From d5a9e24afb4ab38110ebb777588ea0bd0eacbd0a Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Tue, 27 Jan 2009 16:22:11 -0800 Subject: [PATCH] net: Allow RX queue selection to seed TX queue hashing. The idea is that drivers which implement multiqueue RX pre-seed the SKB by recording the RX queue selected by the hardware. If such a seed is found on TX, we'll use that to select the outgoing TX queue. This helps get more consistent load balancing on router and firewall loads. Signed-off-by: David S. Miller --- include/linux/skbuff.h | 15 +++++++++++++++ net/core/dev.c | 8 ++++++++ 2 files changed, 23 insertions(+) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index cf2cb50f77d1..a2c2378a9c58 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1904,6 +1904,21 @@ static inline void skb_copy_queue_mapping(struct sk_buff *to, const struct sk_bu to->queue_mapping = from->queue_mapping; } +static inline void skb_record_rx_queue(struct sk_buff *skb, u16 rx_queue) +{ + skb->queue_mapping = rx_queue + 1; +} + +static inline u16 skb_get_rx_queue(struct sk_buff *skb) +{ + return skb->queue_mapping - 1; +} + +static inline bool skb_rx_queue_recorded(struct sk_buff *skb) +{ + return (skb->queue_mapping != 0); +} + #ifdef CONFIG_XFRM static inline struct sec_path *skb_sec_path(struct sk_buff *skb) { diff --git a/net/core/dev.c b/net/core/dev.c index 5379b0c1190a..b21ad0b47aae 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1722,6 +1722,13 @@ static u16 simple_tx_hash(struct net_device *dev, struct sk_buff *skb) simple_tx_hashrnd_initialized = 1; } + if (skb_rx_queue_recorded(skb)) { + u32 val = skb_get_rx_queue(skb); + + hash = jhash_1word(val, simple_tx_hashrnd); + goto out; + } + switch (skb->protocol) { case htons(ETH_P_IP): if (!(ip_hdr(skb)->frag_off & htons(IP_MF | IP_OFFSET))) @@ -1759,6 +1766,7 @@ static u16 simple_tx_hash(struct net_device *dev, struct sk_buff *skb) hash = jhash_3words(addr1, addr2, ports, simple_tx_hashrnd); +out: return (u16) (((u64) hash * dev->real_num_tx_queues) >> 32); }