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 <davem@davemloft.net>
diff --git a/net/core/dev.c b/net/core/dev.c
index 5379b0c..b21ad0b 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1722,6 +1722,13 @@
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 @@
hash = jhash_3words(addr1, addr2, ports, simple_tx_hashrnd);
+out:
return (u16) (((u64) hash * dev->real_num_tx_queues) >> 32);
}