Read the code. Only way to know for sure. Then use something maybe based on clang-query to check if the path that leads to flushing base on msync() and/or munma

Read the code. Only way to know for sure. Then use something maybe based on clang-query to check if the path that leads to flushing base on msync() and/or munmap() changed. Like, if any code between your syscall and the kernel-internal write-page-to-disk-now-i'm-waiting call changed. You should be able to convince clang-query to spit out a normalized AST of the code, and still be able to easily map it back to the source file location so you can check the source-file diff for the specifics once you demmed the AST diff ass non-trivial (some things should be easier to ignore in an AST diff). In case you end up creating such a tool, please share it with us.