sock: add tracepoint for send recv length

sock: add tracepoint for send recv length

Add 2 tracepoints to monitor the tcp/udp traffic
of per process and per cgroup.

Regarding monitoring the tcp/udp traffic of each process, there are two
existing solutions, the first one is https://www.atoptool.nl/netatop.php.
The second is via kprobe/kretprobe.

Netatop solution is implemented by registering the hook function at the
hook point provided by the netfilter framework.

These hook functions may be in the soft interrupt context and cannot
directly obtain the pid. Some data structures are added to bind packets
and processes. For example, struct taskinfobucket, struct taskinfo ...

Every time the process sends and receives packets it needs multiple
hashmaps,resulting in low performance and it has the problem fo inaccurate
tcp/udp traffic statistics(for example: multiple threads share sockets).

We can obtain the information with kretprobe, but as we know, kprobe gets
the result by trappig in an exception, which loses performance compared
to tracepoint.

We compared the performance of tracepoints with the above two methods, and
the results are as follows:

ab -n 1000000 -c 1000 -r http://127.0.0.1/index.html
without trace:
Time per request: 39.660 [ms] (mean)
Time per request: 0.040 [ms] (mean, across all concurrent requests)

netatop:
Time per request: 50.717 [ms] (mean)
Time per request: 0.051 [ms] (mean, across all concurrent requests)

kr:
Time per request: 43.168 [ms] (mean)
Time per request: 0.043 [ms] (mean, across all concurrent requests)

tracepoint:
Time per request: 41.004 [ms] (mean)
Time per request: 0.041 [ms] (mean, across all concurrent requests

It can be seen that tracepoint has better performance.

Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
Signed-off-by: Xiongchun Duan <duanxiongchun@bytedance.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: David S. Miller <davem@davemloft.net>