/* * net/sched/sch_qfq.c Quick Fair Queueing Scheduler. * * Copyright (c) 2009 Fabio Checconi, Luigi Rizzo, and 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 =================== Sources: 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/ */ /* 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 class<->group mapping. We allow class weights that are * in the range [1, 2^MAX_WSHIFT], and we try to map each class i to the * group with the smallest index that can support the L_i / r_i configured * for the class. * * 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 19 #define QFQ_MAX_WSHIFT 16 #define QFQ_MAX_WEIGHT (1<<QFQ_MAX_WSHIFT) #define QFQ_MAX_WSUM (2*QFQ_MAX_WEIGHT) #define FRAC_BITS 30 /* fixed point arithmetic */ #define ONE_FP (1UL << FRAC_BITS) #define IWSUM (ONE_FP/QFQ_MAX_WSUM) #define QFQ_MTU_SHIFT 11 #define QFQ_MIN_SLOT_SHIFT (FRAC_BITS + QFQ_MTU_SHIFT - QFQ_MAX_INDEX) /* * 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_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_est rate_est; struct Qdisc *qdisc; 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 inv_w; /* ONE_FP/weight */ u32 lmax; /* Max packet size for this flow. */ }; 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 classes. */ struct hlist_head slots[QFQ_MAX_SLOTS]; }; struct qfq_sched { struct tcf_proto *filter_list; struct Qdisc_class_hash clhash; u64 V; /* Precise virtual time. */ u32 wsum; /* weight sum */ unsigned long bitmaps[QFQ_MAX_STATE]; /* Group bitmaps. */ struct qfq_group groups[QFQ_MAX_INDEX + 1]; /* The groups. */ }; 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) { u64 slot_size = (u64)maxlen * inv_w; unsigned long size_map; int index = 0; size_map = slot_size >> QFQ_MIN_SLOT_SHIFT; if (!size_map) goto out; index = __fls(size_map) + 1; /* basically a log_2 */ index -= !(slot_size - (1ULL << (index + QFQ_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 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; struct nlattr *tb[TCA_QFQ_MAX + 1]; u32 weight, lmax, inv_w; int i, err; 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; inv_w = ONE_FP / weight; weight = ONE_FP / inv_w; if (q->wsum + weight > QFQ_MAX_WSUM) { pr_notice("qfq: total weight out of range (%u + %u)\n", weight, q->wsum); return -EINVAL; } if (tb[TCA_QFQ_LMAX]) { lmax = nla_get_u32(tb[TCA_QFQ_LMAX]); if (!lmax || lmax > (1UL << QFQ_MTU_SHIFT)) { pr_notice("qfq: invalid max length %u\n", lmax); return -EINVAL; } } else lmax = 1UL << QFQ_MTU_SHIFT; if (cl != NULL) { if (tca[TCA_RATE]) { err = gen_replace_estimator(&cl->bstats, &cl->rate_est, qdisc_root_sleeping_lock(sch), tca[TCA_RATE]); if (err) return err; } sch_tree_lock(sch); if (tb[TCA_QFQ_WEIGHT]) { q->wsum = weight - ONE_FP / cl->inv_w; cl->inv_w = inv_w; } sch_tree_unlock(sch); return 0; } cl = kzalloc(sizeof(struct qfq_class), GFP_KERNEL); if (cl == NULL) return -ENOBUFS; cl->refcnt = 1; cl->common.classid = classid; cl->lmax = lmax; cl->inv_w = inv_w; i = qfq_calc_index(cl->inv_w, cl->lmax); cl->grp = &q->groups[i]; q->wsum += weight; 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, &cl->rate_est, qdisc_root_sleeping_lock(sch), tca[TCA_RATE]); if (err) { qdisc_destroy(cl->qdisc); kfree(cl); return err; } } sch_tree_lock(sch); qdisc_class_hash_insert(&q->clhash, &cl->common); sch_tree_unlock(sch); qdisc_class_hash_grow(sch, &q->clhash); *arg = (unsigned long)cl; return 0; } static void qfq_destroy_class(struct Qdisc *sch, struct qfq_class *cl) { struct qfq_sched *q = qdisc_priv(sch); if (cl->inv_w) { q->wsum -= ONE_FP / cl->inv_w; cl->inv_w = 0; } 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 **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; NLA_PUT_U32(skb, TCA_QFQ_WEIGHT, ONE_FP/cl->inv_w); NLA_PUT_U32(skb, TCA_QFQ_LMAX, cl->lmax); 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)); cl->qdisc->qstats.qlen = cl->qdisc->q.qlen; xstats.weight = ONE_FP/cl->inv_w; xstats.lmax = cl->lmax; if (gnet_stats_copy_basic(d, &cl->bstats) < 0 || gnet_stats_copy_rate_est(d, &cl->bstats, &cl->rate_est) < 