Thank you Matthew for taking a look at this! I fix both points and send a V2 patch.
> This needs to be cast to an loff_t before shifting. I found that this applies to add_to_page_cache and delete_from_page_cache, too. I could fix them too, but I didn't since it will change the max value of those traces from %lu to %lld on 32 bit environments, which would be a breaking change. However, let me know if you think we should fix existing events as well.
