Merge branch 'net-sched-act_skbedit-lockless-data-path'

Davide Caratti says:

====================
net/sched: act_skbedit: lockless data path

the data path of act_skbedit can be faster if we avoid using spinlocks:
 - patch 1 converts act_skbedit statistics to use per-cpu counters
 - patch 2 lets act_skbedit use RCU to read/update its configuration

test procedure (using pktgen from https://github.com/netoptimizer):

 # ip link add name eth1 type dummy
 # ip link set dev eth1 up
 # tc qdisc add dev eth1 clsact
 # tc filter add dev eth1 egress matchall action skbedit priority c1a0:c1a0
 # for c in 1 2 4 ; do
 > ./pktgen_bench_xmit_mode_queue_xmit.sh -v -s 64 -t $c -n 5000000 -i eth1
 > done

test results (avg. pps/thread)

  $c | before patch |  after patch | improvement
 ----+--------------+--------------+------------
   1 | 3917464 ± 3% | 4000458 ± 3% |  irrelevant
   2 | 3455367 ± 4% | 3953076 ± 1% |        +14%
   4 | 2496594 ± 2% | 3801123 ± 3% |        +52%

v2: rebased on latest net-next
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 27 insertions, 10 deletions

diff --git a/include/net/tc_act/tc_skbedit.h b/include/net/tc_act/tc_skbedit.h
index 19cd3d345804..911bbac838a2 100644
--- a/include/net/tc_act/tc_skbedit.h
+++ b/include/net/tc_act/tc_skbedit.h
@@ -22,14 +22,19 @@
 #include <net/act_api.h>
 #include <linux/tc_act/tc_skbedit.h>
 
+struct tcf_skbedit_params {
+	u32 flags;
+	u32 priority;
+	u32 mark;
+	u32 mask;
+	u16 queue_mapping;
+	u16 ptype;
+	struct rcu_head rcu;
+};
+
 struct tcf_skbedit {
-	struct tc_action	common;
-	u32		flags;
-	u32		priority;
-	u32		mark;
-	u32		mask;
-	u16		queue_mapping;
-	u16		ptype;
+	struct tc_action common;
+	struct tcf_skbedit_params __rcu *params;
 };
 #define to_skbedit(a) ((struct tcf_skbedit *)a)
 
@@ -37,15 +42,27 @@ struct tcf_skbedit {
 static inline bool is_tcf_skbedit_mark(const struct tc_action *a)
 {
 #ifdef CONFIG_NET_CLS_ACT
-	if (a->ops && a->ops->type == TCA_ACT_SKBEDIT)
-		return to_skbedit(a)->flags == SKBEDIT_F_MARK;
+	u32 flags;
+
+	if (a->ops && a->ops->type == TCA_ACT_SKBEDIT) {
+		rcu_read_lock();
+		flags = rcu_dereference(to_skbedit(a)->params)->flags;
+		rcu_read_unlock();
+		return flags == SKBEDIT_F_MARK;
+	}
 #endif
 	return false;
 }
 
 static inline u32 tcf_skbedit_mark(const struct tc_action *a)
 {
-	return to_skbedit(a)->mark;
+	u32 mark;
+
+	rcu_read_lock();
+	mark = rcu_dereference(to_skbedit(a)->params)->mark;
+	rcu_read_unlock();
+
+	return mark;
 }
 
 #endif /* __NET_TC_SKBEDIT_H */