2 * net/sched/sch_htb.c Hierarchical token bucket, feed tree version
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: Martin Devera, <devik@cdi.cz>
11 * Credits (in time order) for older HTB versions:
12 * Stef Coene <stef.coene@docum.org>
13 * HTB support at LARTC mailing list
14 * Ondrej Kraus, <krauso@barr.cz>
15 * found missing INIT_QDISC(htb)
16 * Vladimir Smelhaus, Aamer Akhter, Bert Hubert
17 * helped a lot to locate nasty class stall bug
18 * Andi Kleen, Jamal Hadi, Bert Hubert
19 * code review and helpful comments on shaping
20 * Tomasz Wrona, <tw@eter.tym.pl>
21 * created test case so that I was able to fix nasty bug
23 * spotted bug in dequeue code and helped with fix
25 * fixed requeue routine
26 * and many others. thanks.
28 * $Id: sch_htb.c,v 1.25 2003/12/07 11:08:25 devik Exp devik $
30 #include <linux/module.h>
31 #include <asm/uaccess.h>
32 #include <asm/system.h>
33 #include <linux/bitops.h>
34 #include <linux/types.h>
35 #include <linux/kernel.h>
36 #include <linux/sched.h>
37 #include <linux/string.h>
39 #include <linux/socket.h>
40 #include <linux/sockios.h>
42 #include <linux/errno.h>
43 #include <linux/interrupt.h>
44 #include <linux/if_ether.h>
45 #include <linux/inet.h>
46 #include <linux/netdevice.h>
47 #include <linux/etherdevice.h>
48 #include <linux/notifier.h>
50 #include <net/route.h>
51 #include <linux/skbuff.h>
52 #include <linux/list.h>
53 #include <linux/compiler.h>
55 #include <net/pkt_sched.h>
56 #include <linux/rbtree.h>
60 ========================================================================
61 HTB is like TBF with multiple classes. It is also similar to CBQ because
62 it allows to assign priority to each class in hierarchy.
63 In fact it is another implementation of Floyd's formal sharing.
66 Each class is assigned level. Leaf has ALWAYS level 0 and root
67 classes have level TC_HTB_MAXDEPTH-1. Interior nodes has level
68 one less than their parent.
71 #define HTB_HSIZE 16 /* classid hash size */
72 #define HTB_EWMAC 2 /* rate average over HTB_EWMAC*HTB_HSIZE sec */
73 #define HTB_RATECM 1 /* whether to use rate computer */
74 #define HTB_HYSTERESIS 1/* whether to use mode hysteresis for speedup */
75 #define HTB_VER 0x30011 /* major must be matched with number suplied by TC as version */
77 #if HTB_VER >> 16 != TC_HTB_PROTOVER
78 #error "Mismatched sch_htb.c and pkt_sch.h"
81 /* used internaly to keep status of single class */
83 HTB_CANT_SEND, /* class can't send and can't borrow */
84 HTB_MAY_BORROW, /* class can't send but may borrow */
85 HTB_CAN_SEND /* class can send */
88 /* interior & leaf nodes; props specific to leaves are marked L: */
91 /* general class parameters */
93 struct gnet_stats_basic bstats;
94 struct gnet_stats_queue qstats;
95 struct gnet_stats_rate_est rate_est;
96 struct tc_htb_xstats xstats;/* our special stats */
97 int refcnt; /* usage count of this class */
100 /* rate measurement counters */
101 unsigned long rate_bytes,sum_bytes;
102 unsigned long rate_packets,sum_packets;
106 int level; /* our level (see above) */
107 struct htb_class *parent; /* parent class */
108 struct list_head hlist; /* classid hash list item */
109 struct list_head sibling; /* sibling list item */
110 struct list_head children; /* children list */
113 struct htb_class_leaf {
118 int deficit[TC_HTB_MAXDEPTH];
119 struct list_head drop_list;
121 struct htb_class_inner {
122 struct rb_root feed[TC_HTB_NUMPRIO]; /* feed trees */
123 struct rb_node *ptr[TC_HTB_NUMPRIO]; /* current class ptr */
124 /* When class changes from state 1->2 and disconnects from
125 parent's feed then we lost ptr value and start from the
126 first child again. Here we store classid of the
127 last valid ptr (used when ptr is NULL). */
128 u32 last_ptr_id[TC_HTB_NUMPRIO];
131 struct rb_node node[TC_HTB_NUMPRIO]; /* node for self or feed tree */
132 struct rb_node pq_node; /* node for event queue */
133 unsigned long pq_key; /* the same type as jiffies global */
135 int prio_activity; /* for which prios are we active */
136 enum htb_cmode cmode; /* current mode of the class */
138 /* class attached filters */
139 struct tcf_proto *filter_list;
142 int warned; /* only one warning about non work conserving .. */
144 /* token bucket parameters */
145 struct qdisc_rate_table *rate; /* rate table of the class itself */
146 struct qdisc_rate_table *ceil; /* ceiling rate (limits borrows too) */
147 long buffer,cbuffer; /* token bucket depth/rate */
148 psched_tdiff_t mbuffer; /* max wait time */
149 long tokens,ctokens; /* current number of tokens */
150 psched_time_t t_c; /* checkpoint time */
153 /* TODO: maybe compute rate when size is too large .. or drop ? */
154 static __inline__ long L2T(struct htb_class *cl,struct qdisc_rate_table *rate,
157 int slot = size >> rate->rate.cell_log;
162 return rate->data[slot];
167 struct list_head root; /* root classes list */
168 struct list_head hash[HTB_HSIZE]; /* hashed by classid */
169 struct list_head drops[TC_HTB_NUMPRIO]; /* active leaves (for drops) */
171 /* self list - roots of self generating tree */
172 struct rb_root row[TC_HTB_MAXDEPTH][TC_HTB_NUMPRIO];
173 int row_mask[TC_HTB_MAXDEPTH];
174 struct rb_node *ptr[TC_HTB_MAXDEPTH][TC_HTB_NUMPRIO];
175 u32 last_ptr_id[TC_HTB_MAXDEPTH][TC_HTB_NUMPRIO];
177 /* self wait list - roots of wait PQs per row */
178 struct rb_root wait_pq[TC_HTB_MAXDEPTH];
180 /* time of nearest event per level (row) */
181 unsigned long near_ev_cache[TC_HTB_MAXDEPTH];
183 /* cached value of jiffies in dequeue */
184 unsigned long jiffies;
186 /* whether we hit non-work conserving class during this dequeue; we use */
187 int nwc_hit; /* this to disable mindelay complaint in dequeue */
189 int defcls; /* class where unclassified flows go to */
191 /* filters for qdisc itself */
192 struct tcf_proto *filter_list;
195 int rate2quantum; /* quant = rate / rate2quantum */
196 psched_time_t now; /* cached dequeue time */
197 struct timer_list timer; /* send delay timer */
199 struct timer_list rttim; /* rate computer timer */
200 int recmp_bucket; /* which hash bucket to recompute next */
203 /* non shaped skbs; let them go directly thru */
204 struct sk_buff_head direct_queue;
205 int direct_qlen; /* max qlen of above */
210 /* compute hash of size HTB_HSIZE for given handle */
211 static __inline__ int htb_hash(u32 h)
214 #error "Declare new hash for your HTB_HSIZE"
216 h ^= h>>8; /* stolen from cbq_hash */
221 /* find class in global hash table using given handle */
222 static __inline__ struct htb_class *htb_find(u32 handle, struct Qdisc *sch)
224 struct htb_sched *q = qdisc_priv(sch);
226 if (TC_H_MAJ(handle) != sch->handle)
229 list_for_each (p,q->hash+htb_hash(handle)) {
230 struct htb_class *cl = list_entry(p,struct htb_class,hlist);
231 if (cl->classid == handle)
238 * htb_classify - classify a packet into class
240 * It returns NULL if the packet should be dropped or -1 if the packet
241 * should be passed directly thru. In all other cases leaf class is returned.
