2 * net/sched/sch_qfq.c Quick Fair Queueing Plus Scheduler.
4 * Copyright (c) 2009 Fabio Checconi, Luigi Rizzo, and Paolo Valente.
5 * Copyright (c) 2012 Paolo Valente.
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * version 2 as published by the Free Software Foundation.
12 #include <linux/module.h>
13 #include <linux/init.h>
14 #include <linux/bitops.h>
15 #include <linux/errno.h>
16 #include <linux/netdevice.h>
17 #include <linux/pkt_sched.h>
18 #include <net/sch_generic.h>
19 #include <net/pkt_sched.h>
20 #include <net/pkt_cls.h>
23 /* Quick Fair Queueing Plus
24 ========================
29 "Reducing the Execution Time of Fair-Queueing Schedulers."
30 http://algo.ing.unimo.it/people/paolo/agg-sched/agg-sched.pdf
34 [2] Fabio Checconi, Luigi Rizzo, and Paolo Valente: "QFQ: Efficient
35 Packet Scheduling with Tight Bandwidth Distribution Guarantees."
38 http://retis.sssup.it/~fabio/linux/qfq/
43 QFQ+ divides classes into aggregates of at most MAX_AGG_CLASSES
44 classes. Each aggregate is timestamped with a virtual start time S
45 and a virtual finish time F, and scheduled according to its
46 timestamps. S and F are computed as a function of a system virtual
47 time function V. The classes within each aggregate are instead
50 To speed up operations, QFQ+ divides also aggregates into a limited
51 number of groups. Which group a class belongs to depends on the
52 ratio between the maximum packet length for the class and the weight
53 of the class. Groups have their own S and F. In the end, QFQ+
54 schedules groups, then aggregates within groups, then classes within
55 aggregates. See [1] and [2] for a full description.
57 Virtual time computations.
59 S, F and V are all computed in fixed point arithmetic with
60 FRAC_BITS decimal bits.
62 QFQ_MAX_INDEX is the maximum index allowed for a group. We need
64 QFQ_MAX_WSHIFT is the maximum power of two supported as a weight.
66 The layout of the bits is as below:
68 [ MTU_SHIFT ][ FRAC_BITS ]
69 [ MAX_INDEX ][ MIN_SLOT_SHIFT ]
73 where MIN_SLOT_SHIFT is derived by difference from the others.
75 The max group index corresponds to Lmax/w_min, where
76 Lmax=1<<MTU_SHIFT, w_min = 1 .
77 From this, and knowing how many groups (MAX_INDEX) we want,
78 we can derive the shift corresponding to each group.
80 Because we often need to compute
81 F = S + len/w_i and V = V + len/wsum
82 instead of storing w_i store the value
83 inv_w = (1<<FRAC_BITS)/w_i
84 so we can do F = S + len * inv_w * wsum.
85 We use W_TOT in the formulas so we can easily move between
86 static and adaptive weight sum.
88 The per-scheduler-instance data contain all the data structures
89 for the scheduler: bitmaps and bucket lists.
94 * Maximum number of consecutive slots occupied by backlogged classes
97 #define QFQ_MAX_SLOTS 32
100 * Shifts used for aggregate<->group mapping. We allow class weights that are
101 * in the range [1, 2^MAX_WSHIFT], and we try to map each aggregate i to the
102 * group with the smallest index that can support the L_i / r_i configured
103 * for the classes in the aggregate.
105 * grp->index is the index of the group; and grp->slot_shift
106 * is the shift for the corresponding (scaled) sigma_i.
108 #define QFQ_MAX_INDEX 24
109 #define QFQ_MAX_WSHIFT 10
111 #define QFQ_MAX_WEIGHT (1<<QFQ_MAX_WSHIFT) /* see qfq_slot_insert */
112 #define QFQ_MAX_WSUM (64*QFQ_MAX_WEIGHT)
114 #define FRAC_BITS 30 /* fixed point arithmetic */
115 #define ONE_FP (1UL << FRAC_BITS)
117 #define QFQ_MTU_SHIFT 16 /* to support TSO/GSO */
118 #define QFQ_MIN_LMAX 512 /* see qfq_slot_insert */
120 #define QFQ_MAX_AGG_CLASSES 8 /* max num classes per aggregate allowed */
123 * Possible group states. These values are used as indexes for the bitmaps
124 * array of struct qfq_queue.
126 enum qfq_state
{ ER
, IR
, EB
, IB
, QFQ_MAX_STATE
};
130 struct qfq_aggregate
;
133 struct Qdisc_class_common common
;
136 unsigned int filter_cnt
;
138 struct gnet_stats_basic_packed bstats
;
139 struct gnet_stats_queue qstats
;
140 struct net_rate_estimator __rcu
*rate_est
;
142 struct list_head alist
; /* Link for active-classes list. */
143 struct qfq_aggregate
*agg
; /* Parent aggregate. */
144 int deficit
; /* DRR deficit counter. */
147 struct qfq_aggregate
{
148 struct hlist_node next
; /* Link for the slot list. */
149 u64 S
, F
; /* flow timestamps (exact) */
151 /* group we belong to. In principle we would need the index,
152 * which is log_2(lmax/weight), but we never reference it
153 * directly, only the group.
155 struct qfq_group
*grp
;
157 /* these are copied from the flowset. */
158 u32 class_weight
; /* Weight of each class in this aggregate. */
159 /* Max pkt size for the classes in this aggregate, DRR quantum. */
162 u32 inv_w
; /* ONE_FP/(sum of weights of classes in aggr.). */
163 u32 budgetmax
; /* Max budget for this aggregate. */
164 u32 initial_budget
, budget
; /* Initial and current budget. */
166 int num_classes
; /* Number of classes in this aggr. */
167 struct list_head active
; /* DRR queue of active classes. */
169 struct hlist_node nonfull_next
; /* See nonfull_aggs in qfq_sched. */
173 u64 S
, F
; /* group timestamps (approx). */
174 unsigned int slot_shift
; /* Slot shift. */
175 unsigned int index
; /* Group index. */
176 unsigned int front
; /* Index of the front slot. */
177 unsigned long full_slots
; /* non-empty slots */
179 /* Array of RR lists of active aggregates. */
180 struct hlist_head slots
[QFQ_MAX_SLOTS
];
184 struct tcf_proto __rcu
*filter_list
;
185 struct tcf_block
*block
;
186 struct Qdisc_class_hash clhash
;
188 u64 oldV
, V
; /* Precise virtual times. */
189 struct qfq_aggregate
*in_serv_agg
; /* Aggregate being served. */
190 u32 wsum
; /* weight sum */
191 u32 iwsum
; /* inverse weight sum */
193 unsigned long bitmaps
[QFQ_MAX_STATE
]; /* Group bitmaps. */
194 struct qfq_group groups
[QFQ_MAX_INDEX
+ 1]; /* The groups. */
195 u32 min_slot_shift
; /* Index of the group-0 bit in the bitmaps. */
197 u32 max_agg_classes
; /* Max number of classes per aggr. */
198 struct hlist_head nonfull_aggs
; /* Aggs with room for more classes. */
202 * Possible reasons why the timestamps of an aggregate are updated
203 * enqueue: the aggregate switches from idle to active and must scheduled
205 * requeue: the aggregate finishes its budget, so it stops being served and
206 * must be rescheduled for service
208 enum update_reason
{enqueue
, requeue
};
210 static struct qfq_class
*qfq_find_class(struct Qdisc
*sch
, u32 classid
)
212 struct qfq_sched
*q
= qdisc_priv(sch
);
213 struct Qdisc_class_common
*clc
;
215 clc
= qdisc_class_find(&q
->clhash
, classid
);
218 return container_of(clc
, struct qfq_class
, common
);
221 static void qfq_purge_queue(struct qfq_class
*cl
)
223 unsigned int len
= cl
->qdisc
->q
.qlen
;
224 unsigned int backlog
= cl
->qdisc
->qstats
.backlog
;
226 qdisc_reset(cl
->qdisc
);
227 qdisc_tree_reduce_backlog(cl
->qdisc
, len
, backlog
);
230 static const struct nla_policy qfq_policy
[TCA_QFQ_MAX
+ 1] = {
231 [TCA_QFQ_WEIGHT
] = { .type
= NLA_U32
},
232 [TCA_QFQ_LMAX
] = { .type
= NLA_U32
},
236 * Calculate a flow index, given its weight and maximum packet length.
