[zozbot234]

This claim is a bit apples and oranges (no pun intended!). madvise is all about providing hints to the kernel to tune the page cache and readahead (including possibly disabling readahead altogether). it's not about performing reads into private memory buffers, which is actually where the options you mentioned fit in.

[astrange]

Triggering reads is also how you get pages into the page cache, so it helps to know how to do it.