomic_set(&sch->refcnt, 1);
455 return sch;
456 errout:
457 return ERR_PTR(-err);
460 struct Qdisc * qdisc_create_dflt(struct net_device *dev, struct Qdisc_ops *ops,
461 unsigned int parentid)
463 struct Qdisc *sch;
465 sch = qdisc_alloc(dev, ops);
466 if (IS_ERR(sch))
467 goto errout;
468 sch->stats_lock = &dev->queue_lock;
469 sch->parent = parentid;
471 if (!ops->init || ops->init(sch, NULL) == 0)
472 return sch;
474 qdisc_destroy(sch);
475 errout:
476 return NULL;
479 /* Under dev->queue_lock and BH! */
481 void qdisc_reset(struct Qdisc *qdisc)
483 struct Qdisc_ops *ops = qdisc->ops;
485 if (ops->reset)
486 ops->reset(qdisc);
489 /* this is the rcu callback function to clean up a qdisc when there
490 * are no further references to it */
492 static void __qdisc_destroy(struct rcu_head *head)
494 struct Qdisc *qdisc = container_of(head, struct Qdisc, q_rcu);
495 kfree((char *) qdisc - qdisc->padded);
498 /* Under dev->queue_lock and BH! */
500 void qdisc_destroy(struct Qdisc *qdisc)
502 struct Qdisc_ops *ops = qdisc->ops;
504 if (qdisc->flags & TCQ_F_BUILTIN ||
505 !atomic_dec_and_test(&qdisc->refcnt))
506 return;
508 list_del(&qdisc->list);
509 gen_kill_estimator(&qdisc->bstats, &qdisc->rate_est);
510 if (ops->reset)
511 ops->reset(qdisc);
512 if (ops->destroy)
513 ops->destroy(qdisc);
515 module_put(ops->owner);
516 dev_put(qdisc->dev);
517 call_rcu(&qdisc->q_rcu, __qdisc_destroy);
520 void dev_activate(struct net_device *dev)
522 /* No queueing discipline is attached to device;
523 create default one i.e. pfifo_fast for devices,
524 which need queueing and noqueue_qdisc for
525 virtual interfaces
528 if (dev->qdisc_sleeping == &noop_qdisc) {
529 struct Qdisc *qdisc;
530 if (dev->tx_queue_len) {
531 qdisc = qdisc_create_dflt(dev, &pfifo_fast_ops,
532 TC_H_ROOT);
533 if (qdisc == NULL) {
534 printk(KERN_INFO "%s: activation failed\n", dev->name);
535 return;
537 list_add_tail(&qdisc->list, &dev->qdisc_list);
538 } else {
539 qdisc = &noqueue_qdisc;
541 dev->qdisc_sleeping = qdisc;
544 if (!netif_carrier_ok(dev))
545 /* Delay activation until next carrier-on event */
546 return;
548 spin_lock_bh(&dev->queue_lock);
549 rcu_assign_pointer(dev->qdisc, dev->qdisc_sleeping);
550 if (dev->qdisc != &noqueue_qdisc) {
551 dev->trans_start = jiffies;
552 dev_watchdog_up(dev);
554 spin_unlock_bh(&dev->queue_lock);
557 void dev_deactivate(struct net_device *dev)
559 struct Qdisc *qdisc;
560 struct sk_buff *skb;
562 spin_lock_bh(&dev->queue_lock);
563 qdisc = dev->qdisc;
564 dev->qdisc = &noop_qdisc;
566 qdisc_reset(qdisc);
568 skb = dev->gso_skb;
569 dev->gso_skb = NULL;
570 spin_unlock_bh(&dev->queue_lock);
572 kfree_skb(skb);
574 dev_watchdog_down(dev);
576 /* Wait for outstanding dev_queue_xmit calls. */
577 synchronize_rcu();
579 /* Wait for outstanding qdisc_run calls. */
580 while (test_bit(__LINK_STATE_QDISC_RUNNING, &dev->state))
581 yield();
584 void dev_init_scheduler(struct net_device *dev)
586 qdisc_lock_tree(dev);
587 dev->qdisc = &noop_qdisc;
588 dev->qdisc_sleeping = &noop_qdisc;
589 INIT_LIST_HEAD(&dev->qdisc_list);
590 qdisc_unlock_tree(dev);
592 dev_watchdog_init(dev);
595 void dev_shutdown(struct net_device *dev)
597 struct Qdisc *qdisc;
599 qdisc_lock_tree(dev);
600 qdisc = dev->qdisc_sleeping;
601 dev->qdisc = &noop_qdisc;
602 dev->qdisc_sleeping = &noop_qdisc;
603 qdisc_destroy(qdisc);
604 #if defined(CONFIG_NET_SCH_INGRESS) || defined(CONFIG_NET_SCH_INGRESS_MODULE)
605 if ((qdisc = dev->qdisc_ingress) != NULL) {
606 dev->qdisc_ingress = NULL;
607 qdisc_destroy(qdisc);
609 #endif
610 BUG_TRAP(!timer_pending(&dev->watchdog_timer));
611 qdisc_unlock_tree(dev);
614 EXPORT_SYMBOL(netif_carrier_on);
615 EXPORT_SYMBOL(netif_carrier_off);
616 EXPORT_SYMBOL(noop_qdisc);
617 EXPORT_SYMBOL(qdisc_create_dflt);
618 EXPORT_SYMBOL(qdisc_destroy);
619 EXPORT_SYMBOL(qdisc_reset);
620 EXPORT_SYMBOL(qdisc_lock_tree);
621 EXPORT_SYMBOL(qdisc_unlock_tree);