0 || gnet_stats_copy_queue(d, &cl->qdisc->qstats) < 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; struct hlist_node *n; unsigned int i; if (arg->stop) return; for (i = 0; i < q->clhash.hashsize; i++) { hlist_for_each_entry(cl, n, &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; 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; result = tc_classify(skb, q->filter_list, &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 >>= QFQ_MIN_SLOT_SHIFT; if (old_V) { ... } * */ static void qfq_make_eligible(struct qfq_sched *q, u64 old_V) { unsigned long vslot = q->V >> QFQ_MIN_SLOT_SHIFT; unsigned long old_vslot = old_V >> QFQ_MIN_SLOT_SHIFT; if (vslot != old_vslot) { unsigned long mask = (1UL << fls(vslot ^ old_vslot)) - 1; qfq_move_groups(q, mask, IR, ER); qfq_move_groups(q, mask, IB, EB); } } /* * XXX we should make sure that slot becomes less than 32. * This is guaranteed by the input values. * roundedS is always cl->S rounded on grp->slot_shift bits. */ static void qfq_slot_insert(struct qfq_group *grp, struct qfq_class *cl, u64 roundedS) { u64 slot = (roundedS - grp->S) >> grp->slot_shift; unsigned int i = (grp->front + slot) % QFQ_MAX_SLOTS; hlist_add_head(&cl->next, &grp->slots[i]); __set_bit(slot, &grp->full_slots); } /* Maybe introduce hlist_first_entry?? */ static struct qfq_class *qfq_slot_head(struct qfq_group *grp) { return hlist_entry(grp->slots[grp->front].first, struct qfq_class, next); } /* * remove the entry from the slot */ static void qfq_front_slot_remove(struct qfq_group *grp) { struct qfq_class *cl = qfq_slot_head(grp); BUG_ON(!cl); hlist_del(&cl->next); if (hlist_empty(&grp->slots[grp->front])) __clear_bit(0, &grp->full_slots); } /* * Returns the first full queue in a group. As a side effect, * adjust the bucket list so the first non-empty bucket is at * position 0 in full_slots. */ static struct qfq_class *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, u64 old_V) { 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, old_V); } } /* What is length of next packet in queue (0 if queue is empty) */ static unsigned int qdisc_peek_len(struct Qdisc *sch) { struct sk_buff *skb; skb = sch->ops->peek(sch); return skb ? qdisc_pkt_len(skb) : 0; } /* * Updates the class, returns true if also the group needs to be updated. */ static bool qfq_update_class(struct qfq_group *grp, struct qfq_class *cl) { unsigned int len = qdisc_peek_len(cl->qdisc); cl->S = cl->F; if (!len) qfq_front_slot_remove(grp); /* queue is empty */ else { u64 roundedS; cl->F = cl->S + (u64)len * cl->inv_w; roundedS = qfq_round_down(cl->S, grp->slot_shift); if (roundedS == grp->S) return false; qfq_front_slot_remove(grp); qfq_slot_insert(grp, cl, roundedS); } return true; } static struct sk_buff *qfq_dequeue(struct Qdisc *sch) { struct qfq_sched *q = qdisc_priv(sch); struct qfq_group *grp; struct qfq_class *cl; struct sk_buff *skb; unsigned int len; u64 old_V; if (!q->bitmaps[ER]) return NULL; grp = qfq_ffs(q, q->bitmaps[ER]); cl = qfq_slot_head(grp); skb = qdisc_dequeue_peeked(cl->qdisc); if (!skb) { WARN_ONCE(1, "qfq_dequeue: non-workconserving leaf\n"); return NULL; } sch->q.qlen--; qdisc_bstats_update(sch, skb); old_V = q->V; len = qdisc_pkt_len(skb); q->V += (u64)len * IWSUM; pr_debug("qfq dequeue: len %u F %lld now %lld\n", len, (unsigned long long) cl->F, (unsigned long long) q->V); if (qfq_update_class(grp, cl)) { u64 old_F = grp->F; cl = qfq_slot_scan(grp); if (!cl) __clear_bit(grp->index, &q->bitmaps[ER]); else { u64 roundedS = qfq_round_down(cl->S, grp->slot_shift); unsigned int s; if (grp->S == roundedS) goto skip_unblock; 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); } skip_unblock: qfq_update_eligible(q, old_V); return skb; } /* * Assign a reasonable start time for a new flow k 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 ER. 