242 * We allow direct class selection by classid in priority. The we examine
243 * filters in qdisc and in inner nodes (if higher filter points to the inner
244 * node). If we end up with classid MAJOR:0 we enqueue the skb into special
245 * internal fifo (direct). These packets then go directly thru. If we still
246 * have no valid leaf we try to use MAJOR:default leaf. It still unsuccessfull
247 * then finish and return direct queue.
249 #define HTB_DIRECT (struct htb_class*)-1
250 static inline u32 htb_classid(struct htb_class *cl)
252 return (cl && cl != HTB_DIRECT) ? cl->classid : TC_H_UNSPEC;
255 static struct htb_class *htb_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
257 struct htb_sched *q = qdisc_priv(sch);
258 struct htb_class *cl;
259 struct tcf_result res;
260 struct tcf_proto *tcf;
263 /* allow to select class by setting skb->priority to valid classid;
264 note that nfmark can be used too by attaching filter fw with no
266 if (skb->priority == sch->handle)
267 return HTB_DIRECT; /* X:0 (direct flow) selected */
268 if ((cl = htb_find(skb->priority,sch)) != NULL && cl->level == 0)
271 *qerr = NET_XMIT_BYPASS;
272 tcf = q->filter_list;
273 while (tcf && (result = tc_classify(skb, tcf, &res)) >= 0) {
274 #ifdef CONFIG_NET_CLS_ACT
278 *qerr = NET_XMIT_SUCCESS;
282 #elif defined(CONFIG_NET_CLS_POLICE)
283 if (result == TC_POLICE_SHOT)
286 if ((cl = (void*)res.class) == NULL) {
287 if (res.classid == sch->handle)
288 return HTB_DIRECT; /* X:0 (direct flow) */
289 if ((cl = htb_find(res.classid,sch)) == NULL)
290 break; /* filter selected invalid classid */
293 return cl; /* we hit leaf; return it */
295 /* we have got inner class; apply inner filter chain */
296 tcf = cl->filter_list;
298 /* classification failed; try to use default class */
299 cl = htb_find(TC_H_MAKE(TC_H_MAJ(sch->handle),q->defcls),sch);
300 if (!cl || cl->level)
301 return HTB_DIRECT; /* bad default .. this is safe bet */
306 * htb_add_to_id_tree - adds class to the round robin list
308 * Routine adds class to the list (actually tree) sorted by classid.
309 * Make sure that class is not already on such list for given prio.
311 static void htb_add_to_id_tree (struct rb_root *root,
312 struct htb_class *cl,int prio)
314 struct rb_node **p = &root->rb_node, *parent = NULL;
317 struct htb_class *c; parent = *p;
318 c = rb_entry(parent, struct htb_class, node[prio]);
320 if (cl->classid > c->classid)
321 p = &parent->rb_right;
323 p = &parent->rb_left;
325 rb_link_node(&cl->node[prio], parent, p);
326 rb_insert_color(&cl->node[prio], root);
330 * htb_add_to_wait_tree - adds class to the event queue with delay
332 * The class is added to priority event queue to indicate that class will
333 * change its mode in cl->pq_key microseconds. Make sure that class is not
334 * already in the queue.
336 static void htb_add_to_wait_tree (struct htb_sched *q,
337 struct htb_class *cl,long delay)
339 struct rb_node **p = &q->wait_pq[cl->level].rb_node, *parent = NULL;
341 cl->pq_key = q->jiffies + PSCHED_US2JIFFIE(delay);
342 if (cl->pq_key == q->jiffies)
345 /* update the nearest event cache */
346 if (time_after(q->near_ev_cache[cl->level], cl->pq_key))
347 q->near_ev_cache[cl->level] = cl->pq_key;
350 struct htb_class *c; parent = *p;
351 c = rb_entry(parent, struct htb_class, pq_node);
352 if (time_after_eq(cl->pq_key, c->pq_key))
353 p = &parent->rb_right;
355 p = &parent->rb_left;
357 rb_link_node(&cl->pq_node, parent, p);
358 rb_insert_color(&cl->pq_node, &q->wait_pq[cl->level]);
362 * htb_next_rb_node - finds next node in binary tree
364 * When we are past last key we return NULL.
365 * Average complexity is 2 steps per call.
367 static void htb_next_rb_node(struct rb_node **n)
373 * htb_add_class_to_row - add class to its row
375 * The class is added to row at priorities marked in mask.
376 * It does nothing if mask == 0.
378 static inline void htb_add_class_to_row(struct htb_sched *q,
379 struct htb_class *cl,int mask)
381 q->row_mask[cl->level] |= mask;
383 int prio = ffz(~mask);
384 mask &= ~(1 << prio);
385 htb_add_to_id_tree(q->row[cl->level]+prio,cl,prio);
390 * htb_remove_class_from_row - removes class from its row
392 * The class is removed from row at priorities marked in mask.
