1 // SPDX-License-Identifier: GPL-2.0-only
3 * net/sched/sch_qfq.c Quick Fair Queueing Plus Scheduler.
5 * Copyright (c) 2009 Fabio Checconi, Luigi Rizzo, and Paolo Valente.
6 * Copyright (c) 2012 Paolo Valente.
9 #include <linux/module.h>
10 #include <linux/init.h>
11 #include <linux/bitops.h>
12 #include <linux/errno.h>
13 #include <linux/netdevice.h>
14 #include <linux/pkt_sched.h>
15 #include <net/sch_generic.h>
16 #include <net/pkt_sched.h>
17 #include <net/pkt_cls.h>
20 /* Quick Fair Queueing Plus
21 ========================
26 "Reducing the Execution Time of Fair-Queueing Schedulers."
27 http://algo.ing.unimo.it/people/paolo/agg-sched/agg-sched.pdf
31 [2] Fabio Checconi, Luigi Rizzo, and Paolo Valente: "QFQ: Efficient
32 Packet Scheduling with Tight Bandwidth Distribution Guarantees."
35 http://retis.sssup.it/~fabio/linux/qfq/
40 QFQ+ divides classes into aggregates of at most MAX_AGG_CLASSES
41 classes. Each aggregate is timestamped with a virtual start time S
42 and a virtual finish time F, and scheduled according to its
43 timestamps. S and F are computed as a function of a system virtual
44 time function V. The classes within each aggregate are instead
47 To speed up operations, QFQ+ divides also aggregates into a limited
48 number of groups. Which group a class belongs to depends on the
49 ratio between the maximum packet length for the class and the weight
50 of the class. Groups have their own S and F. In the end, QFQ+
51 schedules groups, then aggregates within groups, then classes within
52 aggregates. See [1] and [2] for a full description.
54 Virtual time computations.
56 S, F and V are all computed in fixed point arithmetic with
57 FRAC_BITS decimal bits.
59 QFQ_MAX_INDEX is the maximum index allowed for a group. We need
61 QFQ_MAX_WSHIFT is the maximum power of two supported as a weight.
63 The layout of the bits is as below:
65 [ MTU_SHIFT ][ FRAC_BITS ]
66 [ MAX_INDEX ][ MIN_SLOT_SHIFT ]
70 where MIN_SLOT_SHIFT is derived by difference from the others.
72 The max group index corresponds to Lmax/w_min, where
73 Lmax=1<<MTU_SHIFT, w_min = 1 .
74 From this, and knowing how many groups (MAX_INDEX) we want,
75 we can derive the shift corresponding to each group.
77 Because we often need to compute
78 F = S + len/w_i and V = V + len/wsum
79 instead of storing w_i store the value
80 inv_w = (1<<FRAC_BITS)/w_i
81 so we can do F = S + len * inv_w * wsum.
82 We use W_TOT in the formulas so we can easily move between
83 static and adaptive weight sum.
85 The per-scheduler-instance data contain all the data structures
86 for the scheduler: bitmaps and bucket lists.
91 * Maximum number of consecutive slots occupied by backlogged classes
94 #define QFQ_MAX_SLOTS 32
97 * Shifts used for aggregate<->group mapping. We allow class weights that are
98 * in the range [1, 2^MAX_WSHIFT], and we try to map each aggregate i to the
99 * group with the smallest index that can support the L_i / r_i configured
100 * for the classes in the aggregate.
102 * grp->index is the index of the group; and grp->slot_shift
103 * is the shift for the corresponding (scaled) sigma_i.
105 #define QFQ_MAX_INDEX 24
106 #define QFQ_MAX_WSHIFT 10
108 #define QFQ_MAX_WEIGHT (1<<QFQ_MAX_WSHIFT) /* see qfq_slot_insert */
109 #define QFQ_MAX_WSUM (64*QFQ_MAX_WEIGHT)
111 #define FRAC_BITS 30 /* fixed point arithmetic */
112 #define ONE_FP (1UL << FRAC_BITS)
114 #define QFQ_MTU_SHIFT 16 /* to support TSO/GSO */
115 #define QFQ_MIN_LMAX 512 /* see qfq_slot_insert */
117 #define QFQ_MAX_AGG_CLASSES 8 /* max num classes per aggregate allowed */
120 * Possible group states. These values are used as indexes for the bitmaps
121 * array of struct qfq_queue.
123 enum qfq_state
{ ER
, IR
, EB
, IB
, QFQ_MAX_STATE
};
127 struct qfq_aggregate
;
130 struct Qdisc_class_common common
;
132 unsigned int filter_cnt
;
134 struct gnet_stats_basic_sync bstats
;
135 struct gnet_stats_queue qstats
;
136 struct net_rate_estimator __rcu
*rate_est
;
138 struct list_head alist
; /* Link for active-classes list. */
139 struct qfq_aggregate
*agg
; /* Parent aggregate. */
140 int deficit
; /* DRR deficit counter. */
143 struct qfq_aggregate
{
144 struct hlist_node next
; /* Link for the slot list. */
145 u64 S
, F
; /* flow timestamps (exact) */
147 /* group we belong to. In principle we would need the index,
148 * which is log_2(lmax/weight), but we never reference it
149 * directly, only the group.
151 struct qfq_group
*grp
;
153 /* these are copied from the flowset. */
154 u32 class_weight
; /* Weight of each class in this aggregate. */
155 /* Max pkt size for the classes in this aggregate, DRR quantum. */
158 u32 inv_w
; /* ONE_FP/(sum of weights of classes in aggr.). */
159 u32 budgetmax
; /* Max budget for this aggregate. */
160 u32 initial_budget
, budget
; /* Initial and current budget. */
162 int num_classes
; /* Number of classes in this aggr. */
163 struct list_head active
; /* DRR queue of active classes. */
165 struct hlist_node nonfull_next
; /* See nonfull_aggs in qfq_sched. */
169 u64 S
, F
; /* group timestamps (approx). */
170 unsigned int slot_shift
; /* Slot shift. */
171 unsigned int index
; /* Group index. */
172 unsigned int front
; /* Index of the front slot. */
173 unsigned long full_slots
; /* non-empty slots */
175 /* Array of RR lists of active aggregates. */
176 struct hlist_head slots
[QFQ_MAX_SLOTS
];
180 struct tcf_proto __rcu
*filter_list
;
181 struct tcf_block
*block
;
182 struct Qdisc_class_hash clhash
;
184 u64 oldV
, V
; /* Precise virtual times. */
185 struct qfq_aggregate
*in_serv_agg
; /* Aggregate being served. */
186 u32 wsum
; /* weight sum */
187 u32 iwsum
; /* inverse weight sum */
189 unsigned long bitmaps
[QFQ_MAX_STATE
]; /* Group bitmaps. */
190 struct qfq_group groups
[QFQ_MAX_INDEX
+ 1]; /* The groups. */
191 u32 min_slot_shift
; /* Index of the group-0 bit in the bitmaps. */
193 u32 max_agg_classes
; /* Max number of classes per aggr. */
194 struct hlist_head nonfull_aggs
; /* Aggs with room for more classes. */
198 * Possible reasons why the timestamps of an aggregate are updated
199 * enqueue: the aggregate switches from idle to active and must scheduled
201 * requeue: the aggregate finishes its budget, so it stops being served and
202 * must be rescheduled for service
204 enum update_reason
{enqueue
, requeue
};
206 static struct qfq_class
*qfq_find_class(struct Qdisc
*sch
, u32 classid
)
208 struct qfq_sched
*q
= qdisc_priv(sch
);
209 struct Qdisc_class_common
*clc
;
211 clc
= qdisc_class_find(&q
->clhash
, classid
);
214 return container_of(clc
, struct qfq_class
, common
);
217 static const struct nla_policy qfq_policy
[TCA_QFQ_MAX
+ 1] = {
218 [TCA_QFQ_WEIGHT
] = { .type
= NLA_U32
},
219 [TCA_QFQ_LMAX
] = { .type
= NLA_U32
},
223 * Calculate a flow index, given its weight and maximum packet length.
