diff options
Diffstat (limited to 'net/sched')
| -rw-r--r-- | net/sched/Kconfig | 11 | ||||
| -rw-r--r-- | net/sched/Makefile | 1 | ||||
| -rw-r--r-- | net/sched/sch_fq_codel.c | 624 |
3 files changed, 636 insertions, 0 deletions
diff --git a/net/sched/Kconfig b/net/sched/Kconfig index fadd2522053d..e7a8976bf25c 100644 --- a/net/sched/Kconfig +++ b/net/sched/Kconfig @@ -261,6 +261,17 @@ config NET_SCH_CODEL If unsure, say N. +config NET_SCH_FQ_CODEL + tristate "Fair Queue Controlled Delay AQM (FQ_CODEL)" + help + Say Y here if you want to use the FQ Controlled Delay (FQ_CODEL) + packet scheduling algorithm. + + To compile this driver as a module, choose M here: the module + will be called sch_fq_codel. + + 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 30fab03b8516..5940a1992f0d 100644 --- a/net/sched/Makefile +++ b/net/sched/Makefile @@ -38,6 +38,7 @@ 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_SCH_CODEL) += sch_codel.o +obj-$(CONFIG_NET_SCH_FQ_CODEL) += sch_fq_codel.o obj-$(CONFIG_NET_CLS_U32) += cls_u32.o obj-$(CONFIG_NET_CLS_ROUTE4) += cls_route.o diff --git a/net/sched/sch_fq_codel.c b/net/sched/sch_fq_codel.c new file mode 100644 index 000000000000..a7b3754d21c8 --- /dev/null +++ b/net/sched/sch_fq_codel.c @@ -0,0 +1,624 @@ +/* + * Fair Queue CoDel 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. + * + * Copyright (C) 2012 Eric Dumazet <edumazet@google.com> + */ + +#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/codel.h> + +/* Fair Queue CoDel. + * + * Principles : + * Packets are classified (internal classifier or external) on flows. + * This is a Stochastic model (as we use a hash, several flows + * might be hashed on same slot) + * Each flow has a CoDel managed queue. + * Flows are linked onto two (Round Robin) lists, + * so that new flows have priority on old ones. + * + * For a given flow, packets are not reordered (CoDel uses a FIFO) + * head drops only. + * ECN capability is on by default. + * Low memory footprint (64 bytes per flow) + */ + +struct fq_codel_flow { + struct sk_buff *head; + struct sk_buff *tail; + struct list_head flowchain; + int deficit; + u32 dropped; /* number of drops (or ECN marks) on this flow */ + struct codel_vars cvars; +}; /* please try to keep this structure <= 64 bytes */ + +struct fq_codel_sched_data { + struct tcf_proto *filter_list; /* optional external classifier */ + struct fq_codel_flow *flows; /* Flows table [flows_cnt] */ + u32 *backlogs; /* backlog table [flows_cnt] */ + u32 flows_cnt; /* number of flows */ + u32 perturbation; /* hash perturbation */ + u32 quantum; /* psched_mtu(qdisc_dev(sch)); */ + struct codel_params cparams; + struct codel_stats cstats; + u32 drop_overlimit; + u32 new_flow_count; + + struct list_head new_flows; /* list of new flows */ + struct list_head old_flows; /* list of old flows */ +}; + +static unsigned int fq_codel_hash(const struct fq_codel_sched_data *q, + const struct sk_buff *skb) +{ + struct flow_keys keys; + unsigned int hash; + + skb_flow_dissect(skb, &keys); + hash = jhash_3words((__force u32)keys.dst, + (__force u32)keys.src ^ keys.ip_proto, + (__force u32)keys.ports, q->perturbation); + return ((u64)hash * q->flows_cnt) >> 32; +} + +static