237 * index = log_2(maxlen/weight) but we need to apply the scaling.
238 * This is used only once at flow creation.
240 static int qfq_calc_index(u32 inv_w
, unsigned int maxlen
, u32 min_slot_shift
)
242 u64 slot_size
= (u64
)maxlen
* inv_w
;
243 unsigned long size_map
;
246 size_map
= slot_size
>> min_slot_shift
;
250 index
= __fls(size_map
) + 1; /* basically a log_2 */
251 index
-= !(slot_size
- (1ULL << (index
+ min_slot_shift
- 1)));
256 pr_debug("qfq calc_index: W = %lu, L = %u, I = %d\n",
257 (unsigned long) ONE_FP
/inv_w
, maxlen
, index
);
262 static void qfq_deactivate_agg(struct qfq_sched
*, struct qfq_aggregate
*);
263 static void qfq_activate_agg(struct qfq_sched
*, struct qfq_aggregate
*,
266 static void qfq_init_agg(struct qfq_sched
*q
, struct qfq_aggregate
*agg
,
267 u32 lmax
, u32 weight
)
269 INIT_LIST_HEAD(&agg
->active
);
270 hlist_add_head(&agg
->nonfull_next
, &q
->nonfull_aggs
);
273 agg
->class_weight
= weight
;
276 static struct qfq_aggregate
*qfq_find_agg(struct qfq_sched
*q
,
277 u32 lmax
, u32 weight
)
279 struct qfq_aggregate
*agg
;
281 hlist_for_each_entry(agg
, &q
->nonfull_aggs
, nonfull_next
)
282 if (agg
->lmax
== lmax
&& agg
->class_weight
== weight
)
289 /* Update aggregate as a function of the new number of classes. */
290 static void qfq_update_agg(struct qfq_sched
*q
, struct qfq_aggregate
*agg
,
295 if (new_num_classes
== q
->max_agg_classes
)
296 hlist_del_init(&agg
->nonfull_next
);
298 if (agg
->num_classes
> new_num_classes
&&
299 new_num_classes
== q
->max_agg_classes
- 1) /* agg no more full */
300 hlist_add_head(&agg
->nonfull_next
, &q
->nonfull_aggs
);
302 /* The next assignment may let
303 * agg->initial_budget > agg->budgetmax
304 * hold, we will take it into account in charge_actual_service().
306 agg
->budgetmax
= new_num_classes
* agg
->lmax
;
307 new_agg_weight
= agg
->class_weight
* new_num_classes
;
308 agg
->inv_w
= ONE_FP
/new_agg_weight
;
310 if (agg
->grp
== NULL
) {
311 int i
= qfq_calc_index(agg
->inv_w
, agg
->budgetmax
,
313 agg
->grp
= &q
->groups
[i
];
317 (int) agg
->class_weight
* (new_num_classes
- agg
->num_classes
);
318 q
->iwsum
= ONE_FP
/ q
->wsum
;
320 agg
->num_classes
= new_num_classes
;
323 /* Add class to aggregate. */
324 static void qfq_add_to_agg(struct qfq_sched
*q
,
325 struct qfq_aggregate
*agg
,
326 struct qfq_class
*cl
)
330 qfq_update_agg(q
, agg
, agg
->num_classes
+1);
331 if (cl
->qdisc
->q
.qlen
> 0) { /* adding an active class */
332 list_add_tail(&cl
->alist
, &agg
->active
);
333 if (list_first_entry(&agg
->active
, struct qfq_class
, alist
) ==
334 cl
&& q
->in_serv_agg
!= agg
) /* agg was inactive */
335 qfq_activate_agg(q
, agg
, enqueue
); /* schedule agg */
339 static struct qfq_aggregate
*qfq_choose_next_agg(struct qfq_sched
*);
341 static void qfq_destroy_agg(struct qfq_sched
*q
, struct qfq_aggregate
*agg
)
343 hlist_del_init(&agg
->nonfull_next
);
344 q
->wsum
-= agg
->class_weight
;
346 q
->iwsum
= ONE_FP
/ q
->wsum
;
348 if (q
->in_serv_agg
== agg
)
349 q
->in_serv_agg
= qfq_choose_next_agg(q
);
353 /* Deschedule class from within its parent aggregate. */
354 static void qfq_deactivate_class(struct qfq_sched
*q
, struct qfq_class
*cl
)
356 struct qfq_aggregate
*agg
= cl
->agg
;
359 list_del(&cl
->alist
); /* remove from RR queue of the aggregate */
360 if (list_empty(&agg
->active
)) /* agg is now inactive */
361 qfq_deactivate_agg(q
, agg
);
364 /* Remove class from its parent aggregate. */
365 static void qfq_rm_from_agg(struct qfq_sched
*q
, struct qfq_class
*cl
)
367 struct qfq_aggregate
*agg
= cl
->agg
;
370 if (agg
->num_classes
== 1) { /* agg being emptied, destroy it */
371 qfq_destroy_agg(q
, agg
);
374 qfq_update_agg(q
, agg
, agg
->num_classes
-1);
377 /* Deschedule class and remove it from its parent aggregate. */