393 * It does nothing if mask == 0.
395 static __inline__ void htb_remove_class_from_row(struct htb_sched *q,
396 struct htb_class *cl,int mask)
401 int prio = ffz(~mask);
402 mask &= ~(1 << prio);
403 if (q->ptr[cl->level][prio] == cl->node+prio)
404 htb_next_rb_node(q->ptr[cl->level]+prio);
405 rb_erase(cl->node + prio,q->row[cl->level]+prio);
406 if (!q->row[cl->level][prio].rb_node)
409 q->row_mask[cl->level] &= ~m;
413 * htb_activate_prios - creates active classe's feed chain
415 * The class is connected to ancestors and/or appropriate rows
416 * for priorities it is participating on. cl->cmode must be new
417 * (activated) mode. It does nothing if cl->prio_activity == 0.
419 static void htb_activate_prios(struct htb_sched *q,struct htb_class *cl)
421 struct htb_class *p = cl->parent;
422 long m,mask = cl->prio_activity;
424 while (cl->cmode == HTB_MAY_BORROW && p && mask) {
426 m = mask; while (m) {
430 if (p->un.inner.feed[prio].rb_node)
431 /* parent already has its feed in use so that
432 reset bit in mask as parent is already ok */
433 mask &= ~(1 << prio);
435 htb_add_to_id_tree(p->un.inner.feed+prio,cl,prio);
437 p->prio_activity |= mask;
438 cl = p; p = cl->parent;
441 if (cl->cmode == HTB_CAN_SEND && mask)
442 htb_add_class_to_row(q,cl,mask);
446 * htb_deactivate_prios - remove class from feed chain
448 * cl->cmode must represent old mode (before deactivation). It does
449 * nothing if cl->prio_activity == 0. Class is removed from all feed
452 static void htb_deactivate_prios(struct htb_sched *q, struct htb_class *cl)
454 struct htb_class *p = cl->parent;
455 long m,mask = cl->prio_activity;
458 while (cl->cmode == HTB_MAY_BORROW && p && mask) {
464 if (p->un.inner.ptr[prio] == cl->node+prio) {
465 /* we are removing child which is pointed to from
466 parent feed - forget the pointer but remember
468 p->un.inner.last_ptr_id[prio] = cl->classid;
469 p->un.inner.ptr[prio] = NULL;
472 rb_erase(cl->node + prio,p->un.inner.feed + prio);
474 if (!p->un.inner.feed[prio].rb_node)
478 p->prio_activity &= ~mask;
479 cl = p; p = cl->parent;
482 if (cl->cmode == HTB_CAN_SEND && mask)
483 htb_remove_class_from_row(q,cl,mask);
487 static inline long htb_lowater(const struct htb_class *cl)
489 return cl->cmode != HTB_CANT_SEND ? -cl->cbuffer : 0;
491 static inline long htb_hiwater(const struct htb_class *cl)
493 return cl->cmode == HTB_CAN_SEND ? -cl->buffer : 0;
496 #define htb_lowater(cl) (0)
497 #define htb_hiwater(cl) (0)
501 * htb_class_mode - computes and returns current class mode
503 * It computes cl's mode at time cl->t_c+diff and returns it. If mode
504 * is not HTB_CAN_SEND then cl->pq_key is updated to time difference
505 * from now to time when cl will change its state.
506 * Also it is worth to note that class mode doesn't change simply
507 * at cl->{c,}tokens == 0 but there can rather be hysteresis of
508 * 0 .. -cl->{c,}buffer range. It is meant to limit number of
509 * mode transitions per time unit. The speed gain is about 1/6.
511 static __inline__ enum htb_cmode
512 htb_class_mode(struct htb_class *cl,long *diff)
516 if ((toks = (cl->ctokens + *diff)) < htb_lowater(cl)) {
518 return HTB_CANT_SEND;
521 if ((toks = (cl->tokens + *diff)) >= htb_hiwater(cl))
525 return HTB_MAY_BORROW;
529 * htb_change_class_mode - changes classe's mode
531 * This should be the only way how to change classe's mode under normal
532 * cirsumstances. Routine will update feed lists linkage, change mode
533 * and add class to the wait event queue if appropriate. New mode should
534 * be different from old one and cl->pq_key has to be valid if changing
535 * to mode other than HTB_CAN_SEND (see htb_add_to_wait_tree).
538 htb_change_class_mode(struct htb_sched *q, struct htb_class *cl, long *diff)
540 enum htb_cmode new_mode = htb_class_mode(cl,diff);
543 if (new_mode == cl->cmode)
546 if (cl->prio_activity) { /* not necessary: speed optimization */
547 if (cl->cmode != HTB_CANT_SEND)
548 htb_deactivate_prios(q,cl);
549 cl->cmode = new_mode;
550 if (new_mode != HTB_CANT_SEND)
551 htb_activate_prios(q,cl);
553 cl->cmode = new_mode;
557 * htb_activate - inserts leaf cl into appropriate active feeds
559 * Routine learns (new) priority of leaf and activates feed chain
560 * for the prio. It can be called on already active leaf safely.
561 * It also adds leaf into droplist.
563 static __inline__ void htb_activate(struct htb_sched *q,struct htb_class *cl)
565 BUG_TRAP(!cl->level && cl->un.leaf.q && cl->un.leaf.q->q.qlen);
567 if (!cl->prio_activity) {
568 cl->prio_activity = 1 << (cl->un.leaf.aprio = cl->un.leaf.prio);
569 htb_activate_prios(q,cl);
570 list_add_tail(&cl->un.leaf.drop_list,q->drops+cl->un.leaf.aprio);
575 * htb_deactivate - remove leaf cl from active feeds
577 * Make sure that leaf is active. In the other words it can't be called
578 * with non-active leaf. It also removes class from the drop list.
