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packet: rework packet_pick_tx_queue() to use common code selection

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Currently packet_pick_tx_queue() is the only caller of
ndo_select_queue() using a fallback argument other than
netdev_pick_tx.

Leveraging rx queue, we can obtain a similar queue selection
behavior using core helpers. After this change, ndo_select_queue()
is always invoked with netdev_pick_tx() as fallback.
We can change ndo_select_queue() signature in a followup patch,
dropping an indirect call per transmitted packet in some scenarios
(e.g. TCP syn and XDP generic xmit)

This changes slightly how af packet queue selection happens when
PACKET_QDISC_BYPASS is set. It's now more similar to plan dev_queue_xmit()
tacking in account both XPS and TC mapping.

 v1  -> v2:
  - rebased after helper name change
 RFC -> v1:
  - initialize sender_cpu to the expected value

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Paolo Abeni 2019-03-20 11:02:05 +01:00 committed by David S. Miller
parent 4bd97d51a5
commit b71b5837f8
3 changed files with 12 additions and 10 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

2
include/linux/netdevice.h
View file

@ -2152,6 +2152,8 @@ static inline void netdev_for_each_tx_queue(struct net_device *dev,
&qdisc_xmit_lock_key); \
}
u16 netdev_pick_tx(struct net_device *dev, struct sk_buff *skb,
struct net_device *sb_dev);
struct netdev_queue *netdev_core_pick_tx(struct net_device *dev,
struct sk_buff *skb,
struct net_device *sb_dev);

5
net/core/dev.c
View file

@ -3704,8 +3704,8 @@ u16 dev_pick_tx_cpu_id(struct net_device *dev, struct sk_buff *skb,
}
EXPORT_SYMBOL(dev_pick_tx_cpu_id);
static u16 netdev_pick_tx(struct net_device *dev, struct sk_buff *skb,
struct net_device *sb_dev)
u16 netdev_pick_tx(struct net_device *dev, struct sk_buff *skb,
struct net_device *sb_dev)
{
struct sock *sk = skb->sk;
int queue_index = sk_tx_queue_get(sk);
@ -3729,6 +3729,7 @@ static u16 netdev_pick_tx(struct net_device *dev, struct sk_buff *skb,
return queue_index;
}
EXPORT_SYMBOL(netdev_pick_tx);
struct netdev_queue *netdev_core_pick_tx(struct net_device *dev,
struct sk_buff *skb,

15
net/packet/af_packet.c
View file

@ -275,24 +275,23 @@ static bool packet_use_direct_xmit(const struct packet_sock *po)
return po->xmit == packet_direct_xmit;
}
static u16 __packet_pick_tx_queue(struct net_device *dev, struct sk_buff *skb,
struct net_device *sb_dev)
{
return dev_pick_tx_cpu_id(dev, skb, sb_dev, NULL);
}
static u16 packet_pick_tx_queue(struct sk_buff *skb)
{
struct net_device *dev = skb->dev;
const struct net_device_ops *ops = dev->netdev_ops;
int cpu = raw_smp_processor_id();
u16 queue_index;
#ifdef CONFIG_XPS
skb->sender_cpu = cpu + 1;
#endif
skb_record_rx_queue(skb, cpu % dev->real_num_tx_queues);
if (ops->ndo_select_queue) {
queue_index = ops->ndo_select_queue(dev, skb, NULL,
__packet_pick_tx_queue);
netdev_pick_tx);
queue_index = netdev_cap_txqueue(dev, queue_index);
} else {
queue_index = __packet_pick_tx_queue(dev, skb, NULL);
queue_index = netdev_pick_tx(dev, skb, NULL);
}
return queue_index;