TAILIEUCHUNG - Understanding Linux Network Internals 2005 phần 3

bằng cách sử dụng cơ chế cũ thời của một lá cờ một lần. Dev_boot_phase biến toàn cầu đã được sử dụng như là một lá cờ Boolean để nhớ cho dù net_dev_init phải được thực hiện. Nó được khởi tạo 1 (tức là, net_dev_init đã không được thực hiện) và đã được dọn sạch net_dev_init. Mỗi register_netdevice thời gian được | This document was created by an unregistered ChmMagic please go to http to register it. Thanks. low latency and scalable. Both networking softirqs are higher in priority than normal tasklets tasklet_softirq but are lower in priority than high-priority tasklets hi_softirq . This prioritization guarantees that other high-priority tasks can proceed in a responsive and timely manner even when a system is under a high network load. The internals of the two handlers are covered in the sections Processing the NET RX SOFTIRQ net rx action in Chapter 10and Processing the NET TX SOFTIRQ net tx action in Chapter 11. 4 PREV NEXT Simpo PDF Merge and Split nnregi2tered Ạergion - Pttp This document was created by an unregistered ChmMagic please go to http to register it. Thanks 4 PREY NEXT . softnet_data Structure We will see in Chapter 10 that each CPU has its own queue for incoming frames . Because each CPU has its own data structure to manage ingress and egress traffic there is no need for any locking among different CPUs. The data structure for this queue softnet_data is defined in include linux as follows struct softnetdata int throttle int cng_level int avg_blog input_pkt_queue poll_list output_queue completion_queue backlog_dev struct sk_buff_head struct list_head struct net_device struct sk_buff struct net_device The structure includes both fields used for reception and fields used for transmission. In other words both the NET_RX_SOFTIRQ and NET_TX_SOFTIRQ softirqs refer to the structure. Ingress frames are queued toinput_pkt_queue and egress frames are placed into the specialized queues handled by Traffic Control the QoS layer instead of being handled by softirqs and the softnet_data structure but softirqs are still used to clean up transmitted buffers afterward to keep that task from slowing transmission. You will see inChapter 10 that this is no longer true for drivers using NAPI. . Fields of .