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 #include <linux/module.h>
29 #include <linux/moduleparam.h>
30 #include <linux/types.h>
31 #include <linux/kernel.h>
32 #include <linux/string.h>
33 #include <linux/errno.h>
34 #include <linux/skbuff.h>
35 #include <linux/list.h>
36 #include <linux/compiler.h>
37 #include <linux/rbtree.h>
38 #include <net/netlink.h>
39 #include <net/pkt_sched.h>
43 ========================================================================
44 HTB is like TBF with multiple classes. It is also similar to CBQ because
45 it allows to assign priority to each class in hierarchy.
46 In fact it is another implementation of Floyd's formal sharing.
49 Each class is assigned level. Leaf has ALWAYS level 0 and root
50 classes have level TC_HTB_MAXDEPTH-1. Interior nodes has level
51 one less than their parent.
54 static int htb_hysteresis __read_mostly = 0; /* whether to use mode hysteresis for speedup */
55 #define HTB_VER 0x30011 /* major must be matched with number suplied by TC as version */
57 #if HTB_VER >> 16 != TC_HTB_PROTOVER
58 #error "Mismatched sch_htb.c and pkt_sch.h"
61 /* Module parameter and sysfs export */
62 module_param (htb_hysteresis, int, 0640);
63 MODULE_PARM_DESC(htb_hysteresis, "Hysteresis mode, less CPU load, less accurate");
65 /* used internaly to keep status of single class */
67 HTB_CANT_SEND, /* class can't send and can't borrow */
68 HTB_MAY_BORROW, /* class can't send but may borrow */
69 HTB_CAN_SEND /* class can send */
72 /* interior & leaf nodes; props specific to leaves are marked L: */
74 struct Qdisc_class_common common;
75 /* general class parameters */
76 struct gnet_stats_basic bstats;
77 struct gnet_stats_queue qstats;
78 struct gnet_stats_rate_est rate_est;
79 struct tc_htb_xstats xstats; /* our special stats */
80 int refcnt; /* usage count of this class */
83 int level; /* our level (see above) */
84 unsigned int children;
85 struct htb_class *parent; /* parent class */
88 struct htb_class_leaf {
93 int deficit[TC_HTB_MAXDEPTH];
94 struct list_head drop_list;
96 struct htb_class_inner {
97 struct rb_root feed[TC_HTB_NUMPRIO]; /* feed trees */
98 struct rb_node *ptr[TC_HTB_NUMPRIO]; /* current class ptr */
99 /* When class changes from state 1->2 and disconnects from
100 parent's feed then we lost ptr value and start from the
101 first child again. Here we store classid of the
102 last valid ptr (used when ptr is NULL). */
103 u32 last_ptr_id[TC_HTB_NUMPRIO];
106 struct rb_node node[TC_HTB_NUMPRIO]; /* node for self or feed tree */
107 struct rb_node pq_node; /* node for event queue */
108 psched_time_t pq_key;
110 int prio_activity; /* for which prios are we active */
111 enum htb_cmode cmode; /* current mode of the class */
113 /* class attached filters */
114 struct tcf_proto *filter_list;
117 int warned; /* only one warning about non work conserving .. */
119 /* token bucket parameters */
120 struct qdisc_rate_table *rate; /* rate table of the class itself */
121 struct qdisc_rate_table *ceil; /* ceiling rate (limits borrows too) */
122 long buffer, cbuffer; /* token bucket depth/rate */
123 psched_tdiff_t mbuffer; /* max wait time */
124 long tokens, ctokens; /* current number of tokens */
125 psched_time_t t_c; /* checkpoint time */
127 int prio; /* For parent to leaf return possible here */
128 int quantum; /* we do backup. Finally full replacement */
129 /* of un.leaf originals should be done. */
132 static inline long L2T(struct htb_class *cl, struct qdisc_rate_table *rate,
135 long result = qdisc_l2t(rate, size);
140 struct Qdisc_class_hash clhash;
141 struct list_head drops[TC_HTB_NUMPRIO];/* active leaves (for drops) */
143 /* self list - roots of self generating tree */
144 struct rb_root row[TC_HTB_MAXDEPTH][TC_HTB_NUMPRIO];
145 int row_mask[TC_HTB_MAXDEPTH];
146 struct rb_node *ptr[TC_HTB_MAXDEPTH][TC_HTB_NUMPRIO];
147 u32 last_ptr_id[TC_HTB_MAXDEPTH][TC_HTB_NUMPRIO];
149 /* self wait list - roots of wait PQs per row */
150 struct rb_root wait_pq[TC_HTB_MAXDEPTH];
152 /* time of nearest event per level (row) */
153 psched_time_t near_ev_cache[TC_HTB_MAXDEPTH];
155 /* whether we hit non-work conserving class during this dequeue; we use */
156 int nwc_hit; /* this to disable mindelay complaint in dequeue */
158 int defcls; /* class where unclassified flows go to */
160 /* filters for qdisc itself */
161 struct tcf_proto *filter_list;
163 int rate2quantum; /* quant = rate / rate2quantum */
164 psched_time_t now; /* cached dequeue time */
165 struct qdisc_watchdog watchdog;
167 /* non shaped skbs; let them go directly thru */
168 struct sk_buff_head direct_queue;
169 int direct_qlen; /* max qlen of above */
174 /* find class in global hash table using given handle */
175 static inline struct htb_class *htb_find(u32 handle, struct Qdisc *sch)
177 struct htb_sched *q = qdisc_priv(sch);
178 struct Qdisc_class_common *clc;
180 clc = qdisc_class_find(&q->clhash, handle);
183 return container_of(clc, struct htb_class, common);
187 * htb_classify - classify a packet into class
189 * It returns NULL if the packet should be dropped or -1 if the packet
190 * should be passed directly thru. In all other cases leaf class is returned.
