linux-kernel - [PATCH net-next 1/2] net sched act_vlan: Change stats update to use per-core stats

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Date:   Tue, 10 Oct 2017 22:32:27 -0400
From:   Manish Kurup <kurup.manish@...il.com>
To:     jhs@...atatu.com, xiyou.wangcong@...il.com, jiri@...nulli.us,
        davem@...emloft.net, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     aring@...atatu.com, mrv@...atatu.com, kurup.manish@...il.com,
        manish.kurup@...izon.com
Subject: [PATCH net-next 1/2] net sched act_vlan: Change stats update to use per-core stats

The VLAN action maintains one set of stats across all cores, and uses a
spinlock to synchronize updates to it from the same. Changed this to use a
per-CPU stats context instead.
This change will result in better performance.

Signed-off-by: Manish Kurup <manish.kurup@...izon.com>
---
 net/sched/act_vlan.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/net/sched/act_vlan.c b/net/sched/act_vlan.c
index 16eb067..14c262c 100644
--- a/net/sched/act_vlan.c
+++ b/net/sched/act_vlan.c
@@ -30,9 +30,10 @@ static int tcf_vlan(struct sk_buff *skb, const struct tc_action *a,
 	int err;
 	u16 tci;
 
-	spin_lock(&v->tcf_lock);
 	tcf_lastuse_update(&v->tcf_tm);
-	bstats_update(&v->tcf_bstats, skb);
+	bstats_cpu_update(this_cpu_ptr(v->common.cpu_bstats), skb);
+
+	spin_lock(&v->tcf_lock);
 	action = v->tcf_action;
 
 	/* Ensure 'data' points at mac_header prior calling vlan manipulating
@@ -85,7 +86,8 @@ static int tcf_vlan(struct sk_buff *skb, const struct tc_action *a,
 
 drop:
 	action = TC_ACT_SHOT;
-	v->tcf_qstats.drops++;
+	qstats_drop_inc(this_cpu_ptr(v->common.cpu_qstats));
+
 unlock:
 	if (skb_at_tc_ingress(skb))
 		skb_pull_rcsum(skb, skb->mac_len);
@@ -172,7 +174,7 @@ static int tcf_vlan_init(struct net *net, struct nlattr *nla,
 
 	if (!exists) {
 		ret = tcf_idr_create(tn, parm->index, est, a,
-				     &act_vlan_ops, bind, false);
+						&act_vlan_ops, bind, true);
 		if (ret)
 			return ret;
 
-- 
2.7.4