root/net/netfilter/ipvs/ip_vs_est.c

DEFINITIONS

1. ip_vs_read_cpu_stats
2. estimation_timer
3. ip_vs_start_estimator
4. ip_vs_stop_estimator
5. ip_vs_zero_estimator
6. ip_vs_read_estimator
7. ip_vs_estimator_net_init
8. ip_vs_estimator_net_cleanup

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * ip_vs_est.c: simple rate estimator for IPVS
   4  *
   5  * Authors:     Wensong Zhang <wensong@linuxvirtualserver.org>
   6  *
   7  * Changes:     Hans Schillstrom <hans.schillstrom@ericsson.com>
   8  *              Network name space (netns) aware.
   9  *              Global data moved to netns i.e struct netns_ipvs
  10  *              Affected data: est_list and est_lock.
  11  *              estimation_timer() runs with timer per netns.
  12  *              get_stats()) do the per cpu summing.
  13  */
  14 
  15 #define KMSG_COMPONENT "IPVS"
  16 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  17 
  18 #include <linux/kernel.h>
  19 #include <linux/jiffies.h>
  20 #include <linux/types.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/sysctl.h>
  23 #include <linux/list.h>
  24 
  25 #include <net/ip_vs.h>
  26 
  27 /*
  28   This code is to estimate rate in a shorter interval (such as 8
  29   seconds) for virtual services and real servers. For measure rate in a
  30   long interval, it is easy to implement a user level daemon which
  31   periodically reads those statistical counters and measure rate.
  32 
  33   Currently, the measurement is activated by slow timer handler. Hope
  34   this measurement will not introduce too much load.
  35 
  36   We measure rate during the last 8 seconds every 2 seconds:
  37 
  38     avgrate = avgrate*(1-W) + rate*W
  39 
  40     where W = 2^(-2)
  41 
  42   NOTES.
  43 
  44   * Average bps is scaled by 2^5, while average pps and cps are scaled by 2^10.
  45 
  46   * Netlink users can see 64-bit values but sockopt users are restricted
  47     to 32-bit values for conns, packets, bps, cps and pps.
  48 
  49   * A lot of code is taken from net/core/gen_estimator.c
  50  */
  51 
  52 
  53 /*
  54  * Make a summary from each cpu
  55  */
  56 static void ip_vs_read_cpu_stats(struct ip_vs_kstats *sum,
  57                                  struct ip_vs_cpu_stats __percpu *stats)
  58 {
  59         int i;
  60         bool add = false;
  61 
  62         for_each_possible_cpu(i) {
  63                 struct ip_vs_cpu_stats *s = per_cpu_ptr(stats, i);
  64                 unsigned int start;
  65                 u64 conns, inpkts, outpkts, inbytes, outbytes;
  66 
  67                 if (add) {
  68                         do {
  69                                 start = u64_stats_fetch_begin(&s->syncp);
  70                                 conns = s->cnt.conns;
  71                                 inpkts = s->cnt.inpkts;
  72                                 outpkts = s->cnt.outpkts;
  73                                 inbytes = s->cnt.inbytes;
  74                                 outbytes = s->cnt.outbytes;
  75                         } while (u64_stats_fetch_retry(&s->syncp, start));
  76                         sum->conns += conns;
  77                         sum->inpkts += inpkts;
  78                         sum->outpkts += outpkts;
  79                         sum->inbytes += inbytes;
  80                         sum->outbytes += outbytes;
  81                 } else {
  82                         add = true;
  83                         do {
  84                                 start = u64_stats_fetch_begin(&s->syncp);
  85                                 sum->conns = s->cnt.conns;
  86                                 sum->inpkts = s->cnt.inpkts;
  87                                 sum->outpkts = s->cnt.outpkts;
  88                                 sum->inbytes = s->cnt.inbytes;
  89                                 sum->outbytes = s->cnt.outbytes;
  90                         } while (u64_stats_fetch_retry(&s->syncp, start));
  91                 }
  92         }
  93 }
  94 
