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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 <baowen.zheng@corigine.com>
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: Louis Peens <louis.peens@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Baowen Zheng 2021-03-12 15:08:31 +01:00 committed by David S. Miller
parent 6a56e19902
commit 2ffe039528
5 changed files with 162 additions and 36 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
include/net/sch_generic.h
View File

@ -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
*/

48
include/net/tc_act/tc_police.h
View File

@ -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)

2
include/uapi/linux/pkt_cls.h
View File

@ -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
};

59
net/sched/act_police.c
View File

@ -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 &&

75
net/sched/sch_generic.c
View File

@ -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)
{
}