linux/include/net/gen_stats.h
Eric Dumazet 1c0d32fde5 net_sched: gen_estimator: complete rewrite of rate estimators
1) Old code was hard to maintain, due to complex lock chains.
   (We probably will be able to remove some kfree_rcu() in callers)

2) Using a single timer to update all estimators does not scale.

3) Code was buggy on 32bit kernel (WRITE_ONCE() on 64bit quantity
   is not supposed to work well)

In this rewrite :

- I removed the RB tree that had to be scanned in
  gen_estimator_active(). qdisc dumps should be much faster.

- Each estimator has its own timer.

- Estimations are maintained in net_rate_estimator structure,
  instead of dirtying the qdisc. Minor, but part of the simplification.

- Reading the estimator uses RCU and a seqcount to provide proper
  support for 32bit kernels.

- We reduce memory need when estimators are not used, since
  we store a pointer, instead of the bytes/packets counters.

- xt_rateest_mt() no longer has to grab a spinlock.
  (In the future, xt_rateest_tg() could be switched to per cpu counters)

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-12-05 15:21:59 -05:00

70 lines
2.3 KiB
C

#ifndef __NET_GEN_STATS_H
#define __NET_GEN_STATS_H
#include <linux/gen_stats.h>
#include <linux/socket.h>
#include <linux/rtnetlink.h>
#include <linux/pkt_sched.h>
struct gnet_stats_basic_cpu {
struct gnet_stats_basic_packed bstats;
struct u64_stats_sync syncp;
};
struct net_rate_estimator;
struct gnet_dump {
spinlock_t * lock;
struct sk_buff * skb;
struct nlattr * tail;
/* Backward compatibility */
int compat_tc_stats;
int compat_xstats;
int padattr;
void * xstats;
int xstats_len;
struct tc_stats tc_stats;
};
int gnet_stats_start_copy(struct sk_buff *skb, int type, spinlock_t *lock,
struct gnet_dump *d, int padattr);
int gnet_stats_start_copy_compat(struct sk_buff *skb, int type,
int tc_stats_type, int xstats_type,
spinlock_t *lock, struct gnet_dump *d,
int padattr);
int gnet_stats_copy_basic(const seqcount_t *running,
struct gnet_dump *d,
struct gnet_stats_basic_cpu __percpu *cpu,
struct gnet_stats_basic_packed *b);
void __gnet_stats_copy_basic(const seqcount_t *running,
struct gnet_stats_basic_packed *bstats,
struct gnet_stats_basic_cpu __percpu *cpu,
struct gnet_stats_basic_packed *b);
int gnet_stats_copy_rate_est(struct gnet_dump *d,
struct net_rate_estimator __rcu **ptr);
int gnet_stats_copy_queue(struct gnet_dump *d,
struct gnet_stats_queue __percpu *cpu_q,
struct gnet_stats_queue *q, __u32 qlen);
int gnet_stats_copy_app(struct gnet_dump *d, void *st, int len);
int gnet_stats_finish_copy(struct gnet_dump *d);
int gen_new_estimator(struct gnet_stats_basic_packed *bstats,
struct gnet_stats_basic_cpu __percpu *cpu_bstats,
struct net_rate_estimator __rcu **rate_est,
spinlock_t *stats_lock,
seqcount_t *running, struct nlattr *opt);
void gen_kill_estimator(struct net_rate_estimator __rcu **ptr);
int gen_replace_estimator(struct gnet_stats_basic_packed *bstats,
struct gnet_stats_basic_cpu __percpu *cpu_bstats,
struct net_rate_estimator __rcu **ptr,
spinlock_t *stats_lock,
seqcount_t *running, struct nlattr *opt);
bool gen_estimator_active(struct net_rate_estimator __rcu **ptr);
bool gen_estimator_read(struct net_rate_estimator __rcu **ptr,
struct gnet_stats_rate_est64 *sample);
#endif