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net: place xmit recursion in softnet data

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This fills a hole in softnet data, so no change in structure size.

Also prepares for xmit_more placement in the same spot;
skb->xmit_more will be removed in followup patch.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Florian Westphal 2019-04-01 16:42:13 +02:00 committed by David S. Miller
parent 74dcb4c1a5
commit 97cdcf37b5
3 changed files with 38 additions and 18 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

40
include/linux/netdevice.h
View file

@ -2659,14 +2659,6 @@ void netdev_freemem(struct net_device *dev);
void synchronize_net(void);
int init_dummy_netdev(struct net_device *dev);
DECLARE_PER_CPU(int, xmit_recursion);
#define XMIT_RECURSION_LIMIT 10
static inline int dev_recursion_level(void)
{
return this_cpu_read(xmit_recursion);
}
struct net_device *dev_get_by_index(struct net *net, int ifindex);
struct net_device *__dev_get_by_index(struct net *net, int ifindex);
struct net_device *dev_get_by_index_rcu(struct net *net, int ifindex);
@ -3015,6 +3007,11 @@ struct softnet_data {
#ifdef CONFIG_XFRM_OFFLOAD
struct sk_buff_head xfrm_backlog;
#endif
/* written and read only by owning cpu: */
struct {
u16 recursion;
u8 more;
} xmit;
#ifdef CONFIG_RPS
/* input_queue_head should be written by cpu owning this struct,
* and only read by other cpus. Worth using a cache line.
@ -3050,6 +3047,28 @@ static inline void input_queue_tail_incr_save(struct softnet_data *sd,
DECLARE_PER_CPU_ALIGNED(struct softnet_data, softnet_data);
static inline int dev_recursion_level(void)
{
return __this_cpu_read(softnet_data.xmit.recursion);
}
#define XMIT_RECURSION_LIMIT 10
static inline bool dev_xmit_recursion(void)
{
return unlikely(__this_cpu_read(softnet_data.xmit.recursion) >
XMIT_RECURSION_LIMIT);
}
static inline void dev_xmit_recursion_inc(void)
{
__this_cpu_inc(softnet_data.xmit.recursion);
}
static inline void dev_xmit_recursion_dec(void)
{
__this_cpu_dec(softnet_data.xmit.recursion);
}
void __netif_schedule(struct Qdisc *q);
void netif_schedule_queue(struct netdev_queue *txq);
@ -4409,6 +4428,11 @@ static inline netdev_tx_t __netdev_start_xmit(const struct net_device_ops *ops,
return ops->ndo_start_xmit(skb, dev);
}
static inline bool netdev_xmit_more(void)
{
return __this_cpu_read(softnet_data.xmit.more);
}
static inline netdev_tx_t netdev_start_xmit(struct sk_buff *skb, struct net_device *dev,
struct netdev_queue *txq, bool more)
{

10
net/core/dev.c
View file

@ -3566,9 +3566,6 @@ static void skb_update_prio(struct sk_buff *skb)
#define skb_update_prio(skb)
#endif
DEFINE_PER_CPU(int, xmit_recursion);
EXPORT_SYMBOL(xmit_recursion);
/**
* dev_loopback_xmit - loop back @skb
* @net: network namespace this loopback is happening in
@ -3857,8 +3854,7 @@ static int __dev_queue_xmit(struct sk_buff *skb, struct net_device *sb_dev)
int cpu = smp_processor_id(); /* ok because BHs are off */
if (txq->xmit_lock_owner != cpu) {
if (unlikely(__this_cpu_read(xmit_recursion) >
XMIT_RECURSION_LIMIT))
if (dev_xmit_recursion())
goto recursion_alert;
skb = validate_xmit_skb(skb, dev, &again);
@ -3868,9 +3864,9 @@ static int __dev_queue_xmit(struct sk_buff *skb, struct net_device *sb_dev)
HARD_TX_LOCK(dev, txq, cpu);
if (!netif_xmit_stopped(txq)) {
__this_cpu_inc(xmit_recursion);
dev_xmit_recursion_inc();
skb = dev_hard_start_xmit(skb, dev, txq, &rc);
__this_cpu_dec(xmit_recursion);
dev_xmit_recursion_dec();
if (dev_xmit_complete(rc)) {
HARD_TX_UNLOCK(dev, txq);
goto out;

6
net/core/filter.c
View file

@ -2016,7 +2016,7 @@ static inline int __bpf_tx_skb(struct net_device *dev, struct sk_buff *skb)
{
int ret;
if (unlikely(__this_cpu_read(xmit_recursion) > XMIT_RECURSION_LIMIT)) {
if (dev_xmit_recursion()) {
net_crit_ratelimited("bpf: recursion limit reached on datapath, buggy bpf program?\n");
kfree_skb(skb);
return -ENETDOWN;
@ -2024,9 +2024,9 @@ static inline int __bpf_tx_skb(struct net_device *dev, struct sk_buff *skb)
skb->dev = dev;
__this_cpu_inc(xmit_recursion);
dev_xmit_recursion_inc();
ret = dev_queue_xmit(skb);
__this_cpu_dec(xmit_recursion);
dev_xmit_recursion_dec();
return ret;
}