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-rw-r--r--include/linux/pkt_sched.h15
-rw-r--r--net/sched/Kconfig11
-rw-r--r--net/sched/Makefile1
-rw-r--r--net/sched/sch_qfq.c1137
4 files changed, 1164 insertions, 0 deletions
diff --git a/include/linux/pkt_sched.h b/include/linux/pkt_sched.h
index b1032a3fafdc..8062e0a68dda 100644
--- a/include/linux/pkt_sched.h
+++ b/include/linux/pkt_sched.h
@@ -588,4 +588,19 @@ struct tc_sfb_xstats {
#define SFB_MAX_PROB 0xFFFF
+/* QFQ */
+enum {
+ TCA_QFQ_UNSPEC,
+ TCA_QFQ_WEIGHT,
+ TCA_QFQ_LMAX,
+ __TCA_QFQ_MAX
+};
+
+#define TCA_QFQ_MAX (__TCA_QFQ_MAX - 1)
+
+struct tc_qfq_stats {
+ __u32 weight;
+ __u32 lmax;
+};
+
#endif
diff --git a/net/sched/Kconfig b/net/sched/Kconfig
index a7a5583d4f68..aeaa2110b699 100644
--- a/net/sched/Kconfig
+++ b/net/sched/Kconfig
@@ -239,6 +239,17 @@ config NET_SCH_CHOKE
To compile this code as a module, choose M here: the
module will be called sch_choke.
+config NET_SCH_QFQ
+ tristate "Quick Fair Queueing scheduler (QFQ)"
+ help
+ Say Y here if you want to use the Quick Fair Queueing Scheduler (QFQ)
+ packet scheduling algorithm.
+
+ To compile this driver as a module, choose M here: the module
+ will be called sch_qfq.
+
+ If unsure, say N.
+
config NET_SCH_INGRESS
tristate "Ingress Qdisc"
depends on NET_CLS_ACT
diff --git a/net/sched/Makefile b/net/sched/Makefile
index 2e77b8dba22e..dc5889c0a15a 100644
--- a/net/sched/Makefile
+++ b/net/sched/Makefile
@@ -35,6 +35,7 @@ obj-$(CONFIG_NET_SCH_NETEM) += sch_netem.o
obj-$(CONFIG_NET_SCH_DRR) += sch_drr.o
obj-$(CONFIG_NET_SCH_MQPRIO) += sch_mqprio.o
obj-$(CONFIG_NET_SCH_CHOKE) += sch_choke.o
+obj-$(CONFIG_NET_SCH_QFQ) += sch_qfq.o
obj-$(CONFIG_NET_CLS_U32) += cls_u32.o
obj-$(CONFIG_NET_CLS_ROUTE4) += cls_route.o
diff --git a/net/sched/sch_qfq.c b/net/sched/sch_qfq.c
new file mode 100644
index 000000000000..103343408593
--- /dev/null
+++ b/net/sched/sch_qfq.c
@@ -0,0 +1,1137 @@
+/*
+ * 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");