Which linux kernel system calls shows bytes read from disk

Question

I have a python program that read Linux kernel system calls (use Lttng), So with this program I could read all kernel calls. I have some operations and then with python program going to analyses system calls, in the operations I have some IO works, then with python program I need to know how many bytes that read from cache and how many read from disk. which system calls show me the bytes read from cache and disk?

Answer 1

Handling read, write, pread, pwrite, readv, writev should be enough.

You just have to check whether the FD refers to the cache or disk. I think it would be easier in kernelspace, by writing a module, but...