--- /dev/null
+/*
+ * net/sched/sch_sfq.c Stochastic Fairness Queueing discipline.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/jiffies.h>
+#include <linux/string.h>
+#include <linux/in.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/skbuff.h>
+#include <linux/jhash.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <net/netlink.h>
+#include <net/pkt_sched.h>
+#include <net/flow_keys.h>
+#include <net/red.h>
+
+
+/* Stochastic Fairness Queuing algorithm.
+ =======================================
+
+ Source:
+ Paul E. McKenney "Stochastic Fairness Queuing",
+ IEEE INFOCOMM'90 Proceedings, San Francisco, 1990.
+
+ Paul E. McKenney "Stochastic Fairness Queuing",
+ "Interworking: Research and Experience", v.2, 1991, p.113-131.
+
+
+ See also:
+ M. Shreedhar and George Varghese "Efficient Fair
+ Queuing using Deficit Round Robin", Proc. SIGCOMM 95.
+
+
+ This is not the thing that is usually called (W)FQ nowadays.
+ It does not use any timestamp mechanism, but instead
+ processes queues in round-robin order.
+
+ ADVANTAGE:
+
+ - It is very cheap. Both CPU and memory requirements are minimal.
+
+ DRAWBACKS:
+
+ - "Stochastic" -> It is not 100% fair.
+ When hash collisions occur, several flows are considered as one.
+
+ - "Round-robin" -> It introduces larger delays than virtual clock
+ based schemes, and should not be used for isolating interactive
+ traffic from non-interactive. It means, that this scheduler
+ should be used as leaf of CBQ or P3, which put interactive traffic
+ to higher priority band.
+
+ We still need true WFQ for top level CSZ, but using WFQ
+ for the best effort traffic is absolutely pointless:
+ SFQ is superior for this purpose.
+
+ IMPLEMENTATION:
+ This implementation limits :
+ - maximal queue length per flow to 127 packets.
+ - max mtu to 2^18-1;
+ - max 65408 flows,
+ - number of hash buckets to 65536.
+
+ It is easy to increase these values, but not in flight. */
+
+#define SFQ_MAX_DEPTH 127 /* max number of packets per flow */
+#define SFQ_DEFAULT_FLOWS 128
+#define SFQ_MAX_FLOWS (0x10000 - SFQ_MAX_DEPTH - 1) /* max number of flows */
+#define SFQ_EMPTY_SLOT 0xffff
+#define SFQ_DEFAULT_HASH_DIVISOR 1024
+
+/* We use 16 bits to store allot, and want to handle packets up to 64K
+ * Scale allot by 8 (1<<3) so that no overflow occurs.
+ */
+#define SFQ_ALLOT_SHIFT 3
+#define SFQ_ALLOT_SIZE(X) DIV_ROUND_UP(X, 1 << SFQ_ALLOT_SHIFT)
+
+/* This type should contain at least SFQ_MAX_DEPTH + 1 + SFQ_MAX_FLOWS values */
+typedef u16 sfq_index;
+
+/*
+ * We dont use pointers to save space.