191 * We allow direct class selection by classid in priority. The we examine
192 * filters in qdisc and in inner nodes (if higher filter points to the inner
193 * node). If we end up with classid MAJOR:0 we enqueue the skb into special
194 * internal fifo (direct). These packets then go directly thru. If we still
195 * have no valid leaf we try to use MAJOR:default leaf. It still unsuccessfull
196 * then finish and return direct queue.
198 #define HTB_DIRECT (struct htb_class*)-1
200 static struct htb_class *htb_classify(struct sk_buff *skb, struct Qdisc *sch,
203 struct htb_sched *q = qdisc_priv(sch);
204 struct htb_class *cl;
205 struct tcf_result res;
206 struct tcf_proto *tcf;
209 /* allow to select class by setting skb->priority to valid classid;
210 note that nfmark can be used too by attaching filter fw with no
212 if (skb->priority == sch->handle)
213 return HTB_DIRECT; /* X:0 (direct flow) selected */
214 if ((cl = htb_find(skb->priority, sch)) != NULL && cl->level == 0)
217 *qerr = NET_XMIT_BYPASS;
218 tcf = q->filter_list;
219 while (tcf && (result = tc_classify(skb, tcf, &res)) >= 0) {
220 #ifdef CONFIG_NET_CLS_ACT
224 *qerr = NET_XMIT_SUCCESS;
229 if ((cl = (void *)res.class) == NULL) {
230 if (res.classid == sch->handle)
231 return HTB_DIRECT; /* X:0 (direct flow) */
232 if ((cl = htb_find(res.classid, sch)) == NULL)
233 break; /* filter selected invalid classid */
236 return cl; /* we hit leaf; return it */
238 /* we have got inner class; apply inner filter chain */
239 tcf = cl->filter_list;
241 /* classification failed; try to use default class */
242 cl = htb_find(TC_H_MAKE(TC_H_MAJ(sch->handle), q->defcls), sch);
243 if (!cl || cl->level)
244 return HTB_DIRECT; /* bad default .. this is safe bet */
249 * htb_add_to_id_tree - adds class to the round robin list
251 * Routine adds class to the list (actually tree) sorted by classid.
252 * Make sure that class is not already on such list for given prio.
254 static void htb_add_to_id_tree(struct rb_root *root,
255 struct htb_class *cl, int prio)
257 struct rb_node **p = &root->rb_node, *parent = NULL;
262 c = rb_entry(parent, struct htb_class, node[prio]);
264 if (cl->common.classid > c->common.classid)
265 p = &parent->rb_right;
267 p = &parent->rb_left;
269 rb_link_node(&cl->node[prio], parent, p);
270 rb_insert_color(&cl->node[prio], root);
274 * htb_add_to_wait_tree - adds class to the event queue with delay
276 * The class is added to priority event queue to indicate that class will
277 * change its mode in cl->pq_key microseconds. Make sure that class is not
278 * already in the queue.
280 static void htb_add_to_wait_tree(struct htb_sched *q,
281 struct htb_class *cl, long delay)
283 struct rb_node **p = &q->wait_pq[cl->level].rb_node, *parent = NULL;
285 cl->pq_key = q->now + delay;
286 if (cl->pq_key == q->now)
289 /* update the nearest event cache */
290 if (q->near_ev_cache[cl->level] > cl->pq_key)
291 q->near_ev_cache[cl->level] = cl->pq_key;
296 c = rb_entry(parent, struct htb_class, pq_node);
297 if (cl->pq_key >= c->pq_key)
298 p = &parent->rb_right;
300 p = &parent->rb_left;
302 rb_link_node(&cl->pq_node, parent, p);
303 rb_insert_color(&cl->pq_node, &q->wait_pq[cl->level]);
307 * htb_next_rb_node - finds next node in binary tree
309 * When we are past last key we return NULL.
310 * Average complexity is 2 steps per call.
312 static inline void htb_next_rb_node(struct rb_node **n)
318 * htb_add_class_to_row - add class to its row
320 * The class is added to row at priorities marked in mask.
321 * It does nothing if mask == 0.
323 static inline void htb_add_class_to_row(struct htb_sched *q,
324 struct htb_class *cl, int mask)
326 q->row_mask[cl->level] |= mask;
328 int prio = ffz(~mask);
329 mask &= ~(1 << prio);
330 htb_add_to_id_tree(q->row[cl->level] + prio, cl, prio);
334 /* If this triggers, it is a bug in this code, but it need not be fatal */
335 static void htb_safe_rb_erase(struct rb_node *rb, struct rb_root *root)
337 if (RB_EMPTY_NODE(rb)) {
347 * htb_remove_class_from_row - removes class from its row
349 * The class is removed from row at priorities marked in mask.
350 * It does nothing if mask == 0.
352 static inline void htb_remove_class_from_row(struct htb_sched *q,
353 struct htb_class *cl, int mask)
358 int prio = ffz(~mask);
360 mask &= ~(1 << prio);
361 if (q->ptr[cl->level][prio] == cl->node + prio)
362 htb_next_rb_node(q->ptr[cl->level] + prio);
364 htb_safe_rb_erase(cl->node + prio, q->row[cl->level] + prio);
365 if (!q->row[cl->level][prio].rb_node)
368 q->row_mask[cl->level] &= ~m;
372 * htb_activate_prios - creates active classe's feed chain
374 * The class is connected to ancestors and/or appropriate rows
375 * for priorities it is participating on. cl->cmode must be new
376 * (activated) mode. It does nothing if cl->prio_activity == 0.
