diff options
Diffstat (limited to 'kernel/net/sched/sch_qfq.c')
| -rw-r--r-- | kernel/net/sched/sch_qfq.c | 1587 |
1 files changed, 1587 insertions, 0 deletions
diff --git a/kernel/net/sched/sch_qfq.c b/kernel/net/sched/sch_qfq.c new file mode 100644 index 000000000..3ec7e88a4 --- /dev/null +++ b/kernel/net/sched/sch_qfq.c @@ -0,0 +1,1587 @@ +/* + * net/sched/sch_qfq.c Quick Fair Queueing Plus Scheduler. + * + * Copyright (c) 2009 Fabio Checconi, Luigi Rizzo, and Paolo Valente. + * Copyright (c) 2012 Paolo Valente. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * version 2 as published by the Free Software Foundation. + */ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/bitops.h> +#include <linux/errno.h> +#include <linux/netdevice.h> +#include <linux/pkt_sched.h> +#include <net/sch_generic.h> +#include <net/pkt_sched.h> +#include <net/pkt_cls.h> + + +/* Quick Fair Queueing Plus + ======================== + + Sources: + + [1] Paolo Valente, + "Reducing the Execution Time of Fair-Queueing Schedulers." + http://algo.ing.unimo.it/people/paolo/agg-sched/agg-sched.pdf + + Sources for QFQ: + + [2] Fabio Checconi, Luigi Rizzo, and Paolo Valente: "QFQ: Efficient + Packet Scheduling with Tight Bandwidth Distribution Guarantees." + + See also: + http://retis.sssup.it/~fabio/linux/qfq/ + */ + +/* + + QFQ+ divides classes into aggregates of at most MAX_AGG_CLASSES + classes. Each aggregate is timestamped with a virtual start time S + and a virtual finish time F, and scheduled according to its + timestamps. S and F are computed as a function of a system virtual + time function V. The classes within each aggregate are instead + scheduled with DRR. + + To speed up operations, QFQ+ divides also aggregates into a limited + number of groups. Which group a class belongs to depends on the + ratio between the maximum packet length for the class and the weight + of the class. Groups have their own S and F. In the end, QFQ+ + schedules groups, then aggregates within groups, then classes within + aggregates. See [1] and [2] for a full description. + + Virtual time computations. + + S, F and V are all computed in fixed point arithmetic with + FRAC_BITS decimal bits. + + QFQ_MAX_INDEX is the maximum index allowed for a group. We need + one bit per index. + QFQ_MAX_WSHIFT is the maximum power of two supported as a weight. + + The layout of the bits is as below: + + [ MTU_SHIFT ][ FRAC_BITS ] + [ MAX_INDEX ][ MIN_SLOT_SHIFT ] + ^.__grp->index = 0 + *.__grp->slot_shift + + where MIN_SLOT_SHIFT is derived by difference from the others. + + The max group index corresponds to Lmax/w_min, where + Lmax=1<<MTU_SHIFT, w_min = 1 . + From this, and knowing how many groups (MAX_INDEX) we want, + we can derive the shift corresponding to each group. + + Because we often need to compute + F = S + len/w_i and V = V + len/wsum + instead of storing w_i store the value + inv_w = (1<<FRAC_BITS)/w_i + so we can do F = S + len * inv_w * wsum. + We use W_TOT in the formulas so we can easily move between + static and adaptive weight sum. + + The per-scheduler-instance data contain all the data structures + for the scheduler: bitmaps and bucket lists. + + */ + +/* + * Maximum number of consecutive slots occupied by backlogged classes + * inside a group. + */ +#define QFQ_MAX_SLOTS 32 + +/* + * Shifts used for aggregate<->group mapping. We allow class weights that are + * in the range [1, 2^MAX_WSHIFT], and we try to map each aggregate i to the + * group with the smallest index that can support the L_i / r_i configured + * for the classes in the aggregate. + * + * grp->index is the index of the group; and grp->slot_shift + * is the shift for the corresponding (scaled) sigma_i. + */ +#define QFQ_MAX_INDEX 24 +#define QFQ_MAX_WSHIFT 10 + +#define QFQ_MAX_WEIGHT (1<<QFQ_MAX_WSHIFT) /* see qfq_slot_insert */ +#define QFQ_MAX_WSUM (64*QFQ_MAX_WEIGHT) + +#define FRAC_BITS 30 /* fixed point arithmetic */ +#define ONE_FP (1UL << FRAC_BITS) + +#define QFQ_MTU_SHIFT 16 /* to support TSO/GSO */ +#define QFQ_MIN_LMAX 512 /* see qfq_slot_insert */ + +#define QFQ_MAX_AGG_CLASSES 8 /* max num classes per aggregate allowed */ + +/* + * Possible group states. These values are used as indexes for the bitmaps + * array of struct qfq_queue. + */ +enum qfq_state { ER, IR, EB, IB, QFQ_MAX_STATE }; + +struct qfq_group; + +struct qfq_aggregate; + +struct qfq_class { + struct Qdisc_class_common common; + + unsigned int refcnt; + unsigned int filter_cnt; + + struct gnet_stats_basic_packed bstats; + struct gnet_stats_queue qstats; + struct gnet_stats_rate_est64 rate_est; + struct Qdisc *qdisc; + struct list_head alist; /* Link for active-classes list. */ + struct qfq_aggregate *agg; /* Parent aggregate. */ + int deficit; /* DRR deficit counter. */ +}; + +struct qfq_aggregate { + struct hlist_node next; /* Link for the slot list. */ + u64 S, F; /* flow timestamps (exact) */ + + /* group we belong to. In principle we would need the index, + * which is log_2(lmax/weight), but we never reference it + * directly, only the group. + */ + struct qfq_group *grp; + + /* these are copied from the flowset. */ + u32 class_weight; /* Weight of each class in this aggregate. */ + /* Max pkt size for the classes in this aggregate, DRR quantum. */ + int lmax; + + u32 inv_w; /* ONE_FP/(sum of weights of classes in aggr.). */ + u32 budgetmax; /* Max budget for this aggregate. */ + u32 initial_budget, budget; /* Initial and current budget. */ + + int num_classes; /* Number of classes in this aggr. */ + struct list_head active; /* DRR queue of active