+ * Small indexes [0 ... SFQ_MAX_FLOWS - 1] are 'pointers' to slots[] array
+ * while following values [SFQ_MAX_FLOWS ... SFQ_MAX_FLOWS + SFQ_MAX_DEPTH]
+ * are 'pointers' to dep[] array
+ */
+struct sfq_head {
+ sfq_index next;
+ sfq_index prev;
+};
+
+struct sfq_slot {
+ struct sk_buff *skblist_next;
+ struct sk_buff *skblist_prev;
+ sfq_index qlen; /* number of skbs in skblist */
+ sfq_index next; /* next slot in sfq RR chain */
+ struct sfq_head dep; /* anchor in dep[] chains */
+ unsigned short hash; /* hash value (index in ht[]) */
+ short allot; /* credit for this slot */
+
+ unsigned int backlog;
+ struct red_vars vars;
+};
+
+struct sfq_sched_data {
+/* frequently used fields */
+ int limit; /* limit of total number of packets in this qdisc */
+ unsigned int divisor; /* number of slots in hash table */
+ u8 headdrop;
+ u8 maxdepth; /* limit of packets per flow */
+
+ u32 perturbation;
+ u8 cur_depth; /* depth of longest slot */
+ u8 flags;
+ unsigned short scaled_quantum; /* SFQ_ALLOT_SIZE(quantum) */
+ struct tcf_proto __rcu *filter_list;
+ sfq_index *ht; /* Hash table ('divisor' slots) */
+ struct sfq_slot *slots; /* Flows table ('maxflows' entries) */
+
+ struct red_parms *red_parms;
+ struct tc_sfqred_stats stats;
+ struct sfq_slot *tail; /* current slot in round */
+
+ struct sfq_head dep[SFQ_MAX_DEPTH + 1];
+ /* Linked lists of slots, indexed by depth
+ * dep[0] : list of unused flows
+ * dep[1] : list of flows with 1 packet
+ * dep[X] : list of flows with X packets
+ */
+
+ unsigned int maxflows; /* number of flows in flows array */
+ int perturb_period;
+ unsigned int quantum; /* Allotment per round: MUST BE >= MTU */
+ struct timer_list perturb_timer;
+};
+
+/*
+ * sfq_head are either in a sfq_slot or in dep[] array
+ */
+static inline struct sfq_head *sfq_dep_head(struct sfq_sched_data *q, sfq_index val)
+{
+ if (val < SFQ_MAX_FLOWS)
+ return &q->slots[val].dep;
+ return &q->dep[val - SFQ_MAX_FLOWS];
+}
+
+/*
+ * In order to be able to quickly rehash our queue when timer changes
+ * q->perturbation, we store flow_keys in skb->cb[]
+ */
+struct sfq_skb_cb {
+ struct flow_keys keys;
+};
+
+static inline struct sfq_skb_cb *sfq_skb_cb(const struct sk_buff *skb)
+{
+ qdisc_cb_private_validate(skb, sizeof(struct sfq_skb_cb));
+ return (struct sfq_skb_cb *)qdisc_skb_cb(skb)->data;
+}
+
+static unsigned int sfq_hash(const struct sfq_sched_data *q,
+ const struct sk_buff *skb)
+{
+ const struct flow_keys *keys = &sfq_skb_cb(skb)->keys;
+ unsigned int hash;
+
+ hash = jhash_3words((__force u32)keys->dst,
+ (__force u32)keys->src ^ keys->ip_proto,
+ (__force u32)keys->ports, q->perturbation);
+ return hash & (q->divisor - 1);
+}
+
+static unsigned int sfq_classify(struct sk_buff *skb, struct Qdisc *sch,
+ int *qerr)
+{
+ struct sfq_sched_data *q = qdisc_priv(sch);
+ struct tcf_result res;
+ struct tcf_proto *fl;
+ int result;
+
+ if (TC_H_MAJ(skb->priority) == sch->handle &&
+ TC_H_MIN(skb->priority) > 0 &&
+ TC_H_MIN(skb->priority) <= q->divisor)
+ return TC_H_MIN(skb->priority);
+
+ fl = rcu_dereference_bh(q->filter_list);
+ if (!fl) {
+ skb_flow_dissect(skb, &sfq_skb_cb(skb)->keys);
+ return sfq_hash(q, skb) + 1;
+ }
+