378 static void qfq_deact_rm_from_agg(struct qfq_sched
*q
, struct qfq_class
*cl
)
380 if (cl
->qdisc
->q
.qlen
> 0) /* class is active */
381 qfq_deactivate_class(q
, cl
);
383 qfq_rm_from_agg(q
, cl
);
386 /* Move class to a new aggregate, matching the new class weight and/or lmax */
387 static int qfq_change_agg(struct Qdisc
*sch
, struct qfq_class
*cl
, u32 weight
,
390 struct qfq_sched
*q
= qdisc_priv(sch
);
391 struct qfq_aggregate
*new_agg
= qfq_find_agg(q
, lmax
, weight
);
393 if (new_agg
== NULL
) { /* create new aggregate */
394 new_agg
= kzalloc(sizeof(*new_agg
), GFP_ATOMIC
);
397 qfq_init_agg(q
, new_agg
, lmax
, weight
);
399 qfq_deact_rm_from_agg(q
, cl
);
400 qfq_add_to_agg(q
, new_agg
, cl
);
405 static int qfq_change_class(struct Qdisc
*sch
, u32 classid
, u32 parentid
,
406 struct nlattr
**tca
, unsigned long *arg
)
408 struct qfq_sched
*q
= qdisc_priv(sch
);
409 struct qfq_class
*cl
= (struct qfq_class
*)*arg
;
410 bool existing
= false;
411 struct nlattr
*tb
[TCA_QFQ_MAX
+ 1];
412 struct qfq_aggregate
*new_agg
= NULL
;
413 u32 weight
, lmax
, inv_w
;
417 if (tca
[TCA_OPTIONS
] == NULL
) {
418 pr_notice("qfq: no options\n");
422 err
= nla_parse_nested(tb
, TCA_QFQ_MAX
, tca
[TCA_OPTIONS
], qfq_policy
,
427 if (tb
[TCA_QFQ_WEIGHT
]) {
428 weight
= nla_get_u32(tb
[TCA_QFQ_WEIGHT
]);
429 if (!weight
|| weight
> (1UL << QFQ_MAX_WSHIFT
)) {
430 pr_notice("qfq: invalid weight %u\n", weight
);
436 if (tb
[TCA_QFQ_LMAX
]) {
437 lmax
= nla_get_u32(tb
[TCA_QFQ_LMAX
]);
438 if (lmax
< QFQ_MIN_LMAX
|| lmax
> (1UL << QFQ_MTU_SHIFT
)) {
439 pr_notice("qfq: invalid max length %u\n", lmax
);
443 lmax
= psched_mtu(qdisc_dev(sch
));
445 inv_w
= ONE_FP
/ weight
;
446 weight
= ONE_FP
/ inv_w
;
449 lmax
== cl
->agg
->lmax
&&
450 weight
== cl
->agg
->class_weight
)
451 return 0; /* nothing to change */
453 delta_w
= weight
- (cl
? cl
->agg
->class_weight
: 0);
455 if (q
->wsum
+ delta_w
> QFQ_MAX_WSUM
) {
456 pr_notice("qfq: total weight out of range (%d + %u)\n",
461 if (cl
!= NULL
) { /* modify existing class */
463 err
= gen_replace_estimator(&cl
->bstats
, NULL
,
466 qdisc_root_sleeping_running(sch
),
475 /* create and init new class */
476 cl
= kzalloc(sizeof(struct qfq_class
), GFP_KERNEL
);
481 cl
->common
.classid
= classid
;
484 cl
->qdisc
= qdisc_create_dflt(sch
->dev_queue
,
485 &pfifo_qdisc_ops
, classid
);
486 if (cl
->qdisc
== NULL
)
487 cl
->qdisc
= &noop_qdisc
;
490 err
= gen_new_estimator(&cl
->bstats
, NULL
,
493 qdisc_root_sleeping_running(sch
),
499 if (cl
->qdisc
!= &noop_qdisc
)
500 qdisc_hash_add(cl
->qdisc
, true);
502 qdisc_class_hash_insert(&q
->clhash
, &cl
->common
);
503 sch_tree_unlock(sch
);
505 qdisc_class_hash_grow(sch
, &q
->clhash
);
509 new_agg
= qfq_find_agg(q
, lmax
, weight
);
510 if (new_agg
== NULL
) { /* create new aggregate */
511 sch_tree_unlock(sch
);
512 new_agg
= kzalloc(sizeof(*new_agg
), GFP_KERNEL
);
513 if (new_agg
== NULL
) {
515 gen_kill_estimator(&cl
->rate_est
);
519 qfq_init_agg(q
, new_agg
, lmax
, weight
);
522 qfq_deact_rm_from_agg(q
, cl
);
523 qfq_add_to_agg(q
, new_agg
, cl
);
524 sch_tree_unlock(sch
);
526 *arg
= (unsigned long)cl
;
530 qdisc_destroy(cl
->qdisc
);
535 static void qfq_destroy_class(struct Qdisc
*sch
, struct qfq_class
*cl
)
537 struct qfq_sched
*q
= qdisc_priv(sch
);
539 qfq_rm_from_agg(q
, cl
);
540 gen_kill_estimator(&cl
->rate_est
);
541 qdisc_destroy(cl
->qdisc
);
545 static int qfq_delete_class(struct Qdisc
*sch
, unsigned long arg
)
547 struct qfq_sched
*q
= qdisc_priv(sch
);
548 struct qfq_class
*cl
= (struct qfq_class
*)arg
;
550 if (cl
->filter_cnt
> 0)
556 qdisc_class_hash_remove(&q
->clhash
, &cl
->common
);
558 BUG_ON(--cl
->refcnt
== 0);
560 * This shouldn't happen: we "hold" one cops->get() when called
561 * from tc_ctl_tclass; the destroy method is done from cops->put().
