Kernel Study Notes

0.1. stepsstep 1. 循环fib_trie, 直到当前节点为空或者是叶子节点时，停止。 1.a 比较当前节点的key跟待插入的key的前pos位, 如果不相等，循环结束。如果相等执行1.b （作为改进，加上父节点已经比较了前posx位， 那么只需比较 (posx，pos)这区间的位即可。 注意posx有可能与pos相等。 1.b 记录已经比较的位数(tn->pos

0.0.1. summary根据用户参数，创建并返回fib_create_info节点。 如果用户参数有问题，则返回空。参数检查过程中，会创建一个新的struct fib_info 节点，如果参数检查失败，该节点会被free_fib_info释放（通过rcu模式） 如果存在一个相同配置参数的节点，则返回已有的struct fib_info 节点。其实已经创建了一个新的struct fib_inf

0.0.0.1. summarytodo!!

0.0.1. summary遍历路由树，查找是否存在key这条路由。如果有则返回对应的节点 struct leaf *，否则返回NULL。 0.0.1.1. 中间节点 和 叶子节点路由树（fib lc tree)是个多叉树,树的每个节点是struct rt_trie_node。每个节点的分叉个数(X)是可变的， 由 struct rt_trie_node里的bits决定。 X = 2

0.0.1. summarypage_to_pfn and pfn_to_page are often used in kernel. for PP81, kernel uses CONFIG_DISCONTIGMEM + NUMA.Every node has node_mem_map and node_start_pfnto help the page/pfn covertion.n

0.0.1. summaryThere is a list xfrm_km_list in kernel.Each node of the list is struct xfrm_mgr,which has several methods to notify usersapce by netlink message.Different methods has corresponding metho

In order to understand kernel route LC-Trie,summary the basic functions here.

0.1. kprobe is a useful tool when debug kernel.It can directly hook the related function of kernel,before or after it run. It also can be used to patch kernel in some special case.

0.1. usage:In version management, we often meet this case: 123When a line/file is deleted for git repo?or who did it ? In this case, we need git bisect. git bisect start git bisect good commit_id1 gi

0.1. Q: Does kernel IPv6 route support route cache ? yes. but it is very different with IPv4. It should be ‘clone’ strictly speaking. For simple let us only focus on ip6_pol_route, and variable st