+ *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
+ result = tc_classify(skb, fl, &res);
+ if (result >= 0) {
+#ifdef CONFIG_NET_CLS_ACT
+ switch (result) {
+ case TC_ACT_STOLEN:
+ case TC_ACT_QUEUED:
+ *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
+ case TC_ACT_SHOT:
+ return 0;
+ }
+#endif
+ if (TC_H_MIN(res.classid) <= q->divisor)
+ return TC_H_MIN(res.classid);
+ }
+ return 0;
+}
+
+/*
+ * x : slot number [0 .. SFQ_MAX_FLOWS - 1]
+ */
+static inline void sfq_link(struct sfq_sched_data *q, sfq_index x)
+{
+ sfq_index p, n;
+ struct sfq_slot *slot = &q->slots[x];
+ int qlen = slot->qlen;
+
+ p = qlen + SFQ_MAX_FLOWS;
+ n = q->dep[qlen].next;
+
+ slot->dep.next = n;
+ slot->dep.prev = p;
+
+ q->dep[qlen].next = x; /* sfq_dep_head(q, p)->next = x */
+ sfq_dep_head(q, n)->prev = x;
+}
+
+#define sfq_unlink(q, x, n, p) \
+ do { \
+ n = q->slots[x].dep.next; \
+ p = q->slots[x].dep.prev; \
+ sfq_dep_head(q, p)->next = n; \
+ sfq_dep_head(q, n)->prev = p; \
+ } while (0)
+
+
+static inline void sfq_dec(struct sfq_sched_data *q, sfq_index x)
+{
+ sfq_index p, n;
+ int d;
+
+ sfq_unlink(q, x, n, p);
+
+ d = q->slots[x].qlen--;
+ if (n == p && q->cur_depth == d)
+ q->cur_depth--;
+ sfq_link(q, x);
+}
+
+static inline void sfq_inc(struct sfq_sched_data *q, sfq_index x)
+{
+ sfq_index p, n;
+ int d;
+
+ sfq_unlink(q, x, n, p);
+
+ d = ++q->slots[x].qlen;
+ if (q->cur_depth < d)
+ q->cur_depth = d;
+ sfq_link(q, x);
+}
+
+/* helper functions : might be changed when/if skb use a standard list_head */
+
+/* remove one skb from tail of slot queue */
+static inline struct sk_buff *slot_dequeue_tail(struct sfq_slot *slot)
+{
+ struct sk_buff *skb = slot->skblist_prev;
+
+ slot->skblist_prev = skb->prev;
+ skb->prev->next = (struct sk_buff *)slot;
+ skb->next = skb->prev = NULL;
+ return skb;
+}
+
+/* remove one skb from head of slot queue */
+static inline struct sk_buff *slot_dequeue_head(struct sfq_slot *slot)
+{
+ struct sk_buff *skb = slot->skblist_next;
+
+ slot->skblist_next = skb->next;
+ skb->next->prev = (struct sk_buff *)slot;
+ skb->next = skb->prev = NULL;
+ return skb;
+}
+
+static inline void slot_queue_init(struct sfq_slot *slot)
+{
+ memset(slot, 0, sizeof(*slot));
+ slot->skblist_prev = slot->skblist_next = (struct sk_buff *)slot;
+}
+
+/* add skb to slot queue (tail add) */
+static inline void slot_queue_add(struct sfq_slot *slot, struct sk_buff *skb)
+{
+ skb->prev = slot->skblist_prev;
+ skb->next = (struct sk_buff *)slot;
+ slot->skblist_prev->next = skb;
+ slot->skblist_prev = skb;
+}
+
+static unsigned int sfq_drop(struct Qdisc *sch)
+{
+ struct sfq_sched_data *q = qdisc_priv(sch);
+ sfq_index x, d = q->cur_depth;
+ struct sk_buff *skb;
+ unsigned int len;
+ struct sfq_slot *slot;
+
+ /* Queue is full! Find the longest slot and drop tail packet from it */
+ if (d > 1) {
+ x = q->dep[d].next;
+ slot = &q->slots[x];
+drop:
+ skb = q->headdrop ? slot_dequeue_head(slot) : slot_dequeue_tail(slot);
+ len = qdisc_pkt_len(skb);
+ slot->backlog -= len;
+ sfq_dec(q, x);
+ kfree_skb(skb);
+ sch->q.qlen--;
+ qdisc_qstats_drop(sch);
+ qdisc_qstats_backlog_dec(sch, skb);
+ return len;
+ }
+
+ if (d == 1) {
+ /* It is difficult to believe, but ALL THE SLOTS HAVE LENGTH 1. */