378 static void htb_activate_prios(struct htb_sched *q, struct htb_class *cl)
380 struct htb_class *p = cl->parent;
381 long m, mask = cl->prio_activity;
383 while (cl->cmode == HTB_MAY_BORROW && p && mask) {
389 if (p->un.inner.feed[prio].rb_node)
390 /* parent already has its feed in use so that
391 reset bit in mask as parent is already ok */
392 mask &= ~(1 << prio);
394 htb_add_to_id_tree(p->un.inner.feed + prio, cl, prio);
396 p->prio_activity |= mask;
401 if (cl->cmode == HTB_CAN_SEND && mask)
402 htb_add_class_to_row(q, cl, mask);
406 * htb_deactivate_prios - remove class from feed chain
408 * cl->cmode must represent old mode (before deactivation). It does
409 * nothing if cl->prio_activity == 0. Class is removed from all feed
412 static void htb_deactivate_prios(struct htb_sched *q, struct htb_class *cl)
414 struct htb_class *p = cl->parent;
415 long m, mask = cl->prio_activity;
417 while (cl->cmode == HTB_MAY_BORROW && p && mask) {
424 if (p->un.inner.ptr[prio] == cl->node + prio) {
425 /* we are removing child which is pointed to from
426 parent feed - forget the pointer but remember
428 p->un.inner.last_ptr_id[prio] = cl->common.classid;
429 p->un.inner.ptr[prio] = NULL;
432 htb_safe_rb_erase(cl->node + prio, p->un.inner.feed + prio);
434 if (!p->un.inner.feed[prio].rb_node)
438 p->prio_activity &= ~mask;
443 if (cl->cmode == HTB_CAN_SEND && mask)
444 htb_remove_class_from_row(q, cl, mask);
447 static inline long htb_lowater(const struct htb_class *cl)
450 return cl->cmode != HTB_CANT_SEND ? -cl->cbuffer : 0;
454 static inline long htb_hiwater(const struct htb_class *cl)
457 return cl->cmode == HTB_CAN_SEND ? -cl->buffer : 0;
464 * htb_class_mode - computes and returns current class mode
466 * It computes cl's mode at time cl->t_c+diff and returns it. If mode
467 * is not HTB_CAN_SEND then cl->pq_key is updated to time difference
468 * from now to time when cl will change its state.
469 * Also it is worth to note that class mode doesn't change simply
470 * at cl->{c,}tokens == 0 but there can rather be hysteresis of
471 * 0 .. -cl->{c,}buffer range. It is meant to limit number of
472 * mode transitions per time unit. The speed gain is about 1/6.
474 static inline enum htb_cmode
475 htb_class_mode(struct htb_class *cl, long *diff)
479 if ((toks = (cl->ctokens + *diff)) < htb_lowater(cl)) {
481 return HTB_CANT_SEND;
484 if ((toks = (cl->tokens + *diff)) >= htb_hiwater(cl))
488 return HTB_MAY_BORROW;
492 * htb_change_class_mode - changes classe's mode
494 * This should be the only way how to change classe's mode under normal
495 * cirsumstances. Routine will update feed lists linkage, change mode
496 * and add class to the wait event queue if appropriate. New mode should
497 * be different from old one and cl->pq_key has to be valid if changing
498 * to mode other than HTB_CAN_SEND (see htb_add_to_wait_tree).
501 htb_change_class_mode(struct htb_sched *q, struct htb_class *cl, long *diff)
503 enum htb_cmode new_mode = htb_class_mode(cl, diff);
505 if (new_mode == cl->cmode)
508 if (cl->prio_activity) { /* not necessary: speed optimization */
509 if (cl->cmode != HTB_CANT_SEND)
510 htb_deactivate_prios(q, cl);
511 cl->cmode = new_mode;
512 if (new_mode != HTB_CANT_SEND)
513 htb_activate_prios(q, cl);
515 cl->cmode = new_mode;
519 * htb_activate - inserts leaf cl into appropriate active feeds
521 * Routine learns (new) priority of leaf and activates feed chain
522 * for the prio. It can be called on already active leaf safely.
523 * It also adds leaf into droplist.
525 static inline void htb_activate(struct htb_sched *q, struct htb_class *cl)
527 BUG_TRAP(!cl->level && cl->un.leaf.q && cl->un.leaf.q->q.qlen);
529 if (!cl->prio_activity) {
530 cl->prio_activity = 1 << (cl->un.leaf.aprio = cl->un.leaf.prio);
531 htb_activate_prios(q, cl);
532 list_add_tail(&cl->un.leaf.drop_list,
533 q->drops + cl->un.leaf.aprio);
538 * htb_deactivate - remove leaf cl from active feeds
540 * Make sure that leaf is active. In the other words it can't be called
541 * with non-active leaf. It also removes class from the drop list.
543 static inline void htb_deactivate(struct htb_sched *q, struct htb_class *cl)
545 BUG_TRAP(cl->prio_activity);
547 htb_deactivate_prios(q, cl);
548 cl->prio_activity = 0;
549 list_del_init(&cl->un.leaf.drop_list);
552 static int htb_enqueue(struct sk_buff *skb, struct Qdisc *sch)
555 struct htb_sched *q = qdisc_priv(sch);
556 struct htb_class *cl = htb_classify(skb, sch, &ret);
558 if (cl == HTB_DIRECT) {
559 /* enqueue to helper queue */
560 if (q->direct_queue.qlen < q->direct_qlen) {
561 __skb_queue_tail(&q->direct_queue, skb);
566 return NET_XMIT_DROP;
568 #ifdef CONFIG_NET_CLS_ACT
570 if (ret == NET_XMIT_BYPASS)
575 } else if (cl->un.leaf.q->enqueue(skb, cl->un.leaf.q) !=
579 return NET_XMIT_DROP;
581 cl->bstats.packets +=
582 skb_is_gso(skb)?skb_shinfo(skb)->gso_segs:1;
583 cl->bstats.bytes += skb->len;
588 sch->bstats.packets += skb_is_gso(skb)?skb_shinfo(skb)->gso_segs:1;
589 sch->bstats.bytes += skb->len;
590 return NET_XMIT_SUCCESS;
593 /* TODO: requeuing packet charges it to policers again !! */
594 static int htb_requeue(struct sk_buff *skb, struct Qdisc *sch)
597 struct htb_sched *q = qdisc_priv(sch);
598 struct htb_class *cl = htb_classify(skb, sch, &ret);
599 struct sk_buff *tskb;
601 if (cl == HTB_DIRECT) {
602 /* enqueue to helper queue */
603 if (q->direct_queue.qlen < q->direct_qlen) {
604 __skb_queue_head(&q->direct_queue, skb);
606 __skb_queue_head(&q->direct_queue, skb);
607 tskb = __skb_dequeue_tail(&q->direct_queue);
612 #ifdef CONFIG_NET_CLS_ACT
614 if (ret == NET_XMIT_BYPASS)
619 } else if (cl->un.leaf.q->ops->requeue(skb, cl->un.leaf.q) !=
623 return NET_XMIT_DROP;
628 sch->qstats.requeues++;
629 return NET_XMIT_SUCCESS;
633 * htb_charge_class - charges amount "bytes" to leaf and ancestors
635 * Routine assumes that packet "bytes" long was dequeued from leaf cl
636 * borrowing from "level". It accounts bytes to ceil leaky bucket for
637 * leaf and all ancestors and to rate bucket for ancestors at levels
638 * "level" and higher. It also handles possible change of mode resulting
639 * from the update. Note that mode can also increase here (MAY_BORROW to
640 * CAN_SEND) because we can use more precise clock that event queue here.
