[ovs-dev] [PATCH 3/3] datapath: refactor do_output() to move skb_clone NULL check out of fast path

Andy Zhou azhou at nicira.com
Thu Jul 10 08:16:32 UTC 2014


skb_clone() NULL check is implemented in do_output(), as past of the
common (fast) path. Refactoring so that NULL check is done in the
slow path, immediately after skb_clone() is called.

Besides optimization, this change also improves code readability by
making the skb_clone() NULL check consistent within OVS datapath
module.

Signed-off-by: Andy Zhou <azhou at nicira.com>
---
 datapath/actions.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/datapath/actions.c b/datapath/actions.c
index daa7b43..6eb83b8 100644
--- a/datapath/actions.c
+++ b/datapath/actions.c
@@ -490,9 +490,6 @@ static int do_output(struct datapath *dp, struct sk_buff *skb, int out_port)
 {
 	struct vport *vport;
 
-	if (unlikely(!skb))
-		return -ENOMEM;
-
 	vport = ovs_vport_rcu(dp, out_port);
 	if (unlikely(!vport)) {
 		kfree_skb(skb);
@@ -693,7 +690,12 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
 		int err = 0;
 
 		if (prev_port != -1) {
-			do_output(dp, skb_clone(skb, GFP_ATOMIC), prev_port);
+			struct sk_buff *out_skb = skb_clone(skb, GFP_ATOMIC);
+
+			if (!out_skb)
+				return -ENOMEM;
+
+			do_output(dp, out_skb, prev_port);
 			prev_port = -1;
 		}
 
-- 
1.9.1




More information about the dev mailing list