580 static __inline__ void
581 htb_deactivate(struct htb_sched *q,struct htb_class *cl)
583 BUG_TRAP(cl->prio_activity);
585 htb_deactivate_prios(q,cl);
586 cl->prio_activity = 0;
587 list_del_init(&cl->un.leaf.drop_list);
590 static int htb_enqueue(struct sk_buff *skb, struct Qdisc *sch)
593 struct htb_sched *q = qdisc_priv(sch);
594 struct htb_class *cl = htb_classify(skb,sch,&ret);
596 if (cl == HTB_DIRECT) {
597 /* enqueue to helper queue */
598 if (q->direct_queue.qlen < q->direct_qlen) {
599 __skb_queue_tail(&q->direct_queue, skb);
604 return NET_XMIT_DROP;
606 #ifdef CONFIG_NET_CLS_ACT
608 if (ret == NET_XMIT_BYPASS)
613 } else if (cl->un.leaf.q->enqueue(skb, cl->un.leaf.q) != NET_XMIT_SUCCESS) {
616 return NET_XMIT_DROP;
618 cl->bstats.packets++; cl->bstats.bytes += skb->len;
623 sch->bstats.packets++; sch->bstats.bytes += skb->len;
624 return NET_XMIT_SUCCESS;
627 /* TODO: requeuing packet charges it to policers again !! */
628 static int htb_requeue(struct sk_buff *skb, struct Qdisc *sch)
630 struct htb_sched *q = qdisc_priv(sch);
631 int ret = NET_XMIT_SUCCESS;
632 struct htb_class *cl = htb_classify(skb,sch, &ret);
633 struct sk_buff *tskb;
635 if (cl == HTB_DIRECT || !cl) {
636 /* enqueue to helper queue */
637 if (q->direct_queue.qlen < q->direct_qlen && cl) {
638 __skb_queue_head(&q->direct_queue, skb);
640 __skb_queue_head(&q->direct_queue, skb);
641 tskb = __skb_dequeue_tail(&q->direct_queue);
646 } else if (cl->un.leaf.q->ops->requeue(skb, cl->un.leaf.q) != NET_XMIT_SUCCESS) {
649 return NET_XMIT_DROP;
654 sch->qstats.requeues++;
655 return NET_XMIT_SUCCESS;
658 static void htb_timer(unsigned long arg)
660 struct Qdisc *sch = (struct Qdisc*)arg;
661 sch->flags &= ~TCQ_F_THROTTLED;
663 netif_schedule(sch->dev);
667 #define RT_GEN(D,R) R+=D-(R/HTB_EWMAC);D=0
668 static void htb_rate_timer(unsigned long arg)
670 struct Qdisc *sch = (struct Qdisc*)arg;
671 struct htb_sched *q = qdisc_priv(sch);
674 /* lock queue so that we can muck with it */
675 spin_lock_bh(&sch->dev->queue_lock);
677 q->rttim.expires = jiffies + HZ;
678 add_timer(&q->rttim);
680 /* scan and recompute one bucket at time */
681 if (++q->recmp_bucket >= HTB_HSIZE)
683 list_for_each (p,q->hash+q->recmp_bucket) {
684 struct htb_class *cl = list_entry(p,struct htb_class,hlist);
686 RT_GEN (cl->sum_bytes,cl->rate_bytes);
687 RT_GEN (cl->sum_packets,cl->rate_packets);
689 spin_unlock_bh(&sch->dev->queue_lock);
694 * htb_charge_class - charges amount "bytes" to leaf and ancestors
696 * Routine assumes that packet "bytes" long was dequeued from leaf cl
697 * borrowing from "level". It accounts bytes to ceil leaky bucket for
698 * leaf and all ancestors and to rate bucket for ancestors at levels
699 * "level" and higher. It also handles possible change of mode resulting
700 * from the update. Note that mode can also increase here (MAY_BORROW to
701 * CAN_SEND) because we can use more precise clock that event queue here.
702 * In such case we remove class from event queue first.
704 static void htb_charge_class(struct htb_sched *q,struct htb_class *cl,
708 enum htb_cmode old_mode;
710 #define HTB_ACCNT(T,B,R) toks = diff + cl->T; \
711 if (toks > cl->B) toks = cl->B; \
712 toks -= L2T(cl, cl->R, bytes); \
713 if (toks <= -cl->mbuffer) toks = 1-cl->mbuffer; \
717 diff = PSCHED_TDIFF_SAFE(q->now, cl->t_c, (u32)cl->mbuffer);
718 if (cl->level >= level) {
719 if (cl->level == level) cl->xstats.lends++;
720 HTB_ACCNT (tokens,buffer,rate);
722 cl->xstats.borrows++;
723 cl->tokens += diff; /* we moved t_c; update tokens */
725 HTB_ACCNT (ctokens,cbuffer,ceil);
728 old_mode = cl->cmode; diff = 0;
729 htb_change_class_mode(q,cl,&diff);
730 if (old_mode != cl->cmode) {
731 if (old_mode != HTB_CAN_SEND)
732 rb_erase(&cl->pq_node,q->wait_pq+cl->level);
733 if (cl->cmode != HTB_CAN_SEND)
734 htb_add_to_wait_tree (q,cl,diff);
738 /* update rate counters */
739 cl->sum_bytes += bytes; cl->sum_packets++;
742 /* update byte stats except for leaves which are already updated */
744 cl->bstats.bytes += bytes;
745 cl->bstats.packets++;
752 * htb_do_events - make mode changes to classes at the level
754 * Scans event queue for pending events and applies them. Returns jiffies to
755 * next pending event (0 for no event in pq).
756 * Note: Aplied are events whose have cl->pq_key <= jiffies.
758 static long htb_do_events(struct htb_sched *q,int level)
762 for (i = 0; i < 500; i++) {
763 struct htb_class *cl;
765 struct rb_node *p = q->wait_pq[level].rb_node;
767 while (p->rb_left) p = p->rb_left;
769 cl = rb_entry(p, struct htb_class, pq_node);
770 if (time_after(cl->pq_key, q->jiffies)) {
771 return cl->pq_key - q->jiffies;
773 rb_erase(p,q->wait_pq+level);
774 diff = PSCHED_TDIFF_SAFE(q->now, cl->t_c, (u32)cl->mbuffer);
775 htb_change_class_mode(q,cl,&diff);
776 if (cl->cmode != HTB_CAN_SEND)
777 htb_add_to_wait_tree (q,cl,diff);
780 printk(KERN_WARNING "htb: too many events !\n");
784 /* Returns class->node+prio from id-tree where classe's id is >= id. NULL
785 is no such one exists. */
786 static struct rb_node *
787 htb_id_find_next_upper(int prio,struct rb_node *n,u32 id)
789 struct rb_node *r = NULL;
791 struct htb_class *cl = rb_entry(n,struct htb_class,node[prio]);
792 if (id == cl->classid) return n;
794 if (id > cl->classid) {
805 * htb_lookup_leaf - returns next leaf class in DRR order
807 * Find leaf where current feed pointers points to.