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_class *cl) { unsigned long mask; uint32_t limit, roundedF; int slot_shift = cl->grp->slot_shift; roundedF = qfq_round_down(cl->F, slot_shift); limit = qfq_round_down(q->V, slot_shift) + (1UL << slot_shift); if (!qfq_gt(cl->F, q->V) || qfq_gt(roundedF, limit)) { /* timestamp was stale */ mask = mask_from(q->bitmaps[ER], cl->grp->index); if (mask) { struct qfq_group *next = qfq_ffs(q, mask); if (qfq_gt(roundedF, next->F)) { cl->S = next->F; return; } } cl->S = q->V; } else /* timestamp is not stale */ cl->S = cl->F; } static int qfq_enqueue(struct sk_buff *skb, struct Qdisc *sch) { struct qfq_sched *q = qdisc_priv(sch); struct qfq_group *grp; struct qfq_class *cl; int err; u64 roundedS; int s; cl = qfq_classify(skb, sch, &err); if (cl == NULL) { if (err & __NET_XMIT_BYPASS) sch->qstats.drops++; kfree_skb(skb); return err; } pr_debug("qfq_enqueue: cl = %x\n", cl->common.classid); 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++; sch->qstats.drops++; } return err; } bstats_update(&cl->bstats, skb); ++sch->q.qlen; /* If the new skb is not the head of queue, then done here. */ if (cl->qdisc->q.qlen != 1) return err; /* If reach this point, queue q was idle */ grp = cl->grp; qfq_update_start(q, cl); /* compute new finish time and rounded start. */ cl->F = cl->S + (u64)qdisc_pkt_len(skb) * cl->inv_w; roundedS = qfq_round_down(cl->S, grp->slot_shift); /* * insert cl in the correct bucket. * If cl->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, cl->S)) goto skip_update; /* create a slot for this cl->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->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) cl->S, (unsigned long long) cl->F, (unsigned long long) q->V); skip_update: qfq_slot_insert(grp, cl, roundedS); return err; } static void qfq_slot_remove(struct qfq_sched *q, struct qfq_group *grp, struct qfq_class *cl) { unsigned int i, offset; u64 roundedS; roundedS = qfq_round_down(cl->S, grp->slot_shift); offset = (roundedS - grp->S) >> grp->slot_shift; i = (grp->front + offset) % QFQ_MAX_SLOTS; hlist_del(&cl->next); if (hlist_empty(&grp->slots[i])) __clear_bit(offset, &grp->full_slots); } /* * called to forcibly destroy a queue. * If the queue is not in the front bucket, or if it has * other queues in the front bucket, we can simply remove * the queue with no other side effects. * Otherwise we must propagate the event up. */ static void qfq_deactivate_class(struct qfq_sched *q, struct qfq_class *cl) { struct qfq_group *grp = cl->grp; unsigned long mask; u64 roundedS; int s; cl->F = cl->S; qfq_slot_remove(q, grp, cl); 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])) { cl = qfq_slot_scan(grp); roundedS = qfq_round_down(cl->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]); } } qfq_update_eligible(q, q->V); } 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(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++) { struct qfq_class *cl; struct hlist_node *n; hlist_for_each_entry(cl, n, &grp->slots[j], next) { if (!cl->qdisc->ops->drop) continue; len = cl->qdisc->ops->drop(cl->qdisc); if (len > 0) { sch->q.qlen--; if (!cl->qdisc->q.qlen) qfq_deactivate_class(q, cl); 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; err = qdisc_class_hash_init(&q->clhash); if (err < 0) return err; for (i = 0; i <= QFQ_MAX_INDEX; i++) { grp = &q->groups[i]; grp->index = i; grp->slot_shift = QFQ_MTU_SHIFT + FRAC_BITS - (QFQ_MAX_INDEX - i); for (j = 0; j < QFQ_MAX_SLOTS; j++) INIT_HLIST_HEAD(&grp->slots[j]); } return 0; } static void qfq_reset_qdisc(struct Qdisc *sch) { struct qfq_sched *q = qdisc_priv(sch); struct qfq_group *grp; struct qfq_class *cl; struct hlist_node *n, *tmp; unsigned int i, j; for (i = 0; i <= QFQ_MAX_INDEX; i++) { grp = &q->groups[i]; for (j = 0; j < QFQ_MAX_SLOTS; j++) { hlist_for_each_entry_safe(cl, n, tmp, &grp->slots[j], next) { qfq_deactivate_class(q, cl); } } } for (i = 0; i < q->clhash.hashsize; i++) { hlist_for_each_entry(cl, n, &q->clhash.hash[i], common.hnode) 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 *n, *next; unsigned int i; tcf_destroy_chain(&q->filter_list); for (i = 0; i < q->clhash.hashsize; i++) { hlist_for_each_entry_safe(cl, n, 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");