641 * In such case we remove class from event queue first.
643 static void htb_charge_class(struct htb_sched *q, struct htb_class *cl,
644 int level, struct sk_buff *skb)
646 int bytes = skb->len;
648 enum htb_cmode old_mode;
650 #define HTB_ACCNT(T,B,R) toks = diff + cl->T; \
651 if (toks > cl->B) toks = cl->B; \
652 toks -= L2T(cl, cl->R, bytes); \
653 if (toks <= -cl->mbuffer) toks = 1-cl->mbuffer; \
657 diff = psched_tdiff_bounded(q->now, cl->t_c, cl->mbuffer);
658 if (cl->level >= level) {
659 if (cl->level == level)
661 HTB_ACCNT(tokens, buffer, rate);
663 cl->xstats.borrows++;
664 cl->tokens += diff; /* we moved t_c; update tokens */
666 HTB_ACCNT(ctokens, cbuffer, ceil);
669 old_mode = cl->cmode;
671 htb_change_class_mode(q, cl, &diff);
672 if (old_mode != cl->cmode) {
673 if (old_mode != HTB_CAN_SEND)
674 htb_safe_rb_erase(&cl->pq_node, q->wait_pq + cl->level);
675 if (cl->cmode != HTB_CAN_SEND)
676 htb_add_to_wait_tree(q, cl, diff);
679 /* update byte stats except for leaves which are already updated */
681 cl->bstats.bytes += bytes;
682 cl->bstats.packets += skb_is_gso(skb)?
683 skb_shinfo(skb)->gso_segs:1;
690 * htb_do_events - make mode changes to classes at the level
692 * Scans event queue for pending events and applies them. Returns time of
693 * next pending event (0 for no event in pq).
694 * Note: Applied are events whose have cl->pq_key <= q->now.
696 static psched_time_t htb_do_events(struct htb_sched *q, int level)
698 /* don't run for longer than 2 jiffies; 2 is used instead of
699 1 to simplify things when jiffy is going to be incremented
701 unsigned long stop_at = jiffies + 2;
702 while (time_before(jiffies, stop_at)) {
703 struct htb_class *cl;
705 struct rb_node *p = rb_first(&q->wait_pq[level]);
710 cl = rb_entry(p, struct htb_class, pq_node);
711 if (cl->pq_key > q->now)
714 htb_safe_rb_erase(p, q->wait_pq + level);
715 diff = psched_tdiff_bounded(q->now, cl->t_c, cl->mbuffer);
716 htb_change_class_mode(q, cl, &diff);
717 if (cl->cmode != HTB_CAN_SEND)
718 htb_add_to_wait_tree(q, cl, diff);
720 /* too much load - let's continue on next jiffie */
721 return q->now + PSCHED_TICKS_PER_SEC / HZ;
724 /* Returns class->node+prio from id-tree where classe's id is >= id. NULL
725 is no such one exists. */
726 static struct rb_node *htb_id_find_next_upper(int prio, struct rb_node *n,
729 struct rb_node *r = NULL;
731 struct htb_class *cl =
732 rb_entry(n, struct htb_class, node[prio]);
733 if (id == cl->common.classid)
736 if (id > cl->common.classid) {
747 * htb_lookup_leaf - returns next leaf class in DRR order
749 * Find leaf where current feed pointers points to.