809 static struct htb_class *
810 htb_lookup_leaf(struct rb_root *tree,int prio,struct rb_node **pptr,u32 *pid)
814 struct rb_node *root;
815 struct rb_node **pptr;
817 } stk[TC_HTB_MAXDEPTH],*sp = stk;
819 BUG_TRAP(tree->rb_node);
820 sp->root = tree->rb_node;
824 for (i = 0; i < 65535; i++) {
825 if (!*sp->pptr && *sp->pid) {
826 /* ptr was invalidated but id is valid - try to recover
827 the original or next ptr */
828 *sp->pptr = htb_id_find_next_upper(prio,sp->root,*sp->pid);
830 *sp->pid = 0; /* ptr is valid now so that remove this hint as it
831 can become out of date quickly */
832 if (!*sp->pptr) { /* we are at right end; rewind & go up */
833 *sp->pptr = sp->root;
834 while ((*sp->pptr)->rb_left)
835 *sp->pptr = (*sp->pptr)->rb_left;
838 BUG_TRAP(*sp->pptr); if(!*sp->pptr) return NULL;
839 htb_next_rb_node (sp->pptr);
842 struct htb_class *cl;
843 cl = rb_entry(*sp->pptr,struct htb_class,node[prio]);
846 (++sp)->root = cl->un.inner.feed[prio].rb_node;
847 sp->pptr = cl->un.inner.ptr+prio;
848 sp->pid = cl->un.inner.last_ptr_id+prio;
855 /* dequeues packet at given priority and level; call only if
856 you are sure that there is active class at prio/level */
857 static struct sk_buff *
858 htb_dequeue_tree(struct htb_sched *q,int prio,int level)
860 struct sk_buff *skb = NULL;
861 struct htb_class *cl,*start;
862 /* look initial class up in the row */
863 start = cl = htb_lookup_leaf (q->row[level]+prio,prio,
864 q->ptr[level]+prio,q->last_ptr_id[level]+prio);
869 if (!cl) return NULL;
871 /* class can be empty - it is unlikely but can be true if leaf
872 qdisc drops packets in enqueue routine or if someone used
873 graft operation on the leaf since last dequeue;
874 simply deactivate and skip such class */
875 if (unlikely(cl->un.leaf.q->q.qlen == 0)) {
876 struct htb_class *next;
877 htb_deactivate(q,cl);
879 /* row/level might become empty */
880 if ((q->row_mask[level] & (1 << prio)) == 0)
883 next = htb_lookup_leaf (q->row[level]+prio,
884 prio,q->ptr[level]+prio,q->last_ptr_id[level]+prio);
886 if (cl == start) /* fix start if we just deleted it */
892 if (likely((skb = cl->un.leaf.q->dequeue(cl->un.leaf.q)) != NULL))
895 printk(KERN_WARNING "htb: class %X isn't work conserving ?!\n",cl->classid);
899 htb_next_rb_node((level?cl->parent->un.inner.ptr:q->ptr[0])+prio);
900 cl = htb_lookup_leaf (q->row[level]+prio,prio,q->ptr[level]+prio,
901 q->last_ptr_id[level]+prio);
903 } while (cl != start);
905 if (likely(skb != NULL)) {
906 if ((cl->un.leaf.deficit[level] -= skb->len) < 0) {
907 cl->un.leaf.deficit[level] += cl->un.leaf.quantum;
908 htb_next_rb_node((level?cl->parent->un.inner.ptr:q->ptr[0])+prio);
910 /* this used to be after charge_class but this constelation
911 gives us slightly better performance */
912 if (!cl->un.leaf.q->q.qlen)
913 htb_deactivate (q,cl);
914 htb_charge_class (q,cl,level,skb->len);
919 static void htb_delay_by(struct Qdisc *sch,long delay)
921 struct htb_sched *q = qdisc_priv(sch);
922 if (delay <= 0) delay = 1;
923 if (unlikely(delay > 5*HZ)) {
925 printk(KERN_INFO "HTB delay %ld > 5sec\n", delay);
928 /* why don't use jiffies here ? because expires can be in past */
929 mod_timer(&q->timer, q->jiffies + delay);
930 sch->flags |= TCQ_F_THROTTLED;
931 sch->qstats.overlimits++;
934 static struct sk_buff *htb_dequeue(struct Qdisc *sch)
936 struct sk_buff *skb = NULL;
937 struct htb_sched *q = qdisc_priv(sch);
941 q->jiffies = jiffies;
943 /* try to dequeue direct packets as high prio (!) to minimize cpu work */
944 if ((skb = __skb_dequeue(&q->direct_queue)) != NULL) {
945 sch->flags &= ~TCQ_F_THROTTLED;
950 if (!sch->q.qlen) goto fin;
951 PSCHED_GET_TIME(q->now);
953 min_delay = LONG_MAX;
955 for (level = 0; level < TC_HTB_MAXDEPTH; level++) {
956 /* common case optimization - skip event handler quickly */
959 if (time_after_eq(q->jiffies, q->near_ev_cache[level])) {
960 delay = htb_do_events(q,level);
961 q->near_ev_cache[level] = q->jiffies + (delay ? delay : HZ);
963 delay = q->near_ev_cache[level] - q->jiffies;
965 if (delay && min_delay > delay)
967 m = ~q->row_mask[level];
968 while (m != (int)(-1)) {
971 skb = htb_dequeue_tree(q,prio,level);
972 if (likely(skb != NULL)) {
974 sch->flags &= ~TCQ_F_THROTTLED;
979 htb_delay_by (sch,min_delay > 5*HZ ? 5*HZ : min_delay);
984 /* try to drop from each class (by prio) until one succeed */
985 static unsigned int htb_drop(struct Qdisc* sch)
987 struct htb_sched *q = qdisc_priv(sch);
990 for (prio = TC_HTB_NUMPRIO - 1; prio >= 0; prio--) {
992 list_for_each (p,q->drops+prio) {
993 struct htb_class *cl = list_entry(p, struct htb_class,
