From ec581f6a42bbbea5271c66da9769a41b46c74e10 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 1 May 2009 09:05:06 -0700 Subject: [PATCH] net: Fix skb_tx_hash() for forwarding workloads. When skb_rx_queue_recorded() is true, we dont want to use jash distribution as the device driver exactly told us which queue was selected at RX time. jhash makes a statistical shuffle, but this wont work with 8 static inputs. Later improvements would be to compute reciprocal value of real_num_tx_queues to avoid a divide here. But this computation should be done once, when real_num_tx_queues is set. This needs a separate patch, and a new field in struct net_device. Reported-by: Andrew Dickinson Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/core/dev.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index 308a7d0c277f..e2e9e4af3ace 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1735,11 +1735,12 @@ u16 skb_tx_hash(const struct net_device *dev, const struct sk_buff *skb) { u32 hash; - if (skb_rx_queue_recorded(skb)) { - hash = skb_get_rx_queue(skb); - } else if (skb->sk && skb->sk->sk_hash) { + if (skb_rx_queue_recorded(skb)) + return skb_get_rx_queue(skb) % dev->real_num_tx_queues; + + if (skb->sk && skb->sk->sk_hash) hash = skb->sk->sk_hash; - } else + else hash = skb->protocol; hash = jhash_1word(hash, skb_tx_hashrnd); -- 2.20.1