/* * net/sched/sch_drr.c Deficit Round Robin scheduler * * Copyright (c) 2008 Patrick McHardy <kaber@trash.net> * * 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/slab.h> #include <linux/init.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> struct drr_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_est64 rate_est; struct list_head alist; struct Qdisc *qdisc; u32 quantum; u32 deficit; }; struct drr_sched { struct list_head active; struct tcf_proto __rcu *filter_list; struct Qdisc_class_hash clhash; }; static struct drr_class *drr_find_class(struct Qdisc *sch, u32 classid) { struct drr_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 drr_class, common); } static void drr_purge_queue(struct drr_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 drr_policy[TCA_DRR_MAX + 1] = { [TCA_DRR_QUANTUM] = { .type = NLA_U32 }, }; static int drr_change_class(struct Qdisc *sch, u32 classid, u32 parentid, struct nlattr **tca, unsigned long *arg) { struct drr_sched *q = qdisc_priv(sch); struct drr_class *cl = (struct drr_class *)*arg; struct nlattr *opt = tca[TCA_OPTIONS]; struct nlattr *tb[TCA_DRR_MAX + 1]; u32 quantum; int err; if (!opt) return -EINVAL; err = nla_parse_nested(tb, TCA_DRR_MAX, opt, drr_policy); if (err < 0) return err; if (tb[TCA_DRR_QUANTUM]) { quantum = nla_get_u32(tb[TCA_DRR_QUANTUM]); if (quantum == 0) return -EINVAL; } else quantum = psched_mtu(qdisc_dev(sch)); if (cl != NULL) { if (tca[TCA_RATE]) { err = gen_replace_estimator(&cl->bstats, NULL, &cl->rate_est, qdisc_root_sleeping_lock(sch), tca[TCA_RATE]); if (err) return err; } sch_tree_lock(sch); if (tb[TCA_DRR_QUANTUM]) cl->quantum = quantum; sch_tree_unlock(sch); return 0; } cl = kzalloc(sizeof(struct drr_class), GFP_KERNEL); if (cl == NULL) return -ENOBUFS; cl->refcnt = 1; cl->common.classid = classid; cl->quantum = quantum; 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_replace_estimator(&cl->bstats, NULL, &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 drr_destroy_class(struct Qdisc *sch, struct drr_class *cl) { gen_kill_estimator(&cl->bstats, &cl->rate_est); qdisc_destroy(cl->qdisc); kfree(cl); } static int drr_delete_class(struct Qdisc *sch, unsigned long arg) { struct drr_sched *q = qdisc_priv(sch); struct drr_class *cl = (struct drr_class *)arg; if (cl->filter_cnt > 0) return -EBUSY; sch_tree_lock(sch); drr_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 drr_get_class(struct Qdisc *sch, u32 classid) { struct drr_class *cl = drr_find_class(sch, classid); if (cl != NULL) cl->refcnt++; return (unsigned long)cl; } static void drr_put_class(struct Qdisc *sch, unsigned long arg) { struct drr_class *cl = (struct drr_class *)arg; if (--cl->refcnt == 0) drr_destroy_class(sch, cl); } static struct tcf_proto __rcu **drr_tcf_chain(struct Qdisc *sch, unsigned long cl) { struct drr_sched *q = qdisc_priv(sch); if (cl) return NULL; return &q->filter_list; } static unsigned long drr_bind_tcf(struct Qdisc *sch, unsigned long parent, u32 classid) { struct drr_class *cl = drr_find_class(sch, classid); if (cl != NULL) cl->filter_cnt++; return (unsigned long)cl; } static void drr_unbind_tcf(struct Qdisc *sch, unsigned long arg) { struct drr_class *cl = (struct drr_class *)arg; cl->filter_cnt--; } static int drr_graft_class(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, struct Qdisc **old) { struct drr_class *cl = (struct drr_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); drr_purge_queue(cl); *old = cl->qdisc; cl->qdisc = new; sch_tree_unlock(sch); return 0; } static struct Qdisc *drr_class_leaf(struct Qdisc *sch, unsigned long arg) { struct drr_class *cl = (struct drr_class *)arg; return cl->qdisc; } static void drr_qlen_notify(struct Qdisc *csh, unsigned long arg) { struct drr_class *cl = (struct drr_class *)arg; if (cl->qdisc->q.qlen == 0) list_del(&cl->alist); } static int drr_dump_class(struct Qdisc *sch, unsigned long arg, struct sk_buff *skb, struct tcmsg *tcm) { struct drr_class *cl = (struct drr_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; if (nla_put_u32(skb, TCA_DRR_QUANTUM, cl->quantum)) goto nla_put_failure; return nla_nest_end(skb, nest); nla_put_failure: nla_nest_cancel(skb, nest); return -EMSGSIZE; } static int drr_dump_class_stats(struct Qdisc *sch, unsigned long arg, struct gnet_dump *d) { struct drr_class *cl = (struct drr_class *)arg; struct tc_drr_stats xstats; memset(&xstats, 0, sizeof(xstats)); if (cl->qdisc->q.qlen) { xstats.deficit = cl->deficit; cl->qdisc->qstats.qlen = cl->qdisc->q.qlen; } if (gnet_stats_copy_basic(d, NULL, &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 drr_walk(struct Qdisc *sch, struct qdisc_walker *arg) { struct drr_sched *q = qdisc_priv(sch); struct drr_class *cl; unsigned int i; if (arg->stop) return; for (i = 0; i < q->clhash.hashsize; i++) { hlist_for_each_entry(cl, &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 drr_class *drr_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr) { struct drr_sched *q = qdisc_priv(sch); struct drr_class *cl; struct tcf_result res; struct tcf_proto *fl; int result; if (TC_H_MAJ(skb->priority ^ sch->handle) == 0) { cl = drr_find_class(sch, skb->priority); if (cl != NULL) return cl; } *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; fl = rcu_dereference_bh(q->filter_list); result = tc_classify(skb, fl, &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 drr_class *)res.class; if (cl == NULL) cl = drr_find_class(sch, res.classid); return cl; } return NULL; } static int drr_enqueue(struct sk_buff *skb, struct Qdisc *sch) { struct drr_sched *q = qdisc_priv(sch); struct drr_class *cl; int err = 0; cl = drr_classify(skb, sch, &err); if (cl == NULL) { if (err & __NET_XMIT_BYPASS) qdisc_qstats_drop(sch); kfree_skb(skb); return err; } err = qdisc_enqueue(skb, cl->qdisc); if (unlikely(err != NET_XMIT_SUCCESS)) { if (net_xmit_drop_count(err)) { cl->qstats.drops++; qdisc_qstats_drop(sch); } return err; } if (cl->qdisc->q.qlen == 1) { list_add_tail(&cl->alist, &q->active); cl->deficit = cl->quantum; } sch->q.qlen++; return err; } static struct sk_buff *drr_dequeue(struct Qdisc *sch) { struct drr_sched *q = qdisc_priv(sch); struct drr_class *cl; struct sk_buff *skb; unsigned int len; if (list_empty(&q->active)) goto out; while (1) { cl = list_first_entry(&q->active, struct drr_class, alist); skb = cl->qdisc->ops->peek(cl->qdisc); if (skb == NULL) { qdisc_warn_nonwc(__func__, cl->qdisc); goto out; } len = qdisc_pkt_len(skb); if (len <= cl->deficit) { cl->deficit -= len; skb = qdisc_dequeue_peeked(cl->qdisc); if (cl->qdisc->q.qlen == 0) list_del(&cl->alist); bstats_update(&cl->bstats, skb); qdisc_bstats_update(sch, skb); sch->q.qlen--; return skb; } cl->deficit += cl->quantum; list_move_tail(&cl->alist, &q->active); } out: return NULL; } static unsigned int drr_drop(struct Qdisc *sch) { struct drr_sched *q = qdisc_priv(sch); struct drr_class *cl; unsigned int len; list_for_each_entry(cl, &q->active, alist) { if (cl->qdisc->ops->drop) { len = cl->qdisc->ops->drop(cl->qdisc); if (len > 0) { sch->q.qlen--; if (cl->qdisc->q.qlen == 0) list_del(&cl->alist); return len; } } } return 0; } static int drr_init_qdisc(struct Qdisc *sch, struct nlattr *opt) { struct drr_sched *q = qdisc_priv(sch); int err; err = qdisc_class_hash_init(&q->clhash); if (err < 0) return err; INIT_LIST_HEAD(&q->active); return 0; } static void drr_reset_qdisc(struct Qdisc *sch) { struct drr_sched *q = qdisc_priv(sch); struct drr_class *cl; unsigned int i; for (i = 0; i < q->clhash.hashsize; i++) { hlist_for_each_entry(cl, &q->clhash.hash[i], common.hnode) { if (cl->qdisc->q.qlen) list_del(&cl->alist); qdisc_reset(cl->qdisc); } } sch->q.qlen = 0; } static void drr_destroy_qdisc(struct Qdisc *sch) { struct drr_sched *q = qdisc_priv(sch); struct drr_class *cl; struct hlist_node *next; unsigned int i; tcf_destroy_chain(&q->filter_list); for (i = 0; i < q->clhash.hashsize; i++) { hlist_for_each_entry_safe(cl, next, &q->clhash.hash[i], common.hnode) drr_destroy_class(sch, cl); } qdisc_class_hash_destroy(&q->clhash); } static const struct Qdisc_class_ops drr_class_ops = { .change = drr_change_class, .delete = drr_delete_class, .get = drr_get_class, .put = drr_put_class, .tcf_chain = drr_tcf_chain, .bind_tcf = drr_bind_tcf, .unbind_tcf = drr_unbind_tcf, .graft = drr_graft_class, .leaf = drr_class_leaf, .qlen_notify = drr_qlen_notify, .dump = drr_dump_class, .dump_stats = drr_dump_class_stats, .walk = drr_walk, }; static struct Qdisc_ops drr_qdisc_ops __read_mostly = { .cl_ops = &drr_class_ops, .id = "drr", .priv_size = sizeof(struct drr_sched), .enqueue = drr_enqueue, .dequeue = drr_dequeue, .peek = qdisc_peek_dequeued, .drop = drr_drop, .init = drr_init_qdisc, .reset = drr_reset_qdisc, .destroy = drr_destroy_qdisc, .owner = THIS_MODULE, }; static int __init drr_init(void) { return register_qdisc(&drr_qdisc_ops); } static void __exit drr_exit(void) { unregister_qdisc(&drr_qdisc_ops); } module_init(drr_init); module_exit(drr_exit); MODULE_LICENSE("GPL");