564 sch_tree_unlock(sch
);
568 static unsigned long qfq_get_class(struct Qdisc
*sch
, u32 classid
)
570 struct qfq_class
*cl
= qfq_find_class(sch
, classid
);
575 return (unsigned long)cl
;
578 static void qfq_put_class(struct Qdisc
*sch
, unsigned long arg
)
580 struct qfq_class
*cl
= (struct qfq_class
*)arg
;
582 if (--cl
->refcnt
== 0)
583 qfq_destroy_class(sch
, cl
);
586 static struct tcf_block
*qfq_tcf_block(struct Qdisc
*sch
, unsigned long cl
)
588 struct qfq_sched
*q
= qdisc_priv(sch
);
596 static unsigned long qfq_bind_tcf(struct Qdisc
*sch
, unsigned long parent
,
599 struct qfq_class
*cl
= qfq_find_class(sch
, classid
);
604 return (unsigned long)cl
;
607 static void qfq_unbind_tcf(struct Qdisc
*sch
, unsigned long arg
)
609 struct qfq_class
*cl
= (struct qfq_class
*)arg
;
614 static int qfq_graft_class(struct Qdisc
*sch
, unsigned long arg
,
615 struct Qdisc
*new, struct Qdisc
**old
)
617 struct qfq_class
*cl
= (struct qfq_class
*)arg
;
620 new = qdisc_create_dflt(sch
->dev_queue
,
621 &pfifo_qdisc_ops
, cl
->common
.classid
);
626 *old
= qdisc_replace(sch
, new, &cl
->qdisc
);
630 static struct Qdisc
*qfq_class_leaf(struct Qdisc
*sch
, unsigned long arg
)
632 struct qfq_class
*cl
= (struct qfq_class
*)arg
;
637 static int qfq_dump_class(struct Qdisc
*sch
, unsigned long arg
,
638 struct sk_buff
*skb
, struct tcmsg
*tcm
)
640 struct qfq_class
*cl
= (struct qfq_class
*)arg
;
643 tcm
->tcm_parent
= TC_H_ROOT
;
644 tcm
->tcm_handle
= cl
->common
.classid
;
645 tcm
->tcm_info
= cl
->qdisc
->handle
;
647 nest
= nla_nest_start(skb
, TCA_OPTIONS
);
649 goto nla_put_failure
;
650 if (nla_put_u32(skb
, TCA_QFQ_WEIGHT
, cl
->agg
->class_weight
) ||
651 nla_put_u32(skb
, TCA_QFQ_LMAX
, cl
->agg
->lmax
))
652 goto nla_put_failure
;
653 return nla_nest_end(skb
, nest
);
656 nla_nest_cancel(skb
, nest
);
660 static int qfq_dump_class_stats(struct Qdisc
*sch
, unsigned long arg
,
663 struct qfq_class
*cl
= (struct qfq_class
*)arg
;
664 struct tc_qfq_stats xstats
;
666 memset(&xstats
, 0, sizeof(xstats
));
668 xstats
.weight
= cl
->agg
->class_weight
;
669 xstats
.lmax
= cl
->agg
->lmax
;
671 if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch
),
672 d
, NULL
, &cl
->bstats
) < 0 ||
673 gnet_stats_copy_rate_est(d
, &cl
->rate_est
) < 0 ||
674 gnet_stats_copy_queue(d
, NULL
,
675 &cl
->qdisc
->qstats
, cl
->qdisc
->q
.qlen
) < 0)
678 return gnet_stats_copy_app(d
, &xstats
, sizeof(xstats
));
681 static void qfq_walk(struct Qdisc
*sch
, struct qdisc_walker
*arg
)
683 struct qfq_sched
*q
= qdisc_priv(sch
);
684 struct qfq_class
*cl
;
690 for (i
= 0; i
< q
->clhash
.hashsize
; i
++) {
691 hlist_for_each_entry(cl
, &q
->clhash
.hash
[i
], common
.hnode
) {
692 if (arg
->count
< arg
->skip
) {
696 if (arg
->fn(sch
, (unsigned long)cl
, arg
) < 0) {
705 static struct qfq_class
*qfq_classify(struct sk_buff
*skb
, struct Qdisc
*sch
,
708 struct qfq_sched
*q
= qdisc_priv(sch
);
709 struct qfq_class
*cl
;
710 struct tcf_result res
;
711 struct tcf_proto
*fl
;
714 if (TC_H_MAJ(skb
->priority
^ sch
->handle
) == 0) {
715 pr_debug("qfq_classify: found %d\n", skb
->priority
);
716 cl
= qfq_find_class(sch
, skb
->priority
);
721 *qerr
= NET_XMIT_SUCCESS
| __NET_XMIT_BYPASS
;
722 fl
= rcu_dereference_bh(q
->filter_list
);
723 result
= tcf_classify(skb
, fl
, &res
, false);
725 #ifdef CONFIG_NET_CLS_ACT
730 *qerr
= NET_XMIT_SUCCESS
| __NET_XMIT_STOLEN
;
735 cl
= (struct qfq_class
*)res
.class;
737 cl
= qfq_find_class(sch
, res
.classid
);
744 /* Generic comparison function, handling wraparound. */
745 static inline int qfq_gt(u64 a
, u64 b
)
747 return (s64
)(a
- b
) > 0;
750 /* Round a precise timestamp to its slotted value. */
751 static inline u64
qfq_round_down(u64 ts
, unsigned int shift
)
753 return ts
& ~((1ULL << shift
) - 1);
756 /* return the pointer to the group with lowest index in the bitmap */
757 static inline struct qfq_group
*qfq_ffs(struct qfq_sched
*q
,
758 unsigned long bitmap
)
760 int index
= __ffs(bitmap
);
761 return &q
->groups
[index
];
763 /* Calculate a mask to mimic what would be ffs_from(). */
764 static inline unsigned long mask_from(unsigned long bitmap
, int from
)
766 return bitmap
& ~((1UL << from
) - 1);
770 * The state computation relies on ER=0, IR=1, EB=2, IB=3
771 * First compute eligibility comparing grp->S, q->V,
772 * then check if someone is blocking us and possibly add EB
774 static int qfq_calc_state(struct qfq_sched
*q
, const struct qfq_group
*grp
)
776 /* if S > V we are not eligible */
777 unsigned int state
= qfq_gt(grp
->S
, q
->V
);
778 unsigned long mask
= mask_from(q
->bitmaps
[ER
], grp
->index
);
779 struct qfq_group
*next
;
782 next
= qfq_ffs(q
, mask
);
783 if (qfq_gt(grp
->F
, next
->F
))
793 * q->bitmaps[dst] |= q->bitmaps[src] & mask;
794 * q->bitmaps[src] &= ~mask;
795 * but we should make sure that src != dst
797 static inline void qfq_move_groups(struct qfq_sched
*q
, unsigned long mask
,
800 q
->bitmaps
[dst
] |= q
->bitmaps
[src
] & mask
;
801 q
->bitmaps
[src
] &= ~mask
;
804 static void qfq_unblock_groups(struct qfq_sched
*q
, int index
, u64 old_F
)
806 unsigned long mask
= mask_from(q
->bitmaps
[ER
], index
+ 1);
807 struct qfq_group
*next
;
810 next
= qfq_ffs(q
, mask
);
811 if (!qfq_gt(next
->F
, old_F
))
815 mask
= (1UL << index
) - 1;
816 qfq_move_groups(q
, mask
, EB
, ER
);
817 qfq_move_groups(q
, mask
, IB
, IR
);
824 old_V >>= q->min_slot_shift;
830 static void qfq_make_eligible(struct qfq_sched
*q
)
832 unsigned long vslot
= q
->V
>> q
->min_slot_shift
;
833 unsigned long old_vslot
= q
->oldV
>> q
->min_slot_shift
;
835 if (vslot
!= old_vslot
) {
837 int last_flip_pos
= fls(vslot
^ old_vslot
);
839 if (last_flip_pos
> 31) /* higher than the number of groups */
840 mask
= ~0UL; /* make all groups eligible */
842 mask
= (1UL << last_flip_pos
) - 1;
844 qfq_move_groups(q
, mask
, IR
, ER
);
845 qfq_move_groups(q
, mask
, IB
, EB
);
850 * The index of the slot in which the input aggregate agg is to be
851 * inserted must not be higher than QFQ_MAX_SLOTS-2. There is a '-2'
852 * and not a '-1' because the start time of the group may be moved
853 * backward by one slot after the aggregate has been inserted, and
854 * this would cause non-empty slots to be right-shifted by one
857 * QFQ+ fully satisfies this bound to the slot index if the parameters
858 * of the classes are not changed dynamically, and if QFQ+ never
859 * happens to postpone the service of agg unjustly, i.e., it never
860 * happens that the aggregate becomes backlogged and eligible, or just
861 * eligible, while an aggregate with a higher approximated finish time
862 * is being served. In particular, in this case QFQ+ guarantees that
863 * the timestamps of agg are low enough that the slot index is never
864 * higher than 2. Unfortunately, QFQ+ cannot provide the same
865 * guarantee if it happens to unjustly postpone the service of agg, or
866 * if the parameters of some class are changed.