unsigned int fq_codel_classify(struct sk_buff *skb, struct Qdisc *sch, + int *qerr) +{ + struct fq_codel_sched_data *q = qdisc_priv(sch); + struct tcf_result res; + int result; + + if (TC_H_MAJ(skb->priority) == sch->handle && + TC_H_MIN(skb->priority) > 0 && + TC_H_MIN(skb->priority) <= q->flows_cnt) + return TC_H_MIN(skb->priority); + + if (!q->filter_list) + return fq_codel_hash(q, skb) + 1; + + *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_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->flows_cnt) + return TC_H_MIN(res.classid); + } + return 0; +} + +/* helper functions : might be changed when/if skb use a standard list_head */ + +/* remove one skb from head of slot queue */ +static inline struct sk_buff *dequeue_head(struct fq_codel_flow *flow) +{ + struct sk_buff *skb = flow->head; + + flow->head = skb->next; + skb->next = NULL; + return skb; +} + +/* add skb to flow queue (tail add) */ +static inline void flow_queue_add(struct fq_codel_flow *flow, + struct sk_buff *skb) +{ + if (flow->head == NULL) + flow->head = skb; + else + flow->tail->next = skb; + flow->tail = skb; + skb->next = NULL; +} + +static unsigned int fq_codel_drop(struct Qdisc *sch) +{ + struct fq_codel_sched_data *q = qdisc_priv(sch); + struct sk_buff *skb; + unsigned int maxbacklog = 0, idx = 0, i, len; + struct fq_codel_flow *flow; + + /* Queue is full! Find the fat flow and drop packet from it. + * This might sound expensive, but with 1024 flows, we scan + * 4KB of memory, and we dont need to handle a complex tree + * in fast path (packet queue/enqueue) with many cache misses. + */ + for (i = 0; i < q->flows_cnt; i++) { + if (q->backlogs[i] > maxbacklog) { + maxbacklog = q->backlogs[i]; + idx = i; + } + } + flow = &q->flows[idx]; + skb = dequeue_head(flow); + len = qdisc_pkt_len(skb); + q->backlogs[idx] -= len; + kfree_skb(skb); + sch->q.qlen--; + sch->qstats.drops++; + sch->qstats.backlog -= len; + flow->dropped++; + return idx; +} + +static int fq_codel_enqueue(struct sk_buff *skb, struct Qdisc *sch) +{ + struct fq_codel_sched_data *q = qdisc_priv(sch); + unsigned int idx; + struct fq_codel_flow *flow; + int uninitialized_var(ret); + + idx = fq_codel_classify(skb, sch, &ret); + if (idx == 0) { + if (ret & __NET_XMIT_BYPASS) + sch->qstats.drops++; + kfree_skb(skb); + return ret; + } + idx--; + + codel_set_enqueue_time(skb); + flow = &q->flows[idx]; + flow_queue_add(flow, skb); + q->backlogs[idx] += qdisc_pkt_len(skb); + sch->qstats.backlog += qdisc_pkt_len(skb); + + if (list_empty(&flow->flowchain)) { + list_add_tail(&flow->flowchain, &q->new_flows); + codel_vars_init(&flow->cvars); + q->new_flow_count++; + flow->deficit = q->quantum; + flow->dropped = 0; + } + if (++sch->q.qlen < sch->limit) + return NET_XMIT_SUCCESS; + + q->drop_overlimit++; + /* Return Congestion Notification only if we dropped a packet + * from this flow. + */ + if (fq_codel_drop(sch) == idx) + 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; +} + +/* This is the specific function called from codel_dequeue() + * to dequeue a packet from queue. Note: backlog is handled in + * codel, we dont need to reduce it here. + */ +static struct sk_buff *dequeue(struct codel_vars *vars, struct Qdisc *sch) +{ + struct fq_codel_flow *flow; + struct sk_buff *skb = NULL; + + flow = container_of(vars, struct fq_codel_flow, cvars); + if (flow->head) { + skb = dequeue_head(flow); + sch->qstats.backlog -= qdisc_pkt_len(skb); + sch->q.qlen--; + } + return skb; +} + +static struct sk_buff *fq_codel_dequeue(struct Qdisc *sch) +{ + struct fq_codel_sched_data *q = qdisc_priv(sch); + struct sk_buff *skb; + struct fq_codel_flow *flow; + struct list_head *head; + u32 prev_drop_count, prev_ecn_mark; + +begin: + head = &q->new_flows; + if (list_empty(head)) { + head = &q->old_flows; + if (list_empty(head)) + return NULL; + } + flow = list_first_entry(head, struct fq_codel_flow, flowchain); + + if (flow->deficit <= 0) { + flow->deficit += q->quantum; + list_move_tail(&flow->flowchain, &q->old_flows); + goto begin; + } + + prev_drop_count = q->cstats.drop_count; + prev_ecn_mark = q->cstats.ecn_mark; + + skb = codel_dequeue(sch, &q->cparams, &flow->cvars, &q->cstats, + dequeue, &q->backlogs[flow - q->flows]); + + flow->dropped += q->cstats.drop_count - prev_drop_count; + flow->dropped += q->cstats.ecn_mark - prev_ecn_mark; + + if (!skb) { + /* force a pass through old_flows to prevent starvation */ + if ((head == &q->new_flows) && !list_empty(&q->old_flows)) + list_move_tail(&flow->flowchain, &q->old_flows); + else + list_del_init(&flow->flowchain); + goto begin; + } + qdisc_bstats_update(sch, skb); + flow->deficit -= qdisc_pkt_len(skb); + /* We cant call qdisc_tree_decrease_qlen() if our qlen is 0, + * or HTB crashes. Defer it for next round. + */ + if (q->cstats.drop_count && sch->q.qlen) { + qdisc_tree_decrease_qlen(sch, q->cstats.drop_count); + q->cstats.drop_count = 0; + } + return skb; +} + +static void fq_codel_reset(struct Qdisc *sch) +{ + struct sk_buff *skb; + + while ((skb = fq_codel_dequeue(sch)) != NULL) + kfree_skb(skb); +} + +static const struct nla_policy fq_codel_policy[TCA_FQ_CODEL_MAX + 1] = { + [TCA_FQ_CODEL_TARGET] = { .type = NLA_U32 }, + [TCA_FQ_CODEL_LIMIT] = { .type = NLA_U32 }, + [TCA_FQ_CODEL_INTERVAL] = { .type = NLA_U32 }, + [TCA_FQ_CODEL_ECN] = { .type = NLA_U32 }, + [TCA_FQ_CODEL_FLOWS] = { .type = NLA_U32 }, + [TCA_FQ_CODEL_QUANTUM] = { .type = NLA_U32 }, +}; + +static int fq_codel_change(struct Qdisc *sch, struct nlattr *opt) +{ + struct fq_codel_sched_data *q = qdisc_priv(sch); + struct nlattr *tb[TCA_FQ_CODEL_MAX + 1]; + int err; + + if (!opt) + return -EINVAL; + + err = nla_parse_nested(tb, TCA_FQ_CODEL_MAX, opt, fq_codel_policy); + if (err < 0) + return err; + if (tb[TCA_FQ_CODEL_FLOWS]) { + if (q->flows) + return -EINVAL; + q->flows_cnt = nla_get_u32(tb[TCA_FQ_CODEL_FLOWS]); + if (!q->flows_cnt || + q->flows_cnt > 65536) + return -EINVAL; + } + sch_tree_lock(sch); + + if (tb[TCA_FQ_CODEL_TARGET]) { + u64 target = nla_get_u32(tb[TCA_FQ_CODEL_TARGET]); + + q->cparams.target = (target * NSEC_PER_USEC) >> CODEL_SHIFT; + } + + if (tb[TCA_FQ_CODEL_INTERVAL]) { + u64 interval = nla_get_u32(tb[TCA_FQ_CODEL_INTERVAL]); + + q->cparams.interval = (interval * NSEC_PER_USEC) >> CODEL_SHIFT; + } + + if (tb[TCA_FQ_CODEL_LIMIT]) + sch->limit = nla_get_u32(tb[TCA_FQ_CODEL_LIMIT]); + + if (tb[TCA_FQ_CODEL_ECN]) + q->cparams.ecn = !!nla_get_u32(tb[TCA_FQ_CODEL_ECN]); + + if (tb[TCA_FQ_CODEL_QUANTUM]) + q->quantum = max(256U, nla_get_u32(tb[TCA_FQ_CODEL_QUANTUM])); + + while (sch->q.qlen > sch->limit) { + struct sk_buff *skb = fq_codel_dequeue(sch); + + kfree_skb(skb); + q->cstats.drop_count++; + } + qdisc_tree_decrease_qlen(sch, q->cstats.drop_count); + q->cstats.drop_count = 0; + + sch_tree_unlock(sch); + return 0; +} + +static void *fq_codel_zalloc(size_t sz) +{ + void *ptr = kzalloc(sz, GFP_KERNEL | __GFP_NOWARN); + + if (!ptr) + ptr = vzalloc(sz); + return ptr; +} + +static void fq_codel_free(void *addr) +{ + if (addr) { + if (is_vmalloc_addr(addr)) + vfree(addr); + else + kfree(addr); + } +} + +static void fq_codel_destroy(struct Qdisc *sch) +{ + struct fq_codel_sched_data *q = qdisc_priv(sch); + + tcf_destroy_chain(&q->filter_list); + fq_codel_free(q->backlogs); + fq_codel_free(q->flows); +} + +static int fq_codel_init(struct Qdisc *sch, struct nlattr *opt) +{ + struct fq_codel_sched_data *q = qdisc_priv(sch); + int i; + + sch->limit = 10*1024; + q->flows_cnt = 1024; + q->quantum = psched_mtu(qdisc_dev(sch)); + q->perturbation = net_random(); + INIT_LIST_HEAD(&q->new_flows); + INIT_LIST_HEAD(&q->old_flows); + codel_params_init(&q->cparams); + codel_stats_init(&q->cstats); + q->cparams.ecn = true; + + if (opt) { + int err = fq_codel_change(sch, opt); + if (err) + return err; + } + + if (!q->flows) { + q->flows = fq_codel_zalloc(q->flows_cnt * + sizeof(struct fq_codel_flow)); + if (!q->flows) + return -ENOMEM; + q->backlogs = fq_codel_zalloc(q->flows_cnt * sizeof(u32)); + if (!q->backlogs) { + fq_codel_free(q->flows); + return -ENOMEM; + } + for (i = 0; i < q->flows_cnt; i++) { + struct fq_codel_flow *flow = q->flows + i; + + INIT_LIST_HEAD(&flow->flowchain); + } + } + if (sch->limit >= 1) + sch->flags |= TCQ_F_CAN_BYPASS; + else + sch->flags &= ~TCQ_F_CAN_BYPASS; + return 0; +} + +static int fq_codel_dump(struct Qdisc *sch, struct sk_buff *skb) +{ + struct fq_codel_sched_data *q = qdisc_priv(sch); + struct nlattr *opts; + + opts = nla_nest_start(skb, TCA_OPTIONS); + if (opts == NULL) + goto nla_put_failure; + + if (nla_put_u32(skb, TCA_FQ_CODEL_TARGET, + codel_time_to_us(q->cparams.target)) || + nla_put_u32(skb, TCA_FQ_CODEL_LIMIT, + sch->limit) || + nla_put_u32(skb, TCA_FQ_CODEL_INTERVAL, + codel_time_to_us(q->cparams.interval)) || + nla_put_u32(skb, TCA_FQ_CODEL_ECN, + q->cparams.ecn) || + nla_put_u32(skb, TCA_FQ_CODEL_QUANTUM, + q->quantum) || + nla_put_u32(skb, TCA_FQ_CODEL_FLOWS, + q->flows_cnt)) + goto nla_put_failure; + + nla_nest_end(skb, opts); + return skb->len; + +nla_put_failure: + return -1; +} + +static int fq_codel_dump_stats(struct Qdisc *sch, struct gnet_dump *d) +{ + struct fq_codel_sched_data *q = qdisc_priv(sch); + struct tc_fq_codel_xstats st = { + .type = TCA_FQ_CODEL_XSTATS_QDISC, + .qdisc_stats.maxpacket = q->cstats.maxpacket, + .qdisc_stats.drop_overlimit = q->drop_overlimit, + .qdisc_stats.ecn_mark = q->cstats.ecn_mark, + .qdisc_stats.new_flow_count = q->new_flow_count, + }; + struct list_head *pos; + + list_for_each(pos, &q->new_flows) + st.qdisc_stats.new_flows_len++; + + list_for_each(pos, &q->old_flows) + st.qdisc_stats.old_flows_len++; + + return gnet_stats_copy_app(d, &st, sizeof(st)); +} + +static