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authorBaowen Zheng <baowen.zheng@corigine.com>2021-03-12 15:08:31 +0100
committerDavid S. Miller <davem@davemloft.net>2021-03-13 14:18:09 -0800
commit2ffe0395288aa237ff7e0143366bd1cd57bfc5b7 (patch)
treee6afb13e32102f6b667b8f69c9a9cf9a0f270755 /net/sched/sch_generic.c
parent6a56e19902af01da447cd3104d5a6e8d01792ee1 (diff)
downloadlwn-2ffe0395288aa237ff7e0143366bd1cd57bfc5b7.tar.gz
lwn-2ffe0395288aa237ff7e0143366bd1cd57bfc5b7.zip
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>
Diffstat (limited to 'net/sched/sch_generic.c')
-rw-r--r--net/sched/sch_generic.c75
1 files changed, 50 insertions, 25 deletions
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)
{
}