classes. */ + + struct hlist_node nonfull_next; /* See nonfull_aggs in qfq_sched. */ +}; + +struct qfq_group { + u64 S, F; /* group timestamps (approx). */ + unsigned int slot_shift; /* Slot shift. */ + unsigned int index; /* Group index. */ + unsigned int front; /* Index of the front slot. */ + unsigned long full_slots; /* non-empty slots */ + + /* Array of RR lists of active aggregates. */ + struct hlist_head slots[QFQ_MAX_SLOTS]; +}; + +struct qfq_sched { + struct tcf_proto __rcu *filter_list; + struct Qdisc_class_hash clhash; + + u64 oldV, V; /* Precise virtual times. */ + struct qfq_aggregate *in_serv_agg; /* Aggregate being served. */ + u32 num_active_agg; /* Num. of active aggregates */ + u32 wsum; /* weight sum */ + u32 iwsum; /* inverse weight sum */ + + unsigned long bitmaps[QFQ_MAX_STATE]; /* Group bitmaps. */ + struct qfq_group groups[QFQ_MAX_INDEX + 1]; /* The groups. */ + u32 min_slot_shift; /* Index of the group-0 bit in the bitmaps. */ + + u32 max_agg_classes; /* Max number of classes per aggr. */ + struct hlist_head nonfull_aggs; /* Aggs with room for more classes. */ +}; + +/* + * Possible reasons why the timestamps of an aggregate are updated + * enqueue: the aggregate switches from idle to active and must scheduled + * for service + * requeue: the aggregate finishes its budget, so it stops being served and + * must be rescheduled for service + */ +enum update_reason {enqueue, requeue}; + +static struct qfq_class *qfq_find_class(struct Qdisc *sch, u32 classid) +{ + struct qfq_sched *q = qdisc_priv(sch); + struct Qdisc_class_common *clc; + + clc = qdisc_class_find(&q->clhash, classid); + if (clc == NULL) + return NULL; + return container_of(clc, struct qfq_class, common); +} + +static void qfq_purge_queue(struct qfq_class *cl) +{ + unsigned int len = cl->qdisc->q.qlen; + + qdisc_reset(cl->qdisc); + qdisc_tree_decrease_qlen(cl->qdisc, len); +} + +static const struct nla_policy qfq_policy[TCA_QFQ_MAX + 1] = { + [TCA_QFQ_WEIGHT] = { .type = NLA_U32 }, + [TCA_QFQ_LMAX] = { .type = NLA_U32 }, +}; + +/* + * Calculate a flow index, given its weight and maximum packet length. + * index = log_2(maxlen/weight) but we need to apply the scaling. + * This is used only once at flow creation. + */ +static int qfq_calc_index(u32 inv_w, unsigned int maxlen, u32 min_slot_shift) +{ + u64 slot_size = (u64)maxlen * inv_w; + unsigned long size_map; + int index = 0; + + size_map = slot_size >> min_slot_shift; + if (!size_map) + goto out; + + index = __fls(size_map) + 1; /* basically a log_2 */ + index -= !(slot_size - (1ULL << (index + min_slot_shift - 1))); + + if (index < 0) + index = 0; +out: + pr_debug("qfq calc_index: W = %lu, L = %u, I = %d\n", + (unsigned long) ONE_FP/inv_w, maxlen, index); + + return index; +} + +static void qfq_deactivate_agg(struct qfq_sched *, struct qfq_aggregate *); +static void qfq_activate_agg(struct qfq_sched *, struct qfq_aggregate *, + enum update_reason); + +static void qfq_init_agg(struct qfq_sched *q, struct qfq_aggregate *agg, + u32 lmax, u32 weight) +{ + INIT_LIST_HEAD(&agg->active); + hlist_add_head(&agg->nonfull_next, &q->nonfull_aggs); + + agg->lmax = lmax; + agg->class_weight = weight; +} + +static struct qfq_aggregate *qfq_find_agg(struct qfq_sched *q, + u32 lmax, u32 weight) +{ + struct qfq_aggregate *agg; + + hlist_for_each_entry(agg, &q->nonfull_aggs, nonfull_next) + if (agg->lmax == lmax && agg->class_weight == weight) + return agg; + + return NULL; +} + + +/* Update aggregate as a function of the new number of classes. */ +static void qfq_update_agg(struct qfq_sched *q, struct qfq_aggregate *agg, + int new_num_classes) +{ + u32 new_agg_weight; + + if (new_num_classes == q->max_agg_classes) + hlist_del_init(&agg->nonfull_next); + + if (agg->num_classes > new_num_classes && + new_num_classes == q->max_agg_classes - 1) /* agg no more full */ + hlist_add_head(&agg->nonfull_next, &q->nonfull_aggs); + + /* The next assignment may let + * agg->initial_budget > agg->budgetmax + * hold, we will take it into account in charge_actual_service(). + */ + agg->budgetmax = new_num_classes * agg->lmax; + new_agg_weight = agg->class_weight * new_num_classes; + agg->inv_w = ONE_FP/new_agg_weight; + + if (agg->grp == NULL) { + int i = qfq_calc_index(agg->inv_w, agg->budgetmax, + q->min_slot_shift); + agg->grp = &q->groups[i]; + } + + q->wsum += + (int) agg->class_weight * (new_num_classes - agg->num_classes); + q->iwsum = ONE_FP / q->wsum; + + agg->num_classes = new_num_classes; +} + +/* Add class to aggregate. */ +static void qfq_add_to_agg(struct qfq_sched *q, + struct qfq_aggregate *agg, + struct qfq_class *cl) +{ + cl->agg = agg; + + qfq_update_agg(q, agg, agg->num_classes+1); + if (cl->qdisc->q.qlen > 0) { /* adding an active class */ + list_add_tail(&cl->alist, &agg->active); + if (list_first_entry(&agg->active, struct qfq_class, alist) == + cl && q->in_serv_agg != agg) /* agg was inactive */ + qfq_activate_agg(q, agg, enqueue); /* schedule agg */ + } +} + +static struct qfq_aggregate *qfq_choose_next_agg(struct qfq_sched *); + +static void qfq_destroy_agg(struct qfq_sched *q, struct qfq_aggregate *agg) +{ + if (!hlist_unhashed(&agg->nonfull_next)) + hlist_del_init(&agg->nonfull_next); + q->wsum -= agg->class_weight; + if (q->wsum != 0) + q->iwsum = ONE_FP / q->wsum; + + if (q->in_serv_agg == agg) + q->in_serv_agg = qfq_choose_next_agg(q); + kfree(agg); +} + +/* Deschedule class from within its parent aggregate. */ +static void qfq_deactivate_class(struct qfq_sched *q, struct qfq_class *cl) +{ + struct qfq_aggregate *agg = cl->agg; + + + list_del(&cl->alist); /* remove from RR queue of the aggregate */ + if (list_empty(&agg->active)) /* agg is now inactive */ + qfq_deactivate_agg(q, agg); +} + +/* Remove class from its parent aggregate. */ +static void qfq_rm_from_agg(struct qfq_sched *q, struct qfq_class *cl) +{ + struct qfq_aggregate *agg = cl->agg; + + cl->agg = NULL; + if (agg->num_classes == 1) { /* agg being emptied, destroy it */ + qfq_destroy_agg(q, agg); + return; + } + qfq_update_agg(q, agg, agg->num_classes-1); +} + +/* Deschedule class and remove it from its parent aggregate. */ +static void qfq_deact_rm_from_agg(struct qfq_sched *q, struct qfq_class *cl) +{ + if (cl->qdisc->q.qlen > 0) /* class is active */ + qfq_deactivate_class(q, cl); + + qfq_rm_from_agg(q, cl); +} + +/* Move class to a new aggregate, matching the new class weight and/or lmax */ +static int qfq_change_agg(struct Qdisc *sch, struct qfq_class *cl, u32 weight, + u32 lmax) +{ + struct qfq_sched *q = qdisc_priv(sch); + struct qfq_aggregate *new_agg = qfq_find_agg(q, lmax, weight); + + if (new_agg == NULL) { /* create new aggregate */ + new_agg = kzalloc(sizeof(*new_agg), GFP_ATOMIC); + if (new_agg == NULL) + return -ENOBUFS; + qfq_init_agg(q, new_agg, lmax, weight); + } + qfq_deact_rm_from_agg(q, cl); + qfq_add_to_agg(q, new_agg, cl); + + return 0; +} + +static int qfq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, + struct nlattr **tca, unsigned long *arg) +{ + struct qfq_sched *q = qdisc_priv(sch); + struct qfq_class *cl = (struct qfq_class *)*arg; + bool existing = false; + struct nlattr *tb[TCA_QFQ_MAX + 1]; + struct qfq_aggregate *new_agg = NULL; + u32 weight, lmax, inv_w; + int err; + int delta_w; + + if (tca[TCA_OPTIONS] == NULL) { + pr_notice("qfq: no options\n"); + return -EINVAL; + } + + err = nla_parse_nested(tb, TCA_QFQ_MAX, tca[TCA_OPTIONS], qfq_policy); + if (err < 0) + return err; + + if (tb[TCA_QFQ_WEIGHT]) { + weight = nla_get_u32(tb[TCA_QFQ_WEIGHT]); + if (!weight || weight > (1UL << QFQ_MAX_WSHIFT)) { + pr_notice("qfq: invalid weight %u\n", weight); + return -EINVAL; + } + } else + weight = 1; + + if (tb[TCA_QFQ_LMAX]) { + lmax = nla_get_u32(tb[TCA_QFQ_LMAX]); + if (lmax < QFQ_MIN_LMAX || lmax > (1UL << QFQ_MTU_SHIFT)) { + pr_notice("qfq: invalid max length %u\n", lmax); + return -EINVAL; + } + } else + lmax = psched_mtu(qdisc_dev(sch)); + + inv_w = ONE_FP / weight; + weight = ONE_FP / inv_w; + + if (cl != NULL && + lmax == cl->agg->lmax && + weight == cl->agg->class_weight) + return 0; /* nothing to change */ + + delta_w = weight - (cl ? cl->agg->class_weight : 0); + + if (q->wsum + delta_w > QFQ_MAX_WSUM) { + pr_notice("qfq: total weight out of range (%d + %u)\n", + delta_w, q->wsum); + return -EINVAL; + } + + if (cl != NULL) { /* modify existing class */ + if (tca[TCA_RATE]) { + err = gen_replace_estimator(&cl->bstats, NULL, + &cl->rate_est, + qdisc_root_sleeping_lock(sch), + tca[TCA_RATE]); + if (err) + return err; + } + existing = true; + goto set_change_agg; + } + + /* create and init new class */ + cl = kzalloc(sizeof(struct qfq_class), GFP_KERNEL); + if (cl == NULL) + return -ENOBUFS; + + cl->refcnt = 1; + cl->common.classid = classid; + cl->deficit = lmax; + + cl->qdisc = qdisc_create_dflt(sch->dev_queue, + &pfifo_qdisc_ops, classid); + if (cl->qdisc == NULL) + cl->qdisc = &noop_qdisc; + + if (tca[TCA_RATE]) { + err = gen_new_estimator(&cl->bstats, NULL, + &cl->rate_est, + qdisc_root_sleeping_lock(sch), + tca[TCA_RATE]); + if (err) + goto destroy_class; + } + + sch_tree_lock(sch); + qdisc_class_hash_insert(&q->clhash, &cl->common); + sch_tree_unlock(sch); + + qdisc_class_hash_grow(sch, &q->clhash); + +set_change_agg: + sch_tree_lock(sch); + new_agg = qfq_find_agg(q, lmax, weight); + if (new_agg == NULL) { /* create new aggregate */ + sch_tree_unlock(sch); + new_agg = kzalloc(sizeof(*new_agg), GFP_KERNEL); + if (new_agg == NULL) { + err = -ENOBUFS; + gen_kill_estimator(&cl->bstats, &cl->rate_est); + goto destroy_class; + } + sch_tree_lock(sch); + qfq_init_agg(q, new_agg, lmax, weight); + } + if (existing) + qfq_deact_rm_from_agg(q, cl); + qfq_add_to_agg(q, new_agg, cl); + sch_tree_unlock(sch); + + *arg = (unsigned long)cl; + return 0; + +destroy_class: + qdisc_destroy(cl->qdisc); + kfree(cl); + return err; +} + +static void qfq_destroy_class(struct Qdisc *sch, struct qfq_class *cl) +{ + struct qfq_sched *q = qdisc_priv(sch); + + qfq_rm_from_agg(q, cl); + gen_kill_estimator(&cl->bstats, &cl->rate_est); + qdisc_destroy(cl->qdisc); + kfree(cl); +} + +static int qfq_delete_class(struct Qdisc *sch, unsigned long arg) +{ + struct qfq_sched *q = qdisc_priv(sch); + struct qfq_class *cl = (struct qfq_class *)arg; + + if (cl->filter_cnt > 0) + return -EBUSY; + + sch_tree_lock(sch); + + qfq_purge_queue(cl); + qdisc_class_hash_remove(&q->clhash, &cl->common); + + BUG_ON(--cl->refcnt == 0); + /* + * This shouldn't happen: we "hold" one cops->get() when called + * from tc_ctl_tclass; the destroy method is done from cops->put(). + */ + + sch_tree_unlock(sch); + return 0; +} + +static unsigned long qfq_get_class(struct Qdisc *sch, u32 classid) +{ + struct qfq_class *cl = qfq_find_class(sch, classid); + + if (cl != NULL) + cl->refcnt++; + + return (unsigned long)cl; +} + +static void qfq_put_class(struct Qdisc *sch, unsigned long arg) +{ + struct qfq_class *cl = (struct qfq_class *)arg; + + if (--cl->refcnt == 0) + qfq_destroy_class(sch, cl); +} + +static struct tcf_proto __rcu **qfq_tcf_chain(struct Qdisc *sch, + unsigned long cl) +{ + struct qfq_sched *q = qdisc_priv(sch); + + if (cl) + return