+ x = q->tail->next;
+ slot = &q->slots[x];
+ q->tail->next = slot->next;
+ q->ht[slot->hash] = SFQ_EMPTY_SLOT;
+ goto drop;
+ }
+
+ return 0;
+}
+
+/* Is ECN parameter configured */
+static int sfq_prob_mark(const struct sfq_sched_data *q)
+{
+ return q->flags & TC_RED_ECN;
+}
+
+/* Should packets over max threshold just be marked */
+static int sfq_hard_mark(const struct sfq_sched_data *q)
+{
+ return (q->flags & (TC_RED_ECN | TC_RED_HARDDROP)) == TC_RED_ECN;
+}
+
+static int sfq_headdrop(const struct sfq_sched_data *q)
+{
+ return q->headdrop;
+}
+
+static int
+sfq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
+{
+ struct sfq_sched_data *q = qdisc_priv(sch);
+ unsigned int hash;
+ sfq_index x, qlen;
+ struct sfq_slot *slot;
+ int uninitialized_var(ret);
+ struct sk_buff *head;
+ int delta;
+
+ hash = sfq_classify(skb, sch, &ret);
+ if (hash == 0) {
+ if (ret & __NET_XMIT_BYPASS)
+ qdisc_qstats_drop(sch);
+ kfree_skb(skb);
+ return ret;
+ }
+ hash--;
+
+ x = q->ht[hash];
+ slot = &q->slots[x];
+ if (x == SFQ_EMPTY_SLOT) {
+ x = q->dep[0].next; /* get a free slot */
+ if (x >= SFQ_MAX_FLOWS)
+ return qdisc_drop(skb, sch);
+ q->ht[hash] = x;
+ slot = &q->slots[x];
+ slot->hash = hash;
+ slot->backlog = 0; /* should already be 0 anyway... */
+ red_set_vars(&slot->vars);
+ goto enqueue;
+ }
+ if (q->red_parms) {
+ slot->vars.qavg = red_calc_qavg_no_idle_time(q->red_parms,
+ &slot->vars,
+ slot->backlog);
+ switch (red_action(q->red_parms,
+ &slot->vars,
+ slot->vars.qavg)) {
+ case RED_DONT_MARK:
+ break;
+
+ case RED_PROB_MARK:
+ qdisc_qstats_overlimit(sch);
+ if (sfq_prob_mark(q)) {
+ /* We know we have at least one packet in queue */
+ if (sfq_headdrop(q) &&
+ INET_ECN_set_ce(slot->skblist_next)) {
+ q->stats.prob_mark_head++;
+ break;
+ }
+ if (INET_ECN_set_ce(skb)) {
+ q->stats.prob_mark++;
+ break;
+ }
+ }
+ q->stats.prob_drop++;
+ goto congestion_drop;
+
+ case RED_HARD_MARK:
+ qdisc_qstats_overlimit(sch);
+ if (sfq_hard_mark(q)) {
+ /* We know we have at least one packet in queue */
+ if (sfq_headdrop(q) &&
+ INET_ECN_set_ce(slot->skblist_next)) {
+ q->stats.forced_mark_head++;
+ break;
+ }
+ if (INET_ECN_set_ce(skb)) {
+ q->stats.forced_mark++;
+ break;
+ }
+ }
+ q->stats.forced_drop++;
+ goto congestion_drop;
+ }
+ }
+
+ if (slot->qlen >= q->maxdepth) {
+congestion_drop:
+ if (!sfq_headdrop(q))
+ return qdisc_drop(skb, sch);
+
+ /* We know we have at least one packet in queue */
+ head = slot_dequeue_head(slot);
+ delta = qdisc_pkt_len(head) - qdisc_pkt_len(skb);
+ sch->qstats.backlog -= delta;
+ slot->backlog -= delta;
+ qdisc_drop(head, sch);
+
+ slot_queue_add(slot, skb);
+ return NET_XMIT_CN;
+ }
+
+enqueue:
+ qdisc_qstats_backlog_inc(sch, skb);
+ slot->backlog += qdisc_pkt_len(skb);
+ slot_queue_add(slot, skb);
+ sfq_inc(q, x);
+ if (slot->qlen == 1) { /* The flow is new */
+ if (q->tail == NULL) { /* It is the first flow */
+ slot->next = x;
+ } else {
+ slot->next = q->tail->next;
+ q->tail->next = x;
+ }
+ /* We put this flow at the end of our flow list.
+ * This might sound unfair for a new flow to wait after old ones,
+ * but we could endup servicing new flows only, and freeze old ones.
