Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [ 35/46] net: revert 8728c544a9c ("net: dev_pick_tx() fix") | Date | Thu, 12 Sep 2013 10:58:46 -0700 |
| |
3.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@google.com>
[ Upstream commit 702821f4ea6f68db18aa1de7d8ed62c6ba586a64 ]
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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/core/flow_dissector.c | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-)
--- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -345,14 +345,9 @@ u16 __netdev_pick_tx(struct net_device * 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; }
| |