224 * index = log_2(maxlen/weight) but we need to apply the scaling.
225 * This is used only once at flow creation.
227 static int qfq_calc_index(u32 inv_w
, unsigned int maxlen
, u32 min_slot_shift
)
229 u64 slot_size
= (u64
)maxlen
* inv_w
;
230 unsigned long size_map
;
233 size_map
= slot_size
>> min_slot_shift
;
237 index
= __fls(size_map
) + 1; /* basically a log_2 */
238 index
-= !(slot_size
- (1ULL << (index
+ min_slot_shift
- 1)));
243 pr_debug("qfq calc_index: W = %lu, L = %u, I = %d\n",
244 (unsigned long) ONE_FP
/inv_w
, maxlen
, index
);
249 static void qfq_deactivate_agg(struct qfq_sched
*, struct qfq_aggregate
*);
250 static void qfq_activate_agg(struct qfq_sched
*, struct qfq_aggregate
*,
253 static void qfq_init_agg(struct qfq_sched
*q
, struct qfq_aggregate
*agg
,
254 u32 lmax
, u32 weight
)
256 INIT_LIST_HEAD(&agg
->active
);
257 hlist_add_head(&agg
->nonfull_next
, &q
->nonfull_aggs
);
260 agg
->class_weight
= weight
;
263 static struct qfq_aggregate
*qfq_find_agg(struct qfq_sched
*q
,
264 u32 lmax
, u32 weight
)
266 struct qfq_aggregate
*agg
;
268 hlist_for_each_entry(agg
, &q
->nonfull_aggs
, nonfull_next
)
269 if (agg
->lmax
== lmax
&& agg
->class_weight
== weight
)
276 /* Update aggregate as a function of the new number of classes. */
277 static void qfq_update_agg(struct qfq_sched
*q
, struct qfq_aggregate
*agg
,
282 if (new_num_classes
== q
->max_agg_classes
)
283 hlist_del_init(&agg
->nonfull_next
);
285 if (agg
->num_classes
> new_num_classes
&&
286 new_num_classes
== q
->max_agg_classes
- 1) /* agg no more full */
287 hlist_add_head(&agg
->nonfull_next
, &q
->nonfull_aggs
);
289 /* The next assignment may let
290 * agg->initial_budget > agg->budgetmax
291 * hold, we will take it into account in charge_actual_service().
293 agg
->budgetmax
= new_num_classes
* agg
->lmax
;
294 new_agg_weight
= agg
->class_weight
* new_num_classes
;
295 agg
->inv_w
= ONE_FP
/new_agg_weight
;
297 if (agg
->grp
== NULL
) {
298 int i
= qfq_calc_index(agg
->inv_w
, agg
->budgetmax
,
300 agg
->grp
= &q
->groups
[i
];
304 (int) agg
->class_weight
* (new_num_classes
- agg
->num_classes
);
305 q
->iwsum
= ONE_FP
/ q
->wsum
;
307 agg
->num_classes
= new_num_classes
;
310 /* Add class to aggregate. */
311 static void qfq_add_to_agg(struct qfq_sched
*q
,
312 struct qfq_aggregate
*agg
,
313 struct qfq_class
*cl
)
317 qfq_update_agg(q
, agg
, agg
->num_classes
+1);
318 if (cl
->qdisc
->q
.qlen
> 0) { /* adding an active class */
319 list_add_tail(&cl
->alist
, &agg
->active
);
320 if (list_first_entry(&agg
->active
, struct qfq_class
, alist
) ==
321 cl
&& q
->in_serv_agg
!= agg
) /* agg was inactive */
322 qfq_activate_agg(q
, agg
, enqueue
); /* schedule agg */
326 static struct qfq_aggregate
*qfq_choose_next_agg(struct qfq_sched
*);
328 static void qfq_destroy_agg(struct qfq_sched
*q
, struct qfq_aggregate
*agg
)
330 hlist_del_init(&agg
->nonfull_next
);
331 q
->wsum
-= agg
->class_weight
;
333 q
->iwsum
= ONE_FP
/ q
->wsum
;
335 if (q
->in_serv_agg
== agg
)
336 q
->in_serv_agg
= qfq_choose_next_agg(q
);
340 /* Deschedule class from within its parent aggregate. */
341 static void qfq_deactivate_class(struct qfq_sched
*q
, struct qfq_class
*cl
)
343 struct qfq_aggregate
*agg
= cl
->agg
;
346 list_del(&cl
->alist
); /* remove from RR queue of the aggregate */
347 if (list_empty(&agg
->active
)) /* agg is now inactive */
348 qfq_deactivate_agg(q
, agg
);
351 /* Remove class from its parent aggregate. */
352 static void qfq_rm_from_agg(struct qfq_sched
*q
, struct qfq_class
*cl
)
354 struct qfq_aggregate
*agg
= cl
->agg
;
357 if (agg
->num_classes
== 1) { /* agg being emptied, destroy it */
358 qfq_destroy_agg(q
, agg
);
361 qfq_update_agg(q
, agg
, agg
->num_classes
-1);
364 /* Deschedule class and remove it from its parent aggregate. */
365 static void qfq_deact_rm_from_agg(struct qfq_sched
*q
, struct qfq_class
*cl
)
367 if (cl
->qdisc
->q
.qlen
> 0) /* class is active */
368 qfq_deactivate_class(q
, cl
);
370 qfq_rm_from_agg(q
, cl
);
373 /* Move class to a new aggregate, matching the new class weight and/or lmax */
374 static int qfq_change_agg(struct Qdisc
*sch
, struct qfq_class
*cl
, u32 weight
,
377 struct qfq_sched
*q
= qdisc_priv(sch
);
378 struct qfq_aggregate
*new_agg
= qfq_find_agg(q
, lmax
, weight
);
380 if (new_agg
== NULL
) { /* create new aggregate */
381 new_agg
= kzalloc(sizeof(*new_agg
), GFP_ATOMIC
);
384 qfq_init_agg(q
, new_agg
, lmax
, weight
);
386 qfq_deact_rm_from_agg(q
, cl
);
387 qfq_add_to_agg(q
, new_agg
, cl
);
392 static int qfq_change_class(struct Qdisc
*sch
, u32 classid
, u32 parentid
,
393 struct nlattr
**tca
, unsigned long *arg
,
394 struct netlink_ext_ack
*extack
)
396 struct qfq_sched
*q
= qdisc_priv(sch
);
397 struct qfq_class
*cl