NULL; + + return &q->filter_list; +} + +static unsigned long qfq_bind_tcf(struct Qdisc *sch, unsigned long parent, + u32 classid) +{ + struct qfq_class *cl = qfq_find_class(sch, classid); + + if (cl != NULL) + cl->filter_cnt++; + + return (unsigned long)cl; +} + +static void qfq_unbind_tcf(struct Qdisc *sch, unsigned long arg) +{ + struct qfq_class *cl = (struct qfq_class *)arg; + + cl->filter_cnt--; +} + +static int qfq_graft_class(struct Qdisc *sch, unsigned long arg, + struct Qdisc *new, struct Qdisc **old) +{ + struct qfq_class *cl = (struct qfq_class *)arg; + + if (new == NULL) { + new = qdisc_create_dflt(sch->dev_queue, + &pfifo_qdisc_ops, cl->common.classid); + if (new == NULL) + new = &noop_qdisc; + } + + sch_tree_lock(sch); + qfq_purge_queue(cl); + *old = cl->qdisc; + cl->qdisc = new; + sch_tree_unlock(sch); + return 0; +} + +static struct Qdisc *qfq_class_leaf(struct Qdisc *sch, unsigned long arg) +{ + struct qfq_class *cl = (struct qfq_class *)arg; + + return cl->qdisc; +} + +static int qfq_dump_class(struct Qdisc *sch, unsigned long arg, + struct sk_buff *skb, struct tcmsg *tcm) +{ + struct qfq_class *cl = (struct qfq_class *)arg; + struct nlattr *nest; + + tcm->tcm_parent = TC_H_ROOT; + tcm->tcm_handle = cl->common.classid; + tcm->tcm_info = cl->qdisc->handle; + + nest = nla_nest_start(skb, TCA_OPTIONS); + if (nest == NULL) + goto nla_put_failure; + if (nla_put_u32(skb, TCA_QFQ_WEIGHT, cl->agg->class_weight) || + nla_put_u32(skb, TCA_QFQ_LMAX, cl->agg->lmax)) + goto nla_put_failure; + return nla_nest_end(skb, nest); + +nla_put_failure: + nla_nest_cancel(skb, nest); + return -EMSGSIZE; +} + +static int qfq_dump_class_stats(struct Qdisc *sch, unsigned long arg, + struct gnet_dump *d) +{ + struct qfq_class *cl = (struct qfq_class *)arg; + struct tc_qfq_stats xstats; + + memset(&xstats, 0, sizeof(xstats)); + + xstats.weight = cl->agg->class_weight; + xstats.lmax = cl->agg->lmax; + + if (gnet_stats_copy_basic(d, NULL, &cl->bstats) < 0 || + gnet_stats_copy_rate_est(d, &cl->bstats, &cl->rate_est) < 0 || + gnet_stats_copy_queue(d, NULL, + &cl->qdisc->qstats, cl->qdisc->q.qlen) < 0) + return -1; + + return gnet_stats_copy_app(d, &xstats, sizeof(xstats)); +} + +static void qfq_walk(struct Qdisc *sch, struct qdisc_walker *arg) +{ + struct qfq_sched *q = qdisc_priv(sch); + struct qfq_class *cl; + unsigned int i; + + if (arg->stop) + return; + + for (i = 0; i < q->clhash.hashsize; i++) { + hlist_for_each_entry(cl, &q->clhash.hash[i], common.hnode) { + if (arg->count < arg->skip) { + arg->count++; + continue; + } + if (arg->fn(sch, (unsigned long)cl, arg) < 0) { + arg->stop = 1; + return; + } + arg->count++; + } + } +} + +static struct qfq_class *qfq_classify(struct sk_buff *skb, struct Qdisc *sch, + int *qerr) +{ + struct qfq_sched *q = qdisc_priv(sch); + struct qfq_class *cl; + struct tcf_result res; + struct tcf_proto *fl; + int result; + + if (TC_H_MAJ(skb->priority ^ sch->handle) == 0) { + pr_debug("qfq_classify: found %d\n", skb->priority); + cl = qfq_find_class(sch, skb->priority); + if (cl != NULL) + return cl; + } + + *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; + fl = rcu_dereference_bh(q->filter_list); + result = tc_classify(skb, fl, &res); + if (result >= 0) { +#ifdef CONFIG_NET_CLS_ACT + switch (result) { + case TC_ACT_QUEUED: + case TC_ACT_STOLEN: + *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN; + case TC_ACT_SHOT: + return NULL; + } +#endif + cl = (struct qfq_class *)res.class; + if (cl == NULL) + cl = qfq_find_class(sch, res.classid); + return cl; + } + + return NULL; +} + +/* Generic comparison function, handling wraparound. */ +static inline int qfq_gt(u64 a, u64 b) +{ + return (s64)(a - b) > 0; +} + +/* Round a precise timestamp to its slotted value. */ +static inline u64 qfq_round_down(u64 ts, unsigned int shift) +{ + return ts & ~((1ULL << shift) - 1); +} + +/* return the pointer to the group with lowest index in the bitmap */ +static inline struct qfq_group *qfq_ffs(struct qfq_sched *q, + unsigned long bitmap) +{ + int index = __ffs(bitmap); + return &q->groups[index]; +} +/* Calculate a mask to mimic what would be ffs_from(). */ +static inline unsigned long mask_from(unsigned long bitmap, int from) +{ + return bitmap & ~((1UL << from) - 1); +} + +/* + * The state computation relies on ER=0, IR=1, EB=2, IB=3 + * First compute eligibility comparing grp->S, q->V, + * then check if someone is blocking us and possibly add EB + */ +static int qfq_calc_state(struct qfq_sched *q, const struct qfq_group *grp) +{ + /* if S > V we are not eligible */ + unsigned int state = qfq_gt(grp->S, q->V); + unsigned long mask = mask_from(q->bitmaps[ER], grp->index); + struct qfq_group *next; + + if (mask) { + next = qfq_ffs(q, mask); + if (qfq_gt(grp->F, next->F)) + state |= EB; + } + + return state; +} + + +/* + * In principle + * q->bitmaps[dst] |= q->bitmaps[src] & mask; + * q->bitmaps[src] &= ~mask; + * but we should make sure that src != dst + */ +static inline void qfq_move_groups(struct qfq_sched *q, unsigned long mask, + int src, int dst) +{ + q->bitmaps[dst] |= q->bitmaps[src] & mask; + q->bitmaps[src] &= ~mask; +} + +static void qfq_unblock_groups(struct qfq_sched *q, int index, u64 old_F) +{ + unsigned long mask = mask_from(q->bitmaps[ER], index + 1); + struct qfq_group *next; + + if (mask) { + next = qfq_ffs(q, mask); + if (!qfq_gt(next->F, old_F)) + return; + } + + mask = (1UL << index) - 1; + qfq_move_groups(q, mask, EB, ER); + qfq_move_groups(q, mask, IB, IR); +} + +/* + * perhaps + * + old_V ^= q->V; + old_V >>= q->min_slot_shift; + if (old_V) { + ... + } + * + */ +static void qfq_make_eligible(struct qfq_sched *q) +{ + unsigned long vslot = q->V >> q->min_slot_shift; + unsigned long old_vslot = q->oldV >> q->min_slot_shift; + + if (vslot != old_vslot) { + unsigned long mask; + int last_flip_pos = fls(vslot ^ old_vslot); + + if (last_flip_pos > 31) /* higher than the number of groups */ + mask = ~0UL; /* make all groups eligible */ + else + mask = (1UL << last_flip_pos) - 1; + + qfq_move_groups(q, mask, IR, ER); + qfq_move_groups(q, mask, IB, EB); + } +} + +/* + * The index of the slot in which the input aggregate agg is to be + * inserted must not be higher than QFQ_MAX_SLOTS-2. There is a '-2' + * and not a '-1' because the start time of the group may be moved + * backward by one slot after the aggregate has been inserted, and + * this would cause non-empty slots to be right-shifted by one + * position. + * + * QFQ+ fully satisfies this bound to the slot index if the parameters + * of the classes are not changed dynamically, and if QFQ+ never + * happens to postpone the service of agg unjustly, i.e., it never + * happens that the aggregate becomes backlogged and eligible, or just + * eligible, while an aggregate with a higher approximated finish time + * is being served. In particular, in this case QFQ+ guarantees that + * the timestamps of agg are low enough that the slot index is never + * higher than 2. Unfortunately, QFQ+ cannot provide the same + * guarantee if it happens to unjustly postpone the service of agg, or + * if the parameters of some class are changed. + * + * As for the first event, i.e., an out-of-order service, the + * upper bound to the slot index guaranteed by QFQ+ grows to + * 2 + + * QFQ_MAX_AGG_CLASSES * ((1<<QFQ_MTU_SHIFT)/QFQ_MIN_LMAX) * + * (current_max_weight/current_wsum) <= 2 + 8 * 128 * 1. + * + * The following function deals with this problem by backward-shifting + * the timestamps of agg, if needed, so as to guarantee that the slot + * index is never higher than QFQ_MAX_SLOTS-2. This backward-shift may + * cause the service of other aggregates to be postponed, yet the + * worst-case guarantees of these aggregates are not violated. In + * fact, in case of no out-of-order service, the timestamps of agg + * would have been even lower than they are after the backward shift, + * because QFQ+ would have guaranteed a maximum value equal to 2 for + * the slot index, and 2 < QFQ_MAX_SLOTS-2. Hence the aggregates whose + * service is postponed because of the backward-shift would have + * however waited for the service of agg before being served. + * + * The other event that may cause the slot index to be higher than 2 + * for agg is a recent change of the parameters of some class. If the + * weight of a class is increased or the lmax (max_pkt_size) of the + * class is decreased, then a new aggregate with smaller slot size + * than the original parent aggregate of the class may happen to be + * activated. The activation of this aggregate should be properly + * delayed to when the service of the class has finished in the ideal + * system tracked by QFQ+. If the activation of the aggregate is not + * delayed to this reference time instant, then this aggregate may be + * unjustly served before other aggregates waiting for service. This + * may cause the above bound to the slot index to be violated for some + * of these unlucky aggregates. + * + * Instead of delaying the activation of the new aggregate, which is + * quite complex, the above-discussed capping of the slot index is + * used to handle also the consequences of a change of the parameters + * of a class. + */ +static void qfq_slot_insert(struct qfq_group *grp, struct qfq_aggregate *agg, + u64 roundedS) +{ + u64 slot = (roundedS - grp->S) >> grp->slot_shift; + unsigned int i; /* slot index in the bucket list */ + + if (unlikely(slot > QFQ_MAX_SLOTS - 2)) { + u64 deltaS = roundedS - grp->S - + ((u64)(QFQ_MAX_SLOTS - 2)<<grp->slot_shift); + agg->S -= deltaS; + agg->F -= deltaS; + slot = QFQ_MAX_SLOTS - 2; + } + + i = (grp->front + slot) % QFQ_MAX_SLOTS; + + hlist_add_head(&agg->next, &grp->slots[i]); + __set_bit(slot, &grp->full_slots); +} + +/* Maybe introduce hlist_first_entry?? */ +static struct qfq_aggregate *qfq_slot_head(struct qfq_group *grp) +{ + return hlist_entry(grp->slots[grp->front].first, + struct qfq_aggregate, next); +} + +/* + * remove the entry from the slot + */ +static void qfq_front_slot_remove(struct qfq_group *grp) +{ + struct qfq_aggregate *agg = qfq_slot_head(grp); + + BUG_ON(!agg); + hlist_del(&agg->next); + if (hlist_empty(&grp->slots[grp->front])) + __clear_bit(0, &grp->full_slots); +} + +/* + * Returns the first aggregate in the first non-empty bucket of the + * group. As a side effect, adjusts the bucket list so the first + * non-empty bucket is at position 0 in full_slots. + */ +static struct qfq_aggregate *qfq_slot_scan(struct qfq_group *grp) +{ + unsigned int i; + + pr_debug("qfq slot_scan: grp %u full %#lx\n", + grp->index, grp->full_slots); + + if (grp->full_slots == 0) + return NULL; + + i = __ffs(grp->full_slots); /* zero based */ + if (i > 0) { + grp->front = (grp->front + i) % QFQ_MAX_SLOTS; + grp->full_slots >>= i; + } + + return qfq_slot_head(grp); +} + +/* + * adjust the bucket list. When the start time of a group decreases, + * we move the index down (modulo QFQ_MAX_SLOTS) so we don't need to + * move the objects. The mask of occupied slots must be shifted + * because we use ffs() to find the first non-empty slot. + * This covers decreases in the group's start time, but what