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Commit bfb564e7 authored by Krishna Kumar's avatar Krishna Kumar Committed by David S. Miller
Browse files

core: Factor out flow calculation from get_rps_cpu 



Factor out flow calculation code from get_rps_cpu, since other
functions can use the same code.

Revisions:

v2 (Ben): Separate flow calcuation out and use in select queue.
v3 (Arnd): Don't re-implement MIN.
v4 (Changli): skb->data points to ethernet header in macvtap, and
	make a fast path. Tested macvtap with this patch.
v5 (Changli):
	- Cache skb->rxhash in skb_get_rxhash
	- macvtap may not have pow(2) queues, so change code for
	  queue selection.
    (Arnd):
	- Use first available queue if all fails.

Signed-off-by: default avatarKrishna Kumar <krkumar2@in.ibm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6891dd25

include/linux/skbuff.h

+9 −0
Original line number Diff line number Diff line
@@ -558,6 +558,15 @@ extern unsigned int skb_find_text(struct sk_buff *skb, unsigned int from, 
				    unsigned int to, struct ts_config *config,

				    struct ts_state *state);



extern __u32 __skb_get_rxhash(struct sk_buff *skb);

static inline __u32 skb_get_rxhash(struct sk_buff *skb)

{

	if (!skb->rxhash)

		skb->rxhash = __skb_get_rxhash(skb);



	return skb->rxhash;

}



#ifdef NET_SKBUFF_DATA_USES_OFFSET

static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)

{

net/core/dev.c

+62 −44
Original line number Diff line number Diff line
@@ -2259,69 +2259,41 @@ static inline void ____napi_schedule(struct softnet_data *sd, 
	__raise_softirq_irqoff(NET_RX_SOFTIRQ);

}



#ifdef CONFIG_RPS



/* One global table that all flow-based protocols share. */

struct rps_sock_flow_table *rps_sock_flow_table __read_mostly;

EXPORT_SYMBOL(rps_sock_flow_table);



/*

 * get_rps_cpu is called from netif_receive_skb and returns the target

 * CPU from the RPS map of the receiving queue for a given skb.

 * rcu_read_lock must be held on entry.

 * __skb_get_rxhash: calculate a flow hash based on src/dst addresses

 * and src/dst port numbers. Returns a non-zero hash number on success

 * and 0 on failure.

 */

static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb,

		       struct rps_dev_flow **rflowp)

__u32 __skb_get_rxhash(struct sk_buff *skb)

{

	int nhoff, hash = 0;

	struct ipv6hdr *ip6;

	struct iphdr *ip;

	struct netdev_rx_queue *rxqueue;

	struct rps_map *map;

	struct rps_dev_flow_table *flow_table;

	struct rps_sock_flow_table *sock_flow_table;

	int cpu = -1;

	u8 ip_proto;

	u16 tcpu;

	u32 addr1, addr2, ihl;

	union {

		u32 v32;

		u16 v16[2];

	} ports;



	if (skb_rx_queue_recorded(skb)) {

		u16 index = skb_get_rx_queue(skb);

		if (unlikely(index >= dev->num_rx_queues)) {

			WARN_ONCE(dev->num_rx_queues > 1, "%s received packet "

				"on queue %u, but number of RX queues is %u\n",

				dev->name, index, dev->num_rx_queues);

			goto done;

		}

		rxqueue = dev->_rx + index;

	} else

		rxqueue = dev->_rx;



	if (!rxqueue->rps_map && !rxqueue->rps_flow_table)

		goto done;



	if (skb->rxhash)

		goto got_hash; /* Skip hash computation on packet header */

	nhoff = skb_network_offset(skb);



	switch (skb->protocol) {

	case __constant_htons(ETH_P_IP):

		if (!pskb_may_pull(skb, sizeof(*ip)))

		if (!pskb_may_pull(skb, sizeof(*ip) + nhoff))

			goto done;



		ip = (struct iphdr *) skb->data;

		ip = (struct iphdr *) skb->data + nhoff;

		ip_proto = ip->protocol;

		addr1 = (__force u32) ip->saddr;

		addr2 = (__force u32) ip->daddr;

		ihl = ip->ihl;

		break;

	case __constant_htons(ETH_P_IPV6):

		if (!pskb_may_pull(skb, sizeof(*ip6)))

		if (!pskb_may_pull(skb, sizeof(*ip6) + nhoff))

			goto done;



		ip6 = (struct ipv6hdr *) skb->data;

		ip6 = (struct ipv6hdr *) skb->data + nhoff;

		ip_proto = ip6->nexthdr;

		addr1 = (__force u32) ip6->saddr.s6_addr32[3];

		addr2 = (__force u32) ip6->daddr.s6_addr32[3];
@@ -2330,6 +2302,7 @@ static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb, 
	default:

		goto done;

	}



	switch (ip_proto) {

	case IPPROTO_TCP:

	case IPPROTO_UDP:
@@ -2338,8 +2311,9 @@ static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb, 
	case IPPROTO_AH:

	case IPPROTO_SCTP:

	case IPPROTO_UDPLITE:

		if (pskb_may_pull(skb, (ihl * 4) + 4)) {

			ports.v32 = * (__force u32 *) (skb->data + (ihl * 4));

		if (pskb_may_pull(skb, (ihl * 4) + 4 + nhoff)) {

			ports.v32 = * (__force u32 *) (skb->data + nhoff +

						       (ihl * 4));

			if (ports.v16[1] < ports.v16[0])

				swap(ports.v16[0], ports.v16[1]);

			break;
@@ -2352,11 +2326,55 @@ static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb, 
	/* get a consistent hash (same value on both flow directions) */

	if (addr2 < addr1)

		swap(addr1, addr2);

	skb->rxhash = jhash_3words(addr1, addr2, ports.v32, hashrnd);

	if (!skb->rxhash)

		skb->rxhash = 1;



got_hash:

	hash = jhash_3words(addr1, addr2, ports.v32, hashrnd);

	if (!hash)

		hash = 1;



done:

	return hash;

}

EXPORT_SYMBOL(__skb_get_rxhash);



#ifdef CONFIG_RPS



/* One global table that all flow-based protocols share. */

struct rps_sock_flow_table *rps_sock_flow_table __read_mostly;

EXPORT_SYMBOL(rps_sock_flow_table);



/*

 * get_rps_cpu is called from netif_receive_skb and returns the target

 * CPU from the RPS map of the receiving queue for a given skb.

 * rcu_read_lock must be held on entry.

 */

static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb,

		       struct rps_dev_flow **rflowp)

{

	struct netdev_rx_queue *rxqueue;

	struct rps_map *map;

	struct rps_dev_flow_table *flow_table;

	struct rps_sock_flow_table *sock_flow_table;

	int cpu = -1;

	u16 tcpu;



	if (skb_rx_queue_recorded(skb)) {

		u16 index = skb_get_rx_queue(skb);

		if (unlikely(index >= dev->num_rx_queues)) {

			WARN_ONCE(dev->num_rx_queues > 1, "%s received packet "

				"on queue %u, but number of RX queues is %u\n",

				dev->name, index, dev->num_rx_queues);

			goto done;

		}

		rxqueue = dev->_rx + index;

	} else

		rxqueue = dev->_rx;



	if (!rxqueue->rps_map && !rxqueue->rps_flow_table)

		goto done;



	if (!skb_get_rxhash(skb))

		goto done;



	flow_table = rcu_dereference(rxqueue->rps_flow_table);

	sock_flow_table = rcu_dereference(rps_sock_flow_table);

	if (flow_table && sock_flow_table) {