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Date: Tue, 10 Oct 2017 22:33:39 -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 2/2] net sched act_vlan: VLAN action rewrite to use RCU lock/unlock and update
Using a spinlock in the VLAN action causes performance issues when the VLAN
action is used on multiple cores. Rewrote the VLAN action to use RCU read
locking for reads and updates instead.
Signed-off-by: Manish Kurup <manish.kurup@...izon.com>
---
include/net/tc_act/tc_vlan.h | 21 ++++++++-----
net/sched/act_vlan.c | 73 ++++++++++++++++++++++++++++++--------------
2 files changed, 63 insertions(+), 31 deletions(-)
diff --git a/include/net/tc_act/tc_vlan.h b/include/net/tc_act/tc_vlan.h
index c2090df..67fd355 100644
--- a/include/net/tc_act/tc_vlan.h
+++ b/include/net/tc_act/tc_vlan.h
@@ -13,12 +13,17 @@
#include <net/act_api.h>
#include <linux/tc_act/tc_vlan.h>
+struct tcf_vlan_params {
+ struct rcu_head rcu;
+ int tcfv_action;
+ u16 tcfv_push_vid;
+ __be16 tcfv_push_proto;
+ u8 tcfv_push_prio;
+};
+
struct tcf_vlan {
struct tc_action common;
- int tcfv_action;
- u16 tcfv_push_vid;
- __be16 tcfv_push_proto;
- u8 tcfv_push_prio;
+ struct tcf_vlan_params __rcu *vlan_p;
};
#define to_vlan(a) ((struct tcf_vlan *)a)
@@ -33,22 +38,22 @@ static inline bool is_tcf_vlan(const struct tc_action *a)
static inline u32 tcf_vlan_action(const struct tc_action *a)
{
- return to_vlan(a)->tcfv_action;
+ return to_vlan(a)->vlan_p->tcfv_action;
}
static inline u16 tcf_vlan_push_vid(const struct tc_action *a)
{
- return to_vlan(a)->tcfv_push_vid;
+ return to_vlan(a)->vlan_p->tcfv_push_vid;
}
static inline __be16 tcf_vlan_push_proto(const struct tc_action *a)
{
- return to_vlan(a)->tcfv_push_proto;
+ return to_vlan(a)->vlan_p->tcfv_push_proto;
}
static inline u8 tcf_vlan_push_prio(const struct tc_action *a)
{
- return to_vlan(a)->tcfv_push_prio;
+ return to_vlan(a)->vlan_p->tcfv_push_prio;
}
#endif /* __NET_TC_VLAN_H */
diff --git a/net/sched/act_vlan.c b/net/sched/act_vlan.c
index 14c262c..9bb0236 100644
--- a/net/sched/act_vlan.c
+++ b/net/sched/act_vlan.c
@@ -29,31 +29,37 @@ static int tcf_vlan(struct sk_buff *skb, const struct tc_action *a,
int action;
int err;
u16 tci;
+ struct tcf_vlan_params *p;
tcf_lastuse_update(&v->tcf_tm);
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
* functions.
*/
if (skb_at_tc_ingress(skb))
skb_push_rcsum(skb, skb->mac_len);
- switch (v->tcfv_action) {
+ rcu_read_lock();
+
+ action = READ_ONCE(v->tcf_action);
+
+ p = rcu_dereference(v->vlan_p);
+
+ switch (p->tcfv_action) {
case TCA_VLAN_ACT_POP:
err = skb_vlan_pop(skb);
if (err)
goto drop;
break;
+
case TCA_VLAN_ACT_PUSH:
- err = skb_vlan_push(skb, v->tcfv_push_proto, v->tcfv_push_vid |
- (v->tcfv_push_prio << VLAN_PRIO_SHIFT));
+ err = skb_vlan_push(skb, p->tcfv_push_proto, p->tcfv_push_vid |
+ (p->tcfv_push_prio << VLAN_PRIO_SHIFT));
if (err)
goto drop;
break;
+
case TCA_VLAN_ACT_MODIFY:
/* No-op if no vlan tag (either hw-accel or in-payload) */
if (!skb_vlan_tagged(skb))