868 * As for the first event, i.e., an out-of-order service, the
869 * upper bound to the slot index guaranteed by QFQ+ grows to
871 * QFQ_MAX_AGG_CLASSES * ((1<<QFQ_MTU_SHIFT)/QFQ_MIN_LMAX) *
872 * (current_max_weight/current_wsum) <= 2 + 8 * 128 * 1.
874 * The following function deals with this problem by backward-shifting
875 * the timestamps of agg, if needed, so as to guarantee that the slot
876 * index is never higher than QFQ_MAX_SLOTS-2. This backward-shift may
877 * cause the service of other aggregates to be postponed, yet the
878 * worst-case guarantees of these aggregates are not violated. In
879 * fact, in case of no out-of-order service, the timestamps of agg
880 * would have been even lower than they are after the backward shift,
881 * because QFQ+ would have guaranteed a maximum value equal to 2 for
882 * the slot index, and 2 < QFQ_MAX_SLOTS-2. Hence the aggregates whose
883 * service is postponed because of the backward-shift would have
884 * however waited for the service of agg before being served.
886 * The other event that may cause the slot index to be higher than 2
887 * for agg is a recent change of the parameters of some class. If the
888 * weight of a class is increased or the lmax (max_pkt_size) of the
889 * class is decreased, then a new aggregate with smaller slot size
890 * than the original parent aggregate of the class may happen to be
891 * activated. The activation of this aggregate should be properly
892 * delayed to when the service of the class has finished in the ideal
893 * system tracked by QFQ+. If the activation of the aggregate is not
894 * delayed to this reference time instant, then this aggregate may be
895 * unjustly served before other aggregates waiting for service. This
896 * may cause the above bound to the slot index to be violated for some
897 * of these unlucky aggregates.
899 * Instead of delaying the activation of the new aggregate, which is
900 * quite complex, the above-discussed capping of the slot index is
901 * used to handle also the consequences of a change of the parameters
904 static void qfq_slot_insert(struct qfq_group
*grp
, struct qfq_aggregate
*agg
,
907 u64 slot
= (roundedS
- grp
->S
) >> grp
->slot_shift
;
908 unsigned int i
; /* slot index in the bucket list */
910 if (unlikely(slot
> QFQ_MAX_SLOTS
- 2)) {
911 u64 deltaS
= roundedS
- grp
->S
-
912 ((u64
)(QFQ_MAX_SLOTS
- 2)<<grp
->slot_shift
);
915 slot
= QFQ_MAX_SLOTS
- 2;
918 i
= (grp
->front
+ slot
) % QFQ_MAX_SLOTS
;
920 hlist_add_head(&agg
->next
, &grp
->slots
[i
]);
921 __set_bit(slot
, &grp
->full_slots
);
924 /* Maybe introduce hlist_first_entry?? */
925 static struct qfq_aggregate
*qfq_slot_head(struct qfq_group
*grp
)
927 return hlist_entry(grp
->slots
[grp
->front
].first
,
928 struct qfq_aggregate
, next
);
932 * remove the entry from the slot
934 static void qfq_front_slot_remove(struct qfq_group
*grp
)
936 struct qfq_aggregate
*agg
= qfq_slot_head(grp
);
939 hlist_del(&agg
->next
);
940 if (hlist_empty(&grp
->slots
[grp
->front
]))
941 __clear_bit(0, &grp
->full_slots
);
945 * Returns the first aggregate in the first non-empty bucket of the
946 * group. As a side effect, adjusts the bucket list so the first
947 * non-empty bucket is at position 0 in full_slots.
949 static struct qfq_aggregate
*qfq_slot_scan(struct qfq_group
*grp
)
953 pr_debug("qfq slot_scan: grp %u full %#lx\n",
954 grp
->index
, grp
->full_slots
);
956 if (grp
->full_slots
== 0)
959 i
= __ffs(grp
->full_slots
); /* zero based */
961 grp
->front
= (grp
->front
+ i
) % QFQ_MAX_SLOTS
;
962 grp
->full_slots
>>= i
;
965 return qfq_slot_head(grp
);
969 * adjust the bucket list. When the start time of a group decreases,
970 * we move the index down (modulo QFQ_MAX_SLOTS) so we don't need to
971 * move the objects. The mask of occupied slots must be shifted
972 * because we use ffs() to find the first non-empty slot.
973 * This covers decreases in the group's start time, but what about
974 * increases of the start time ?
975 * Here too we should make sure that i is less than 32
977 static void qfq_slot_rotate(struct qfq_group
*grp
, u64 roundedS
)
979 unsigned int i
= (grp
->S
- roundedS
) >> grp
->slot_shift
;
981 grp
->full_slots
<<= i
;
982 grp
->front
= (grp
->front
- i
) % QFQ_MAX_SLOTS
;
985 static void qfq_update_eligible(struct qfq_sched
*q
)
987 struct qfq_group
*grp
;
988 unsigned long ineligible
;
990 ineligible
= q
->bitmaps
[IR
] | q
->bitmaps
[IB
];
992 if (!q
->bitmaps
[ER
]) {
993 grp
= qfq_ffs(q
, ineligible
);
994 if (qfq_gt(grp
->S
, q
->V
))
997 qfq_make_eligible(q
);
1001 /* Dequeue head packet of the head class in the DRR queue of the aggregate. */
1002 static void agg_dequeue(struct qfq_aggregate
*agg
,
1003 struct qfq_class
*cl
, unsigned int len
)
1005 qdisc_dequeue_peeked(cl
->qdisc
);
1007 cl
->deficit
-= (int) len
;
1009 if (cl
->qdisc
->q
.qlen
== 0) /* no more packets, remove from list */
1010 list_del(&cl
->alist
);
1011 else if (cl
->deficit
< qdisc_pkt_len(cl
->qdisc
->ops
->peek(cl
->qdisc
))) {
1012 cl
->deficit
+= agg
->lmax
;
1013 list_move_tail(&cl
->alist
, &agg
->active
);
1017 static inline struct sk_buff
*qfq_peek_skb(struct qfq_aggregate
*agg
,
1018 struct qfq_class
**cl
,
1021 struct sk_buff
*skb
;
1023 *cl
= list_first_entry(&agg
->active
, struct qfq_class
, alist
);
1024 skb
= (*cl
)->qdisc
->ops
->peek((*cl
)->qdisc
);
1026 WARN_ONCE(1, "qfq_dequeue: non-workconserving leaf\n");
1028 *len
= qdisc_pkt_len(skb
);
1033 /* Update F according to the actual service received by the aggregate. */
1034 static inline void charge_actual_service(struct qfq_aggregate
*agg
)
1036 /* Compute the service received by the aggregate, taking into
1037 * account that, after decreasing the number of classes in
1038 * agg, it may happen that
1039 * agg->initial_budget - agg->budget > agg->bugdetmax
1041 u32 service_received
= min(agg
->budgetmax
,
1042 agg
->initial_budget
- agg
->budget
);
1044 agg
->F
= agg
->S
+ (u64
)service_received
* agg
->inv_w
;
1047 /* Assign a reasonable start time for a new aggregate in group i.