+ */
+ q->tail = slot;
+ /* We could use a bigger initial quantum for new flows */
+ slot->allot = q->scaled_quantum;
+ }
+ if (++sch->q.qlen <= q->limit)
+ return NET_XMIT_SUCCESS;
+
+ qlen = slot->qlen;
+ sfq_drop(sch);
+ /* Return Congestion Notification only if we dropped a packet
+ * from this flow.
+ */
+ if (qlen != slot->qlen)
+ return NET_XMIT_CN;
+
+ /* As we dropped a packet, better let upper stack know this */
+ qdisc_tree_decrease_qlen(sch, 1);
+ return NET_XMIT_SUCCESS;
+}
+
+static struct sk_buff *
+sfq_dequeue(struct Qdisc *sch)
+{
+ struct sfq_sched_data *q = qdisc_priv(sch);
+ struct sk_buff *skb;
+ sfq_index a, next_a;
+ struct sfq_slot *slot;
+
+ /* No active slots */
+ if (q->tail == NULL)
+ return NULL;
+
+next_slot:
+ a = q->tail->next;
+ slot = &q->slots[a];
+ if (slot->allot <= 0) {
+ q->tail = slot;
+ slot->allot += q->scaled_quantum;
+ goto next_slot;
+ }
+ skb = slot_dequeue_head(slot);
+ sfq_dec(q, a);
+ qdisc_bstats_update(sch, skb);
+ sch->q.qlen--;
+ qdisc_qstats_backlog_dec(sch, skb);
+ slot->backlog -= qdisc_pkt_len(skb);
+ /* Is the slot empty? */
+ if (slot->qlen == 0) {
+ q->ht[slot->hash] = SFQ_EMPTY_SLOT;
+ next_a = slot->next;
+ if (a == next_a) {
+ q->tail = NULL; /* no more active slots */
+ return skb;
+ }
+ q->tail->next = next_a;
+ } else {
+ slot->allot -= SFQ_ALLOT_SIZE(qdisc_pkt_len(skb));
+ }
+ return skb;
+}
+
+static void
+sfq_reset(struct Qdisc *sch)
+{
+ struct sk_buff *skb;
+
+ while ((skb = sfq_dequeue(sch)) != NULL)
+ kfree_skb(skb);
+}
+
+/*
+ * When q->perturbation is changed, we rehash all queued skbs
+ * to avoid OOO (Out Of Order) effects.
+ * We dont use sfq_dequeue()/sfq_enqueue() because we dont want to change
+ * counters.
+ */
+static void sfq_rehash(struct Qdisc *sch)
+{
+ struct sfq_sched_data *q = qdisc_priv(sch);
+ struct sk_buff *skb;
+ int i;
+ struct sfq_slot *slot;
+ struct sk_buff_head list;
+ int dropped = 0;
+
+ __skb_queue_head_init(&list);
+
+ for (i = 0; i < q->maxflows; i++) {
+ slot = &q->slots[i];
+ if (!slot->qlen)
+ continue;
+ while (slot->qlen) {
+ skb = slot_dequeue_head(slot);
+ sfq_dec(q, i);
+ __skb_queue_tail(&list, skb);
+ }
+ slot->backlog = 0;
+ red_set_vars(&slot->vars);
+ q->ht[slot->hash] = SFQ_EMPTY_SLOT;
+ }
+ q->tail = NULL;
+
+ while ((skb = __skb_dequeue(&list)) != NULL) {
+ unsigned int hash = sfq_hash(q, skb);
+ sfq_index x = q->ht[hash];
+
+ slot = &q->slots[x];
+ if (x == SFQ_EMPTY_SLOT) {
+ x = q->dep[0].next; /* get a free slot */
+ if (x >= SFQ_MAX_FLOWS) {
+drop:
+ qdisc_qstats_backlog_dec(sch, skb);
+ kfree_skb(skb);
+ dropped++;
+ continue;
+ }
+ q->ht[hash] = x;
+ slot = &q->slots[x];
+ slot->hash = hash;
+ }
+ if (slot->qlen >= q->maxdepth)
