| /* |
| * 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/pkt_cls.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; |
| struct tcf_block *block; |
| 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]; |
| } |
| |
| static unsigned int sfq_hash(const struct sfq_sched_data *q, |
| const struct sk_buff *skb) |
| { |
| return skb_get_hash_perturb(skb, q->perturbation) & (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) |
| return sfq_hash(q, skb) + 1; |
| |
| *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; |
| result = tcf_classify(skb, fl, &res, false); |
| if (result >= 0) { |
| #ifdef CONFIG_NET_CLS_ACT |
| switch (result) { |
| case TC_ACT_STOLEN: |
| case TC_ACT_QUEUED: |
| case TC_ACT_TRAP: |
| *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 sk_buff **to_free) |
| { |
| 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); |
| sch->q.qlen--; |
| qdisc_qstats_backlog_dec(sch, skb); |
| qdisc_drop(skb, sch, to_free); |
| 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 sk_buff **to_free) |
| { |
| struct sfq_sched_data *q = qdisc_priv(sch); |
| unsigned int hash, dropped; |
| 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); |
| __qdisc_drop(skb, to_free); |
| 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, to_free); |
| 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, to_free); |
| |
| /* 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, to_free); |
| |
| slot_queue_add(slot, skb); |
| qdisc_tree_reduce_backlog(sch, 0, delta); |
| 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; |
| dropped = sfq_drop(sch, to_free); |
| /* Return Congestion Notification only if we dropped a packet |
| * from this flow. |
| */ |
| if (qlen != slot->qlen) { |
| qdisc_tree_reduce_backlog(sch, 0, dropped - qdisc_pkt_len(skb)); |
| return NET_XMIT_CN; |
| } |
| |
| /* As we dropped a packet, better let upper stack know this */ |
| qdisc_tree_reduce_backlog(sch, 1, dropped); |
| 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) |
| rtnl_kfree_skbs(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; |
| unsigned int drop_len = 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); |
| drop_len += qdisc_pkt_len(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_reduce_backlog(sch, dropped, drop_len); |
| } |
| |
| 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, dropped = 0; |
| struct red_parms *p = NULL; |
| struct sk_buff *to_free = NULL; |
| struct sk_buff *tail = 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) { |
| dropped += sfq_drop(sch, &to_free); |
| if (!tail) |
| tail = to_free; |
| } |
| |
| rtnl_kfree_skbs(to_free, tail); |
| qdisc_tree_reduce_backlog(sch, qlen - sch->q.qlen, dropped); |
| |
| 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) |
| { |
| return kvmalloc(sz, GFP_KERNEL); |
| } |
| |
| static void sfq_free(void *addr) |
| { |
| kvfree(addr); |
| } |
| |
| static void sfq_destroy(struct Qdisc *sch) |
| { |
| struct sfq_sched_data *q = qdisc_priv(sch); |
| |
| tcf_block_put(q->block); |
| 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; |
| int err; |
| |
| setup_deferrable_timer(&q->perturb_timer, sfq_perturbation, |
| (unsigned long)sch); |
| |
| err = tcf_block_get(&q->block, &q->filter_list, sch); |
| if (err) |
| return err; |
| |
| 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) { |
| /* Note: sfq_destroy() will be called by our caller */ |
| 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_find(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_unbind(struct Qdisc *q, unsigned long cl) |
| { |
| } |
| |
| static struct tcf_block *sfq_tcf_block(struct Qdisc *sch, unsigned long cl) |
| { |
| struct sfq_sched_data *q = qdisc_priv(sch); |
| |
| if (cl) |
| return NULL; |
| return q->block; |
| } |
| |
| 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, |
| .find = sfq_find, |
| .tcf_block = sfq_tcf_block, |
| .bind_tcf = sfq_bind, |
| .unbind_tcf = sfq_unbind, |
| .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, |
| .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"); |