1048 * Admissible values for \hat(F) are multiples of \sigma_i
1049 * no greater than V+\sigma_i . Larger values mean that
1050 * we had a wraparound so we consider the timestamp to be stale.
1052 * If F is not stale and F >= V then we set S = F.
1053 * Otherwise we should assign S = V, but this may violate
1054 * the ordering in EB (see [2]). So, if we have groups in ER,
1055 * set S to the F_j of the first group j which would be blocking us.
1056 * We are guaranteed not to move S backward because
1057 * otherwise our group i would still be blocked.
1059 static void qfq_update_start(struct qfq_sched
*q
, struct qfq_aggregate
*agg
)
1062 u64 limit
, roundedF
;
1063 int slot_shift
= agg
->grp
->slot_shift
;
1065 roundedF
= qfq_round_down(agg
->F
, slot_shift
);
1066 limit
= qfq_round_down(q
->V
, slot_shift
) + (1ULL << slot_shift
);
1068 if (!qfq_gt(agg
->F
, q
->V
) || qfq_gt(roundedF
, limit
)) {
1069 /* timestamp was stale */
1070 mask
= mask_from(q
->bitmaps
[ER
], agg
->grp
->index
);
1072 struct qfq_group
*next
= qfq_ffs(q
, mask
);
1073 if (qfq_gt(roundedF
, next
->F
)) {
1074 if (qfq_gt(limit
, next
->F
))
1076 else /* preserve timestamp correctness */
1082 } else /* timestamp is not stale */
1086 /* Update the timestamps of agg before scheduling/rescheduling it for
1087 * service. In particular, assign to agg->F its maximum possible
1088 * value, i.e., the virtual finish time with which the aggregate
1089 * should be labeled if it used all its budget once in service.
1092 qfq_update_agg_ts(struct qfq_sched
*q
,
1093 struct qfq_aggregate
*agg
, enum update_reason reason
)
1095 if (reason
!= requeue
)
1096 qfq_update_start(q
, agg
);
1097 else /* just charge agg for the service received */
1100 agg
->F
= agg
->S
+ (u64
)agg
->budgetmax
* agg
->inv_w
;
1103 static void qfq_schedule_agg(struct qfq_sched
*q
, struct qfq_aggregate
*agg
);
1105 static struct sk_buff
*qfq_dequeue(struct Qdisc
*sch
)
1107 struct qfq_sched
*q
= qdisc_priv(sch
);
1108 struct qfq_aggregate
*in_serv_agg
= q
->in_serv_agg
;
1109 struct qfq_class
*cl
;
1110 struct sk_buff
*skb
= NULL
;
1111 /* next-packet len, 0 means no more active classes in in-service agg */
1112 unsigned int len
= 0;
1114 if (in_serv_agg
== NULL
)
1117 if (!list_empty(&in_serv_agg
->active
))
1118 skb
= qfq_peek_skb(in_serv_agg
, &cl
, &len
);
1121 * If there are no active classes in the in-service aggregate,
1122 * or if the aggregate has not enough budget to serve its next
1123 * class, then choose the next aggregate to serve.
1125 if (len
== 0 || in_serv_agg
->budget
< len
) {
1126 charge_actual_service(in_serv_agg
);
1128 /* recharge the budget of the aggregate */
1129 in_serv_agg
->initial_budget
= in_serv_agg
->budget
=
1130 in_serv_agg
->budgetmax
;
1132 if (!list_empty(&in_serv_agg
->active
)) {
1134 * Still active: reschedule for
1135 * service. Possible optimization: if no other
1136 * aggregate is active, then there is no point
1137 * in rescheduling this aggregate, and we can
1138 * just keep it as the in-service one. This
1139 * should be however a corner case, and to
1140 * handle it, we would need to maintain an
1141 * extra num_active_aggs field.
1143 qfq_update_agg_ts(q
, in_serv_agg
, requeue
);
1144 qfq_schedule_agg(q
, in_serv_agg
);
1145 } else if (sch
->q
.qlen
== 0) { /* no aggregate to serve */
1146 q
->in_serv_agg
= NULL
;
1151 * If we get here, there are other aggregates queued:
1152 * choose the new aggregate to serve.
1154 in_serv_agg
= q
->in_serv_agg
= qfq_choose_next_agg(q
);
1155 skb
= qfq_peek_skb(in_serv_agg
, &cl
, &len
);
1160 qdisc_qstats_backlog_dec(sch
, skb
);
1162 qdisc_bstats_update(sch
, skb
);
1164 agg_dequeue(in_serv_agg
, cl
, len
);
1165 /* If lmax is lowered, through qfq_change_class, for a class
1166 * owning pending packets with larger size than the new value
1167 * of lmax, then the following condition may hold.