  95 
  96 static void estimation_timer(struct timer_list *t)
  97 {
  98         struct ip_vs_estimator *e;
  99         struct ip_vs_stats *s;
 100         u64 rate;
 101         struct netns_ipvs *ipvs = from_timer(ipvs, t, est_timer);
 102 
 103         spin_lock(&ipvs->est_lock);
 104         list_for_each_entry(e, &ipvs->est_list, list) {
 105                 s = container_of(e, struct ip_vs_stats, est);
 106 
 107                 spin_lock(&s->lock);
 108                 ip_vs_read_cpu_stats(&s->kstats, s->cpustats);
 109 
 110                 /* scaled by 2^10, but divided 2 seconds */
 111                 rate = (s->kstats.conns - e->last_conns) << 9;
 112                 e->last_conns = s->kstats.conns;
 113                 e->cps += ((s64)rate - (s64)e->cps) >> 2;
 114 
 115                 rate = (s->kstats.inpkts - e->last_inpkts) << 9;
 116                 e->last_inpkts = s->kstats.inpkts;
 117                 e->inpps += ((s64)rate - (s64)e->inpps) >> 2;
 118 
 119                 rate = (s->kstats.outpkts - e->last_outpkts) << 9;
 120                 e->last_outpkts = s->kstats.outpkts;
 121                 e->outpps += ((s64)rate - (s64)e->outpps) >> 2;
 122 
 123                 /* scaled by 2^5, but divided 2 seconds */
 124                 rate = (s->kstats.inbytes - e->last_inbytes) << 4;
 125                 e->last_inbytes = s->kstats.inbytes;
 126                 e->inbps += ((s64)rate - (s64)e->inbps) >> 2;
 127 
 128                 rate = (s->kstats.outbytes - e->last_outbytes) << 4;
 129                 e->last_outbytes = s->kstats.outbytes;
 130                 e->outbps += ((s64)rate - (s64)e->outbps) >> 2;
 131                 spin_unlock(&s->lock);
 132         }
 133         spin_unlock(&ipvs->est_lock);
 134         mod_timer(&ipvs->est_timer, jiffies + 2*HZ);
 135 }
 136 
 137 void ip_vs_start_estimator(struct netns_ipvs *ipvs, struct ip_vs_stats *stats)
 138 {
 139         struct ip_vs_estimator *est = &stats->est;
 140 
 141         INIT_LIST_HEAD(&est->list);
 142 
 143         spin_lock_bh(&ipvs->est_lock);
 144         list_add(&est->list, &ipvs->est_list);
 145         spin_unlock_bh(&ipvs->est_lock);
 146 }
 147 
 148 void ip_vs_stop_estimator(struct netns_ipvs *ipvs, struct ip_vs_stats *stats)
 149 {
 150         struct ip_vs_estimator *est = &stats->est;
 151 
 152         spin_lock_bh(&ipvs->est_lock);
 153         list_del(&est->list);
 154         spin_unlock_bh(&ipvs->est_lock);
 155 }
 156 
 157 void ip_vs_zero_estimator(struct ip_vs_stats *stats)
 158 {
 159         struct ip_vs_estimator *est = &stats->est;
 160         struct ip_vs_kstats *k = &stats->kstats;
 161 
 162         /* reset counters, caller must hold the stats->lock lock */
 163         est->last_inbytes = k->inbytes;
 164         est->last_outbytes = k->outbytes;
 165         est->last_conns = k->conns;
 166         est->last_inpkts = k->inpkts;
 167         est->last_outpkts = k->outpkts;
 168         est->cps = 0;
 169         est->inpps = 0;
 170         est->outpps = 0;
 171         est->inbps = 0;
 172         est->outbps = 0;
 173 }
 174 
 175 /* Get decoded rates */
 176 void ip_vs_read_estimator(struct ip_vs_kstats *dst, struct ip_vs_stats *stats)
 177 {
 178         struct ip_vs_estimator *e = &stats->est;
 179 
 180         dst->cps = (e->cps + 0x1FF) >> 10;
 181         dst->inpps = (e->inpps + 0x1FF) >> 10;
 182         dst->outpps = (e->outpps + 0x1FF) >> 10;
 183         dst->inbps = (e->inbps + 0xF) >> 5;
 184         dst->outbps = (e->outbps + 0xF) >> 5;
 185 }
 186 
 187 int __net_init ip_vs_estimator_net_init(struct netns_ipvs *ipvs)
 188 {
 189         INIT_LIST_HEAD(&ipvs->est_list);
 190         spin_lock_init(&ipvs->est_lock);
 191         timer_setup(&ipvs->est_timer, estimation_timer, 0);
 192         mod_timer(&ipvs->est_timer, jiffies + 2 * HZ);
 193         return 0;
 194 }
 195 
 196 void __net_exit ip_vs_estimator_net_cleanup(struct netns_ipvs *ipvs)
 197 {
 198         del_timer_sync(&ipvs->est_timer);
 199 }