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  • 2014-12-11 11:48
Exported symbols for the inflate functionality.
  • inflate_syms.c
  • gen_estimator.c
/* * net/sched/gen_estimator.c Simple rate estimator. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * Authors: Alexey Kuznetsov, <> * * Changes: * Jamal Hadi Salim - moved it to net/core and reshulfed * names to make it usable in general net subsystem. */ #include <asm/uaccess.h rel='nofollow' onclick='return false;'> #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/rbtree.h> #include <linux/slab.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. Unfortunately, rate estimation is not a very easy task. F.e. I did not find a simple way to estimate the current peak rate and even failed to formulate the problem 8)8) So I preferred not to built an estimator into the scheduler, but run this task separately. Ideally, it should be kernel thread(s), but for now it runs from timers, which puts apparent top bounds on the number of rated flows, has minimal overhead on small, but is enough to handle controlled load service, sets of aggregates. We measure rate over A=(1<<interval) seconds and evaluate EWMA: avrate = avrate*(1-W) + rate*W where W is chosen as negative power of 2: W = 2^(-ewma_log) The resulting time constant is: T = A/(-ln(1-W)) NOTES. * avbps is scaled by 2^5, avpps is scaled by 2^10. * both values are reported as 32 bit unsigned values. bps can overflow for fast links : max speed being 34360Mbit/sec * Minimal interval is HZ/4=250msec (it is the greatest common divisor for HZ=100 and HZ=1024 8)), maximal interval is (HZ*2^EST_MAX_INTERVAL)/4 = 8sec. Shorter intervals are too expensive, longer ones can be implemented at user level painlessly. */ #define EST_MAX_INTERVAL 5 struct gen_estimator { struct list_head list; struct gnet_stats_basic_packed *bstats; struct gnet_stats_rate_est64 *rate_est; spinlock_t *stats_lock; int ewma_log; u64 last_bytes; u64 avbps; u32 last_packets; u32 avpps; struct rcu_head e_rcu; struct rb_node node; }; struct gen_estimator_head { struct timer_list timer; struct list_head list; }; static struct gen_estimator_head elist[EST_MAX_INTERVAL+1]; /* Protects against NULL dereference */ static DEFINE_RWLOCK(est_lock); /* Protects against soft lockup during large deletion */ static struct rb_root est_root = RB_ROOT; static DEFINE_SPINLOCK(est_tree_lock); static void est_timer(unsigned long arg) { int idx = (int)arg; struct gen_estimator *e; rcu_read_lock(); list_for_each_entry_rcu(e, &elist[idx].list, list) { u64 nbytes; u64 brate; u32 npackets; u32 rate; spin_lock(e->stats_lock); read_lock(&est_lock); if (e->bstats == NULL) goto skip; nbytes = e->bstats->bytes; npackets = e->bstats->packets; brate = (nbytes - e->last_bytes)<<(7 - idx); e->last_bytes = nbytes; e->avbps += (brate >> e->ewma_log) - (e->avbps >> e->ewma_log); e->rate_est->bps = (e->avbps+0xF)>>5; rate = (npackets - e->last_packets)<<(12 - idx); e->last_packets = npackets; e->avpps += (rate >> e->ewma_log) - (e->avpps >> e->ewma_log); e->rate_est->pps = (e->avpps+0x1FF)>>10; skip: read_unlock(&est_lock); spin_unlock(e->stats_lock); } if (!list_empty(&elist[idx].list)) mod_timer(&elist[idx].timer, jiffies + ((HZ/4) << idx)); rcu_read_unlock(); } static void gen_add_node(struct gen_estimator *est) { struct rb_node **p = &est_root.rb_node, *parent = NULL; while (*p) { struct gen_estimator *e; parent = *p; e = rb_entry(parent, struct gen_estimator, node); if (est->bstats > e->bstats) p = &parent->rb_right; else p = &parent->rb_left; } rb_link_node(&est->node, parent, p); rb_insert_color(&est->node, &est_root); } static struct gen_estimator *gen_find_node(const struct gnet_stats_basic_packed *bstats, const struct gnet_stats_rate_est64 *rate_est) { struct rb_node *p = est_root.rb_node; while (p) { struct gen_estimator *e; e = rb_entry(p, struct gen_estimator, node); if (bstats > e->bstats) p = p->rb_right; else if (bstats < e->bstats || rate_est != e->rate_est) p = p->rb_left; else return e; } return NULL; } /** * gen_new_estimator - create a new rate estimator * @bstats: basic statistics * @rate_est: rate estimator statistics * @stats_lock: statistics lock * @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 grabed during this period. * * Returns 0 on success or a negative error code. * */ int gen_new_estimator(struct gnet_stats_basic_packed *bstats, struct gnet_stats_rate_est64 *rate_est, spinlock_t *stats_lock, struct nlattr *opt) { struct gen_estimator *est; struct gnet_estimator *parm = nla_data(opt); int idx; if (nla_len(opt) < sizeof(*parm)) return -EINVAL; if (parm->interval < -2 || parm->interval > 3) return -EINVAL; est = kzalloc(sizeof(*est), GFP_KERNEL); if (est == NULL) return -ENOBUFS; idx = parm->interval + 2; est->bstats = bstats; est->rate_est = rate_est; est->stats_lock = stats_lock; est->ewma_log = parm->ewma_log; est->last_bytes = bstats->bytes; est->avbps = rate_est->bps<<5; est->last_packets = bstats->packets; est->avpps = rate_est->pps<<10; spin_lock_bh(&est_tree_lock); if (!elist[idx].timer.function) { INIT_LIST_HEAD(&elist[idx].list); setup_timer(&elist[idx].timer, est_timer, idx); } if (list_empty(&elist[idx].list)) mod_timer(&elist[idx].timer, jiffies + ((HZ/4) << idx)); list_add_rcu(&est->list, &elist[idx].list); gen_add_node(est); spin_unlock_bh(&est_tree_lock); return 0; } EXPORT_SYMBOL(gen_new_estimator); /** * gen_kill_estimator - remove a rate estimator * @bstats: basic statistics * @rate_est: rate estimator statistics * * Removes the rate estimator specified by &bstats and &rate_est. * * Note : Caller should respect an RCU grace period before freeing stats_lock */ void gen_kill_estimator(struct gnet_stats_basic_packed *bstats, struct gnet_stats_rate_est64 *rate_est) { struct gen_estimator *e; spin_lock_bh(&est_tree_lock); while ((e = gen_find_node(bstats, rate_est))) { rb_erase(&e->node, &est_root); write_lock(&est_lock); e->bstats = NULL; write_unlock(&est_lock); list_del_rcu(&e->list); kfree_rcu(e, e_rcu); } spin_unlock_bh(&est_tree_lock); } EXPORT_SYMBOL(gen_kill_estimator); /** * gen_replace_estimator - replace rate estimator configuration * @bstats: basic statistics * @rate_est: rate estimator statistics * @stats_lock: statistics lock * @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_packed *bstats, struct gnet_stats_rate_est64 *rate_est, spinlock_t *stats_lock, struct nlattr *opt) { gen_kill_estima