1169 if (unlikely(in_serv_agg
->budget
< len
))
1170 in_serv_agg
->budget
= 0;
1172 in_serv_agg
->budget
-= len
;
1174 q
->V
+= (u64
)len
* q
->iwsum
;
1175 pr_debug("qfq dequeue: len %u F %lld now %lld\n",
1176 len
, (unsigned long long) in_serv_agg
->F
,
1177 (unsigned long long) q
->V
);
1182 static struct qfq_aggregate
*qfq_choose_next_agg(struct qfq_sched
*q
)
1184 struct qfq_group
*grp
;
1185 struct qfq_aggregate
*agg
, *new_front_agg
;
1188 qfq_update_eligible(q
);
1191 if (!q
->bitmaps
[ER
])
1194 grp
= qfq_ffs(q
, q
->bitmaps
[ER
]);
1197 agg
= qfq_slot_head(grp
);
1199 /* agg starts to be served, remove it from schedule */
1200 qfq_front_slot_remove(grp
);
1202 new_front_agg
= qfq_slot_scan(grp
);
1204 if (new_front_agg
== NULL
) /* group is now inactive, remove from ER */
1205 __clear_bit(grp
->index
, &q
->bitmaps
[ER
]);
1207 u64 roundedS
= qfq_round_down(new_front_agg
->S
,
1211 if (grp
->S
== roundedS
)
1214 grp
->F
= roundedS
+ (2ULL << grp
->slot_shift
);
1215 __clear_bit(grp
->index
, &q
->bitmaps
[ER
]);
1216 s
= qfq_calc_state(q
, grp
);
1217 __set_bit(grp
->index
, &q
->bitmaps
[s
]);
1220 qfq_unblock_groups(q
, grp
->index
, old_F
);
1225 static int qfq_enqueue(struct sk_buff
*skb
, struct Qdisc
*sch
,
1226 struct sk_buff
**to_free
)
1228 struct qfq_sched
*q
= qdisc_priv(sch
);
1229 struct qfq_class
*cl
;
1230 struct qfq_aggregate
*agg
;
1233 cl
= qfq_classify(skb
, sch
, &err
);
1235 if (err
& __NET_XMIT_BYPASS
)
1236 qdisc_qstats_drop(sch
);
1240 pr_debug("qfq_enqueue: cl = %x\n", cl
->common
.classid
);
1242 if (unlikely(cl
->agg
->lmax
< qdisc_pkt_len(skb
))) {
1243 pr_debug("qfq: increasing maxpkt from %u to %u for class %u",
1244 cl
->agg
->lmax
, qdisc_pkt_len(skb
), cl
->common
.classid
);
1245 err
= qfq_change_agg(sch
, cl
, cl
->agg
->class_weight
,
1246 qdisc_pkt_len(skb
));
1249 return qdisc_drop(skb
, sch
, to_free
);
1253 err
= qdisc_enqueue(skb
, cl
->qdisc
, to_free
);
1254 if (unlikely(err
!= NET_XMIT_SUCCESS
)) {
1255 pr_debug("qfq_enqueue: enqueue failed %d\n", err
);
1256 if (net_xmit_drop_count(err
)) {
1258 qdisc_qstats_drop(sch
);
1263 bstats_update(&cl
->bstats
, skb
);
1264 qdisc_qstats_backlog_inc(sch
, skb
);
1268 /* if the queue was not empty, then done here */
1269 if (cl
->qdisc
->q
.qlen
!= 1) {
1270 if (unlikely(skb
== cl
->qdisc
->ops
->peek(cl
->qdisc
)) &&
1271 list_first_entry(&agg
->active
, struct qfq_class
, alist
)
1272 == cl
&& cl
->deficit
< qdisc_pkt_len(skb
))
1273 list_move_tail(&cl
->alist
, &agg
->active
);
1278 /* schedule class for service within the aggregate */
1279 cl
->deficit
= agg
->lmax
;
1280 list_add_tail(&cl
->alist
, &agg
->active
);
1282 if (list_first_entry(&agg
->active
, struct qfq_class
, alist
) != cl
||
1283 q
->in_serv_agg
== agg
)
1284 return err
; /* non-empty or in service, nothing else to do */
1286 qfq_activate_agg(q
, agg
, enqueue
);
1292 * Schedule aggregate according to its timestamps.
1294 static void qfq_schedule_agg(struct qfq_sched
*q
, struct qfq_aggregate
*agg
)
1296 struct qfq_group
*grp
= agg
->grp
;
1300 roundedS
= qfq_round_down(agg
->S
, grp
->slot_shift
);
1303 * Insert agg in the correct bucket.
1304 * If agg->S >= grp->S we don't need to adjust the
1305 * bucket list and simply go to the insertion phase.
1306 * Otherwise grp->S is decreasing, we must make room
1307 * in the bucket list, and also recompute the group state.
1308 * Finally, if there were no flows in this group and nobody
1309 * was in ER make sure to adjust V.
1311 if (grp
->full_slots
) {
1312 if (!qfq_gt(grp
->S
, agg
->S
))
1315 /* create a slot for this agg->S */
1316 qfq_slot_rotate(grp
, roundedS
);
1317 /* group was surely ineligible, remove */
1318 __clear_bit(grp
->index
, &q
->bitmaps
[IR
]);
1319 __clear_bit(grp
->index
, &q
->bitmaps
[IB
]);
1320 } else if (!q
->bitmaps
[ER
] && qfq_gt(roundedS
, q
->V
) &&
1321 q
->in_serv_agg
== NULL
)
1325 grp
->F
= roundedS
+ (2ULL << grp
->slot_shift
);
1326 s
= qfq_calc_state(q
, grp
);
1327 __set_bit(grp
->index
, &q
->bitmaps
[s
]);
1329 pr_debug("qfq enqueue: new state %d %#lx S %lld F %lld V %lld\n",
1331 (unsigned long long) agg
->S
,
1332 (unsigned long long) agg
->F
,
1333 (unsigned long long) q
->V
);
1336 qfq_slot_insert(grp
, agg
, roundedS
);
1340 /* Update agg ts and schedule agg for service */
1341 static void qfq_activate_agg(struct qfq_sched
*q
, struct qfq_aggregate
*agg
,
1342 enum update_reason reason
)
1344 agg
->initial_budget
= agg
->budget
= agg
->budgetmax
; /* recharge budg. */
1346 qfq_update_agg_ts(q
, agg
, reason
);
1347 if (q
->in_serv_agg
== NULL
) { /* no aggr. in service or scheduled */
1348 q
->in_serv_agg
= agg
; /* start serving this aggregate */
1349 /* update V: to be in service, agg must be eligible */
1350 q
->oldV
= q
->V
= agg
->S
;
1351 } else if (agg
!= q
->in_serv_agg
)
1352 qfq_schedule_agg(q
, agg
);
1355 static void qfq_slot_remove(struct qfq_sched
*q
, struct qfq_group
*grp
,
1356 struct qfq_aggregate
*agg
)
1358 unsigned int i
, offset
;
1361 roundedS
= qfq_round_down(agg
->S
, grp
->slot_shift
);
1362 offset
= (roundedS
- grp
->S
) >> grp
->slot_shift
;
1364 i
= (grp
->front
+ offset
) % QFQ_MAX_SLOTS
;
1366 hlist_del(&agg
->next
);
1367 if (hlist_empty(&grp
->slots
[i
]))
1368 __clear_bit(offset
, &grp
->full_slots
);
1372 * Called to forcibly deschedule an aggregate. If the aggregate is
1373 * not in the front bucket, or if the latter has other aggregates in
1374 * the front bucket, we can simply remove the aggregate with no other
1376 * Otherwise we must propagate the event up.