751 static struct htb_class *htb_lookup_leaf(struct rb_root *tree, int prio,
752 struct rb_node **pptr, u32 * pid)
756 struct rb_node *root;
757 struct rb_node **pptr;
759 } stk[TC_HTB_MAXDEPTH], *sp = stk;
761 BUG_TRAP(tree->rb_node);
762 sp->root = tree->rb_node;
766 for (i = 0; i < 65535; i++) {
767 if (!*sp->pptr && *sp->pid) {
768 /* ptr was invalidated but id is valid - try to recover
769 the original or next ptr */
771 htb_id_find_next_upper(prio, sp->root, *sp->pid);
773 *sp->pid = 0; /* ptr is valid now so that remove this hint as it
774 can become out of date quickly */
775 if (!*sp->pptr) { /* we are at right end; rewind & go up */
776 *sp->pptr = sp->root;
777 while ((*sp->pptr)->rb_left)
778 *sp->pptr = (*sp->pptr)->rb_left;
784 htb_next_rb_node(sp->pptr);
787 struct htb_class *cl;
788 cl = rb_entry(*sp->pptr, struct htb_class, node[prio]);
791 (++sp)->root = cl->un.inner.feed[prio].rb_node;
792 sp->pptr = cl->un.inner.ptr + prio;
793 sp->pid = cl->un.inner.last_ptr_id + prio;
800 /* dequeues packet at given priority and level; call only if
801 you are sure that there is active class at prio/level */
802 static struct sk_buff *htb_dequeue_tree(struct htb_sched *q, int prio,
805 struct sk_buff *skb = NULL;
806 struct htb_class *cl, *start;
807 /* look initial class up in the row */
808 start = cl = htb_lookup_leaf(q->row[level] + prio, prio,
809 q->ptr[level] + prio,
810 q->last_ptr_id[level] + prio);
818 /* class can be empty - it is unlikely but can be true if leaf
819 qdisc drops packets in enqueue routine or if someone used
820 graft operation on the leaf since last dequeue;
821 simply deactivate and skip such class */
822 if (unlikely(cl->un.leaf.q->q.qlen == 0)) {
823 struct htb_class *next;
824 htb_deactivate(q, cl);
826 /* row/level might become empty */
827 if ((q->row_mask[level] & (1 << prio)) == 0)
830 next = htb_lookup_leaf(q->row[level] + prio,
831 prio, q->ptr[level] + prio,
832 q->last_ptr_id[level] + prio);
834 if (cl == start) /* fix start if we just deleted it */
840 skb = cl->un.leaf.q->dequeue(cl->un.leaf.q);
841 if (likely(skb != NULL))
845 "htb: class %X isn't work conserving ?!\n",
850 htb_next_rb_node((level ? cl->parent->un.inner.ptr : q->
852 cl = htb_lookup_leaf(q->row[level] + prio, prio,
853 q->ptr[level] + prio,
854 q->last_ptr_id[level] + prio);
856 } while (cl != start);
858 if (likely(skb != NULL)) {
859 if ((cl->un.leaf.deficit[level] -= skb->len) < 0) {
860 cl->un.leaf.deficit[level] += cl->un.leaf.quantum;
861 htb_next_rb_node((level ? cl->parent->un.inner.ptr : q->
864 /* this used to be after charge_class but this constelation
865 gives us slightly better performance */
866 if (!cl->un.leaf.q->q.qlen)
867 htb_deactivate(q, cl);
868 htb_charge_class(q, cl, level, skb);
873 static struct sk_buff *htb_dequeue(struct Qdisc *sch)
875 struct sk_buff *skb = NULL;
876 struct htb_sched *q = qdisc_priv(sch);
878 psched_time_t next_event;
880 /* try to dequeue direct packets as high prio (!) to minimize cpu work */
881 skb = __skb_dequeue(&q->direct_queue);
883 sch->flags &= ~TCQ_F_THROTTLED;
890 q->now = psched_get_time();
892 next_event = q->now + 5 * PSCHED_TICKS_PER_SEC;
894 for (level = 0; level < TC_HTB_MAXDEPTH; level++) {
895 /* common case optimization - skip event handler quickly */
899 if (q->now >= q->near_ev_cache[level]) {
900 event = htb_do_events(q, level);
902 event = q->now + PSCHED_TICKS_PER_SEC;
903 q->near_ev_cache[level] = event;
905 event = q->near_ev_cache[level];
907 if (event && next_event > event)
910 m = ~q->row_mask[level];
911 while (m != (int)(-1)) {
914 skb = htb_dequeue_tree(q, prio, level);
915 if (likely(skb != NULL)) {
917 sch->flags &= ~TCQ_F_THROTTLED;
922 sch->qstats.overlimits++;
923 qdisc_watchdog_schedule(&q->watchdog, next_event);
928 /* try to drop from each class (by prio) until one succeed */
929 static unsigned int htb_drop(struct Qdisc *sch)
931 struct htb_sched *q = qdisc_priv(sch);
934 for (prio = TC_HTB_NUMPRIO - 1; prio >= 0; prio--) {
936 list_for_each(p, q->drops + prio) {
937 struct htb_class *cl = list_entry(p, struct htb_class,
940 if (cl->un.leaf.q->ops->drop &&
941 (len = cl->un.leaf.q->ops->drop(cl->un.leaf.q))) {
943 if (!cl->un.leaf.q->q.qlen)
944 htb_deactivate(q, cl);
952 /* reset all classes */
953 /* always caled under BH & queue lock */
954 static void htb_reset(struct Qdisc *sch)
956 struct htb_sched *q = qdisc_priv(sch);
957 struct htb_class *cl;
958 struct hlist_node *n;
961 for (i = 0; i < q->clhash.hashsize; i++) {
962 hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
964 memset(&cl->un.inner, 0, sizeof(cl->un.inner));
967 qdisc_reset(cl->un.leaf.q);
968 INIT_LIST_HEAD(&cl->un.leaf.drop_list);
970 cl->prio_activity = 0;
971 cl->cmode = HTB_CAN_SEND;
975 qdisc_watchdog_cancel(&q->watchdog);
976 __skb_queue_purge(&q->direct_queue);
