diff options
Diffstat (limited to 'net/core/gen_estimator.c')
-rw-r--r-- | net/core/gen_estimator.c | 278 |
1 files changed, 278 insertions, 0 deletions
diff --git a/net/core/gen_estimator.c b/net/core/gen_estimator.c new file mode 100644 index 0000000000..fae9c46941 --- /dev/null +++ b/net/core/gen_estimator.c @@ -0,0 +1,278 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * net/sched/gen_estimator.c Simple rate estimator. + * + * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> + * Eric Dumazet <edumazet@google.com> + * + * Changes: + * Jamal Hadi Salim - moved it to net/core and reshulfed + * names to make it usable in general net subsystem. + */ + +#include <linux/uaccess.h> +#include <linux/bitops.h> +#include <linux/module.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/jiffies.h> +#include <linux/string.h> +#include <linux/mm.h> +#include <linux/socket.h> +#include <linux/sockios.h> +#include <linux/in.h> +#include <linux/errno.h> +#include <linux/interrupt.h> +#include <linux/netdevice.h> +#include <linux/skbuff.h> +#include <linux/rtnetlink.h> +#include <linux/init.h> +#include <linux/slab.h> +#include <linux/seqlock.h> +#include <net/sock.h> +#include <net/gen_stats.h> + +/* This code is NOT intended to be used for statistics collection, + * its purpose is to provide a base for statistical multiplexing + * for controlled load service. + * If you need only statistics, run a user level daemon which + * periodically reads byte counters. + */ + +struct net_rate_estimator { + struct gnet_stats_basic_sync *bstats; + spinlock_t *stats_lock; + bool running; + struct gnet_stats_basic_sync __percpu *cpu_bstats; + u8 ewma_log; + u8 intvl_log; /* period : (250ms << intvl_log) */ + + seqcount_t seq; + u64 last_packets; + u64 last_bytes; + + u64 avpps; + u64 avbps; + + unsigned long next_jiffies; + struct timer_list timer; + struct rcu_head rcu; +}; + +static void est_fetch_counters(struct net_rate_estimator *e, + struct gnet_stats_basic_sync *b) +{ + gnet_stats_basic_sync_init(b); + if (e->stats_lock) + spin_lock(e->stats_lock); + + gnet_stats_add_basic(b, e->cpu_bstats, e->bstats, e->running); + + if (e->stats_lock) + spin_unlock(e->stats_lock); + +} + +static void est_timer(struct timer_list *t) +{ + struct net_rate_estimator *est = from_timer(est, t, timer); + struct gnet_stats_basic_sync b; + u64 b_bytes, b_packets; + u64 rate, brate; + + est_fetch_counters(est, &b); + b_bytes = u64_stats_read(&b.bytes); + b_packets = u64_stats_read(&b.packets); + + brate = (b_bytes - est->last_bytes) << (10 - est->intvl_log); + brate = (brate >> est->ewma_log) - (est->avbps >> est->ewma_log); + + rate = (b_packets - est->last_packets) << (10 - est->intvl_log); + rate = (rate >> est->ewma_log) - (est->avpps >> est->ewma_log); + + write_seqcount_begin(&est->seq); + est->avbps += brate; + est->avpps += rate; + write_seqcount_end(&est->seq); + + est->last_bytes = b_bytes; + est->last_packets = b_packets; + + est->next_jiffies += ((HZ/4) << est->intvl_log); + + if (unlikely(time_after_eq(jiffies, est->next_jiffies))) { + /* Ouch... timer was delayed. */ + est->next_jiffies = jiffies + 1; + } + mod_timer(&est->timer, est->next_jiffies); +} + +/** + * gen_new_estimator - create a new rate estimator + * @bstats: basic statistics + * @cpu_bstats: bstats per cpu + * @rate_est: rate estimator statistics + * @lock: lock for statistics and control path + * @running: true if @bstats represents a running qdisc, thus @bstats' + * internal values might change during basic reads. Only used + * if @bstats_cpu is NULL + * @opt: rate estimator configuration TLV + * + * Creates a new rate estimator with &bstats as source and &rate_est + * as destination. A new timer with the interval specified in the + * configuration TLV is created. Upon each interval, the latest statistics + * will be read from &bstats and the estimated rate will be stored in + * &rate_est with the statistics lock grabbed during this