| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * 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. |
| */ |
| |
| #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 filter_cnt; |
| |
| struct gnet_stats_basic_packed bstats; |
| struct gnet_stats_queue qstats; |
| struct net_rate_estimator __rcu *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 tcf_block *block; |
| struct Qdisc_class_hash clhash; |
| |
| u64 oldV, V; /* Precise virtual times. */ |
| struct qfq_aggregate *in_serv_agg; /* Aggregate being served. */ |
| 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 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) |
| { |
| 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 netlink_ext_ack *extack) |
| { |
| 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_deprecated(tb, TCA_QFQ_MAX, tca[TCA_OPTIONS], |
| qfq_policy, NULL); |
| 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, |
| NULL, |
| qdisc_root_sleeping_running(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->common.classid = classid; |
| cl->deficit = lmax; |
| |
| cl->qdisc = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, |
| classid, NULL); |
| if (cl->qdisc == NULL) |
| cl->qdisc = &noop_qdisc; |
| |
| if (tca[TCA_RATE]) { |
| err = gen_new_estimator(&cl->bstats, NULL, |
| &cl->rate_est, |
| NULL, |
| qdisc_root_sleeping_running(sch), |
| tca[TCA_RATE]); |
| if (err) |
| goto destroy_class; |
| } |
| |
| if (cl->qdisc != &noop_qdisc) |
| qdisc_hash_add(cl->qdisc, true); |
| |
| 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->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); |
| else |
| qdisc_class_hash_insert(&q->clhash, &cl->common); |
| qfq_add_to_agg(q, new_agg, cl); |
| sch_tree_unlock(sch); |
| qdisc_class_hash_grow(sch, &q->clhash); |
| |
| *arg = (unsigned long)cl; |
| return 0; |
| |
| destroy_class: |
| qdisc_put(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->rate_est); |
| qdisc_put(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); |
| |
| qdisc_purge_queue(cl->qdisc); |
| qdisc_class_hash_remove(&q->clhash, &cl->common); |
| |
| sch_tree_unlock(sch); |
| |
| qfq_destroy_class(sch, cl); |
| return 0; |
| } |
| |
| static unsigned long qfq_search_class(struct Qdisc *sch, u32 classid) |
| { |
| return (unsigned long)qfq_find_class(sch, classid); |
| } |
| |
| static struct tcf_block *qfq_tcf_block(struct Qdisc *sch, unsigned long cl, |
| struct netlink_ext_ack *extack) |
| { |
| struct qfq_sched *q = qdisc_priv(sch); |
| |
| if (cl) |
| return NULL; |
| |
| return q->block; |
| } |
| |
| 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 netlink_ext_ack *extack) |
| { |
| struct qfq_class *cl = (struct qfq_class *)arg; |
| |
| if (new == NULL) { |
| new = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, |
| cl->common.classid, NULL); |
| if (new == NULL) |
| new = &noop_qdisc; |
| } |
| |
| *old = qdisc_replace(sch, new, &cl->qdisc); |
| 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_noflag(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(qdisc_root_sleeping_running(sch), |
| d, NULL, &cl->bstats) < 0 || |
| gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 || |
| qdisc_qstats_copy(d, cl->qdisc) < 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 = tcf_classify(skb, fl, &res, false); |
| if (result >= 0) { |
| #ifdef CONFIG_NET_CLS_ACT |
| switch (result) { |
| case TC_ACT_QUEUED: |
| case TC_ACT_STOLEN: |
| case TC_ACT_TRAP: |
| *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN; |
| fallthrough; |
| 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; |
| |
| qdisc_qstats_backlog_dec(sch, skb); |
| 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 sk_buff **to_free) |
| { |
| unsigned int len = qdisc_pkt_len(skb), gso_segs; |
| struct qfq_sched *q = qdisc_priv(sch); |
| struct qfq_class *cl; |
| struct qfq_aggregate *agg; |
| int err = 0; |
| bool first; |
| |
| cl = qfq_classify(skb, sch, &err); |
| if (cl == NULL) { |
| if (err & __NET_XMIT_BYPASS) |
| qdisc_qstats_drop(sch); |
| __qdisc_drop(skb, to_free); |
| return err; |
| } |
| pr_debug("qfq_enqueue: cl = %x\n", cl->common.classid); |
| |
| if (unlikely(cl->agg->lmax < len)) { |
| pr_debug("qfq: increasing maxpkt from %u to %u for class %u", |
| cl->agg->lmax, len, cl->common.classid); |
| err = qfq_change_agg(sch, cl, cl->agg->class_weight, len); |
| if (err) { |
| cl->qstats.drops++; |
| return qdisc_drop(skb, sch, to_free); |
| } |
| } |
| |
| gso_segs = skb_is_gso(skb) ? skb_shinfo(skb)->gso_segs : 1; |
| first = !cl->qdisc->q.qlen; |
| err = qdisc_enqueue(skb, cl->qdisc, to_free); |
| 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; |
| } |
| |
| cl->bstats.bytes += len; |
| cl->bstats.packets += gso_segs; |
| sch->qstats.backlog += len; |
| ++sch->q.qlen; |
| |
| agg = cl->agg; |
| /* if the queue was not empty, then done here */ |
| if (!first) { |
| if (unlikely(skb == cl->qdisc->ops->peek(cl->qdisc)) && |
| list_first_entry(&agg->active, struct qfq_class, alist) |
| == cl && cl->deficit < len) |
| 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; |
| |
| qfq_deactivate_class(q, cl); |
| } |
| |
| static int qfq_init_qdisc(struct Qdisc *sch, struct nlattr *opt, |
| struct netlink_ext_ack *extack) |
| { |
| struct qfq_sched *q = qdisc_priv(sch); |
| struct qfq_group *grp; |
| int i, j, err; |
| u32 max_cl_shift, maxbudg_shift, max_classes; |
| |
| err = tcf_block_get(&q->block, &q->filter_list, sch, extack); |
| if (err) |
| return err; |
| |
| 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->qstats.backlog = 0; |
| 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_block_put(q->block); |
| |
| 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, |
| .find = qfq_search_class, |
| .tcf_block = qfq_tcf_block, |
| .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, |
| .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"); |