Commit d5a9e24a authored by David S. Miller's avatar David S. Miller
Browse files

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: default avatarDavid S. Miller <davem@davemloft.net>
parent a73efd0a

include/linux/skbuff.h

+15 −0
Original line number Diff line number Diff line
@@ -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)

{

net/core/dev.c

+8 −0
Original line number Diff line number Diff line
@@ -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);

}

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