@@ -69,15 +75,16 @@ static int tcf_vlan(struct sk_buff *skb, const struct tc_action *a,
goto drop;
}
/* replace the vid */
- tci = (tci & ~VLAN_VID_MASK) | v->tcfv_push_vid;
+ tci = (tci & ~VLAN_VID_MASK) | p->tcfv_push_vid;
/* replace prio bits, if tcfv_push_prio specified */
- if (v->tcfv_push_prio) {
+ if (p->tcfv_push_prio) {
tci &= ~VLAN_PRIO_MASK;
- tci |= v->tcfv_push_prio << VLAN_PRIO_SHIFT;
+ tci |= p->tcfv_push_prio << VLAN_PRIO_SHIFT;
}
/* put updated tci as hwaccel tag */
- __vlan_hwaccel_put_tag(skb, v->tcfv_push_proto, tci);
+ __vlan_hwaccel_put_tag(skb, p->tcfv_push_proto, tci);
break;
+
default:
BUG();
}
@@ -89,6 +96,7 @@ static int tcf_vlan(struct sk_buff *skb, const struct tc_action *a,
qstats_drop_inc(this_cpu_ptr(v->common.cpu_qstats));
unlock:
+ rcu_read_unlock();
if (skb_at_tc_ingress(skb))
skb_pull_rcsum(skb, skb->mac_len);
@@ -111,6 +119,7 @@ static int tcf_vlan_init(struct net *net, struct nlattr *nla,
struct nlattr *tb[TCA_VLAN_MAX + 1];
struct tc_vlan *parm;
struct tcf_vlan *v;
+ struct tcf_vlan_params *p, *p_old;
int action;
__be16 push_vid = 0;
__be16 push_proto = 0;
@@ -187,16 +196,33 @@ static int tcf_vlan_init(struct net *net, struct nlattr *nla,
v = to_vlan(*a);
- spin_lock_bh(&v->tcf_lock);
-
- v->tcfv_action = action;
- v->tcfv_push_vid = push_vid;
- v->tcfv_push_prio = push_prio;
- v->tcfv_push_proto = push_proto;
+ ASSERT_RTNL();
+ p = kzalloc(sizeof(*p), GFP_KERNEL);
+ if (unlikely(!p)) {
+ if (ovr)
+ tcf_idr_release(*a, bind);
+ return -ENOMEM;
+ }
v->tcf_action = parm->action;
- spin_unlock_bh(&v->tcf_lock);
+ p_old = rtnl_dereference(v->vlan_p);
+
+ if (ovr)
+ spin_lock_bh(&v->tcf_lock);
+
+ p->tcfv_action = action;
+ p->tcfv_push_vid = push_vid;
+ p->tcfv_push_prio = push_prio;
+ p->tcfv_push_proto = push_proto;
+
+ rcu_assign_pointer(v->vlan_p, p);
+
+ if (ovr)
+ spin_unlock_bh(&v->tcf_lock);
+
+ if (p_old)
+ kfree_rcu(p_old, rcu);
if (ret == ACT_P_CREATED)
tcf_idr_insert(tn, *a);
@@ -208,25 +234,26 @@ static int tcf_vlan_dump(struct sk_buff *skb, struct tc_action *a,
{
unsigned char *b = skb_tail_pointer(skb);
struct tcf_vlan *v = to_vlan(a);
+ struct tcf_vlan_params *p = rtnl_dereference(v->vlan_p);
struct tc_vlan opt = {
.index = v->tcf_index,
.refcnt = v->tcf_refcnt - ref,
.bindcnt = v->tcf_bindcnt - bind,
.action = v->tcf_action,
- .v_action = v->tcfv_action,
+ .v_action = p->tcfv_action,
};
struct tcf_t t;
if (nla_put(skb, TCA_VLAN_PARMS, sizeof(opt), &opt))
goto nla_put_failure;
- if ((v->tcfv_action == TCA_VLAN_ACT_PUSH ||
- v->tcfv_action == TCA_VLAN_ACT_MODIFY) &&
- (nla_put_u16(skb, TCA_VLAN_PUSH_VLAN_ID, v->tcfv_push_vid) ||
+ if ((p->tcfv_action == TCA_VLAN_ACT_PUSH ||
+ p->tcfv_action == TCA_VLAN_ACT_MODIFY) &&
+ (nla_put_u16(skb, TCA_VLAN_PUSH_VLAN_ID, p->tcfv_push_vid) ||
nla_put_be16(skb, TCA_VLAN_PUSH_VLAN_PROTOCOL,
- v->tcfv_push_proto) ||
+ p->tcfv_push_proto) ||
(nla_put_u8(skb, TCA_VLAN_PUSH_VLAN_PRIORITY,
- v->tcfv_push_prio))))
+ p->tcfv_push_prio))))
goto nla_put_failure;
tcf_tm_dump(&t, &v->tcf_tm);
--
2.7.4
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