From 2ffe0395288aa237ff7e0143366bd1cd57bfc5b7 Mon Sep 17 00:00:00 2001 From: Baowen Zheng Date: Fri, 12 Mar 2021 15:08:31 +0100 Subject: [PATCH] net/sched: act_police: add support for packet-per-second policing Allow a policer action to enforce a rate-limit based on packets-per-second, configurable using a packet-per-second rate and burst parameters. e.g. tc filter add dev tap1 parent ffff: u32 match \ u32 0 0 police pkts_rate 3000 pkts_burst 1000 Testing was unable to uncover a performance impact of this change on existing features. Signed-off-by: Baowen Zheng Signed-off-by: Simon Horman Signed-off-by: Louis Peens Signed-off-by: David S. Miller --- include/net/sch_generic.h | 14 ++++++++ include/net/tc_act/tc_police.h | 48 ++++++++++++++++++++++++--- include/uapi/linux/pkt_cls.h | 2 ++ net/sched/act_police.c | 59 +++++++++++++++++++++++++++++---- net/sched/sch_generic.c | 75 ++++++++++++++++++++++++++++-------------- 5 files changed, 162 insertions(+), 36 deletions(-) diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h index 2d6eb60c58c8..f7a6e14491fb 100644 --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -1242,6 +1242,20 @@ static inline void psched_ratecfg_getrate(struct tc_ratespec *res, res->linklayer = (r->linklayer & TC_LINKLAYER_MASK); } +struct psched_pktrate { + u64 rate_pkts_ps; /* packets per second */ + u32 mult; + u8 shift; +}; + +static inline u64 psched_pkt2t_ns(const struct psched_pktrate *r, + unsigned int pkt_num) +{ + return ((u64)pkt_num * r->mult) >> r->shift; +} + +void psched_ppscfg_precompute(struct psched_pktrate *r, u64 pktrate64); + /* Mini Qdisc serves for specific needs of ingress/clsact Qdisc. * The fast path only needs to access filter list and to update stats */ diff --git a/include/net/tc_act/tc_police.h b/include/net/tc_act/tc_police.h index ae117f7937d5..72649512dcdd 100644 --- a/include/net/tc_act/tc_police.h +++ b/include/net/tc_act/tc_police.h @@ -10,10 +10,13 @@ struct tcf_police_params { s64 tcfp_burst; u32 tcfp_mtu; s64 tcfp_mtu_ptoks; + s64 tcfp_pkt_burst; struct psched_ratecfg rate; bool rate_present; struct psched_ratecfg peak; bool peak_present; + struct psched_pktrate ppsrate; + bool pps_present; struct rcu_head rcu; }; @@ -24,6 +27,7 @@ struct tcf_police { spinlock_t tcfp_lock ____cacheline_aligned_in_smp; s64 tcfp_toks; s64 tcfp_ptoks; + s64 tcfp_pkttoks; s64 tcfp_t_c; }; @@ -99,14 +103,50 @@ static inline u32 tcf_police_burst(const struct tc_action *act) static inline u64 tcf_police_rate_pkt_ps(const struct tc_action *act) { - /* Not implemented */ - return 0; + struct tcf_police *police = to_police(act); + struct tcf_police_params *params; + + params = rcu_dereference_protected(police->params, + lockdep_is_held(&police->tcf_lock)); + return params->ppsrate.rate_pkts_ps; } static inline u32 tcf_police_burst_pkt(const struct tc_action *act) { - /* Not implemented */ - return 0; + struct tcf_police *police = to_police(act); + struct tcf_police_params *params; + u32 burst; + + params = rcu_dereference_protected(police->params, + lockdep_is_held(&police->tcf_lock)); + + /* + * "rate" pkts "burst" nanoseconds + * ------------ * ------------------- + * 1 second 2^6 ticks + * + * ------------------------------------ + * NSEC_PER_SEC nanoseconds + * ------------------------ + * 2^6 ticks + * + * "rate" pkts "burst" nanoseconds 2^6 ticks + * = ------------ * ------------------- * ------------------------ + * 1 second 2^6 ticks NSEC_PER_SEC nanoseconds + * + * "rate" * "burst" + * = ---------------- pkts/nanosecond + * NSEC_PER_SEC^2 + * + * + * "rate" * "burst" + * = ---------------- pkts/second + * NSEC_PER_SEC + */ + burst = div_u64(params->tcfp_pkt_burst * params->ppsrate.rate_pkts_ps, + NSEC_PER_SEC); + + return burst; } static inline u32 tcf_police_tcfp_mtu(const struct tc_action *act) diff --git a/include/uapi/linux/pkt_cls.h b/include/uapi/linux/pkt_cls.h index 7ea59cfe1fa7..025c40fef93d 100644 --- a/include/uapi/linux/pkt_cls.h +++ b/include/uapi/linux/pkt_cls.h @@ -190,6 +190,8 @@ enum { TCA_POLICE_PAD, TCA_POLICE_RATE64, TCA_POLICE_PEAKRATE64, + TCA_POLICE_PKTRATE64, + TCA_POLICE_PKTBURST64, __TCA_POLICE_MAX #define TCA_POLICE_RESULT TCA_POLICE_RESULT }; diff --git a/net/sched/act_police.c b/net/sched/act_police.c index 8d8452b1cdd4..0fab8de176d2 100644 --- a/net/sched/act_police.c +++ b/net/sched/act_police.c @@ -42,6 +42,8 @@ static const struct nla_policy police_policy[TCA_POLICE_MAX + 1] = { [TCA_POLICE_RESULT] = { .type = NLA_U32 }, [TCA_POLICE_RATE64] = { .type = NLA_U64 }, [TCA_POLICE_PEAKRATE64] = { .type = NLA_U64 }, + [TCA_POLICE_PKTRATE64] = { .type = NLA_U64, .min = 1 }, + [TCA_POLICE_PKTBURST64] = { .type = NLA_U64, .min = 1 }, }; static int tcf_police_init(struct net *net, struct nlattr *nla, @@ -61,6 +63,7 @@ static int tcf_police_init(struct net *net, struct nlattr *nla, bool exists = false; u32 index; u64 rate64, prate64; + u64 pps, ppsburst; if (nla == NULL) return -EINVAL; @@ -142,6 +145,21 @@ static int tcf_police_init(struct net *net, struct nlattr *nla, } } + if ((tb[TCA_POLICE_PKTRATE64] && !tb[TCA_POLICE_PKTBURST64]) || + (!tb[TCA_POLICE_PKTRATE64] && tb[TCA_POLICE_PKTBURST64])) { + NL_SET_ERR_MSG(extack, + "Both or neither packet-per-second burst and rate must be provided"); + err = -EINVAL; + goto failure; + } + + if (tb[TCA_POLICE_PKTRATE64] && R_tab) { + NL_SET_ERR_MSG(extack, + "packet-per-second and byte-per-second rate limits not allowed in same action"); + err = -EINVAL; + goto failure; + } + new = kzalloc(sizeof(*new), GFP_KERNEL); if (unlikely(!new)) { err = -ENOMEM; @@ -183,6 +201,14 @@ static int tcf_police_init(struct net *net, struct nlattr *nla, if (tb[TCA_POLICE_AVRATE]) new->tcfp_ewma_rate = nla_get_u32(tb[TCA_POLICE_AVRATE]); + if (tb[TCA_POLICE_PKTRATE64]) { + pps = nla_get_u64(tb[TCA_POLICE_PKTRATE64]); + ppsburst = nla_get_u64(tb[TCA_POLICE_PKTBURST64]); + new->pps_present = true; + new->tcfp_pkt_burst = PSCHED_TICKS2NS(ppsburst); + psched_ppscfg_precompute(&new->ppsrate, pps); + } + spin_lock_bh(&police->tcf_lock); spin_lock_bh(&police->tcfp_lock); police->tcfp_t_c = ktime_get_ns(); @@ -217,8 +243,8 @@ static int tcf_police_act(struct sk_buff *skb, const struct tc_action *a, struct tcf_result *res) { struct tcf_police *police = to_police(a); + s64 now, toks, ppstoks = 0, ptoks = 0; struct tcf_police_params *p; - s64 now, toks, ptoks = 0; int ret; tcf_lastuse_update(&police->tcf_tm); @@ -236,7 +262,7 @@ static int tcf_police_act(struct sk_buff *skb, const struct tc_action *a, } if (qdisc_pkt_len(skb) <= p->tcfp_mtu) { - if (!p->rate_present) { + if (!p->rate_present && !p->pps_present) { ret = p->tcfp_result; goto end; } @@ -251,14 +277,23 @@ static int tcf_police_act(struct sk_buff *skb, const struct tc_action *a, ptoks -= (s64)psched_l2t_ns(&p->peak, qdisc_pkt_len(skb)); } - toks += police->tcfp_toks; - if (toks > p->tcfp_burst) - toks = p->tcfp_burst; - toks -= (s64)psched_l2t_ns(&p->rate, qdisc_pkt_len(skb)); - if ((toks|ptoks) >= 0) { + if (p->rate_present) { + toks += police->tcfp_toks; + if (toks > p->tcfp_burst) + toks = p->tcfp_burst; + toks -= (s64)psched_l2t_ns(&p->rate, qdisc_pkt_len(skb)); + } else if (p->pps_present) { + ppstoks = min_t(s64, now - police->tcfp_t_c, p->tcfp_pkt_burst); + ppstoks += police->tcfp_pkttoks; + if (ppstoks > p->tcfp_pkt_burst) + ppstoks = p->tcfp_pkt_burst; + ppstoks -= (s64)psched_pkt2t_ns(&p->ppsrate, 1); + } + if ((toks | ptoks | ppstoks) >= 0) { police->tcfp_t_c = now; police->tcfp_toks = toks; police->tcfp_ptoks = ptoks; + police->tcfp_pkttoks = ppstoks; spin_unlock_bh(&police->tcfp_lock); ret = p->tcfp_result; goto inc_drops; @@ -331,6 +366,16 @@ static int tcf_police_dump(struct sk_buff *skb, struct tc_action *a, TCA_POLICE_PAD)) goto nla_put_failure; } + if (p->pps_present) { + if (nla_put_u64_64bit(skb, TCA_POLICE_PKTRATE64, + police->params->ppsrate.rate_pkts_ps, + TCA_POLICE_PAD)) + goto nla_put_failure; + if (nla_put_u64_64bit(skb, TCA_POLICE_PKTBURST64, + PSCHED_NS2TICKS(p->tcfp_pkt_burst), + TCA_POLICE_PAD)) + goto nla_put_failure; + } if (nla_put(skb, TCA_POLICE_TBF, sizeof(opt), &opt)) goto nla_put_failure; if (p->tcfp_result && diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 49eae93d1489..44991ea726fc 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -1325,6 +1325,48 @@ void dev_shutdown(struct net_device *dev) WARN_ON(timer_pending(&dev->watchdog_timer)); } +/** + * psched_ratecfg_precompute__() - Pre-compute values for reciprocal division + * @rate: Rate to compute reciprocal division values of + * @mult: Multiplier for reciprocal division + * @shift: Shift for reciprocal division + * + * The multiplier and shift for reciprocal division by rate are stored + * in mult and shift. + * + * The deal here is to replace a divide by a reciprocal one + * in fast path (a reciprocal divide is a multiply and a shift) + * + * Normal formula would be : + * time_in_ns = (NSEC_PER_SEC * len) / rate_bps + * + * We compute mult/shift to use instead : + * time_in_ns = (len * mult) >> shift; + * + * We try to get the highest possible mult value for accuracy, + * but have to make sure no overflows will ever happen. + * + * reciprocal_value() is not used here it doesn't handle 64-bit values. + */ +static void psched_ratecfg_precompute__(u64 rate, u32 *mult, u8 *shift) +{ + u64 factor = NSEC_PER_SEC; + + *mult = 1; + *shift = 0; + + if (rate <= 0) + return; + + for (;;) { + *mult = div64_u64(factor, rate); + if (*mult & (1U << 31) || factor & (1ULL << 63)) + break; + factor <<= 1; + (*shift)++; + } +} + void psched_ratecfg_precompute(struct psched_ratecfg *r, const struct tc_ratespec *conf, u64 rate64) @@ -1333,34 +1375,17 @@ void psched_ratecfg_precompute(struct psched_ratecfg *r, r->overhead = conf->overhead; r->rate_bytes_ps = max_t(u64, conf->rate, rate64); r->linklayer = (conf->linklayer & TC_LINKLAYER_MASK); - r->mult = 1; - /* - * The deal here is to replace a divide by a reciprocal one - * in fast path (a reciprocal divide is a multiply and a shift) - * - * Normal formula would be : - * time_in_ns = (NSEC_PER_SEC * len) / rate_bps - * - * We compute mult/shift to use instead : - * time_in_ns = (len * mult) >> shift; - * - * We try to get the highest possible mult value for accuracy, - * but have to make sure no overflows will ever happen. - */ - if (r->rate_bytes_ps > 0) { - u64 factor = NSEC_PER_SEC; - - for (;;) { - r->mult = div64_u64(factor, r->rate_bytes_ps); - if (r->mult & (1U << 31) || factor & (1ULL << 63)) - break; - factor <<= 1; - r->shift++; - } - } + psched_ratecfg_precompute__(r->rate_bytes_ps, &r->mult, &r->shift); } EXPORT_SYMBOL(psched_ratecfg_precompute); +void psched_ppscfg_precompute(struct psched_pktrate *r, u64 pktrate64) +{ + r->rate_pkts_ps = pktrate64; + psched_ratecfg_precompute__(r->rate_pkts_ps, &r->mult, &r->shift); +} +EXPORT_SYMBOL(psched_ppscfg_precompute); + static void mini_qdisc_rcu_func(struct rcu_head *head) { } -- 2.11.0