+ goto drop;
+ slot_queue_add(slot, skb);
+ if (q->red_parms)
+ slot->vars.qavg = red_calc_qavg(q->red_parms,
+ &slot->vars,
+ slot->backlog);
+ slot->backlog += qdisc_pkt_len(skb);
+ sfq_inc(q, x);
+ if (slot->qlen == 1) { /* The flow is new */
+ if (q->tail == NULL) { /* It is the first flow */
+ slot->next = x;
+ } else {
+ slot->next = q->tail->next;
+ q->tail->next = x;
+ }
+ q->tail = slot;
+ slot->allot = q->scaled_quantum;
+ }
+ }
+ sch->q.qlen -= dropped;
+ qdisc_tree_decrease_qlen(sch, dropped);
+}
+
+static void sfq_perturbation(unsigned long arg)
+{
+ struct Qdisc *sch = (struct Qdisc *)arg;
+ struct sfq_sched_data *q = qdisc_priv(sch);
+ spinlock_t *root_lock = qdisc_lock(qdisc_root_sleeping(sch));
+
+ spin_lock(root_lock);
+ q->perturbation = prandom_u32();
+ if (!q->filter_list && q->tail)
+ sfq_rehash(sch);
+ spin_unlock(root_lock);
+
+ if (q->perturb_period)
+ mod_timer(&q->perturb_timer, jiffies + q->perturb_period);
+}
+
+static int sfq_change(struct Qdisc *sch, struct nlattr *opt)
+{
+ struct sfq_sched_data *q = qdisc_priv(sch);
+ struct tc_sfq_qopt *ctl = nla_data(opt);
+ struct tc_sfq_qopt_v1 *ctl_v1 = NULL;
+ unsigned int qlen;
+ struct red_parms *p = NULL;
+
+ if (opt->nla_len < nla_attr_size(sizeof(*ctl)))
+ return -EINVAL;
+ if (opt->nla_len >= nla_attr_size(sizeof(*ctl_v1)))
+ ctl_v1 = nla_data(opt);
+ if (ctl->divisor &&
+ (!is_power_of_2(ctl->divisor) || ctl->divisor > 65536))
+ return -EINVAL;
+ if (ctl_v1 && ctl_v1->qth_min) {
+ p = kmalloc(sizeof(*p), GFP_KERNEL);
+ if (!p)
+ return -ENOMEM;
+ }
+ sch_tree_lock(sch);
+ if (ctl->quantum) {
+ q->quantum = ctl->quantum;
+ q->scaled_quantum = SFQ_ALLOT_SIZE(q->quantum);
+ }
+ q->perturb_period = ctl->perturb_period * HZ;
+ if (ctl->flows)
+ q->maxflows = min_t(u32, ctl->flows, SFQ_MAX_FLOWS);
+ if (ctl->divisor) {
+ q->divisor = ctl->divisor;
+ q->maxflows = min_t(u32, q->maxflows, q->divisor);
+ }
+ if (ctl_v1) {
+ if (ctl_v1->depth)
+ q->maxdepth = min_t(u32, ctl_v1->depth, SFQ_MAX_DEPTH);
+ if (p) {
+ swap(q->red_parms, p);
+ red_set_parms(q->red_parms,
+ ctl_v1->qth_min, ctl_v1->qth_max,
+ ctl_v1->Wlog,
+ ctl_v1->Plog, ctl_v1->Scell_log,
+ NULL,
+ ctl_v1->max_P);
+ }
+ q->flags = ctl_v1->flags;
+ q->headdrop = ctl_v1->headdrop;
+ }
+ if (ctl->limit) {
+ q->limit = min_t(u32, ctl->limit, q->maxdepth * q->maxflows);
+ q->maxflows = min_t(u32, q->maxflows, q->limit);
+ }
+
+ qlen = sch->q.qlen;
+ while (sch->q.qlen > q->limit)
+ sfq_drop(sch);
+ qdisc_tree_decrease_qlen(sch, qlen - sch->q.qlen);
+
+ del_timer(&q->perturb_timer);
+ if (q->perturb_period) {
+ mod_timer(&q->perturb_timer, jiffies + q->perturb_period);
+ q->perturbation = prandom_u32();
+ }