978 memset(q->row, 0, sizeof(q->row));
979 memset(q->row_mask, 0, sizeof(q->row_mask));
980 memset(q->wait_pq, 0, sizeof(q->wait_pq));
981 memset(q->ptr, 0, sizeof(q->ptr));
982 for (i = 0; i < TC_HTB_NUMPRIO; i++)
983 INIT_LIST_HEAD(q->drops + i);
986 static const struct nla_policy htb_policy[TCA_HTB_MAX + 1] = {
987 [TCA_HTB_PARMS] = { .len = sizeof(struct tc_htb_opt) },
988 [TCA_HTB_INIT] = { .len = sizeof(struct tc_htb_glob) },
989 [TCA_HTB_CTAB] = { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
990 [TCA_HTB_RTAB] = { .type = NLA_BINARY, .len = TC_RTAB_SIZE },
993 static int htb_init(struct Qdisc *sch, struct nlattr *opt)
995 struct htb_sched *q = qdisc_priv(sch);
996 struct nlattr *tb[TCA_HTB_INIT + 1];
997 struct tc_htb_glob *gopt;
1004 err = nla_parse_nested(tb, TCA_HTB_INIT, opt, htb_policy);
1008 if (tb[TCA_HTB_INIT] == NULL) {
1009 printk(KERN_ERR "HTB: hey probably you have bad tc tool ?\n");
1012 gopt = nla_data(tb[TCA_HTB_INIT]);
1013 if (gopt->version != HTB_VER >> 16) {
1015 "HTB: need tc/htb version %d (minor is %d), you have %d\n",
1016 HTB_VER >> 16, HTB_VER & 0xffff, gopt->version);
1020 err = qdisc_class_hash_init(&q->clhash);
1023 for (i = 0; i < TC_HTB_NUMPRIO; i++)
1024 INIT_LIST_HEAD(q->drops + i);
1026 qdisc_watchdog_init(&q->watchdog, sch);
1027 skb_queue_head_init(&q->direct_queue);
1029 q->direct_qlen = sch->dev->tx_queue_len;
1030 if (q->direct_qlen < 2) /* some devices have zero tx_queue_len */
1033 if ((q->rate2quantum = gopt->rate2quantum) < 1)
1034 q->rate2quantum = 1;
1035 q->defcls = gopt->defcls;
1040 static int htb_dump(struct Qdisc *sch, struct sk_buff *skb)
1042 struct htb_sched *q = qdisc_priv(sch);
1043 struct nlattr *nest;
1044 struct tc_htb_glob gopt;
1046 spin_lock_bh(&sch->dev->queue_lock);
1048 gopt.direct_pkts = q->direct_pkts;
1049 gopt.version = HTB_VER;
1050 gopt.rate2quantum = q->rate2quantum;
1051 gopt.defcls = q->defcls;
1054 nest = nla_nest_start(skb, TCA_OPTIONS);
1056 goto nla_put_failure;
1057 NLA_PUT(skb, TCA_HTB_INIT, sizeof(gopt), &gopt);
1058 nla_nest_end(skb, nest);
1060 spin_unlock_bh(&sch->dev->queue_lock);
1064 spin_unlock_bh(&sch->dev->queue_lock);
1065 nla_nest_cancel(skb, nest);
1069 static int htb_dump_class(struct Qdisc *sch, unsigned long arg,
1070 struct sk_buff *skb, struct tcmsg *tcm)
1072 struct htb_class *cl = (struct htb_class *)arg;
1073 struct nlattr *nest;
1074 struct tc_htb_opt opt;
1076 spin_lock_bh(&sch->dev->queue_lock);
1077 tcm->tcm_parent = cl->parent ? cl->parent->common.classid : TC_H_ROOT;
1078 tcm->tcm_handle = cl->common.classid;
1079 if (!cl->level && cl->un.leaf.q)
1080 tcm->tcm_info = cl->un.leaf.q->handle;
1082 nest = nla_nest_start(skb, TCA_OPTIONS);
1084 goto nla_put_failure;
1086 memset(&opt, 0, sizeof(opt));
1088 opt.rate = cl->rate->rate;
1089 opt.buffer = cl->buffer;
1090 opt.ceil = cl->ceil->rate;
1091 opt.cbuffer = cl->cbuffer;
1092 opt.quantum = cl->un.leaf.quantum;
1093 opt.prio = cl->un.leaf.prio;
1094 opt.level = cl->level;
1095 NLA_PUT(skb, TCA_HTB_PARMS, sizeof(opt), &opt);
1097 nla_nest_end(skb, nest);
1098 spin_unlock_bh(&sch->dev->queue_lock);
1102 spin_unlock_bh(&sch->dev->queue_lock);
1103 nla_nest_cancel(skb, nest);
1108 htb_dump_class_stats(struct Qdisc *sch, unsigned long arg, struct gnet_dump *d)
1110 struct htb_class *cl = (struct htb_class *)arg;
1112 if (!cl->level && cl->un.leaf.q)
1113 cl->qstats.qlen = cl->un.leaf.q->q.qlen;
1114 cl->xstats.tokens = cl->tokens;
1115 cl->xstats.ctokens = cl->ctokens;
1117 if (gnet_stats_copy_basic(d, &cl->bstats) < 0 ||
1118 gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 ||
1119 gnet_stats_copy_queue(d, &cl->qstats) < 0)
1122 return gnet_stats_copy_app(d, &cl->xstats, sizeof(cl->xstats));
1125 static int htb_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
1128 struct htb_class *cl = (struct htb_class *)arg;
1130 if (cl && !cl->level) {
1132 (new = qdisc_create_dflt(sch->dev, sch->dev_queue,
1134 cl->common.classid))
1138 if ((*old = xchg(&cl->un.leaf.q, new)) != NULL) {
1139 qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
1142 sch_tree_unlock(sch);
1148 static struct Qdisc *htb_leaf(struct Qdisc *sch, unsigned long arg)
1150 struct htb_class *cl = (struct htb_class *)arg;
1151 return (cl && !cl->level) ? cl->un.leaf.q : NULL;
1154 static void htb_qlen_notify(struct Qdisc *sch, unsigned long arg)
1156 struct htb_class *cl = (struct htb_class *)arg;
1158 if (cl->un.leaf.q->q.qlen == 0)
1159 htb_deactivate(qdisc_priv(sch), cl);
1162 static unsigned long htb_get(struct Qdisc *sch, u32 classid)
1164 struct htb_class *cl = htb_find(classid, sch);
1167 return (unsigned long)cl;
1170 static inline int htb_parent_last_child(struct htb_class *cl)
1173 /* the root class */
1175 if (cl->parent->children > 1)
1176 /* not the last child */