= (struct qfq_class
*)*arg
;
398 bool existing
= false;
399 struct nlattr
*tb
[TCA_QFQ_MAX
+ 1];
400 struct qfq_aggregate
*new_agg
= NULL
;
401 u32 weight
, lmax
, inv_w
;
405 if (tca
[TCA_OPTIONS
] == NULL
) {
406 pr_notice("qfq: no options\n");
410 err
= nla_parse_nested_deprecated(tb
, TCA_QFQ_MAX
, tca
[TCA_OPTIONS
],
415 if (tb
[TCA_QFQ_WEIGHT
]) {
416 weight
= nla_get_u32(tb
[TCA_QFQ_WEIGHT
]);
417 if (!weight
|| weight
> (1UL << QFQ_MAX_WSHIFT
)) {
418 pr_notice("qfq: invalid weight %u\n", weight
);
424 if (tb
[TCA_QFQ_LMAX
]) {
425 lmax
= nla_get_u32(tb
[TCA_QFQ_LMAX
]);
426 if (lmax
< QFQ_MIN_LMAX
|| lmax
> (1UL << QFQ_MTU_SHIFT
)) {
427 pr_notice("qfq: invalid max length %u\n", lmax
);
431 lmax
= psched_mtu(qdisc_dev(sch
));
433 inv_w
= ONE_FP
/ weight
;
434 weight
= ONE_FP
/ inv_w
;
437 lmax
== cl
->agg
->lmax
&&
438 weight
== cl
->agg
->class_weight
)
439 return 0; /* nothing to change */
441 delta_w
= weight
- (cl
? cl
->agg
->class_weight
: 0);
443 if (q
->wsum
+ delta_w
> QFQ_MAX_WSUM
) {
444 pr_notice("qfq: total weight out of range (%d + %u)\n",
449 if (cl
!= NULL
) { /* modify existing class */
451 err
= gen_replace_estimator(&cl
->bstats
, NULL
,
463 /* create and init new class */
464 cl
= kzalloc(sizeof(struct qfq_class
), GFP_KERNEL
);
468 gnet_stats_basic_sync_init(&cl
->bstats
);
469 cl
->common
.classid
= classid
;
472 cl
->qdisc
= qdisc_create_dflt(sch
->dev_queue
, &pfifo_qdisc_ops
,
474 if (cl
->qdisc
== NULL
)
475 cl
->qdisc
= &noop_qdisc
;
478 err
= gen_new_estimator(&cl
->bstats
, NULL
,
487 if (cl
->qdisc
!= &noop_qdisc
)
488 qdisc_hash_add(cl
->qdisc
, true);
492 new_agg
= qfq_find_agg(q
, lmax
, weight
);
493 if (new_agg
== NULL
) { /* create new aggregate */
494 sch_tree_unlock(sch
);
495 new_agg
= kzalloc(sizeof(*new_agg
), GFP_KERNEL
);
496 if (new_agg
== NULL
) {
498 gen_kill_estimator(&cl
->rate_est
);
502 qfq_init_agg(q
, new_agg
, lmax
, weight
);
505 qfq_deact_rm_from_agg(q
, cl
);
507 qdisc_class_hash_insert(&q
->clhash
, &cl
->common
);
508 qfq_add_to_agg(q
, new_agg
, cl
);
509 sch_tree_unlock(sch
);
510 qdisc_class_hash_grow(sch
, &q
->clhash
);
512 *arg
= (unsigned long)cl
;
516 qdisc_put(cl
->qdisc
);
521 static void qfq_destroy_class(struct Qdisc
*sch
, struct qfq_class
*cl
)
523 struct qfq_sched
*q
= qdisc_priv(sch
);
525 qfq_rm_from_agg(q
, cl
);
526 gen_kill_estimator(&cl
->rate_est
);
527 qdisc_put(cl
->qdisc
);
531 static int qfq_delete_class(struct Qdisc
*sch
, unsigned long arg
,
532 struct netlink_ext_ack
*extack
)
534 struct qfq_sched
*q
= qdisc_priv(sch
);
535 struct qfq_class
*cl
= (struct qfq_class
*)arg
;
537 if (cl
->filter_cnt
> 0)
542 qdisc_purge_queue(cl
->qdisc
);
543 qdisc_class_hash_remove(&q
->clhash
, &cl
->common
);
545 sch_tree_unlock(sch
);
547 qfq_destroy_class(sch
, cl
);
551 static unsigned long qfq_search_class(struct Qdisc
*sch
, u32 classid
)
553 return (unsigned long)qfq_find_class(sch
, classid
);
556 static struct tcf_block
*qfq_tcf_block(struct Qdisc
*sch
, unsigned long cl
,
557 struct netlink_ext_ack
*extack
)
559 struct qfq_sched
*q
= qdisc_priv(sch
);
567 static unsigned long qfq_bind_tcf(struct Qdisc
*sch
, unsigned long parent
,
570 struct qfq_class
*cl
= qfq_find_class(sch
, classid
);
575 return (unsigned long)cl
;
578 static void qfq_unbind_tcf(struct Qdisc
*sch
, unsigned long arg
)
580 struct qfq_class
*cl
= (struct qfq_class
*)arg
;
585 static int qfq_graft_class(struct Qdisc
*sch
, unsigned long arg
,
586 struct Qdisc
*new, struct Qdisc
**old
,
587 struct netlink_ext_ack
*extack
)
589 struct qfq_class
*cl
= (struct qfq_class
*)arg
;
592 new = qdisc_create_dflt(sch
->dev_queue
, &pfifo_qdisc_ops
,
593 cl
->common
.classid
, NULL
);
598 *old
= qdisc_replace(sch
, new, &cl
->qdisc
);
602 static struct Qdisc
*qfq_class_leaf(struct Qdisc
*sch
, unsigned long arg
)
604 struct qfq_class
*cl
= (struct qfq_class
*)arg
;
609 static int qfq_dump_class(struct Qdisc
*sch
, unsigned long arg
,
610 struct sk_buff
*skb
, struct tcmsg
*tcm
)
612 struct qfq_class
*cl
= (struct qfq_class
*)arg
;
615 tcm
->tcm_parent
= TC_H_ROOT
;
616 tcm
->tcm_handle
= cl
->common
.classid
;
617 tcm
->tcm_info
= cl
->qdisc
->handle
;
619 nest
= nla_nest_start_noflag(skb
, TCA_OPTIONS
);
621 goto nla_put_failure
;
622 if (nla_put_u32(skb
, TCA_QFQ_WEIGHT
, cl
->agg
->class_weight
) ||
623 nla_put_u32(skb
, TCA_QFQ_LMAX
, cl
->agg
->lmax
))
624 goto nla_put_failure
;
625 return nla_nest_end(skb
, nest
);
628 nla_nest_cancel(skb
, nest
);
632 static int qfq_dump_class_stats(struct Qdisc
*sch
, unsigned long arg
,
635 struct qfq_class
*cl
= (struct qfq_class
*)arg
;
636 struct tc_qfq_stats xstats
;
638 memset(&xstats
, 0, sizeof(xstats
));
640 xstats
.weight
= cl
->agg
->class_weight
;
641 xstats
.lmax
= cl
->agg