996 if (cl->un.leaf.q->ops->drop &&
997 (len = cl->un.leaf.q->ops->drop(cl->un.leaf.q))) {
999 if (!cl->un.leaf.q->q.qlen)
1000 htb_deactivate (q,cl);
1008 /* reset all classes */
1009 /* always caled under BH & queue lock */
1010 static void htb_reset(struct Qdisc* sch)
1012 struct htb_sched *q = qdisc_priv(sch);
1015 for (i = 0; i < HTB_HSIZE; i++) {
1016 struct list_head *p;
1017 list_for_each (p,q->hash+i) {
1018 struct htb_class *cl = list_entry(p,struct htb_class,hlist);
1020 memset(&cl->un.inner,0,sizeof(cl->un.inner));
1023 qdisc_reset(cl->un.leaf.q);
1024 INIT_LIST_HEAD(&cl->un.leaf.drop_list);
1026 cl->prio_activity = 0;
1027 cl->cmode = HTB_CAN_SEND;
1031 sch->flags &= ~TCQ_F_THROTTLED;
1032 del_timer(&q->timer);
1033 __skb_queue_purge(&q->direct_queue);
1035 memset(q->row,0,sizeof(q->row));
1036 memset(q->row_mask,0,sizeof(q->row_mask));
1037 memset(q->wait_pq,0,sizeof(q->wait_pq));
1038 memset(q->ptr,0,sizeof(q->ptr));
1039 for (i = 0; i < TC_HTB_NUMPRIO; i++)
1040 INIT_LIST_HEAD(q->drops+i);
1043 static int htb_init(struct Qdisc *sch, struct rtattr *opt)
1045 struct htb_sched *q = qdisc_priv(sch);
1046 struct rtattr *tb[TCA_HTB_INIT];
1047 struct tc_htb_glob *gopt;
1049 if (!opt || rtattr_parse_nested(tb, TCA_HTB_INIT, opt) ||
1050 tb[TCA_HTB_INIT-1] == NULL ||
1051 RTA_PAYLOAD(tb[TCA_HTB_INIT-1]) < sizeof(*gopt)) {
1052 printk(KERN_ERR "HTB: hey probably you have bad tc tool ?\n");
1055 gopt = RTA_DATA(tb[TCA_HTB_INIT-1]);
1056 if (gopt->version != HTB_VER >> 16) {
1057 printk(KERN_ERR "HTB: need tc/htb version %d (minor is %d), you have %d\n",
1058 HTB_VER >> 16,HTB_VER & 0xffff,gopt->version);
1062 INIT_LIST_HEAD(&q->root);
1063 for (i = 0; i < HTB_HSIZE; i++)
1064 INIT_LIST_HEAD(q->hash+i);
1065 for (i = 0; i < TC_HTB_NUMPRIO; i++)
1066 INIT_LIST_HEAD(q->drops+i);
1068 init_timer(&q->timer);
1069 skb_queue_head_init(&q->direct_queue);
1071 q->direct_qlen = sch->dev->tx_queue_len;
1072 if (q->direct_qlen < 2) /* some devices have zero tx_queue_len */
1074 q->timer.function = htb_timer;
1075 q->timer.data = (unsigned long)sch;
1078 init_timer(&q->rttim);
1079 q->rttim.function = htb_rate_timer;
1080 q->rttim.data = (unsigned long)sch;
1081 q->rttim.expires = jiffies + HZ;
1082 add_timer(&q->rttim);
1084 if ((q->rate2quantum = gopt->rate2quantum) < 1)
1085 q->rate2quantum = 1;
1086 q->defcls = gopt->defcls;
1091 static int htb_dump(struct Qdisc *sch, struct sk_buff *skb)
1093 struct htb_sched *q = qdisc_priv(sch);
1094 unsigned char *b = skb->tail;
1096 struct tc_htb_glob gopt;
1097 spin_lock_bh(&sch->dev->queue_lock);
1098 gopt.direct_pkts = q->direct_pkts;
1100 gopt.version = HTB_VER;
1101 gopt.rate2quantum = q->rate2quantum;
1102 gopt.defcls = q->defcls;
1104 rta = (struct rtattr*)b;
1105 RTA_PUT(skb, TCA_OPTIONS, 0, NULL);
1106 RTA_PUT(skb, TCA_HTB_INIT, sizeof(gopt), &gopt);
1107 rta->rta_len = skb->tail - b;
1108 spin_unlock_bh(&sch->dev->queue_lock);
1111 spin_unlock_bh(&sch->dev->queue_lock);
1112 skb_trim(skb, skb->tail - skb->data);
1116 static int htb_dump_class(struct Qdisc *sch, unsigned long arg,
1117 struct sk_buff *skb, struct tcmsg *tcm)
1119 struct htb_class *cl = (struct htb_class*)arg;
1120 unsigned char *b = skb->tail;
1122 struct tc_htb_opt opt;
1124 spin_lock_bh(&sch->dev->queue_lock);
1125 tcm->tcm_parent = cl->parent ? cl->parent->classid : TC_H_ROOT;
1126 tcm->tcm_handle = cl->classid;
1127 if (!cl->level && cl->un.leaf.q)
1128 tcm->tcm_info = cl->un.leaf.q->handle;
1130 rta = (struct rtattr*)b;
1131 RTA_PUT(skb, TCA_OPTIONS, 0, NULL);
1133 memset (&opt,0,sizeof(opt));
1135 opt.rate = cl->rate->rate; opt.buffer = cl->buffer;
1136 opt.ceil = cl->ceil->rate; opt.cbuffer = cl->cbuffer;
1137 opt.quantum = cl->un.leaf.quantum; opt.prio = cl->un.leaf.prio;
1138 opt.level = cl->level;
1139 RTA_PUT(skb, TCA_HTB_PARMS, sizeof(opt), &opt);
1140 rta->rta_len = skb->tail - b;
1141 spin_unlock_bh(&sch->dev->queue_lock);
1144 spin_unlock_bh(&sch->dev->queue_lock);
1145 skb_trim(skb, b - skb->data);
1150 htb_dump_class_stats(struct Qdisc *sch, unsigned long arg,
1151 struct gnet_dump *d)
1153 struct htb_class *cl = (struct htb_class*)arg;
1156 cl->rate_est.bps = cl->rate_bytes/(HTB_EWMAC*HTB_HSIZE);
1157 cl->rate_est.pps = cl->rate_packets/(HTB_EWMAC*HTB_HSIZE);
1160 if (!cl->level && cl->un.leaf.q)
1161 cl->qstats.qlen = cl->un.leaf.q->q.qlen;
1162 cl->xstats.tokens = cl->tokens;
1163 cl->xstats.ctokens = cl->ctokens;
1165 if (gnet_stats_copy_basic(d, &cl->bstats) < 0 ||
1166 gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 ||
1167 gnet_stats_copy_queue(d, &cl->qstats) < 0)
1170 return gnet_stats_copy_app(d, &cl->xstats, sizeof(cl->xstats));