1181 static void htb_parent_to_leaf(struct htb_sched *q, struct htb_class *cl,
1182 struct Qdisc *new_q)
1184 struct htb_class *parent = cl->parent;
1186 BUG_TRAP(!cl->level && cl->un.leaf.q && !cl->prio_activity);
1188 if (parent->cmode != HTB_CAN_SEND)
1189 htb_safe_rb_erase(&parent->pq_node, q->wait_pq + parent->level);
1192 memset(&parent->un.inner, 0, sizeof(parent->un.inner));
1193 INIT_LIST_HEAD(&parent->un.leaf.drop_list);
1194 parent->un.leaf.q = new_q ? new_q : &noop_qdisc;
1195 parent->un.leaf.quantum = parent->quantum;
1196 parent->un.leaf.prio = parent->prio;
1197 parent->tokens = parent->buffer;
1198 parent->ctokens = parent->cbuffer;
1199 parent->t_c = psched_get_time();
1200 parent->cmode = HTB_CAN_SEND;
1203 static void htb_destroy_class(struct Qdisc *sch, struct htb_class *cl)
1206 BUG_TRAP(cl->un.leaf.q);
1207 qdisc_destroy(cl->un.leaf.q);
1209 gen_kill_estimator(&cl->bstats, &cl->rate_est);
1210 qdisc_put_rtab(cl->rate);
1211 qdisc_put_rtab(cl->ceil);
1213 tcf_destroy_chain(&cl->filter_list);
1217 /* always caled under BH & queue lock */
1218 static void htb_destroy(struct Qdisc *sch)
1220 struct htb_sched *q = qdisc_priv(sch);
1221 struct hlist_node *n, *next;
1222 struct htb_class *cl;
1225 qdisc_watchdog_cancel(&q->watchdog);
1226 /* This line used to be after htb_destroy_class call below
1227 and surprisingly it worked in 2.4. But it must precede it
1228 because filter need its target class alive to be able to call
1229 unbind_filter on it (without Oops). */
1230 tcf_destroy_chain(&q->filter_list);
1232 for (i = 0; i < q->clhash.hashsize; i++) {
1233 hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode)
1234 tcf_destroy_chain(&cl->filter_list);
1236 for (i = 0; i < q->clhash.hashsize; i++) {
1237 hlist_for_each_entry_safe(cl, n, next, &q->clhash.hash[i],
1239 htb_destroy_class(sch, cl);
1241 qdisc_class_hash_destroy(&q->clhash);
1242 __skb_queue_purge(&q->direct_queue);
1245 static int htb_delete(struct Qdisc *sch, unsigned long arg)
1247 struct htb_sched *q = qdisc_priv(sch);
1248 struct htb_class *cl = (struct htb_class *)arg;
1250 struct Qdisc *new_q = NULL;
1253 // TODO: why don't allow to delete subtree ? references ? does
1254 // tc subsys quarantee us that in htb_destroy it holds no class
1255 // refs so that we can remove children safely there ?
1256 if (cl->children || cl->filter_cnt)
1259 if (!cl->level && htb_parent_last_child(cl)) {
1260 new_q = qdisc_create_dflt(sch->dev, sch->dev_queue,
1262 cl->parent->common.classid);
1269 qlen = cl->un.leaf.q->q.qlen;
1270 qdisc_reset(cl->un.leaf.q);
1271 qdisc_tree_decrease_qlen(cl->un.leaf.q, qlen);
1274 /* delete from hash and active; remainder in destroy_class */
1275 qdisc_class_hash_remove(&q->clhash, &cl->common);
1276 cl->parent->children--;
1278 if (cl->prio_activity)
1279 htb_deactivate(q, cl);
1281 if (cl->cmode != HTB_CAN_SEND)
1282 htb_safe_rb_erase(&cl->pq_node, q->wait_pq + cl->level);
1285 htb_parent_to_leaf(q, cl, new_q);
1287 if (--cl->refcnt == 0)
1288 htb_destroy_class(sch, cl);
1290 sch_tree_unlock(sch);
1294 static void htb_put(struct Qdisc *sch, unsigned long arg)
1296 struct htb_class *cl = (struct htb_class *)arg;
1298 if (--cl->refcnt == 0)
1299 htb_destroy_class(sch, cl);
1302 static int htb_change_class(struct Qdisc *sch, u32 classid,
1303 u32 parentid, struct nlattr **tca,
1307 struct htb_sched *q = qdisc_priv(sch);
1308 struct htb_class *cl = (struct htb_class *)*arg, *parent;
1309 struct nlattr *opt = tca[TCA_OPTIONS];
1310 struct qdisc_rate_table *rtab = NULL, *ctab = NULL;
1311 struct nlattr *tb[TCA_HTB_RTAB + 1];
1312 struct tc_htb_opt *hopt;
1314 /* extract all subattrs from opt attr */
1318 err = nla_parse_nested(tb, TCA_HTB_RTAB, opt, htb_policy);
1323 if (tb[TCA_HTB_PARMS] == NULL)
1326 parent = parentid == TC_H_ROOT ? NULL : htb_find(parentid, sch);
1328 hopt = nla_data(tb[TCA_HTB_PARMS]);
1330 rtab = qdisc_get_rtab(&hopt->rate, tb[TCA_HTB_RTAB]);
1331 ctab = qdisc_get_rtab(&hopt->ceil, tb[TCA_HTB_CTAB]);
1335 if (!cl) { /* new class */
1336 struct Qdisc *new_q;
1340 struct gnet_estimator opt;
1343 .nla_len = nla_attr_size(sizeof(est.opt)),
1344 .nla_type = TCA_RATE,
1347 /* 4s interval, 16s averaging constant */
1353 /* check for valid classid */
1354 if (!classid || TC_H_MAJ(classid ^ sch->handle)
1355 || htb_find(classid, sch))
1358 /* check maximal depth */
1359 if (parent && parent->parent && parent->parent->level < 2) {
1360 printk(KERN_ERR "htb: tree is too deep\n");
1364 if ((cl = kzalloc(sizeof(*cl), GFP_KERNEL)) == NULL)
1367 gen_new_estimator(&cl->bstats, &cl->rate_est,
1368 &sch->dev->queue_lock,
1369 tca[TCA_RATE] ? : &est.nla);
1372 INIT_LIST_HEAD(&cl->un.leaf.drop_list);
1373 RB_CLEAR_NODE(&cl->pq_node);
1375 for (prio = 0; prio < TC_HTB_NUMPRIO; prio++)
1376 RB_CLEAR_NODE(&cl->node[prio]);