->lmax
;
643 if (gnet_stats_copy_basic(d
, NULL
, &cl
->bstats
, true) < 0 ||
644 gnet_stats_copy_rate_est(d
, &cl
->rate_est
) < 0 ||
645 qdisc_qstats_copy(d
, cl
->qdisc
) < 0)
648 return gnet_stats_copy_app(d
, &xstats
, sizeof(xstats
));
651 static void qfq_walk(struct Qdisc
*sch
, struct qdisc_walker
*arg
)
653 struct qfq_sched
*q
= qdisc_priv(sch
);
654 struct qfq_class
*cl
;
660 for (i
= 0; i
< q
->clhash
.hashsize
; i
++) {
661 hlist_for_each_entry(cl
, &q
->clhash
.hash
[i
], common
.hnode
) {
662 if (arg
->count
< arg
->skip
) {
666 if (arg
->fn(sch
, (unsigned long)cl
, arg
) < 0) {
675 static struct qfq_class
*qfq_classify(struct sk_buff
*skb
, struct Qdisc
*sch
,
678 struct qfq_sched
*q
= qdisc_priv(sch
);
679 struct qfq_class
*cl
;
680 struct tcf_result res
;
681 struct tcf_proto
*fl
;
684 if (TC_H_MAJ(skb
->priority
^ sch
->handle
) == 0) {
685 pr_debug("qfq_classify: found %d\n", skb
->priority
);
686 cl
= qfq_find_class(sch
, skb
->priority
);
691 *qerr
= NET_XMIT_SUCCESS
| __NET_XMIT_BYPASS
;
692 fl
= rcu_dereference_bh(q
->filter_list
);
693 result
= tcf_classify(skb
, NULL
, fl
, &res
, false);
695 #ifdef CONFIG_NET_CLS_ACT
700 *qerr
= NET_XMIT_SUCCESS
| __NET_XMIT_STOLEN
;
706 cl
= (struct qfq_class
*)res
.class;
708 cl
= qfq_find_class(sch
, res
.classid
);
715 /* Generic comparison function, handling wraparound. */
716 static inline int qfq_gt(u64 a
, u64 b
)
718 return (s64
)(a
- b
) > 0;
721 /* Round a precise timestamp to its slotted value. */
722 static inline u64
qfq_round_down(u64 ts
, unsigned int shift
)
724 return ts
& ~((1ULL << shift
) - 1);
727 /* return the pointer to the group with lowest index in the bitmap */
728 static inline struct qfq_group
*qfq_ffs(struct qfq_sched
*q
,
729 unsigned long bitmap
)
731 int index
= __ffs(bitmap
);
732 return &q
->groups
[index
];
734 /* Calculate a mask to mimic what would be ffs_from(). */
735 static inline unsigned long mask_from(unsigned long bitmap
, int from
)
737 return bitmap
& ~((1UL << from
) - 1);
741 * The state computation relies on ER=0, IR=1, EB=2, IB=3
742 * First compute eligibility comparing grp->S, q->V,
743 * then check if someone is blocking us and possibly add EB
745 static int qfq_calc_state(struct qfq_sched
*q
, const struct qfq_group
*grp
)
747 /* if S > V we are not eligible */
748 unsigned int state
= qfq_gt(grp
->S
, q
->V
);
749 unsigned long mask
= mask_from(q
->bitmaps
[ER
], grp
->index
);
750 struct qfq_group
*next
;
753 next
= qfq_ffs(q
, mask
);
754 if (qfq_gt(grp
->F
, next
->F
))
764 * q->bitmaps[dst] |= q->bitmaps[src] & mask;
765 * q->bitmaps[src] &= ~mask;
766 * but we should make sure that src != dst
768 static inline void qfq_move_groups(struct qfq_sched
*q
, unsigned long mask
,
771 q
->bitmaps
[dst
] |= q
->bitmaps
[src
] & mask
;
772 q
->bitmaps
[src
] &= ~mask
;
775 static void qfq_unblock_groups(struct qfq_sched
*q
, int index
, u64 old_F
)
777 unsigned long mask
= mask_from(q
->bitmaps
[ER
], index
+ 1);
778 struct qfq_group
*next
;
781 next
= qfq_ffs(q
, mask
);
782 if (!qfq_gt(next
->F
, old_F
))
786 mask
= (1UL << index
) - 1;
787 qfq_move_groups(q
, mask
, EB
, ER
);
788 qfq_move_groups(q
, mask
, IB
, IR
);
795 old_V >>= q->min_slot_shift;
801 static void qfq_make_eligible(struct qfq_sched
*q
)
803 unsigned long vslot
= q
->V
>> q
->min_slot_shift
;
804 unsigned long old_vslot
= q
->oldV
>> q
->min_slot_shift
;
806 if (vslot
!= old_vslot
) {
808 int last_flip_pos
= fls(vslot
^ old_vslot
);
810 if (last_flip_pos
> 31) /* higher than the number of groups */
811 mask
= ~0UL; /* make all groups eligible */
813 mask
= (1UL << last_flip_pos
) - 1;
815 qfq_move_groups(q
, mask
, IR
, ER
);
816 qfq_move_groups(q
, mask
, IB
, EB
);
821 * The index of the slot in which the input aggregate agg is to be
822 * inserted must not be higher than QFQ_MAX_SLOTS-2. There is a '-2'
823 * and not a '-1' because the start time of the group may be moved
824 * backward by one slot after the aggregate has been inserted, and
825 * this would cause non-empty slots to be right-shifted by one
828 * QFQ+ fully satisfies this bound to the slot index if the parameters
829 * of the classes are not changed dynamically, and if QFQ+ never
830 * happens to postpone the service of agg unjustly, i.e., it never
831 * happens that the aggregate becomes backlogged and eligible, or just
832 * eligible, while an aggregate with a higher approximated finish time
833 * is being served. In particular, in this case QFQ+ guarantees that
834 * the timestamps of agg are low enough that the slot index is never
835 * higher than 2. Unfortunately, QFQ+ cannot provide the same
836 * guarantee if it happens to unjustly postpone the service of agg, or
837 * if the parameters of some class are changed.