1173 static int htb_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
1176 struct htb_class *cl = (struct htb_class*)arg;
1178 if (cl && !cl->level) {
1179 if (new == NULL && (new = qdisc_create_dflt(sch->dev,
1180 &pfifo_qdisc_ops)) == NULL)
1183 if ((*old = xchg(&cl->un.leaf.q, new)) != NULL) {
1184 if (cl->prio_activity)
1185 htb_deactivate (qdisc_priv(sch),cl);
1187 /* TODO: is it correct ? Why CBQ doesn't do it ? */
1188 sch->q.qlen -= (*old)->q.qlen;
1191 sch_tree_unlock(sch);
1197 static struct Qdisc * htb_leaf(struct Qdisc *sch, unsigned long arg)
1199 struct htb_class *cl = (struct htb_class*)arg;
1200 return (cl && !cl->level) ? cl->un.leaf.q : NULL;
1203 static unsigned long htb_get(struct Qdisc *sch, u32 classid)
1205 struct htb_class *cl = htb_find(classid,sch);
1208 return (unsigned long)cl;
1211 static void htb_destroy_filters(struct tcf_proto **fl)
1213 struct tcf_proto *tp;
1215 while ((tp = *fl) != NULL) {
1221 static void htb_destroy_class(struct Qdisc* sch,struct htb_class *cl)
1223 struct htb_sched *q = qdisc_priv(sch);
1225 BUG_TRAP(cl->un.leaf.q);
1226 sch->q.qlen -= cl->un.leaf.q->q.qlen;
1227 qdisc_destroy(cl->un.leaf.q);
1229 qdisc_put_rtab(cl->rate);
1230 qdisc_put_rtab(cl->ceil);
1232 htb_destroy_filters (&cl->filter_list);
1234 while (!list_empty(&cl->children))
1235 htb_destroy_class (sch,list_entry(cl->children.next,
1236 struct htb_class,sibling));
1238 /* note: this delete may happen twice (see htb_delete) */
1239 list_del(&cl->hlist);
1240 list_del(&cl->sibling);
1242 if (cl->prio_activity)
1243 htb_deactivate (q,cl);
1245 if (cl->cmode != HTB_CAN_SEND)
1246 rb_erase(&cl->pq_node,q->wait_pq+cl->level);
1251 /* always caled under BH & queue lock */
1252 static void htb_destroy(struct Qdisc* sch)
1254 struct htb_sched *q = qdisc_priv(sch);
1256 del_timer_sync (&q->timer);
1258 del_timer_sync (&q->rttim);
1260 /* This line used to be after htb_destroy_class call below
1261 and surprisingly it worked in 2.4. But it must precede it
1262 because filter need its target class alive to be able to call
1263 unbind_filter on it (without Oops). */
1264 htb_destroy_filters(&q->filter_list);
1266 while (!list_empty(&q->root))
1267 htb_destroy_class (sch,list_entry(q->root.next,
1268 struct htb_class,sibling));
1270 __skb_queue_purge(&q->direct_queue);
1273 static int htb_delete(struct Qdisc *sch, unsigned long arg)
1275 struct htb_sched *q = qdisc_priv(sch);
1276 struct htb_class *cl = (struct htb_class*)arg;
1278 // TODO: why don't allow to delete subtree ? references ? does
1279 // tc subsys quarantee us that in htb_destroy it holds no class
1280 // refs so that we can remove children safely there ?
1281 if (!list_empty(&cl->children) || cl->filter_cnt)
1286 /* delete from hash and active; remainder in destroy_class */
1287 list_del_init(&cl->hlist);
1288 if (cl->prio_activity)
1289 htb_deactivate (q,cl);
1291 if (--cl->refcnt == 0)
1292 htb_destroy_class(sch,cl);
1294 sch_tree_unlock(sch);
1298 static void htb_put(struct Qdisc *sch, unsigned long arg)
1300 struct htb_class *cl = (struct htb_class*)arg;
1302 if (--cl->refcnt == 0)
1303 htb_destroy_class(sch,cl);
1306 static int htb_change_class(struct Qdisc *sch, u32 classid,
1307 u32 parentid, struct rtattr **tca, unsigned long *arg)
1310 struct htb_sched *q = qdisc_priv(sch);
1311 struct htb_class *cl = (struct htb_class*)*arg,*parent;
1312 struct rtattr *opt = tca[TCA_OPTIONS-1];
1313 struct qdisc_rate_table *rtab = NULL, *ctab = NULL;
1314 struct rtattr *tb[TCA_HTB_RTAB];
1315 struct tc_htb_opt *hopt;
1317 /* extract all subattrs from opt attr */
1318 if (!opt || rtattr_parse_nested(tb, TCA_HTB_RTAB, opt) ||
1319 tb[TCA_HTB_PARMS-1] == NULL ||
1320 RTA_PAYLOAD(tb[TCA_HTB_PARMS-1]) < sizeof(*hopt))
1323 parent = parentid == TC_H_ROOT ? NULL : htb_find (parentid,sch);
1325 hopt = RTA_DATA(tb[TCA_HTB_PARMS-1]);
1327 rtab = qdisc_get_rtab(&hopt->rate, tb[TCA_HTB_RTAB-1]);
1328 ctab = qdisc_get_rtab(&hopt->ceil, tb[TCA_HTB_CTAB-1]);
1329 if (!rtab || !ctab) goto failure;
1331 if (!cl) { /* new class */
1332 struct Qdisc *new_q;
1333 /* check for valid classid */
1334 if (!classid || TC_H_MAJ(classid^sch->handle) || htb_find(classid,sch))
1337 /* check maximal depth */
1338 if (parent && parent->parent && parent->parent->level < 2) {
1339 printk(KERN_ERR "htb: tree is too deep\n");
1343 if ((cl = kzalloc(sizeof(*cl), GFP_KERNEL)) == NULL)
1347 INIT_LIST_HEAD(&cl->sibling);
1348 INIT_LIST_HEAD(&cl->hlist);
1349 INIT_LIST_HEAD(&cl->children);
1350 INIT_LIST_HEAD(&cl->un.leaf.drop_list);
1352 /* create leaf qdisc early because it uses kmalloc(GFP_KERNEL)
