net: skb_tx_hash() fix relative to skb_orphan_try()
commit fc6055a5ba31e2 (net: Introduce skb_orphan_try()) added early
orphaning of skbs.
This unfortunately added a performance regression in skb_tx_hash() in
case of stacked devices (bonding, vlans, ...)
Since skb->sk is now NULL, we cannot access sk->sk_hash anymore to
spread tx packets to multiple NIC queues on multiqueue devices.
skb_tx_hash() in this case only uses skb->protocol, same value for all
flows.
skb_orphan_try() can copy sk->sk_hash into skb->rxhash and skb_tx_hash()
can use this saved sk_hash value to compute its internal hash value.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/dev.c b/net/core/dev.c
index 723a347..4b05fdf 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1911,8 +1911,16 @@
*/
static inline void skb_orphan_try(struct sk_buff *skb)
{
- if (!skb_tx(skb)->flags)
+ struct sock *sk = skb->sk;
+
+ if (sk && !skb_tx(skb)->flags) {
+ /* skb_tx_hash() wont be able to get sk.
+ * We copy sk_hash into skb->rxhash
+ */
+ if (!skb->rxhash)
+ skb->rxhash = sk->sk_hash;
skb_orphan(skb);
+ }
}
int dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev,
@@ -1998,8 +2006,7 @@
if (skb->sk && skb->sk->sk_hash)
hash = skb->sk->sk_hash;
else
- hash = (__force u16) skb->protocol;
-
+ hash = (__force u16) skb->protocol ^ skb->rxhash;
hash = jhash_1word(hash, hashrnd);
return (u16) (((u64) hash * dev->real_num_tx_queues) >> 32);