Softnet_data

Softnet_data的初始化：

每个CPU的softnet_data是在net_dev_init中初始化的，代码如下：

 1 "/net/core/dev.c" "static int __init net_dev_init(void)"

 2 for_each_possible_cpu(i) {

 3 struct softnet_data *queue; 

 5 queue = &per_cpu(softnet_data, i);

 6 skb_queue_head_init(&queue->input_pkt_queue);

 7 queue->completion_queue = NULL;

 8 INIT_LIST_HEAD(&queue->poll_list);

 9 

10 queue->backlog.poll = process_backlog;

11 queue->backlog.weight = weight_p;

12 queue->backlog.gro_list = NULL;

13 queue->backlog.gro_count = 0;

14 }

15 

16 "include/linux/netdevice.h"

17 struct softnet_data

18 {

19         struct Qdisc            *output_queue;

20         struct sk_buff_head     input_pkt_queue;

21         struct list_head        poll_list;

22         struct sk_buff          *completion_queue;

23 

24         struct napi_struct      backlog;

25 };

26 

27 struct napi_struct {

28         /* The poll_list must only be managed by the entity which

29          * changes the state of the NAPI_STATE_SCHED bit.  This means

30          * whoever atomically sets that bit can add this napi_struct

31          * to the per-cpu poll_list, and whoever clears that bit

32          * can remove from the list right before clearing the bit.

33          */

34         struct list_head        poll_list;

35 

36         unsigned long           state;

37         int                     weight;

38         int                     (*poll)(struct napi_struct *, int);

39 #ifdef CONFIG_NETPOLL

40         spinlock_t              poll_lock;

41         int                     poll_owner;

42 #endif

43 

44         unsigned int            gro_count;

45 

46         struct net_device       *dev;

47         struct list_head        dev_list;

48         struct sk_buff          *gro_list;

49         struct sk_buff          *skb;

50 };