1378 static void qfq_deactivate_agg(struct qfq_sched
*q
, struct qfq_aggregate
*agg
)
1380 struct qfq_group
*grp
= agg
->grp
;
1385 if (agg
== q
->in_serv_agg
) {
1386 charge_actual_service(agg
);
1387 q
->in_serv_agg
= qfq_choose_next_agg(q
);
1392 qfq_slot_remove(q
, grp
, agg
);
1394 if (!grp
->full_slots
) {
1395 __clear_bit(grp
->index
, &q
->bitmaps
[IR
]);
1396 __clear_bit(grp
->index
, &q
->bitmaps
[EB
]);
1397 __clear_bit(grp
->index
, &q
->bitmaps
[IB
]);
1399 if (test_bit(grp
->index
, &q
->bitmaps
[ER
]) &&
1400 !(q
->bitmaps
[ER
] & ~((1UL << grp
->index
) - 1))) {
1401 mask
= q
->bitmaps
[ER
] & ((1UL << grp
->index
) - 1);
1403 mask
= ~((1UL << __fls(mask
)) - 1);
1406 qfq_move_groups(q
, mask
, EB
, ER
);
1407 qfq_move_groups(q
, mask
, IB
, IR
);
1409 __clear_bit(grp
->index
, &q
->bitmaps
[ER
]);
1410 } else if (hlist_empty(&grp
->slots
[grp
->front
])) {
1411 agg
= qfq_slot_scan(grp
);
1412 roundedS
= qfq_round_down(agg
->S
, grp
->slot_shift
);
1413 if (grp
->S
!= roundedS
) {
1414 __clear_bit(grp
->index
, &q
->bitmaps
[ER
]);
1415 __clear_bit(grp
->index
, &q
->bitmaps
[IR
]);
1416 __clear_bit(grp
->index
, &q
->bitmaps
[EB
]);
1417 __clear_bit(grp
->index
, &q
->bitmaps
[IB
]);
1419 grp
->F
= roundedS
+ (2ULL << grp
->slot_shift
);
1420 s
= qfq_calc_state(q
, grp
);
1421 __set_bit(grp
->index
, &q
->bitmaps
[s
]);
1426 static void qfq_qlen_notify(struct Qdisc
*sch
, unsigned long arg
)
1428 struct qfq_sched
*q
= qdisc_priv(sch
);
1429 struct qfq_class
*cl
= (struct qfq_class
*)arg
;
1431 if (cl
->qdisc
->q
.qlen
== 0)
1432 qfq_deactivate_class(q
, cl
);
1435 static int qfq_init_qdisc(struct Qdisc
*sch
, struct nlattr
*opt
)
1437 struct qfq_sched
*q
= qdisc_priv(sch
);
1438 struct qfq_group
*grp
;
1440 u32 max_cl_shift
, maxbudg_shift
, max_classes
;
1442 err
= tcf_block_get(&q
->block
, &q
->filter_list
);
1446 err
= qdisc_class_hash_init(&q
->clhash
);
1450 if (qdisc_dev(sch
)->tx_queue_len
+ 1 > QFQ_MAX_AGG_CLASSES
)
1451 max_classes
= QFQ_MAX_AGG_CLASSES
;
1453 max_classes
= qdisc_dev(sch
)->tx_queue_len
+ 1;
1454 /* max_cl_shift = floor(log_2(max_classes)) */
1455 max_cl_shift
= __fls(max_classes
);
1456 q
->max_agg_classes
= 1<<max_cl_shift
;
1458 /* maxbudg_shift = log2(max_len * max_classes_per_agg) */
1459 maxbudg_shift
= QFQ_MTU_SHIFT
+ max_cl_shift
;
1460 q
->min_slot_shift
= FRAC_BITS
+ maxbudg_shift
- QFQ_MAX_INDEX
;
1462 for (i
= 0; i
<= QFQ_MAX_INDEX
; i
++) {
1463 grp
= &q
->groups
[i
];
1465 grp
->slot_shift
= q
->min_slot_shift
+ i
;
1466 for (j
= 0; j
< QFQ_MAX_SLOTS
; j
++)
1467 INIT_HLIST_HEAD(&grp
->slots
[j
]);
1470 INIT_HLIST_HEAD(&q
->nonfull_aggs
);
1475 static void qfq_reset_qdisc(struct Qdisc
*sch
)
1477 struct qfq_sched
*q
= qdisc_priv(sch
);
1478 struct qfq_class
*cl
;
1481 for (i
= 0; i
< q
->clhash
.hashsize
; i
++) {
1482 hlist_for_each_entry(cl
, &q
->clhash
.hash
[i
], common
.hnode
) {
1483 if (cl
->qdisc
->q
.qlen
> 0)
1484 qfq_deactivate_class(q
, cl
);
1486 qdisc_reset(cl
->qdisc
);
1489 sch
->qstats
.backlog
= 0;
1493 static void qfq_destroy_qdisc(struct Qdisc
*sch
)
1495 struct qfq_sched
*q
= qdisc_priv(sch
);
1496 struct qfq_class
*cl
;
1497 struct hlist_node
*next
;
1500 tcf_block_put(q
->block
);
1502 for (i
= 0; i
< q
->clhash
.hashsize
; i
++) {
1503 hlist_for_each_entry_safe(cl
, next
, &q
->clhash
.hash
[i
],
1505 qfq_destroy_class(sch
, cl
);
1508 qdisc_class_hash_destroy(&q
->clhash
);
1511 static const struct Qdisc_class_ops qfq_class_ops
= {
1512 .change
= qfq_change_class
,
1513 .delete = qfq_delete_class
,
1514 .get
= qfq_get_class
,
1515 .put
= qfq_put_class
,
1516 .tcf_block
= qfq_tcf_block
,
1517 .bind_tcf
= qfq_bind_tcf
,
1518 .unbind_tcf
= qfq_unbind_tcf
,
1519 .graft
= qfq_graft_class
,
1520 .leaf
= qfq_class_leaf
,
1521 .qlen_notify
= qfq_qlen_notify
,
1522 .dump
= qfq_dump_class
,
1523 .dump_stats
= qfq_dump_class_stats
,
1527 static struct Qdisc_ops qfq_qdisc_ops __read_mostly
= {
1528 .cl_ops
= &qfq_class_ops
,
1530 .priv_size
= sizeof(struct qfq_sched
),
1531 .enqueue
= qfq_enqueue
,
1532 .dequeue
= qfq_dequeue
,
1533 .peek
= qdisc_peek_dequeued
,
1534 .init
= qfq_init_qdisc
,
1535 .reset
= qfq_reset_qdisc
,
1536 .destroy
= qfq_destroy_qdisc
,
1537 .owner
= THIS_MODULE
,
1540 static int __init
qfq_init(void)
1542 return register_qdisc(&qfq_qdisc_ops
);
1545 static void __exit
qfq_exit(void)
1547 unregister_qdisc(&qfq_qdisc_ops
);
1550 module_init(qfq_init
);
1551 module_exit(qfq_exit
);
1552 MODULE_LICENSE("GPL");