1378 /* create leaf qdisc early because it uses kmalloc(GFP_KERNEL)
1379 so that can't be used inside of sch_tree_lock
1380 -- thanks to Karlis Peisenieks */
1381 new_q = qdisc_create_dflt(sch->dev, sch->dev_queue,
1382 &pfifo_qdisc_ops, classid);
1384 if (parent && !parent->level) {
1385 unsigned int qlen = parent->un.leaf.q->q.qlen;
1387 /* turn parent into inner node */
1388 qdisc_reset(parent->un.leaf.q);
1389 qdisc_tree_decrease_qlen(parent->un.leaf.q, qlen);
1390 qdisc_destroy(parent->un.leaf.q);
1391 if (parent->prio_activity)
1392 htb_deactivate(q, parent);
1394 /* remove from evt list because of level change */
1395 if (parent->cmode != HTB_CAN_SEND) {
1396 htb_safe_rb_erase(&parent->pq_node, q->wait_pq);
1397 parent->cmode = HTB_CAN_SEND;
1399 parent->level = (parent->parent ? parent->parent->level
1400 : TC_HTB_MAXDEPTH) - 1;
1401 memset(&parent->un.inner, 0, sizeof(parent->un.inner));
1403 /* leaf (we) needs elementary qdisc */
1404 cl->un.leaf.q = new_q ? new_q : &noop_qdisc;
1406 cl->common.classid = classid;
1407 cl->parent = parent;
1409 /* set class to be in HTB_CAN_SEND state */
1410 cl->tokens = hopt->buffer;
1411 cl->ctokens = hopt->cbuffer;
1412 cl->mbuffer = 60 * PSCHED_TICKS_PER_SEC; /* 1min */
1413 cl->t_c = psched_get_time();
1414 cl->cmode = HTB_CAN_SEND;
1416 /* attach to the hash list and parent's family */
1417 qdisc_class_hash_insert(&q->clhash, &cl->common);
1422 gen_replace_estimator(&cl->bstats, &cl->rate_est,
1423 &sch->dev->queue_lock,
1428 /* it used to be a nasty bug here, we have to check that node
1429 is really leaf before changing cl->un.leaf ! */
1431 cl->un.leaf.quantum = rtab->rate.rate / q->rate2quantum;
1432 if (!hopt->quantum && cl->un.leaf.quantum < 1000) {
1434 "HTB: quantum of class %X is small. Consider r2q change.\n",
1435 cl->common.classid);
1436 cl->un.leaf.quantum = 1000;
1438 if (!hopt->quantum && cl->un.leaf.quantum > 200000) {
1440 "HTB: quantum of class %X is big. Consider r2q change.\n",
1441 cl->common.classid);
1442 cl->un.leaf.quantum = 200000;
1445 cl->un.leaf.quantum = hopt->quantum;
1446 if ((cl->un.leaf.prio = hopt->prio) >= TC_HTB_NUMPRIO)
1447 cl->un.leaf.prio = TC_HTB_NUMPRIO - 1;
1449 /* backup for htb_parent_to_leaf */
1450 cl->quantum = cl->un.leaf.quantum;
1451 cl->prio = cl->un.leaf.prio;
1454 cl->buffer = hopt->buffer;
1455 cl->cbuffer = hopt->cbuffer;
1457 qdisc_put_rtab(cl->rate);
1460 qdisc_put_rtab(cl->ceil);
1462 sch_tree_unlock(sch);
1464 qdisc_class_hash_grow(sch, &q->clhash);
1466 *arg = (unsigned long)cl;
1471 qdisc_put_rtab(rtab);
1473 qdisc_put_rtab(ctab);
1477 static struct tcf_proto **htb_find_tcf(struct Qdisc *sch, unsigned long arg)
1479 struct htb_sched *q = qdisc_priv(sch);
1480 struct htb_class *cl = (struct htb_class *)arg;
1481 struct tcf_proto **fl = cl ? &cl->filter_list : &q->filter_list;
1486 static unsigned long htb_bind_filter(struct Qdisc *sch, unsigned long parent,
1489 struct htb_class *cl = htb_find(classid, sch);
1491 /*if (cl && !cl->level) return 0;
1492 The line above used to be there to prevent attaching filters to
1493 leaves. But at least tc_index filter uses this just to get class
1494 for other reasons so that we have to allow for it.
1496 19.6.2002 As Werner explained it is ok - bind filter is just
1497 another way to "lock" the class - unlike "get" this lock can
1498 be broken by class during destroy IIUC.
1502 return (unsigned long)cl;
1505 static void htb_unbind_filter(struct Qdisc *sch, unsigned long arg)
1507 struct htb_class *cl = (struct htb_class *)arg;
1513 static void htb_walk(struct Qdisc *sch, struct qdisc_walker *arg)
1515 struct htb_sched *q = qdisc_priv(sch);
1516 struct htb_class *cl;
1517 struct hlist_node *n;
1523 for (i = 0; i < q->clhash.hashsize; i++) {
1524 hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) {
1525 if (arg->count < arg->skip) {
1529 if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
1538 static const struct Qdisc_class_ops htb_class_ops = {
1541 .qlen_notify = htb_qlen_notify,
1544 .change = htb_change_class,
1545 .delete = htb_delete,
1547 .tcf_chain = htb_find_tcf,
1548 .bind_tcf = htb_bind_filter,
1549 .unbind_tcf = htb_unbind_filter,
1550 .dump = htb_dump_class,
1551 .dump_stats = htb_dump_class_stats,
1554 static struct Qdisc_ops htb_qdisc_ops __read_mostly = {
1556 .cl_ops = &htb_class_ops,
1558 .priv_size = sizeof(struct htb_sched),
1559 .enqueue = htb_enqueue,
1560 .dequeue = htb_dequeue,
1561 .requeue = htb_requeue,
1565 .destroy = htb_destroy,
1566 .change = NULL /* htb_change */,
1568 .owner = THIS_MODULE,
1571 static int __init htb_module_init(void)
1573 return register_qdisc(&htb_qdisc_ops);
1575 static void __exit htb_module_exit(void)
1577 unregister_qdisc(&htb_qdisc_ops);
1580 module_init(htb_module_init)
1581 module_exit(htb_module_exit)
1582 MODULE_LICENSE("GPL");