Re: [PATCH v2] filemap: add trace events for get_pages, map_pages, and fault

Hello all, and thank you so much for the review, Steven and Masami.

I'm currently considering replacing the `max_ofs` output with
`length`. Please let me know your thoughts.
With the current design, a memory range of an event is an inclusive
range of [ofs, max_ofs + 4096]. I found the `+4096` part confusing
during the ureadahead's upstreaming work. Replacing `max_ofs` with
`length` makes the range specified by an event much more concise.