Skip to content

Commit

Permalink
net: move rx and tx hash functions to net/core/flow_dissector.c
Browse files Browse the repository at this point in the history 
__skb_tx_hash() and __skb_get_rxhash() are all for calculating hash
value based by some fields in skb, mostly used for selecting queues
by device drivers.

Meanwhile, net/core/dev.c is bloating.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
  • Loading branch information
Cong Wang authored and David S. Miller committed Jan 21, 2013
1 parent cd5f204 commit 441d9d3
Show file tree
Hide file tree
Showing 2 changed files with 173 additions and 175 deletions.
175 changes: 0 additions & 175 deletions net/core/dev.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -134,7 +134,6 @@
#include <linux/cpu_rmap.h>
#include <linux/net_tstamp.h>
#include <linux/static_key.h>
#include <net/flow_keys.h>

#include "net-sysfs.h"

Expand Down Expand Up @@ -2636,136 +2635,6 @@ int dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev,
return rc;
}

static u32 hashrnd __read_mostly;

/*
* Returns a Tx hash based on the given packet descriptor a Tx queues' number
* to be used as a distribution range.
*/
u16 __skb_tx_hash(const struct net_device *dev, const struct sk_buff *skb,
unsigned int num_tx_queues)
{
u32 hash;
u16 qoffset = 0;
u16 qcount = num_tx_queues;

if (skb_rx_queue_recorded(skb)) {
hash = skb_get_rx_queue(skb);
while (unlikely(hash >= num_tx_queues))
hash -= num_tx_queues;
return hash;
}

if (dev->num_tc) {
u8 tc = netdev_get_prio_tc_map(dev, skb->priority);
qoffset = dev->tc_to_txq[tc].offset;
qcount = dev->tc_to_txq[tc].count;
}

if (skb->sk && skb->sk->sk_hash)
hash = skb->sk->sk_hash;
else
hash = (__force u16) skb->protocol;
hash = jhash_1word(hash, hashrnd);

return (u16) (((u64) hash * qcount) >> 32) + qoffset;
}
EXPORT_SYMBOL(__skb_tx_hash);

static inline u16 dev_cap_txqueue(struct net_device *dev, u16 queue_index)
{
if (unlikely(queue_index >= dev->real_num_tx_queues)) {
net_warn_ratelimited("%s selects TX queue %d, but real number of TX queues is %d\n",
dev->name, queue_index,
dev->real_num_tx_queues);
return 0;
}
return queue_index;
}

static inline int get_xps_queue(struct net_device *dev, struct sk_buff *skb)
{
#ifdef CONFIG_XPS
struct xps_dev_maps *dev_maps;
struct xps_map *map;
int queue_index = -1;

rcu_read_lock();
dev_maps = rcu_dereference(dev->xps_maps);
if (dev_maps) {
map = rcu_dereference(
dev_maps->cpu_map[raw_smp_processor_id()]);
if (map) {
if (map->len == 1)
queue_index = map->queues[0];
else {
u32 hash;
if (skb->sk && skb->sk->sk_hash)
hash = skb->sk->sk_hash;
else
hash = (__force u16) skb->protocol ^
skb->rxhash;
hash = jhash_1word(hash, hashrnd);
queue_index = map->queues[
((u64)hash * map->len) >> 32];
}
if (unlikely(queue_index >= dev->real_num_tx_queues))
queue_index = -1;
}
}
rcu_read_unlock();

return queue_index;
#else
return -1;
#endif
}

u16 __netdev_pick_tx(struct net_device *dev, struct sk_buff *skb)
{
struct sock *sk = skb->sk;
int queue_index = sk_tx_queue_get(sk);

if (queue_index < 0 || skb->ooo_okay ||
queue_index >= dev->real_num_tx_queues) {
int new_index = get_xps_queue(dev, skb);
if (new_index < 0)
new_index = skb_tx_hash(dev, skb);

if (queue_index != new_index && sk) {
struct dst_entry *dst =
rcu_dereference_check(sk->sk_dst_cache, 1);

if (dst && skb_dst(skb) == dst)
sk_tx_queue_set(sk, queue_index);