struct Qdisc *fq_codel_leaf(struct Qdisc *sch, unsigned long arg) +{ + return NULL; +} + +static unsigned long fq_codel_get(struct Qdisc *sch, u32 classid) +{ + return 0; +} + +static unsigned long fq_codel_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 fq_codel_put(struct Qdisc *q, unsigned long cl) +{ +} + +static struct tcf_proto **fq_codel_find_tcf(struct Qdisc *sch, unsigned long cl) +{ + struct fq_codel_sched_data *q = qdisc_priv(sch); + + if (cl) + return NULL; + return &q->filter_list; +} + +static int fq_codel_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 fq_codel_dump_class_stats(struct Qdisc *sch, unsigned long cl, + struct gnet_dump *d) +{ + struct fq_codel_sched_data *q = qdisc_priv(sch); + u32 idx = cl - 1; + struct gnet_stats_queue qs = { 0 }; + struct tc_fq_codel_xstats xstats; + + if (idx < q->flows_cnt) { + const struct fq_codel_flow *flow = &q->flows[idx]; + const struct sk_buff *skb = flow->head; + + memset(&xstats, 0, sizeof(xstats)); + xstats.type = TCA_FQ_CODEL_XSTATS_CLASS; + xstats.class_stats.deficit = flow->deficit; + xstats.class_stats.ldelay = + codel_time_to_us(flow->cvars.ldelay); + xstats.class_stats.count = flow->cvars.count; + xstats.class_stats.lastcount = flow->cvars.lastcount; + xstats.class_stats.dropping = flow->cvars.dropping; + if (flow->cvars.dropping) { + codel_tdiff_t delta = flow->cvars.drop_next - + codel_get_time(); + + xstats.class_stats.drop_next = (delta >= 0) ? + codel_time_to_us(delta) : + -codel_time_to_us(-delta); + } + while (skb) { + qs.qlen++; + skb = skb->next; + } + qs.backlog = q->backlogs[idx]; + qs.drops = flow->dropped; + } + if (gnet_stats_copy_queue(d, &qs) < 0) + return -1; + if (idx < q->flows_cnt) + return gnet_stats_copy_app(d, &xstats, sizeof(xstats)); + return 0; +} + +static void fq_codel_walk(struct Qdisc *sch, struct qdisc_walker *arg) +{ + struct fq_codel_sched_data *q = qdisc_priv(sch); + unsigned int i; + + if (arg->stop) + return; + + for (i = 0; i < q->flows_cnt; i++) { + if (list_empty(&q->flows[i].flowchain) || + 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 fq_codel_class_ops = { + .leaf = fq_codel_leaf, + .get = fq_codel_get, + .put = fq_codel_put, + .tcf_chain = fq_codel_find_tcf, + .bind_tcf = fq_codel_bind, + .unbind_tcf = fq_codel_put, + .dump = fq_codel_dump_class, + .dump_stats = fq_codel_dump_class_stats, + .walk = fq_codel_walk, +}; + +static struct Qdisc_ops fq_codel_qdisc_ops __read_mostly = { + .cl_ops = &fq_codel_class_ops, + .id = "fq_codel", + .priv_size = sizeof(struct fq_codel_sched_data), + .enqueue = fq_codel_enqueue, + .dequeue = fq_codel_dequeue, + .peek = qdisc_peek_dequeued, + .drop = fq_codel_drop, + .init = fq_codel_init, + .reset = fq_codel_reset, + .destroy = fq_codel_destroy, + .change = fq_codel_change, + .dump = fq_codel_dump, + .dump_stats = fq_codel_dump_stats, + .owner = THIS_MODULE, +}; + +static int __init fq_codel_module_init(void) +{ + return register_qdisc(&fq_codel_qdisc_ops); +} + +static void __exit fq_codel_module_exit(void) +{ + unregister_qdisc(&fq_codel_qdisc_ops); +} + +module_init(fq_codel_module_init) +module_exit(fq_codel_module_exit) +MODULE_AUTHOR("Eric Dumazet"); +MODULE_LICENSE("GPL"); |