839 * As for the first event, i.e., an out-of-order service, the
840 * upper bound to the slot index guaranteed by QFQ+ grows to
842 * QFQ_MAX_AGG_CLASSES * ((1<<QFQ_MTU_SHIFT)/QFQ_MIN_LMAX) *
843 * (current_max_weight/current_wsum) <= 2 + 8 * 128 * 1.
845 * The following function deals with this problem by backward-shifting
846 * the timestamps of agg, if needed, so as to guarantee that the slot
847 * index is never higher than QFQ_MAX_SLOTS-2. This backward-shift may
848 * cause the service of other aggregates to be postponed, yet the
849 * worst-case guarantees of these aggregates are not violated. In
850 * fact, in case of no out-of-order service, the timestamps of agg
851 * would have been even lower than they are after the backward shift,
852 * because QFQ+ would have guaranteed a maximum value equal to 2 for
853 * the slot index, and 2 < QFQ_MAX_SLOTS-2. Hence the aggregates whose
854 * service is postponed because of the backward-shift would have
855 * however waited for the service of agg before being served.
857 * The other event that may cause the slot index to be higher than 2
858 * for agg is a recent change of the parameters of some class. If the
859 * weight of a class is increased or the lmax (max_pkt_size) of the
860 * class is decreased, then a new aggregate with smaller slot size
861 * than the original parent aggregate of the class may happen to be
862 * activated. The activation of this aggregate should be properly
863 * delayed to when the service of the class has finished in the ideal
864 * system tracked by QFQ+. If the activation of the aggregate is not
865 * delayed to this reference time instant, then this aggregate may be
866 * unjustly served before other aggregates waiting for service. This
867 * may cause the above bound to the slot index to be violated for some
868 * of these unlucky aggregates.
870 * Instead of delaying the activation of the new aggregate, which is
871 * quite complex, the above-discussed capping of the slot index is
872 * used to handle also the consequences of a change of the parameters
875 static void qfq_slot_insert(struct qfq_group
*grp
, struct qfq_aggregate
*agg
,
878 u64 slot
= (roundedS
- grp
->S
) >> grp
->slot_shift
;
879 unsigned int i
; /* slot index in the bucket list */
881 if (unlikely(slot
> QFQ_MAX_SLOTS
- 2)) {
882 u64 deltaS
= roundedS
- grp
->S
-
883 ((u64
)(QFQ_MAX_SLOTS
- 2)<<grp
->slot_shift
);
886 slot
= QFQ_MAX_SLOTS
- 2;
889 i
= (grp
->front
+ slot
) % QFQ_MAX_SLOTS
;
891 hlist_add_head(&agg
->next
, &grp
->slots
[i
]);
892 __set_bit(slot
, &grp
->full_slots
);
895 /* Maybe introduce hlist_first_entry?? */
896 static struct qfq_aggregate
*qfq_slot_head(struct qfq_group
*grp
)
898 return hlist_entry(grp
->slots
[grp
->front
].first
,
899 struct qfq_aggregate
, next
);
903 * remove the entry from the slot
905 static void qfq_front_slot_remove(struct qfq_group
*grp
)
907 struct qfq_aggregate
*agg
= qfq_slot_head(grp
);
910 hlist_del(&agg
->next
);
911 if (hlist_empty(&grp
->slots
[grp
->front
]))
912 __clear_bit(0, &grp
->full_slots
);
916 * Returns the first aggregate in the first non-empty bucket of the
917 * group. As a side effect, adjusts the bucket list so the first
918 * non-empty bucket is at position 0 in full_slots.
920 static struct qfq_aggregate
*qfq_slot_scan(struct qfq_group
*grp
)
924 pr_debug("qfq slot_scan: grp %u full %#lx\n",
925 grp
->index
, grp
->full_slots
);
927 if (grp
->full_slots
== 0)
930 i
= __ffs(grp
->full_slots
); /* zero based */
932 grp
->front
= (grp
->front
+ i
) % QFQ_MAX_SLOTS
;
933 grp
->full_slots
>>= i
;
936 return qfq_slot_head(grp
);
940 * adjust the bucket list. When the start time of a group decreases,
941 * we move the index down (modulo QFQ_MAX_SLOTS) so we don't need to
942 * move the objects. The mask of occupied slots must be shifted
943 * because we use ffs() to find the first non-empty slot.
944 * This covers decreases in the group's start time, but what about
945 * increases of the start time ?
946 * Here too we should make sure that i is less than 32
948 static void qfq_slot_rotate(struct qfq_group
*grp
, u64 roundedS
)
950 unsigned int i
= (grp
->S
- roundedS
) >> grp
->slot_shift
;
952 grp
->full_slots
<<= i
;
953 grp
->front
= (grp
->front
- i
) % QFQ_MAX_SLOTS
;
956 static void qfq_update_eligible(struct qfq_sched
*q
)
958 struct qfq_group
*grp
;
959 unsigned long ineligible
;
961 ineligible
= q
->bitmaps
[IR
] | q
->bitmaps
[IB
];
963 if (!q
->bitmaps
[ER
]) {
964 grp
= qfq_ffs(q
, ineligible
);
965 if (qfq_gt(grp
->S
, q
->V
))
968 qfq_make_eligible(q
);
972 /* Dequeue head packet of the head class in the DRR queue of the aggregate. */
973 static void agg_dequeue(struct qfq_aggregate
*agg
,
974 struct qfq_class
*cl
, unsigned int len
)
976 qdisc_dequeue_peeked(cl
->qdisc
);
978 cl
->deficit
-= (int) len
;
980 if (cl
->qdisc
->q
.qlen
== 0) /* no more packets, remove from list */
981 list_del(&cl
->alist
);
982 else if (cl
->deficit
< qdisc_pkt_len(cl
->qdisc
->ops
->peek(cl
->qdisc
))) {
983 cl
->deficit
+= agg
->lmax
;
984 list_move_tail(&cl
->alist
, &agg
->active
);
988 static inline struct sk_buff
*qfq_peek_skb(struct qfq_aggregate
*agg
,
989 struct qfq_class
**cl
,
994 *cl
= list_first_entry(&agg
->active
, struct qfq_class
, alist
);
995 skb
= (*cl
)->qdisc
->ops
->peek((*cl
)->qdisc
);
997 WARN_ONCE(1, "qfq_dequeue: non-workconserving leaf\n");
999 *len
= qdisc_pkt_len(skb
);
1004 /* Update F according to the actual service received by the aggregate. */
1005 static inline void charge_actual_service(struct qfq_aggregate
*agg
)
1007 /* Compute the service received by the aggregate, taking into
1008 * account that, after decreasing the number of classes in
1009 * agg, it may happen that
1010 * agg->initial_budget - agg->budget > agg->bugdetmax
1012 u32 service_received
= min(agg
->budgetmax
,
1013 agg
->initial_budget
- agg
->budget
);
1015 agg
->F
= agg
->S
+ (u64
)service_received
* agg
->inv_w
;
1018 /* Assign a reasonable start time for a new aggregate in group i.
