标签：如何 max cas cgroup NPU get 分类 ret put
tc的学习原来是想着直接从用户态学习的，但是万万没想到哇，qdisc class两个概念直接把我给搞晕了，直接看代码吧
调用：tc qdisc add dev tap0 root handle 1: htb default 2
%stc 0xffffffff81744fe0 : qdisc_create+0x0/0x410 [kernel] 0xffffffff81745597 : tc_modify_qdisc+0x1a7/0x5b0 [kernel] 0xffffffff8172b336 : rtnetlink_rcv_msg+0xe6/0x230 [kernel] 0xffffffff8174ee24 : netlink_rcv_skb+0xa4/0xc0 [kernel] 0xffffffff8172b248 : rtnetlink_rcv+0x28/0x30 [kernel] 0xffffffff8174e5da : netlink_unicast+0x12a/0x1b0 [kernel] 0xffffffff8174eb01 : netlink_sendmsg+0x4a1/0x5f0 [kernel] 0xffffffff816fe098 : sock_sendmsg+0x38/0x50 [kernel] 0xffffffff816feb41 : ___sys_sendmsg+0x281/0x290 [kernel] 0xffffffff816ff491 : __sys_sendmsg+0x51/0x90 [kernel] 0xffffffff816ff4e2 : sys_sendmsg+0x12/0x20 [kernel] 0xffffffff818244f2 : entry_SYSCALL_64_fastpath+0x16/0x71 [kernel]
在增加tc class的时候的调用栈是：
tc 0xffffffff81741950 : qdisc_create_dflt+0x0/0x80 [kernel] 0xffffffffc0a87abf [sch_htb] 0xffffffff81744d85 : tc_ctl_tclass+0x3b5/0x400 [kernel] (inexact) 0xffffffff8172b336 : rtnetlink_rcv_msg+0xe6/0x230 [kernel] (inexact) 0xffffffff81706bd7 : __alloc_skb+0x87/0x1f0 [kernel] (inexact) 0xffffffff8172b250 : rtnetlink_rcv_msg+0x0/0x230 [kernel] (inexact) 0xffffffff8174ee24 : netlink_rcv_skb+0xa4/0xc0 [kernel] (inexact) 0xffffffff8172b248 : rtnetlink_rcv+0x28/0x30 [kernel] (inexact) 0xffffffff8174e5da : netlink_unicast+0x12a/0x1b0 [kernel] (inexact) 0xffffffff8174eb01 : netlink_sendmsg+0x4a1/0x5f0 [kernel] (inexact) 0xffffffff813912f1 : aa_sock_msg_perm+0x61/0x150 [kernel] (inexact) 0xffffffff816fe098 : sock_sendmsg+0x38/0x50 [kernel] (inexact) 0xffffffff816feb41 : ___sys_sendmsg+0x281/0x290 [kernel] (inexact) 0xffffffff8120018b : mem_cgroup_try_charge+0x6b/0x1b0 [kernel] (inexact) 0xffffffff8119dfd7 : lru_cache_add_active_or_unevictable+0x27/0xa0 [kernel] (inexact) 0xffffffff811bf87a : handle_mm_fault+0xcaa/0x1820 [kernel] (inexact) 0xffffffff816ff491 : __sys_sendmsg+0x51/0x90 [kernel] (inexact) 0xffffffff816ff4e2 : sys_sendmsg+0x12/0x20 [kernel] (inexact) 0xffffffff818244f2 : entry_SYSCALL_64_fastpath+0x16/0x71 [kernel] (inexact)
在qdisc中打点，发现每创建一个分类都会导致创建一个新的qdisc，然后这个qdisc会放到哪里？
rt_netlink
4068 static int __net_init rtnetlink_net_init(struct net *net)
4069 {
4070 struct sock *sk;
4071 struct netlink_kernel_cfg cfg = {
4072 .groups = RTNLGRP_MAX,
4073 .input = rtnetlink_rcv,
4074 .cb_mutex = &rtnl_mutex,
4075 .flags = NL_CFG_F_NONROOT_RECV,
4076 };
4077
4078 sk = netlink_kernel_create(net, NETLINK_ROUTE, &cfg);
4079 if (!sk)
4080 return -ENOMEM;
4081 net->rtnl = sk;
4082 return 0;
4083 }
注册了这样的一种网络的协议，然后这种协议专门处理网络收发包的策略
htb_qdisc_ops函数的原型如下：
1582 static const struct Qdisc_class_ops htb_class_ops = {
1583 .graft = htb_graft,
1584 .leaf = htb_leaf,
1585 .qlen_notify = htb_qlen_notify,
1586 .get = htb_get,
1587 .put = htb_put,
1588 .change = htb_change_class,
1589 .delete = htb_delete,
1590 .walk = htb_walk,
1591 .tcf_chain = htb_find_tcf,
1592 .bind_tcf = htb_bind_filter,
1593 .unbind_tcf = htb_unbind_filter,
1594 .dump = htb_dump_class,
1595 .dump_stats = htb_dump_class_stats,
1596 };
1597
1598 static struct Qdisc_ops htb_qdisc_ops __read_mostly = {
1599 .cl_ops = &htb_class_ops,
1600 .id = "htb",
1601 .priv_size = sizeof(struct htb_sched),
1602 .enqueue = htb_enqueue,
1603 .dequeue = htb_dequeue,
1604 .peek = qdisc_peek_dequeued,
1605 .init = htb_init,
1606 .reset = htb_reset,
1607 .destroy = htb_destroy,
1608 .dump = htb_dump,
1609 .owner = THIS_MODULE,
1610 };
tc_ctl_tclass就是对ｃｌａｓｓ的处理！！！！！
子队列是怎么关联到父队列中去的？对于ｈｔｂ算法来说，到底是怎么管理的这棵树的？
207 static struct htb_class *htb_classify(struct sk_buff *skb, struct Qdisc *sch,
如何htb_classify，把数据包放到对应的队列中去。
标签：如何 max cas cgroup NPU get 分类 ret put
原文地址：https://www.cnblogs.com/honpey/p/9822961.html
