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authorEric Dumazet <edumazet@google.com>2013-08-28 18:10:43 -0700
committerDavid S. Miller <davem@davemloft.net>2013-08-30 17:48:04 -0400
commit702821f4ea6f68db18aa1de7d8ed62c6ba586a64 (patch)
treea0e3a4ba9577812f220224d7e6380146c193dc2e
parent25ad6117e73656071b38fd19fa67ae325471c758 (diff)
downloadlinux-702821f4ea6f68db18aa1de7d8ed62c6ba586a64.tar.gz
net: revert 8728c544a9c ("net: dev_pick_tx() fix")
commit 8728c544a9cbdc ("net: dev_pick_tx() fix") and commit b6fe83e9525a ("bonding: refine IFF_XMIT_DST_RELEASE capability") are quite incompatible : Queue selection is disabled because skb dst was dropped before entering bonding device. This causes major performance regression, mainly because TCP packets for a given flow can be sent to multiple queues. This is particularly visible when using the new FQ packet scheduler with MQ + FQ setup on the slaves. We can safely revert the first commit now that 416186fbf8c5b ("net: Split core bits of netdev_pick_tx into __netdev_pick_tx") properly caps the queue_index. Reported-by: Xi Wang <xii@google.com> Diagnosed-by: Xi Wang <xii@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Cc: Alexander Duyck <alexander.h.duyck@intel.com> Cc: Denys Fedorysychenko <nuclearcat@nuclearcat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/core/flow_dissector.c11
1 files changed, 3 insertions, 8 deletions
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index b84a1b1..d12e3a9 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -346,14 +346,9 @@ u16 __netdev_pick_tx(struct net_device *dev, struct sk_buff *skb)
if (new_index < 0)
new_index = skb_tx_hash(dev, skb);
- if (queue_index != new_index && sk) {
- struct dst_entry *dst =
- rcu_dereference_check(sk->sk_dst_cache, 1);
-
- if (dst && skb_dst(skb) == dst)
- sk_tx_queue_set(sk, queue_index);
-
- }
+ if (queue_index != new_index && sk &&
+ rcu_access_pointer(sk->sk_dst_cache))
+ sk_tx_queue_set(sk, queue_index);
queue_index = new_index;
}