+ sch_tree_unlock(sch);
+ kfree(p);
+ return 0;
+}
+
+static void *sfq_alloc(size_t sz)
+{
+ void *ptr = kmalloc(sz, GFP_KERNEL | __GFP_NOWARN);
+
+ if (!ptr)
+ ptr = vmalloc(sz);
+ return ptr;
+}
+
+static void sfq_free(void *addr)
+{
+ kvfree(addr);
+}
+
+static void sfq_destroy(struct Qdisc *sch)
+{
+ struct sfq_sched_data *q = qdisc_priv(sch);
+
+ tcf_destroy_chain(&q->filter_list);
+ q->perturb_period = 0;
+ del_timer_sync(&q->perturb_timer);
+ sfq_free(q->ht);
+ sfq_free(q->slots);
+ kfree(q->red_parms);
+}
+
+static int sfq_init(struct Qdisc *sch, struct nlattr *opt)
+{
+ struct sfq_sched_data *q = qdisc_priv(sch);
+ int i;
+
+ q->perturb_timer.function = sfq_perturbation;
+ q->perturb_timer.data = (unsigned long)sch;
+ init_timer_deferrable(&q->perturb_timer);
+
+ for (i = 0; i < SFQ_MAX_DEPTH + 1; i++) {
+ q->dep[i].next = i + SFQ_MAX_FLOWS;
+ q->dep[i].prev = i + SFQ_MAX_FLOWS;
+ }
+
+ q->limit = SFQ_MAX_DEPTH;
+ q->maxdepth = SFQ_MAX_DEPTH;
+ q->cur_depth = 0;
+ q->tail = NULL;
+ q->divisor = SFQ_DEFAULT_HASH_DIVISOR;
+ q->maxflows = SFQ_DEFAULT_FLOWS;
+ q->quantum = psched_mtu(qdisc_dev(sch));
+ q->scaled_quantum = SFQ_ALLOT_SIZE(q->quantum);
+ q->perturb_period = 0;
+ q->perturbation = prandom_u32();
+
+ if (opt) {
+ int err = sfq_change(sch, opt);
+ if (err)
+ return err;
+ }
+
+ q->ht = sfq_alloc(sizeof(q->ht[0]) * q->divisor);
+ q->slots = sfq_alloc(sizeof(q->slots[0]) * q->maxflows);
+ if (!q->ht || !q->slots) {
+ sfq_destroy(sch);
+ return -ENOMEM;
+ }
+ for (i = 0; i < q->divisor; i++)
+ q->ht[i] = SFQ_EMPTY_SLOT;
+
+ for (i = 0; i < q->maxflows; i++) {
+ slot_queue_init(&q->slots[i]);
+ sfq_link(q, i);
+ }
+ if (q->limit >= 1)
+ sch->flags |= TCQ_F_CAN_BYPASS;
+ else
+ sch->flags &= ~TCQ_F_CAN_BYPASS;
+ return 0;
+}
+
+static int sfq_dump(struct Qdisc *sch, struct sk_buff *skb)
+{
+ struct sfq_sched_data *q = qdisc_priv(sch);
+ unsigned char *b = skb_tail_pointer(skb);
+ struct tc_sfq_qopt_v1 opt;
+ struct red_parms *p = q->red_parms;
+
+ memset(&opt, 0, sizeof(opt));
+ opt.v0.quantum = q->quantum;
+ opt.v0.perturb_period = q->perturb_period / HZ;
+ opt.v0.limit = q->limit;
+ opt.v0.divisor = q->divisor;
+ opt.v0.flows = q->maxflows;
+ opt.depth = q->maxdepth;
+ opt.headdrop = q->headdrop;
+
+ if (p) {
+ opt.qth_min = p->qth_min >> p->Wlog;
+ opt.qth_max = p->qth_max >> p->Wlog;
+ opt.Wlog = p->Wlog;
+ opt.Plog = p->Plog;
+ opt.Scell_log = p->Scell_log;
+ opt.max_P = p->max_P;
+ }
+ memcpy(&opt.stats, &q->stats, sizeof(opt.stats));
+ opt.flags = q->flags;
+
+ if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
+ goto nla_put_failure;
+
+ return skb->len;
+
+nla_put_failure:
+ nlmsg_trim(skb, b);
+ return -1;
+}
+
