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authorEric Dumazet <edumazet@google.com>2016-12-04 18:48:16 +0100
committerDavid S. Miller <davem@davemloft.net>2016-12-05 21:21:59 +0100
commit1c0d32fde5bdf1184bc274f864c09799278a1114 (patch)
tree47367d46dfc125e19294c3f5fa9a021520bd5660 /include/net
parentnet/sched: cls_flower: Set the filter Hardware device for all use-cases (diff)
downloadlinux-1c0d32fde5bdf1184bc274f864c09799278a1114.tar.xz
linux-1c0d32fde5bdf1184bc274f864c09799278a1114.zip
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>
Diffstat (limited to 'include/net')
-rw-r--r--include/net/act_api.h2
-rw-r--r--include/net/gen_stats.h17
-rw-r--r--include/net/netfilter/xt_rateest.h10
-rw-r--r--include/net/sch_generic.h2
4 files changed, 18 insertions, 13 deletions
diff --git a/include/net/act_api.h b/include/net/act_api.h
index 9dddf77a69cc..1d716449209e 100644
--- a/include/net/act_api.h
+++ b/include/net/act_api.h
@@ -36,7 +36,7 @@ struct tc_action {
struct tcf_t tcfa_tm;
struct gnet_stats_basic_packed tcfa_bstats;
struct gnet_stats_queue tcfa_qstats;
- struct gnet_stats_rate_est64 tcfa_rate_est;
+ struct net_rate_estimator __rcu *tcfa_rate_est;
spinlock_t tcfa_lock;
struct rcu_head tcfa_rcu;
struct gnet_stats_basic_cpu __percpu *cpu_bstats;
diff --git a/include/net/gen_stats.h b/include/net/gen_stats.h
index 231e121cc7d9..8b7aa370e7a4 100644
--- a/include/net/gen_stats.h
+++ b/include/net/gen_stats.h
@@ -11,6 +11,8 @@ struct gnet_stats_basic_cpu {
struct u64_stats_sync syncp;
};
+struct net_rate_estimator;
+
struct gnet_dump {
spinlock_t * lock;
struct sk_buff * skb;
@@ -42,8 +44,7 @@ void __gnet_stats_copy_basic(const seqcount_t *running,
struct gnet_stats_basic_cpu __percpu *cpu,
struct gnet_stats_basic_packed *b);
int gnet_stats_copy_rate_est(struct gnet_dump *d,
- const struct gnet_stats_basic_packed *b,
- struct gnet_stats_rate_est64 *r);
+ 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);
@@ -53,16 +54,16 @@ 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 gnet_stats_rate_est64 *rate_est,
+ struct net_rate_estimator __rcu **rate_est,
spinlock_t *stats_lock,
seqcount_t *running, struct nlattr *opt);
-void gen_kill_estimator(struct gnet_stats_basic_packed *bstats,
- struct gnet_stats_rate_est64 *rate_est);
+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 gnet_stats_rate_est64 *rate_est,
+ struct net_rate_estimator __rcu **ptr,
spinlock_t *stats_lock,
seqcount_t *running, struct nlattr *opt);
-bool gen_estimator_active(const struct gnet_stats_basic_packed *bstats,
- const struct gnet_stats_rate_est64 *rate_est);
+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
diff --git a/include/net/netfilter/xt_rateest.h b/include/net/netfilter/xt_rateest.h
index 79f45e19f31e..130e58361f99 100644
--- a/include/net/netfilter/xt_rateest.h
+++ b/include/net/netfilter/xt_rateest.h
@@ -1,19 +1,23 @@
#ifndef _XT_RATEEST_H
#define _XT_RATEEST_H
+#include <net/gen_stats.h>
+
struct xt_rateest {
/* keep lock and bstats on same cache line to speedup xt_rateest_tg() */
struct gnet_stats_basic_packed bstats;
spinlock_t lock;
- /* keep rstats and lock on same cache line to speedup xt_rateest_mt() */
- struct gnet_stats_rate_est64 rstats;
+
/* following fields not accessed in hot path */
+ unsigned int refcnt;
struct hlist_node list;
char name[IFNAMSIZ];
- unsigned int refcnt;
struct gnet_estimator params;
struct rcu_head rcu;
+
+ /* keep this field far away to speedup xt_rateest_mt() */
+ struct net_rate_estimator __rcu *rate_est;
};
struct xt_rateest *xt_rateest_lookup(const char *name);
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index e6aa0a249672..498f81b229a4 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -76,7 +76,7 @@ struct Qdisc {
struct netdev_queue *dev_queue;
- struct gnet_stats_rate_est64 rate_est;
+ struct net_rate_estimator __rcu *rate_est;
struct gnet_stats_basic_cpu __percpu *cpu_bstats;
struct gnet_stats_queue __percpu *cpu_qstats;