}

queue_index = new_index;
}

return queue_index;
}
EXPORT_SYMBOL(__netdev_pick_tx);

struct netdev_queue *netdev_pick_tx(struct net_device *dev,
struct sk_buff *skb)
{
int queue_index = 0;

if (dev->real_num_tx_queues != 1) {
const struct net_device_ops *ops = dev->netdev_ops;
if (ops->ndo_select_queue)
queue_index = ops->ndo_select_queue(dev, skb);
else
queue_index = __netdev_pick_tx(dev, skb);
queue_index = dev_cap_txqueue(dev, queue_index);
}

skb_set_queue_mapping(skb, queue_index);
return netdev_get_tx_queue(dev, queue_index);
}

static void qdisc_pkt_len_init(struct sk_buff *skb)
{
const struct skb_shared_info *shinfo = skb_shinfo(skb);
Expand Down Expand Up @@ -3015,41 +2884,6 @@ static inline void ____napi_schedule(struct softnet_data *sd,
__raise_softirq_irqoff(NET_RX_SOFTIRQ);
}

/*
* __skb_get_rxhash: calculate a flow hash based on src/dst addresses
* and src/dst port numbers. Sets rxhash in skb to non-zero hash value
* on success, zero indicates no valid hash. Also, sets l4_rxhash in skb
* if hash is a canonical 4-tuple hash over transport ports.
*/
void __skb_get_rxhash(struct sk_buff *skb)
{
struct flow_keys keys;
u32 hash;

if (!skb_flow_dissect(skb, &keys))
return;

if (keys.ports)
skb->l4_rxhash = 1;

/* get a consistent hash (same value on both flow directions) */
if (((__force u32)keys.dst < (__force u32)keys.src) ||
(((__force u32)keys.dst == (__force u32)keys.src) &&
((__force u16)keys.port16[1] < (__force u16)keys.port16[0]))) {
swap(keys.dst, keys.src);
swap(keys.port16[0], keys.port16[1]);
}

hash = jhash_3words((__force u32)keys.dst,
(__force u32)keys.src,
(__force u32)keys.ports, hashrnd);
if (!hash)
hash = 1;

skb->rxhash = hash;
}
EXPORT_SYMBOL(__skb_get_rxhash);

#ifdef CONFIG_RPS

/* One global table that all flow-based protocols share. */
Expand Down Expand Up @@ -7308,12 +7142,3 @@ static int __init net_dev_init(void)
}

subsys_initcall(net_dev_init);

static int __init initialize_hashrnd(void)
{
get_random_bytes(&hashrnd, sizeof(hashrnd));
return 0;
}

late_initcall_sync(initialize_hashrnd);

173 changes: 173 additions & 0 deletions net/core/flow_dissector.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -143,3 +143,176 @@ bool skb_flow_dissect(const struct sk_buff *skb, struct flow_keys *flow)
return true;
}
EXPORT_SYMBOL(skb_flow_dissect);

static u32 hashrnd __read_mostly;

/*
* __skb_get_rxhash: calculate a flow hash based on src/dst addresses
* and src/dst port numbers. Sets rxhash in skb to non-zero hash value
* on success, zero indicates no valid hash. Also, sets l4_rxhash in skb
* if hash is a canonical 4-tuple hash over transport ports.
*/
void __skb_get_rxhash(struct sk_buff *skb)
{
struct flow_keys keys;
u32 hash;

if (!skb_flow_dissect(skb, &keys))
return;

if (keys.ports)
skb->l4_rxhash = 1;

/* get a consistent hash (same value on both flow directions) */
if (((__force u32)keys.dst < (__force u32)keys.src) ||
(((__force u32)keys.dst == (__force u32)keys.src) &&
((__force u16)keys.port16[1] < (__force u16)keys.port16[0]))) {
swap(keys.dst, keys.src);
swap(keys.port16[0], keys.port16[1]);
}

hash = jhash_3words((__force u32)keys.dst,
(__force u32)keys.src,
(__force u32)keys.ports, hashrnd);
if (!hash)
hash = 1;

skb->rxhash = hash;
}
EXPORT_SYMBOL(__skb_get_rxhash);