period. + * + * Returns 0 on success or a negative error code. + * + */ +int gen_new_estimator(struct gnet_stats_basic_sync *bstats, + struct gnet_stats_basic_sync __percpu *cpu_bstats, + struct net_rate_estimator __rcu **rate_est, + spinlock_t *lock, + bool running, + struct nlattr *opt) +{ + struct gnet_estimator *parm = nla_data(opt); + struct net_rate_estimator *old, *est; + struct gnet_stats_basic_sync b; + int intvl_log; + + if (nla_len(opt) < sizeof(*parm)) + return -EINVAL; + + /* allowed timer periods are : + * -2 : 250ms, -1 : 500ms, 0 : 1 sec + * 1 : 2 sec, 2 : 4 sec, 3 : 8 sec + */ + if (parm->interval < -2 || parm->interval > 3) + return -EINVAL; + + if (parm->ewma_log == 0 || parm->ewma_log >= 31) + return -EINVAL; + + est = kzalloc(sizeof(*est), GFP_KERNEL); + if (!est) + return -ENOBUFS; + + seqcount_init(&est->seq); + intvl_log = parm->interval + 2; + est->bstats = bstats; + est->stats_lock = lock; + est->running = running; + est->ewma_log = parm->ewma_log; + est->intvl_log = intvl_log; + est->cpu_bstats = cpu_bstats; + + if (lock) + local_bh_disable(); + est_fetch_counters(est, &b); + if (lock) + local_bh_enable(); + est->last_bytes = u64_stats_read(&b.bytes); + est->last_packets = u64_stats_read(&b.packets); + + if (lock) + spin_lock_bh(lock); + old = rcu_dereference_protected(*rate_est, 1); + if (old) { + del_timer_sync(&old->timer); + est->avbps = old->avbps; + est->avpps = old->avpps; + } + + est->next_jiffies = jiffies + ((HZ/4) << intvl_log); + timer_setup(&est->timer, est_timer, 0); + mod_timer(&est->timer, est->next_jiffies); + + rcu_assign_pointer(*rate_est, est); + if (lock) + spin_unlock_bh(lock); + if (old) + kfree_rcu(old, rcu); + return 0; +} +EXPORT_SYMBOL(gen_new_estimator); + +/** + * gen_kill_estimator - remove a rate estimator + * @rate_est: rate estimator + * + * Removes the rate estimator. + * + */ +void gen_kill_estimator(struct net_rate_estimator __rcu **rate_est) +{ + struct net_rate_estimator *est; + + est = xchg((__force struct net_rate_estimator **)rate_est, NULL); + if (est) { + timer_shutdown_sync(&est->timer); + kfree_rcu(est, rcu); + } +} +EXPORT_SYMBOL(gen_kill_estimator); + +/** + * gen_replace_estimator - replace rate estimator configuration + * @bstats: basic statistics + * @cpu_bstats: bstats per cpu + * @rate_est: rate estimator statistics + * @lock: lock for statistics and control path + * @running: true if @bstats represents a running qdisc, thus @bstats' + * internal values might change during basic reads. Only used + * if @cpu_bstats is NULL + * @opt: rate estimator configuration TLV + * + * Replaces the configuration of a rate estimator by calling + * gen_kill_estimator() and gen_new_estimator(). + * + * Returns 0 on success or a negative error code. + */ +int gen_replace_estimator(struct gnet_stats_basic_sync *bstats, + struct gnet_stats_basic_sync __percpu *cpu_bstats, + struct net_rate_estimator __rcu **rate_est, + spinlock_t *lock, + bool running, struct nlattr *opt) +{ + return gen_new_estimator(bstats, cpu_bstats, rate_est, + lock, running, opt); +} +EXPORT_SYMBOL(gen_replace_estimator); + +/** + * gen_estimator_active - test if estimator is currently in use + * @rate_est: rate estimator + * + * Returns true if estimator is active, and false if not. + */ +bool gen_estimator_active(struct net_rate_estimator __rcu **rate_est) +{ + return !!rcu_access_pointer(*rate_est); +} +EXPORT_SYMBOL(gen_estimator_active); + +bool gen_estimator_read(struct net_rate_estimator __rcu **rate_est, + struct gnet_stats_rate_est64 *sample) +{ + struct net_rate_estimator *est; + unsigned seq; + + rcu_read_lock(); + est = rcu_dereference(*rate_est); + if (!est) { + rcu_read_unlock(); + return false; + } + + do { + seq = read_seqcount_begin(&est->seq); + sample->bps = est->avbps >> 8; + sample->pps = est->avpps >> 8; + } while (read_seqcount_retry(&est->seq, seq)); + + rcu_read_unlock(); + return true; +} +EXPORT_SYMBOL(gen_estimator_read); |