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authorEric Dumazet <eric.dumazet@gmail.com>2010-07-13 05:24:20 +0000
committerDavid S. Miller <davem@davemloft.net>2010-07-14 15:33:27 -0700
commit87fd308cfc6b2e880bf717a740bd5c58d2aed10c (patch)
tree15c27522669b08a6d26efbcd447abf3d78ad13fb /net
parent3a047bf87b1b6f69c62ab9fb28072c639cb7e2fa (diff)
downloadlinux-2.6.34-ux500-87fd308cfc6b2e880bf717a740bd5c58d2aed10c.tar.gz
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>
Diffstat (limited to 'net')
-rw-r--r--net/core/dev.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index 723a34710ad..4b05fdf762a 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1911,8 +1911,16 @@ static int dev_gso_segment(struct sk_buff *skb)
*/
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 @@ u16 skb_tx_hash(const struct net_device *dev, const struct sk_buff *skb)
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);