/*
* Returns a Tx hash based on the given packet descriptor a Tx queues' number
* to be used as a distribution range.
*/
u16 __skb_tx_hash(const struct net_device *dev, const struct sk_buff *skb,
unsigned int num_tx_queues)
{
u32 hash;
u16 qoffset = 0;
u16 qcount = num_tx_queues;

if (skb_rx_queue_recorded(skb)) {
hash = skb_get_rx_queue(skb);
while (unlikely(hash >= num_tx_queues))
hash -= num_tx_queues;
return hash;
}

if (dev->num_tc) {
u8 tc = netdev_get_prio_tc_map(dev, skb->priority);
qoffset = dev->tc_to_txq[tc].offset;
qcount = dev->tc_to_txq[tc].count;
}

if (skb->sk && skb->sk->sk_hash)
hash = skb->sk->sk_hash;
else
hash = (__force u16) skb->protocol;
hash = jhash_1word(hash, hashrnd);

return (u16) (((u64) hash * qcount) >> 32) + qoffset;
}
EXPORT_SYMBOL(__skb_tx_hash);

static inline u16 dev_cap_txqueue(struct net_device *dev, u16 queue_index)
{
if (unlikely(queue_index >= dev->real_num_tx_queues)) {
net_warn_ratelimited("%s selects TX queue %d, but real number of TX queues is %d\n",
dev->name, queue_index,
dev->real_num_tx_queues);
return 0;
}
return queue_index;
}

static inline int get_xps_queue(struct net_device *dev, struct sk_buff *skb)
{
#ifdef CONFIG_XPS
struct xps_dev_maps *dev_maps;
struct xps_map *map;
int queue_index = -1;

rcu_read_lock();
dev_maps = rcu_dereference(dev->xps_maps);
if (dev_maps) {
map = rcu_dereference(
dev_maps->cpu_map[raw_smp_processor_id()]);
if (map) {
if (map->len == 1)
queue_index = map->queues[0];
else {
u32 hash;
if (skb->sk && skb->sk->sk_hash)
hash = skb->sk->sk_hash;
else
hash = (__force u16) skb->protocol ^
skb->rxhash;
hash = jhash_1word(hash, hashrnd);
queue_index = map->queues[
((u64)hash * map->len) >> 32];
}
if (unlikely(queue_index >= dev->real_num_tx_queues))
queue_index = -1;
}
}
rcu_read_unlock();

return queue_index;
#else
return -1;
#endif
}

u16 __netdev_pick_tx(struct net_device *dev, struct sk_buff *skb)
{
struct sock *sk = skb->sk;
int queue_index = sk_tx_queue_get(sk);

if (queue_index < 0 || skb->ooo_okay ||
queue_index >= dev->real_num_tx_queues) {
int new_index = get_xps_queue(dev, skb);
if (new_index < 0)
new_index = skb_tx_hash(dev, skb);

if (queue_index != new_index && sk) {
struct dst_entry *dst =
rcu_dereference_check(sk->sk_dst_cache, 1);

if (dst && skb_dst(skb) == dst)
sk_tx_queue_set(sk, queue_index);

}

queue_index = new_index;
}

return queue_index;
}
EXPORT_SYMBOL(__netdev_pick_tx);

struct netdev_queue *netdev_pick_tx(struct net_device *dev,
struct sk_buff *skb)
{
int queue_index = 0;

if (dev->real_num_tx_queues != 1) {
const struct net_device_ops *ops = dev->netdev_ops;
if (ops->ndo_select_queue)
queue_index = ops->ndo_select_queue(dev, skb);
else
queue_index = __netdev_pick_tx(dev, skb);
queue_index = dev_cap_txqueue(dev, queue_index);
}

skb_set_queue_mapping(skb, queue_index);
return netdev_get_tx_queue(dev, queue_index);
}

static int __init initialize_hashrnd(void)
{
get_random_bytes(&hashrnd, sizeof(hashrnd));
return 0;
}

late_initcall_sync(initialize_hashrnd);

0 comments on commit 441d9d3

Please sign in to comment.