net_sched: add performance counters for basic filter

Similar to u32 filter, it is useful to know how many times
we reach each basic filter and how many times we pass the
ematch attached to it.

Sample output:

filter protocol arp pref 49152 basic chain 0
filter protocol arp pref 49152 basic chain 0 handle 0x1  (rule hit 3 success 3)
	action order 1: gact action pass
	 random type none pass val 0
	 index 1 ref 1 bind 1 installed 81 sec used 4 sec
	Action statistics:
	Sent 126 bytes 3 pkt (dropped 0, overlimits 0 requeues 0)
	backlog 0b 0p requeues 0

Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/pkt_cls.h

@@ -333,12 +333,19 @@ enum {
 
 /* Basic filter */
 
+struct tc_basic_pcnt {
+	__u64 rcnt;
+	__u64 rhit;
+};
+
 enum {
 	TCA_BASIC_UNSPEC,
 	TCA_BASIC_CLASSID,
 	TCA_BASIC_EMATCHES,
 	TCA_BASIC_ACT,
 	TCA_BASIC_POLICE,
+	TCA_BASIC_PCNT,
+	TCA_BASIC_PAD,
 	__TCA_BASIC_MAX
 };
 

net/sched/cls_basic.c

@@ -18,6 +18,7 @@
 #include <linux/rtnetlink.h>
 #include <linux/skbuff.h>
 #include <linux/idr.h>
+#include <linux/percpu.h>
 #include <net/netlink.h>
 #include <net/act_api.h>
 #include <net/pkt_cls.h>
@@ -35,6 +36,7 @@ struct basic_filter {
 	struct tcf_result	res;
 	struct tcf_proto	*tp;
 	struct list_head	link;
+	struct tc_basic_pcnt __percpu *pf;
 	struct rcu_work		rwork;
 };
 
@@ -46,8 +48,10 @@ static int basic_classify(struct sk_buff *skb, const struct tcf_proto *tp,
 	struct basic_filter *f;
 
 	list_for_each_entry_rcu(f, &head->flist, link) {
+		__this_cpu_inc(f->pf->rcnt);
 		if (!tcf_em_tree_match(skb, &f->ematches, NULL))
 			continue;
+		__this_cpu_inc(f->pf->rhit);
 		*res = f->res;
 		r = tcf_exts_exec(skb, &f->exts, res);
 		if (r < 0)
@@ -89,6 +93,7 @@ static void __basic_delete_filter(struct basic_filter *f)
 	tcf_exts_destroy(&f->exts);
 	tcf_em_tree_destroy(&f->ematches);
 	tcf_exts_put_net(&f->exts);
+	free_percpu(f->pf);
 	kfree(f);
 }
 
@@ -208,6 +213,11 @@ static int basic_change(struct net *net, struct sk_buff *in_skb,
 	if (err)
 		goto errout;
 	fnew->handle = handle;
+	fnew->pf = alloc_percpu(struct tc_basic_pcnt);
+	if (!fnew->pf) {
+		err = -ENOMEM;
+		goto errout;
+	}
 
 	err = basic_set_parms(net, tp, fnew, base, tb, tca[TCA_RATE], ovr,
 			      extack);
@@ -231,6 +241,7 @@ static int basic_change(struct net *net, struct sk_buff *in_skb,
 
 	return 0;
 errout:
+	free_percpu(fnew->pf);
 	tcf_exts_destroy(&fnew->exts);
 	kfree(fnew);
 	return err;
@@ -265,8 +276,10 @@ static void basic_bind_class(void *fh, u32 classid, unsigned long cl)
 static int basic_dump(struct net *net, struct tcf_proto *tp, void *fh,
 		      struct sk_buff *skb, struct tcmsg *t)
 {
+	struct tc_basic_pcnt gpf = {};
 	struct basic_filter *f = fh;
 	struct nlattr *nest;
+	int cpu;
 
 	if (f == NULL)
 		return skb->len;
@@ -281,6 +294,18 @@ static int basic_dump(struct net *net, struct tcf_proto *tp, void *fh,
 	    nla_put_u32(skb, TCA_BASIC_CLASSID, f->res.classid))
 		goto nla_put_failure;
 
+	for_each_possible_cpu(cpu) {
+		struct tc_basic_pcnt *pf = per_cpu_ptr(f->pf, cpu);
+
+		gpf.rcnt += pf->rcnt;
+		gpf.rhit += pf->rhit;
+	}
+
+	if (nla_put_64bit(skb, TCA_BASIC_PCNT,
+			  sizeof(struct tc_basic_pcnt),
+			  &gpf, TCA_BASIC_PAD))
+		goto nla_put_failure;
+
 	if (tcf_exts_dump(skb, &f->exts) < 0 ||
 	    tcf_em_tree_dump(skb, &f->ematches, TCA_BASIC_EMATCHES) < 0)
 		goto nla_put_failure;