网络[四]：路由表

inet_init() -> ip_init() -> ip_rt_init()

rt_hash_table = (struct rt_hash_bucket *)

         alloc_large_system_hash("IP route cache",

                                     sizeof(struct rt_hash_bucket),

                                     rhash_entries,

                                     (totalram_pages >= 128 * 1024) ?

                                      15 : 17,

                                     0,

                                     &rt_hash_log,

                                     &rt_hash_mask,

                                      rhash_entries ? 0 : 512 * 1024);