about + * increases of the start time ? + * Here too we should make sure that i is less than 32 + */ +static void qfq_slot_rotate(struct qfq_group *grp, u64 roundedS) +{ + unsigned int i = (grp->S - roundedS) >> grp->slot_shift; + + grp->full_slots <<= i; + grp->front = (grp->front - i) % QFQ_MAX_SLOTS; +} + +static void qfq_update_eligible(struct qfq_sched *q) +{ + struct qfq_group *grp; + unsigned long ineligible; + + ineligible = q->bitmaps[IR] | q->bitmaps[IB]; + if (ineligible) { + if (!q->bitmaps[ER]) { + grp = qfq_ffs(q, ineligible); + if (qfq_gt(grp->S, q->V)) + q->V = grp->S; + } + qfq_make_eligible(q); + } +} + +/* Dequeue head packet of the head class in the DRR queue of the aggregate. */ +static void agg_dequeue(struct qfq_aggregate *agg, + struct qfq_class *cl, unsigned int len) +{ + qdisc_dequeue_peeked(cl->qdisc); + + cl->deficit -= (int) len; + + if (cl->qdisc->q.qlen == 0) /* no more packets, remove from list */ + list_del(&cl->alist); + else if (cl->deficit < qdisc_pkt_len(cl->qdisc->ops->peek(cl->qdisc))) { + cl->deficit += agg->lmax; + list_move_tail(&cl->alist, &agg->active); + } +} + +static inline struct sk_buff *qfq_peek_skb(struct qfq_aggregate *agg, + struct qfq_class **cl, + unsigned int *len) +{ + struct sk_buff *skb; + + *cl = list_first_entry(&agg->active, struct qfq_class, alist); + skb = (*cl)->qdisc->ops->peek((*cl)->qdisc); + if (skb == NULL) + WARN_ONCE(1, "qfq_dequeue: non-workconserving leaf\n"); + else + *len = qdisc_pkt_len(skb); + + return skb; +} + +/* Update F according to the actual service received by the aggregate. */ +static inline void charge_actual_service(struct qfq_aggregate *agg) +{ + /* Compute the service received by the aggregate, taking into + * account that, after decreasing the number of classes in + * agg, it may happen that + * agg->initial_budget - agg->budget > agg->bugdetmax + */ + u32 service_received = min(agg->budgetmax, + agg->initial_budget - agg->budget); + + agg->F = agg->S + (u64)service_received * agg->inv_w; +} + +/* Assign a reasonable start time for a new aggregate in group i. + * Admissible values for \hat(F) are multiples of \sigma_i + * no greater than V+\sigma_i . Larger values mean that + * we had a wraparound so we consider the timestamp to be stale. + * + * If F is not stale and F >= V then we set S = F. + * Otherwise we should assign S = V, but this may violate + * the ordering in EB (see [2]). So, if we have groups in ER, + * set S to the F_j of the first group j which would be blocking us. + * We are guaranteed not to move S backward because + * otherwise our group i would still be blocked. + */ +static void qfq_update_start(struct qfq_sched *q, struct qfq_aggregate *agg) +{ + unsigned long mask; + u64 limit, roundedF; + int slot_shift = agg->grp->slot_shift; + + roundedF = qfq_round_down(agg->F, slot_shift); + limit = qfq_round_down(q->V, slot_shift) + (1ULL << slot_shift); + + if (!qfq_gt(agg->F, q->V) || qfq_gt(roundedF, limit)) { + /* timestamp was stale */ + mask = mask_from(q->bitmaps[ER], agg->grp->index); + if (mask) { + struct qfq_group *next = qfq_ffs(q, mask); + if (qfq_gt(roundedF, next->F)) { + if (qfq_gt(limit, next->F)) + agg->S = next->F; + else /* preserve timestamp correctness */ + agg->S = limit; + return; + } + } + agg->S = q->V; + } else /* timestamp is not stale */ + agg->S = agg->F; +} + +/* Update the timestamps of agg before scheduling/rescheduling it for + * service. In particular, assign to agg->F its maximum possible + * value, i.e., the virtual finish time with which the aggregate + * should be labeled if it used all its budget once in service. + */ +static inline void +qfq_update_agg_ts(struct qfq_sched *q, + struct qfq_aggregate *agg, enum update_reason reason) +{ + if (reason != requeue) + qfq_update_start(q, agg); + else /* just charge agg for the service received */ + agg->S = agg->F; + + agg->F = agg->S + (u64)agg->budgetmax * agg->inv_w; +} + +static void qfq_schedule_agg(struct qfq_sched *q, struct qfq_aggregate *agg); + +static struct sk_buff *qfq_dequeue(struct Qdisc *sch) +{ + struct qfq_sched *q = qdisc_priv(sch); + struct qfq_aggregate *in_serv_agg = q->in_serv_agg; + struct qfq_class *cl; + struct sk_buff *skb = NULL; + /* next-packet len, 0 means no more active classes in in-service agg */ + unsigned int len = 0; + + if (in_serv_agg == NULL) + return NULL; + + if (!list_empty(&in_serv_agg->active)) + skb = qfq_peek_skb(in_serv_agg, &cl, &len); + + /* + * If there are no active classes in the in-service aggregate, + * or if the aggregate has not enough budget to serve its next + * class, then choose the next aggregate to serve. + */ + if (len == 0 || in_serv_agg->budget < len) { + charge_actual_service(in_serv_agg); + + /* recharge the budget of the aggregate */ + in_serv_agg->initial_budget = in_serv_agg->budget = + in_serv_agg->budgetmax; + + if (!list_empty(&in_serv_agg->active)) { + /* + * Still active: reschedule for + * service. Possible optimization: if no other + * aggregate is active, then there is no point + * in rescheduling this aggregate, and we can + * just keep it as the in-service one. This + * should be however a corner case, and to + * handle it, we would need to maintain an + * extra num_active_aggs field. + */ + qfq_update_agg_ts(q, in_serv_agg, requeue); + qfq_schedule_agg(q, in_serv_agg); + } else if (sch->q.qlen == 0) { /* no aggregate to serve */ + q->in_serv_agg = NULL; + return NULL; + } + + /* + * If we get here, there are other aggregates queued: + * choose the new aggregate to serve. + */ + in_serv_agg = q->in_serv_agg = qfq_choose_next_agg(q); + skb = qfq_peek_skb(in_serv_agg, &cl, &len); + } + if (!skb) + return NULL; + + sch->q.qlen--; + qdisc_bstats_update(sch, skb); + + agg_dequeue(in_serv_agg, cl, len); + /* If lmax is lowered, through qfq_change_class, for a class + * owning pending packets with larger size than the new value + * of lmax, then the following condition may hold. + */ + if (unlikely(in_serv_agg->budget < len)) + in_serv_agg->budget = 0; + else + in_serv_agg->budget -= len; + + q->V += (u64)len * q->iwsum; + pr_debug("qfq dequeue: len %u F %lld now %lld\n", + len, (unsigned long long) in_serv_agg->F, + (unsigned long long) q->V); + + return skb; +} + +static struct qfq_aggregate *qfq_choose_next_agg(struct qfq_sched *q) +{ + struct qfq_group *grp; + struct qfq_aggregate *agg, *new_front_agg; + u64 old_F; + + qfq_update_eligible(q); + q->oldV = q->V; + + if (!q->bitmaps[ER]) + return NULL; + + grp = qfq_ffs(q, q->bitmaps[ER]); + old_F = grp->F; + + agg = qfq_slot_head(grp); + + /* agg starts to be served, remove it from schedule */ + qfq_front_slot_remove(grp); + + new_front_agg = qfq_slot_scan(grp); + + if (new_front_agg == NULL) /* group is now inactive, remove from ER */ + __clear_bit(grp->index, &q->bitmaps[ER]); + else { + u64 roundedS = qfq_round_down(new_front_agg->S, + grp->slot_shift); + unsigned int s; + + if (grp->S == roundedS) + return agg; + grp->S = roundedS; + grp->F = roundedS + (2ULL << grp->slot_shift); + __clear_bit(grp->index, &q->bitmaps[ER]); + s = qfq_calc_state(q, grp); + __set_bit(grp->index, &q->bitmaps[s]); + } + + qfq_unblock_groups(q, grp->index, old_F); + + return agg; +} + +static int qfq_enqueue(struct sk_buff *skb, struct Qdisc *sch) +{ + struct qfq_sched *q = qdisc_priv(sch); + struct qfq_class *cl; + struct qfq_aggregate *agg; + int err = 0; + + cl = qfq_classify(skb, sch, &err); + if (cl == NULL) { + if (err & __NET_XMIT_BYPASS) + qdisc_qstats_drop(sch); + kfree_skb(skb); + return err; + } + pr_debug("qfq_enqueue: cl = %x\n", cl->common.classid); + + if (unlikely(cl->agg->lmax < qdisc_pkt_len(skb))) { + pr_debug("qfq: increasing maxpkt from %u to %u for class %u", + cl->agg->lmax, qdisc_pkt_len(skb), cl->common.classid); + err = qfq_change_agg(sch, cl, cl->agg->class_weight, + qdisc_pkt_len(skb)); + if (err) + return err; + } + + err = qdisc_enqueue(skb, cl->qdisc); + if (unlikely(err != NET_XMIT_SUCCESS)) { + pr_debug("qfq_enqueue: enqueue failed %d\n", err); + if (net_xmit_drop_count(err)) { + cl->qstats.drops++; + qdisc_qstats_drop(sch); + } + return err; + } + + bstats_update(&cl->bstats, skb); + ++sch->q.qlen; + + agg = cl->agg; + /* if the queue was not empty, then done here */ + if (cl->qdisc->q.qlen != 1) { + if (unlikely(skb == cl->qdisc->ops->peek(cl->qdisc)) && + list_first_entry(&agg->active, struct qfq_class, alist) + == cl && cl->deficit < qdisc_pkt_len(skb)) + list_move_tail(&cl->alist, &agg->active); + + return err; + } + + /* schedule class for service within the aggregate */ + cl->deficit = agg->lmax; + list_add_tail(&cl->alist, &agg->active); + + if (list_first_entry(&agg->active, struct qfq_class, alist) != cl || + q->in_serv_agg == agg) + return err; /* non-empty or in service, nothing else to do */ + + qfq_activate_agg(q, agg, enqueue); + + return err; +} + +/* + * Schedule aggregate according to its timestamps. + */ +static void qfq_schedule_agg(struct qfq_sched *q, struct qfq_aggregate *agg) +{ + struct qfq_group *grp = agg->grp; + u64 roundedS; + int s; + + roundedS = qfq_round_down(agg->S, grp->slot_shift); + + /* + * Insert agg in the correct bucket. + * If agg->S >= grp->S we don't need to adjust the + * bucket list and simply go to the insertion phase. + * Otherwise grp->S is decreasing, we must make room + * in the bucket list, and also recompute the group state. + * Finally, if there were no flows in this group and nobody + * was in ER make sure to adjust V. + */ + if (grp->full_slots) { + if (!qfq_gt(grp->S, agg->S)) + goto skip_update; + + /* create a slot for this agg->S */ + qfq_slot_rotate(grp, roundedS); + /* group was surely ineligible, remove */ + __clear_bit(grp->index, &q->bitmaps[IR]); + __clear_bit(grp->index, &q->bitmaps[IB]); + } else if (!q->bitmaps[ER] && qfq_gt(roundedS, q->V) && + q->in_serv_agg == NULL) + q->V = roundedS; + + grp->S = roundedS; + grp->F = roundedS + (2ULL << grp->slot_shift); + s = qfq_calc_state(q, grp); + __set_bit(grp->index, &q->bitmaps[s]); + + pr_debug("qfq enqueue: new state %d %#lx S %lld F %lld V %lld\n", + s, q->bitmaps[s], + (unsigned long long) agg->S, + (unsigned long long) agg->F, + (unsigned long long) q->V); + +skip_update: + qfq_slot_insert(grp, agg, roundedS); +} + + +/* Update agg ts and schedule agg for service */ +static void qfq_activate_agg(struct qfq_sched *q, struct qfq_aggregate *agg, + enum update_reason reason) +{ + agg->initial_budget = agg->budget = agg->budgetmax; /* recharge budg. */ + + qfq_update_agg_ts(q, agg, reason); + if (q->in_serv_agg == NULL) { /* no aggr. in service or scheduled */ + q->in_serv_agg = agg; /* start serving this aggregate */ + /* update V: to be in service, agg must be eligible */ + q->oldV = q->V = agg->S; + } else if (agg != q->in_serv_agg) + qfq_schedule_agg(q, agg); +} + +static void qfq_slot_remove(struct qfq_sched *q, struct qfq_group *grp, + struct qfq_aggregate *agg) +{ + unsigned int i, offset; + u64 roundedS; + + roundedS = qfq_round_down(agg->S, grp->slot_shift); + offset = (roundedS - grp->S) >> grp->slot_shift; + + i = (grp->front + offset) % QFQ_MAX_SLOTS; + + hlist_del(&agg->next); + if (hlist_empty(&grp->slots[i])) + __clear_bit(offset, &grp->full_slots); +} + +/* + * Called to forcibly deschedule an aggregate. If the aggregate is + * not in the front bucket, or if the latter has other aggregates in + * the front bucket, we can simply remove the aggregate with no other + * side effects. + * Otherwise we must propagate the event up. + */ +static void qfq_deactivate_agg(struct qfq_sched *q, struct qfq_aggregate *agg) +{ + struct qfq_group *grp = agg->grp; + unsigned long mask; + u64 roundedS; + int s; + + if (agg == q->in_serv_agg) { + charge_actual_service(agg); + q->in_serv_agg = qfq_choose_next_agg(q); + return; + } + + agg->F = agg->S; + qfq_slot_remove(q, grp, agg); + + if (!grp->full_slots) { + __clear_bit(grp->index, &q->bitmaps[IR]); + __clear_bit(grp->index, &q->bitmaps[EB]); + __clear_bit(grp->index, &q->bitmaps[IB]); + + if (test_bit(grp->index, &q->bitmaps[ER]) && + !(q->bitmaps[ER] & ~((1UL << grp->index) - 1))) { + mask = q->bitmaps[ER] & ((1UL << grp->index) - 1); + if (mask) + mask = ~((1UL << __fls(mask)) - 1); + else + mask = ~0UL; + qfq_move_groups(q, mask, EB, ER); + qfq_move_groups(q, mask, IB, IR); + } + __clear_bit(grp->index, &q->bitmaps[ER]); + } else if (hlist_empty(&grp->slots[grp->front])) { + agg = qfq_slot_scan(grp); + roundedS = qfq_round_down(agg->S, grp->slot_shift); + if (grp->S != roundedS) { + __clear_bit(grp->index, &q->bitmaps[ER]); + __clear_bit(grp->index, &q->bitmaps[IR]); + __clear_bit(grp->index, &q->bitmaps[EB]); + __clear_bit(grp->index, &q->bitmaps[IB]); + grp->S = roundedS; + grp->F = roundedS + (2ULL << grp->slot_shift); + s = qfq_calc_state(q, grp); + __set_bit(grp->index, &q->bitmaps[s]); + } + } +} + +static void qfq_qlen_notify(struct Qdisc *sch, unsigned long arg) +{ + struct qfq_sched *q = qdisc_priv(sch); + struct qfq_class *cl = (struct qfq_class *)arg; + + if (cl->qdisc->q.qlen == 0) + qfq_deactivate_class(q, cl); +} + +static unsigned int qfq_drop_from_slot(struct qfq_sched *q, + struct hlist_head *slot) +{ + struct qfq_aggregate *agg; + struct qfq_class *cl; + unsigned int len; + + hlist_for_each_entry(agg, slot, next) { + list_for_each_entry(cl, &agg->active, alist) { + + if (!cl->qdisc->ops->drop) + continue; + + len = cl->qdisc->ops->drop(cl->qdisc); + if (len > 0) { + if (cl->qdisc->q.qlen == 0) + qfq_deactivate_class(q, cl); + + return len; + } + } + } + return 0; +} + +static unsigned int qfq_drop(struct Qdisc *sch) +{ + struct qfq_sched *q = qdisc_priv(sch); + struct qfq_group *grp; + unsigned int i, j, len; + + for (i = 0; i <= QFQ_MAX_INDEX; i++) { + grp = &q->groups[i]; + for (j = 0; j < QFQ_MAX_SLOTS; j++) { + len = qfq_drop_from_slot(q, &grp->slots[j]); + if (len > 0) { + sch->q.qlen--; + return len; + } + } + + } + + return 0; +} + +static int qfq_init_qdisc(struct Qdisc *sch, struct nlattr *opt) +{ + struct qfq_sched *q = qdisc_priv(sch); + struct qfq_group *grp; + int i, j, err; + u32 max_cl_shift, maxbudg_shift, max_classes; + + err = qdisc_class_hash_init(&q->clhash); + if (err < 0) + return err; + + if (qdisc_dev(sch)->tx_queue_len + 1 > QFQ_MAX_AGG_CLASSES) + max_classes = QFQ_MAX_AGG_CLASSES; + else + max_classes = qdisc_dev(sch)->tx_queue_len + 1; + /* max_cl_shift = floor(log_2(max_classes)) */ + max_cl_shift = __fls(max_classes); + q->max_agg_classes = 1<<max_cl_shift; + + /* maxbudg_shift = log2(max_len * max_classes_per_agg) */ + maxbudg_shift = QFQ_MTU_SHIFT + max_cl_shift; + q->min_slot_shift = FRAC_BITS + maxbudg_shift - QFQ_MAX_INDEX; + + for (i = 0; i <= QFQ_MAX_INDEX; i++) { + grp = &q->groups[i]; + grp->index = i; + grp->slot_shift = q->min_slot_shift + i; + for (j = 0; j < QFQ_MAX_SLOTS; j++) + INIT_HLIST_HEAD(&grp->slots[j]); + } + + INIT_HLIST_HEAD(&q->nonfull_aggs); + + return 0; +} + +static void qfq_reset_qdisc(struct Qdisc *sch) +{ + struct qfq_sched *q = qdisc_priv(sch); + struct qfq_class *cl; + unsigned int i; + + for (i = 0; i < q->clhash.hashsize; i++) { + hlist_for_each_entry(cl, &q->clhash.hash[i], common.hnode) { + if (cl->qdisc->q.qlen > 0) + qfq_deactivate_class(q, cl); + + qdisc_reset(cl->qdisc); + } + } + sch->q.qlen = 0; +} + +static void qfq_destroy_qdisc(struct Qdisc *sch) +{ + struct qfq_sched *q = qdisc_priv(sch); + struct qfq_class *cl; + struct hlist_node *next; + unsigned int i; + + tcf_destroy_chain(&q->filter_list); + + for (i = 0; i < q->clhash.hashsize; i++) { + hlist_for_each_entry_safe(cl, next, &q->clhash.hash[i], + common.hnode) { + qfq_destroy_class(sch, cl); + } + } + qdisc_class_hash_destroy(&q->clhash); +} + +static const struct Qdisc_class_ops qfq_class_ops = { + .change = qfq_change_class, + .delete = qfq_delete_class, + .get = qfq_get_class, + .put = qfq_put_class, + .tcf_chain = qfq_tcf_chain, + .bind_tcf = qfq_bind_tcf, + .unbind_tcf = qfq_unbind_tcf, + .graft = qfq_graft_class, + .leaf = qfq_class_leaf, + .qlen_notify = qfq_qlen_notify, + .dump = qfq_dump_class, + .dump_stats = qfq_dump_class_stats, + .walk = qfq_walk, +}; + +static struct Qdisc_ops qfq_qdisc_ops __read_mostly = { + .cl_ops = &qfq_class_ops, + .id = "qfq", + .priv_size = sizeof(struct qfq_sched), + .enqueue = qfq_enqueue, + .dequeue = qfq_dequeue, + .peek = qdisc_peek_dequeued, + .drop = qfq_drop, + .init = qfq_init_qdisc, + .reset = qfq_reset_qdisc, + .destroy = qfq_destroy_qdisc, + .owner = THIS_MODULE, +}; + +static int __init qfq_init(void) +{ + return register_qdisc(&qfq_qdisc_ops); +} + +static void __exit qfq_exit(void) +{ + unregister_qdisc(&qfq_qdisc_ops); +} + +module_init(qfq_init); +module_exit(qfq_exit); +MODULE_LICENSE("GPL"); |