1019 * Admissible values for \hat(F) are multiples of \sigma_i
1020 * no greater than V+\sigma_i . Larger values mean that
1021 * we had a wraparound so we consider the timestamp to be stale.
1023 * If F is not stale and F >= V then we set S = F.
1024 * Otherwise we should assign S = V, but this may violate
1025 * the ordering in EB (see [2]). So, if we have groups in ER,
1026 * set S to the F_j of the first group j which would be blocking us.
1027 * We are guaranteed not to move S backward because
1028 * otherwise our group i would still be blocked.
1030 static void qfq_update_start(struct qfq_sched
*q
, struct qfq_aggregate
*agg
)
1033 u64 limit
, roundedF
;
1034 int slot_shift
= agg
->grp
->slot_shift
;
1036 roundedF
= qfq_round_down(agg
->F
, slot_shift
);
1037 limit
= qfq_round_down(q
->V
, slot_shift
) + (1ULL << slot_shift
);
1039 if (!qfq_gt(agg
->F
, q
->V
) || qfq_gt(roundedF
, limit
)) {
1040 /* timestamp was stale */
1041 mask
= mask_from(q
->bitmaps
[ER
], agg
->grp
->index
);
1043 struct qfq_group
*next
= qfq_ffs(q
, mask
);
1044 if (qfq_gt(roundedF
, next
->F
)) {
1045 if (qfq_gt(limit
, next
->F
))
1047 else /* preserve timestamp correctness */
1053 } else /* timestamp is not stale */
1057 /* Update the timestamps of agg before scheduling/rescheduling it for
1058 * service. In particular, assign to agg->F its maximum possible
1059 * value, i.e., the virtual finish time with which the aggregate
1060 * should be labeled if it used all its budget once in service.
1063 qfq_update_agg_ts(struct qfq_sched
*q
,
1064 struct qfq_aggregate
*agg
, enum update_reason reason
)
1066 if (reason
!= requeue
)
1067 qfq_update_start(q
, agg
);
1068 else /* just charge agg for the service received */
1071 agg
->F
= agg
->S
+ (u64
)agg
->budgetmax
* agg
->inv_w
;
1074 static void qfq_schedule_agg(struct qfq_sched
*q
, struct qfq_aggregate
*agg
);
1076 static struct sk_buff
*qfq_dequeue(struct Qdisc
*sch
)
1078 struct qfq_sched
*q
= qdisc_priv(sch
);
1079 struct qfq_aggregate
*in_serv_agg
= q
->in_serv_agg
;
1080 struct qfq_class
*cl
;
1081 struct sk_buff
*skb
= NULL
;
1082 /* next-packet len, 0 means no more active classes in in-service agg */
1083 unsigned int len
= 0;
1085 if (in_serv_agg
== NULL
)
1088 if (!list_empty(&in_serv_agg
->active
))
1089 skb
= qfq_peek_skb(in_serv_agg
, &cl
, &len
);
1092 * If there are no active classes in the in-service aggregate,
1093 * or if the aggregate has not enough budget to serve its next
1094 * class, then choose the next aggregate to serve.
1096 if (len
== 0 || in_serv_agg
->budget
< len
) {
1097 charge_actual_service(in_serv_agg
);
1099 /* recharge the budget of the aggregate */
1100 in_serv_agg
->initial_budget
= in_serv_agg
->budget
=
1101 in_serv_agg
->budgetmax
;
1103 if (!list_empty(&in_serv_agg
->active
)) {
1105 * Still active: reschedule for
1106 * service. Possible optimization: if no other
1107 * aggregate is active, then there is no point
1108 * in rescheduling this aggregate, and we can
1109 * just keep it as the in-service one. This
1110 * should be however a corner case, and to
1111 * handle it, we would need to maintain an
1112 * extra num_active_aggs field.
1114 qfq_update_agg_ts(q
, in_serv_agg
, requeue
);
1115 qfq_schedule_agg(q
, in_serv_agg
);
1116 } else if (sch
->q
.qlen
== 0) { /* no aggregate to serve */
1117 q
->in_serv_agg
= NULL
;
1122 * If we get here, there are other aggregates queued:
1123 * choose the new aggregate to serve.
1125 in_serv_agg
= q
->in_serv_agg
= qfq_choose_next_agg(q
);
1126 skb
= qfq_peek_skb(in_serv_agg
, &cl
, &len
);
1131 qdisc_qstats_backlog_dec(sch
, skb
);
1133 qdisc_bstats_update(sch
, skb
);
1135 agg_dequeue(in_serv_agg
, cl
, len
);
1136 /* If lmax is lowered, through qfq_change_class, for a class
1137 * owning pending packets with larger size than the new value
1138 * of lmax, then the following condition may hold.
1140 if (unlikely(in_serv_agg
->budget
< len
))
1141 in_serv_agg
->budget
= 0;
1143 in_serv_agg
->budget
-= len
;
1145 q
->V
+= (u64
)len
* q
->iwsum
;
1146 pr_debug("qfq dequeue: len %u F %lld now %lld\n",
1147 len
, (unsigned long long) in_serv_agg
->F
,
1148 (unsigned long long) q
->V
);
1153 static struct qfq_aggregate
*qfq_choose_next_agg(struct qfq_sched
*q
)
1155 struct qfq_group
*grp
;
1156 struct qfq_aggregate
*agg
, *new_front_agg
;
1159 qfq_update_eligible(q
);
1162 if (!q
->bitmaps
[ER
])
1165 grp
= qfq_ffs(q
, q
->bitmaps
[ER
]);
1168 agg
= qfq_slot_head(grp
);
1170 /* agg starts to be served, remove it from schedule */
1171 qfq_front_slot_remove(grp
);
1173 new_front_agg
= qfq_slot_scan(grp
);
1175 if (new_front_agg
== NULL
) /* group is now inactive, remove from ER */
1176 __clear_bit(grp
->index
, &q
->bitmaps
[ER
]);
1178 u64 roundedS
= qfq_round_down(new_front_agg
->S
,
1182 if (grp
->S
== roundedS
)
1185 grp
->F
= roundedS
+ (2ULL << grp
->slot_shift
);
1186 __clear_bit(grp
->index
, &q
->bitmaps
[ER
]);
1187 s
= qfq_calc_state(q
, grp
);
1188 __set_bit(grp
->index
, &q
->bitmaps
[s
]);
1191 qfq_unblock_groups(q
, grp
->index
, old_F
);
1196 static int qfq_enqueue(struct sk_buff
*skb
, struct Qdisc
*sch
,
1197 struct sk_buff
**to_free
)
1199 unsigned int len
= qdisc_pkt_len(skb
), gso_segs
;
1200 struct qfq_sched
*q
= qdisc_priv(sch
);
1201 struct qfq_class
*cl
;
1202 struct qfq_aggregate
*agg
;
1206 cl
= qfq_classify(skb
, sch
, &err
);
1208 if (err
& __NET_XMIT_BYPASS
)
1209 qdisc_qstats_drop(sch
);
1210 __qdisc_drop(skb
, to_free
);
1213 pr_debug("qfq_enqueue: cl = %x\n", cl
->common
.classid
);
1215 if (unlikely(cl
->agg
->lmax
< len
)) {
1216 pr_debug("qfq: increasing maxpkt from %u to %u for class %u",
1217 cl
->agg
->lmax
, len
, cl
->common
.classid
);
1218 err
= qfq_change_agg(sch
, cl
, cl
->agg
->class_weight
, len
);
1221 return qdisc_drop(skb
, sch
, to_free
);
1225 gso_segs
= skb_is_gso(skb
) ? skb_shinfo(skb
)->gso_segs
: 1;
1226 first
= !cl
->qdisc
->q
.qlen
;
1227 err
= qdisc_enqueue(skb
, cl
->qdisc
, to_free
);
1228 if (unlikely(err
!= NET_XMIT_SUCCESS
)) {
1229 pr_debug("qfq_enqueue: enqueue failed %d\n", err
);
1230 if (net_xmit_drop_count(err
)) {
1232 qdisc_qstats_drop(sch
);
1237 _bstats_update(&cl
->bstats
, len
, gso_segs
);
1238 sch
->qstats
.backlog
+= len
;
1242 /* if the queue was not empty, then done here */
1244 if (unlikely(skb
== cl
->qdisc
->ops
->peek(cl
->qdisc
)) &&
1245 list_first_entry(&agg
->active
, struct qfq_class
, alist
)
1246 == cl
&& cl
->deficit
< len
)
1247 list_move_tail(&cl
->alist
, &agg
->active
);
1252 /* schedule class for service within the aggregate */
1253 cl
->deficit
= agg
->lmax
;
1254 list_add_tail(&cl
->alist
, &agg
->active
);
1256 if (list_first_entry(&agg
->active
, struct qfq_class
, alist
) != cl
||
1257 q
->in_serv_agg
== agg
)
1258 return err
; /* non-empty or in service, nothing else to do */
1260 qfq_activate_agg(q
, agg
, enqueue
);
1266 * Schedule aggregate according to its timestamps.
1268 static void qfq_schedule_agg(struct qfq_sched
*q
, struct qfq_aggregate
*agg
)
1270 struct qfq_group
*grp
= agg
->grp
;
1274 roundedS
= qfq_round_down(agg
->S
, grp
->slot_shift
);
1277 * Insert agg in the correct bucket.
1278 * If agg->S >= grp->S we don't need to adjust the
1279 * bucket list and simply go to the insertion phase.
1280 * Otherwise grp->S is decreasing, we must make room
1281 * in the bucket list, and also recompute the group state.
1282 * Finally, if there were no flows in this group and nobody
1283 * was in ER make sure to adjust V.
1285 if (grp
->full_slots
) {
1286 if (!qfq_gt(grp
->S
, agg
->S
))
1289 /* create a slot for this agg->S */
1290 qfq_slot_rotate(grp
, roundedS
);
1291 /* group was surely ineligible, remove */
1292 __clear_bit(grp
->index
, &q
->bitmaps
[IR
]);
1293 __clear_bit(grp
->index
, &q
->bitmaps
[IB
]);
1294 } else if (!q
->bitmaps
[ER
] && qfq_gt(roundedS
, q
->V
) &&
1295 q
->in_serv_agg
== NULL
)
1299 grp
->F
= roundedS
+ (2ULL << grp
->slot_shift
);
1300 s
= qfq_calc_state(q
, grp
);
1301 __set_bit(grp
->index
, &q
->bitmaps
[s
]);
1303 pr_debug("qfq enqueue: new state %d %#lx S %lld F %lld V %lld\n",
1305 (unsigned long long) agg
->S
,
1306 (unsigned long long) agg
->F
,
1307 (unsigned long long) q
->V
);
1310 qfq_slot_insert(grp
, agg
, roundedS
);
1314 /* Update agg ts and schedule agg for service */
1315 static void qfq_activate_agg(struct qfq_sched
*q
, struct qfq_aggregate
*agg
,
1316 enum update_reason reason
)
1318 agg
->initial_budget
= agg
->budget
= agg
->budgetmax
; /* recharge budg. */
1320 qfq_update_agg_ts(q
, agg
, reason
);
1321 if (q
->in_serv_agg
== NULL
) { /* no aggr. in service or scheduled */
1322 q
->in_serv_agg
= agg
; /* start serving this aggregate */
1323 /* update V: to be in service, agg must be eligible */
1324 q
->oldV
= q
->V
= agg
->S
;
1325 } else if (agg
!= q
->in_serv_agg
)
1326 qfq_schedule_agg(q
, agg
);
1329 static void qfq_slot_remove(struct qfq_sched
*q
, struct qfq_group
*grp
,
1330 struct qfq_aggregate
*agg
)
1332 unsigned int i
, offset
;
1335 roundedS
= qfq_round_down(agg
->S
, grp
->slot_shift
);
1336 offset
= (roundedS
- grp
->S
) >> grp
->slot_shift
;
1338 i
= (grp
->front
+ offset
) % QFQ_MAX_SLOTS
;
1340 hlist_del(&agg
->next
);
1341 if (hlist_empty(&grp
->slots
[i
]))
1342 __clear_bit(offset
, &grp
->full_slots
);
1346 * Called to forcibly deschedule an aggregate. If the aggregate is
1347 * not in the front bucket, or if the latter has other aggregates in
1348 * the front bucket, we can simply remove the aggregate with no other
1350 * Otherwise we must propagate the event up.
1352 static void qfq_deactivate_agg(struct qfq_sched
*q
, struct qfq_aggregate
*agg
)
1354 struct qfq_group
*grp
= agg
->grp
;
1359 if (agg
== q
->in_serv_agg
) {
1360 charge_actual_service(agg
);
1361 q
->in_serv_agg
= qfq_choose_next_agg(q
);
1366 qfq_slot_remove(q
, grp
, agg
);
1368 if (!grp
->full_slots
) {
1369 __clear_bit(grp
->index
, &q
->bitmaps
[IR
]);
1370 __clear_bit(grp
->index
, &q
->bitmaps
[EB
]);
1371 __clear_bit(grp
->index
, &q
->bitmaps
[IB
]);
1373 if (test_bit(grp
->index
, &q
->bitmaps
[ER
]) &&
1374 !(q
->bitmaps
[ER
] & ~((1UL << grp
->index
) - 1))) {
1375 mask
= q
->bitmaps
[ER
] & ((1UL << grp
->index
) - 1);
1377 mask
= ~((1UL << __fls(mask
)) - 1);
1380 qfq_move_groups(q
, mask
, EB
, ER
);
1381 qfq_move_groups(q
, mask
, IB
, IR
);
1383 __clear_bit(grp
->index
, &q
->bitmaps
[ER
]);
1384 } else if (hlist_empty(&grp
->slots
[grp
->front
])) {
1385 agg
= qfq_slot_scan(grp
);
1386 roundedS
= qfq_round_down(agg
->S
, grp
->slot_shift
);
1387 if (grp
->S
!= roundedS
) {
1388 __clear_bit(grp
->index
, &q
->bitmaps
[ER
]);
1389 __clear_bit(grp
->index
, &q
->bitmaps
[IR
]);
1390 __clear_bit(grp
->index
, &q
->bitmaps
[EB
]);
1391 __clear_bit(grp
->index
, &q
->bitmaps
[IB
]);
1393 grp
->F
= roundedS
+ (2ULL << grp
->slot_shift
);
1394 s
= qfq_calc_state(q
, grp
);
1395 __set_bit(grp
->index
, &q
->bitmaps
[s
]);
1400 static void qfq_qlen_notify(struct Qdisc
*sch
, unsigned long arg
)
1402 struct qfq_sched
*q
= qdisc_priv(sch
);
1403 struct qfq_class
*cl
= (struct qfq_class
*)arg
;
1405 qfq_deactivate_class(q
, cl
);
1408 static int qfq_init_qdisc(struct Qdisc
*sch
, struct nlattr
*opt
,
1409 struct netlink_ext_ack
*extack
)
1411 struct qfq_sched
*q
= qdisc_priv(sch
);
1412 struct qfq_group
*grp
;
1414 u32 max_cl_shift
, maxbudg_shift
, max_classes
;
1416 err
= tcf_block_get(&q
->block
, &q
->filter_list
, sch
, extack
);
1420 err
= qdisc_class_hash_init(&q
->clhash
);
1424 max_classes
= min_t(u64
, (u64
)qdisc_dev(sch
)->tx_queue_len
+ 1,
1425 QFQ_MAX_AGG_CLASSES
);
1426 /* max_cl_shift = floor(log_2(max_classes)) */
1427 max_cl_shift
= __fls(max_classes
);
1428 q
->max_agg_classes
= 1<<max_cl_shift
;
1430 /* maxbudg_shift = log2(max_len * max_classes_per_agg) */
1431 maxbudg_shift
= QFQ_MTU_SHIFT
+ max_cl_shift
;
1432 q
->min_slot_shift
= FRAC_BITS
+ maxbudg_shift
- QFQ_MAX_INDEX
;
1434 for (i
= 0; i
<= QFQ_MAX_INDEX
; i
++) {
1435 grp
= &q
->groups
[i
];
1437 grp
->slot_shift
= q
->min_slot_shift
+ i
;
1438 for (j
= 0; j
< QFQ_MAX_SLOTS
; j
++)
1439 INIT_HLIST_HEAD(&grp
->slots
[j
]);
1442 INIT_HLIST_HEAD(&q
->nonfull_aggs
);
1447 static void qfq_reset_qdisc(struct Qdisc
*sch
)
1449 struct qfq_sched
*q
= qdisc_priv(sch
);
1450 struct qfq_class
*cl
;
1453 for (i
= 0; i
< q
->clhash
.hashsize
; i
++) {
1454 hlist_for_each_entry(cl
, &q
->clhash
.hash
[i
], common
.hnode
) {
1455 if (cl
->qdisc
->q
.qlen
> 0)
1456 qfq_deactivate_class(q
, cl
);
1458 qdisc_reset(cl
->qdisc
);
1461 sch
->qstats
.backlog
= 0;
1465 static void qfq_destroy_qdisc(struct Qdisc
*sch
)
1467 struct qfq_sched
*q
= qdisc_priv(sch
);
1468 struct qfq_class
*cl
;
1469 struct hlist_node
*next
;
1472 tcf_block_put(q
->block
);
1474 for (i
= 0; i
< q
->clhash
.hashsize
; i
++) {
1475 hlist_for_each_entry_safe(cl
, next
, &q
->clhash
.hash
[i
],
1477 qfq_destroy_class(sch
, cl
);
1480 qdisc_class_hash_destroy(&q
->clhash
);
1483 static const struct Qdisc_class_ops qfq_class_ops
= {
1484 .change
= qfq_change_class
,
1485 .delete = qfq_delete_class
,
1486 .find
= qfq_search_class
,
1487 .tcf_block
= qfq_tcf_block
,
1488 .bind_tcf
= qfq_bind_tcf
,
1489 .unbind_tcf
= qfq_unbind_tcf
,
1490 .graft
= qfq_graft_class
,
1491 .leaf
= qfq_class_leaf
,
1492 .qlen_notify
= qfq_qlen_notify
,
1493 .dump
= qfq_dump_class
,
1494 .dump_stats
= qfq_dump_class_stats
,
1498 static struct Qdisc_ops qfq_qdisc_ops __read_mostly
= {
1499 .cl_ops
= &qfq_class_ops
,
1501 .priv_size
= sizeof(struct qfq_sched
),
1502 .enqueue
= qfq_enqueue
,
1503 .dequeue
= qfq_dequeue
,
1504 .peek
= qdisc_peek_dequeued
,
1505 .init
= qfq_init_qdisc
,
1506 .reset
= qfq_reset_qdisc
,
1507 .destroy
= qfq_destroy_qdisc
,
1508 .owner
= THIS_MODULE
,
1511 static int __init
qfq_init(void)
1513 return register_qdisc(&qfq_qdisc_ops
);
1516 static void __exit
qfq_exit(void)
1518 unregister_qdisc(&qfq_qdisc_ops
);
1521 module_init(qfq_init
);
1522 module_exit(qfq_exit
);
1523 MODULE_LICENSE("GPL");