1353 so that can't be used inside of sch_tree_lock
1354 -- thanks to Karlis Peisenieks */
1355 new_q = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops);
1357 if (parent && !parent->level) {
1358 /* turn parent into inner node */
1359 sch->q.qlen -= parent->un.leaf.q->q.qlen;
1360 qdisc_destroy (parent->un.leaf.q);
1361 if (parent->prio_activity)
1362 htb_deactivate (q,parent);
1364 /* remove from evt list because of level change */
1365 if (parent->cmode != HTB_CAN_SEND) {
1366 rb_erase(&parent->pq_node,q->wait_pq);
1367 parent->cmode = HTB_CAN_SEND;
1369 parent->level = (parent->parent ? parent->parent->level
1370 : TC_HTB_MAXDEPTH) - 1;
1371 memset (&parent->un.inner,0,sizeof(parent->un.inner));
1373 /* leaf (we) needs elementary qdisc */
1374 cl->un.leaf.q = new_q ? new_q : &noop_qdisc;
1376 cl->classid = classid; cl->parent = parent;
1378 /* set class to be in HTB_CAN_SEND state */
1379 cl->tokens = hopt->buffer;
1380 cl->ctokens = hopt->cbuffer;
1381 cl->mbuffer = PSCHED_JIFFIE2US(HZ*60); /* 1min */
1382 PSCHED_GET_TIME(cl->t_c);
1383 cl->cmode = HTB_CAN_SEND;
1385 /* attach to the hash list and parent's family */
1386 list_add_tail(&cl->hlist, q->hash+htb_hash(classid));
1387 list_add_tail(&cl->sibling, parent ? &parent->children : &q->root);
1388 } else sch_tree_lock(sch);
1390 /* it used to be a nasty bug here, we have to check that node
1391 is really leaf before changing cl->un.leaf ! */
1393 cl->un.leaf.quantum = rtab->rate.rate / q->rate2quantum;
1394 if (!hopt->quantum && cl->un.leaf.quantum < 1000) {
1395 printk(KERN_WARNING "HTB: quantum of class %X is small. Consider r2q change.\n", cl->classid);
1396 cl->un.leaf.quantum = 1000;
1398 if (!hopt->quantum && cl->un.leaf.quantum > 200000) {
1399 printk(KERN_WARNING "HTB: quantum of class %X is big. Consider r2q change.\n", cl->classid);
1400 cl->un.leaf.quantum = 200000;
1403 cl->un.leaf.quantum = hopt->quantum;
1404 if ((cl->un.leaf.prio = hopt->prio) >= TC_HTB_NUMPRIO)
1405 cl->un.leaf.prio = TC_HTB_NUMPRIO - 1;
1408 cl->buffer = hopt->buffer;
1409 cl->cbuffer = hopt->cbuffer;
1410 if (cl->rate) qdisc_put_rtab(cl->rate); cl->rate = rtab;
1411 if (cl->ceil) qdisc_put_rtab(cl->ceil); cl->ceil = ctab;
1412 sch_tree_unlock(sch);
1414 *arg = (unsigned long)cl;
1418 if (rtab) qdisc_put_rtab(rtab);
1419 if (ctab) qdisc_put_rtab(ctab);
1423 static struct tcf_proto **htb_find_tcf(struct Qdisc *sch, unsigned long arg)
1425 struct htb_sched *q = qdisc_priv(sch);
1426 struct htb_class *cl = (struct htb_class *)arg;
1427 struct tcf_proto **fl = cl ? &cl->filter_list : &q->filter_list;
1432 static unsigned long htb_bind_filter(struct Qdisc *sch, unsigned long parent,
1435 struct htb_sched *q = qdisc_priv(sch);
1436 struct htb_class *cl = htb_find (classid,sch);
1438 /*if (cl && !cl->level) return 0;
1439 The line above used to be there to prevent attaching filters to
1440 leaves. But at least tc_index filter uses this just to get class
1441 for other reasons so that we have to allow for it.
1443 19.6.2002 As Werner explained it is ok - bind filter is just
1444 another way to "lock" the class - unlike "get" this lock can
1445 be broken by class during destroy IIUC.
1451 return (unsigned long)cl;
1454 static void htb_unbind_filter(struct Qdisc *sch, unsigned long arg)
1456 struct htb_sched *q = qdisc_priv(sch);
1457 struct htb_class *cl = (struct htb_class *)arg;
1465 static void htb_walk(struct Qdisc *sch, struct qdisc_walker *arg)
1467 struct htb_sched *q = qdisc_priv(sch);
1473 for (i = 0; i < HTB_HSIZE; i++) {
1474 struct list_head *p;
1475 list_for_each (p,q->hash+i) {
1476 struct htb_class *cl = list_entry(p,struct htb_class,hlist);
1477 if (arg->count < arg->skip) {
1481 if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
1490 static struct Qdisc_class_ops htb_class_ops = {
1495 .change = htb_change_class,
1496 .delete = htb_delete,
1498 .tcf_chain = htb_find_tcf,
1499 .bind_tcf = htb_bind_filter,
1500 .unbind_tcf = htb_unbind_filter,
1501 .dump = htb_dump_class,
1502 .dump_stats = htb_dump_class_stats,
1505 static struct Qdisc_ops htb_qdisc_ops = {
1507 .cl_ops = &htb_class_ops,
1509 .priv_size = sizeof(struct htb_sched),
1510 .enqueue = htb_enqueue,
1511 .dequeue = htb_dequeue,
1512 .requeue = htb_requeue,
1516 .destroy = htb_destroy,
1517 .change = NULL /* htb_change */,
1519 .owner = THIS_MODULE,
1522 static int __init htb_module_init(void)
1524 return register_qdisc(&htb_qdisc_ops);
1526 static void __exit htb_module_exit(void)
1528 unregister_qdisc(&htb_qdisc_ops);
1530 module_init(htb_module_init)
1531 module_exit(htb_module_exit)
1532 MODULE_LICENSE("GPL");