+static struct Qdisc *sfq_leaf(struct Qdisc *sch, unsigned long arg)
+{
+ return NULL;
+}
+
+static unsigned long sfq_get(struct Qdisc *sch, u32 classid)
+{
+ return 0;
+}
+
+static unsigned long sfq_bind(struct Qdisc *sch, unsigned long parent,
+ u32 classid)
+{
+ /* we cannot bypass queue discipline anymore */
+ sch->flags &= ~TCQ_F_CAN_BYPASS;
+ return 0;
+}
+
+static void sfq_put(struct Qdisc *q, unsigned long cl)
+{
+}
+
+static struct tcf_proto __rcu **sfq_find_tcf(struct Qdisc *sch,
+ unsigned long cl)
+{
+ struct sfq_sched_data *q = qdisc_priv(sch);
+
+ if (cl)
+ return NULL;
+ return &q->filter_list;
+}
+
+static int sfq_dump_class(struct Qdisc *sch, unsigned long cl,
+ struct sk_buff *skb, struct tcmsg *tcm)
+{
+ tcm->tcm_handle |= TC_H_MIN(cl);
+ return 0;
+}
+
+static int sfq_dump_class_stats(struct Qdisc *sch, unsigned long cl,
+ struct gnet_dump *d)
+{
+ struct sfq_sched_data *q = qdisc_priv(sch);
+ sfq_index idx = q->ht[cl - 1];
+ struct gnet_stats_queue qs = { 0 };
+ struct tc_sfq_xstats xstats = { 0 };
+
+ if (idx != SFQ_EMPTY_SLOT) {
+ const struct sfq_slot *slot = &q->slots[idx];
+
+ xstats.allot = slot->allot << SFQ_ALLOT_SHIFT;
+ qs.qlen = slot->qlen;
+ qs.backlog = slot->backlog;
+ }
+ if (gnet_stats_copy_queue(d, NULL, &qs, qs.qlen) < 0)
+ return -1;
+ return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
+}
+
+static void sfq_walk(struct Qdisc *sch, struct qdisc_walker *arg)
+{
+ struct sfq_sched_data *q = qdisc_priv(sch);
+ unsigned int i;
+
+ if (arg->stop)
+ return;
+
+ for (i = 0; i < q->divisor; i++) {
+ if (q->ht[i] == SFQ_EMPTY_SLOT ||
+ arg->count < arg->skip) {
+ arg->count++;
+ continue;
+ }
+ if (arg->fn(sch, i + 1, arg) < 0) {
+ arg->stop = 1;
+ break;
+ }
+ arg->count++;
+ }
+}
+
+static const struct Qdisc_class_ops sfq_class_ops = {
+ .leaf = sfq_leaf,
+ .get = sfq_get,
+ .put = sfq_put,
+ .tcf_chain = sfq_find_tcf,
+ .bind_tcf = sfq_bind,
+ .unbind_tcf = sfq_put,
+ .dump = sfq_dump_class,
+ .dump_stats = sfq_dump_class_stats,
+ .walk = sfq_walk,
+};
+
+static struct Qdisc_ops sfq_qdisc_ops __read_mostly = {
+ .cl_ops = &sfq_class_ops,
+ .id = "sfq",
+ .priv_size = sizeof(struct sfq_sched_data),
+ .enqueue = sfq_enqueue,
+ .dequeue = sfq_dequeue,
+ .peek = qdisc_peek_dequeued,
+ .drop = sfq_drop,
+ .init = sfq_init,
+ .reset = sfq_reset,
+ .destroy = sfq_destroy,
+ .change = NULL,
+ .dump = sfq_dump,
+ .owner = THIS_MODULE,
+};
+
+static int __init sfq_module_init(void)
+{
+ return register_qdisc(&sfq_qdisc_ops);
+}
+static void __exit sfq_module_exit(void)
+{
+ unregister_qdisc(&sfq_qdisc_ops);
+}
+module_init(sfq_module_init)
+module_exit(sfq_module_exit)
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff