[justincormack]

That is not strictly true. Look at Snabb switch, written almost entirely in LuaJIT for example https://github.com/SnabbCo/snabbswitch - you need some kind of ffi to mmap device memory, but it is quite possible. (LuaJIT is fast of course which helps for 10Gb ethernet).

[OneMoreIdol]

That's kinda what I was thinking when I commented, and there are sure to be exceptions. But I don't see anything different with your Snabb switch example. You can probably use Java and JNI for that matter to call mmap, but would you be able to write an implementation of mmap in LuaJIT ?

[justincormack]

Yes you can call mmap with the ffi in LuaJIT just fine. It is not very complicated, it just asks the kernel to do it. Implementing what the kernel does, well that does need some assembly.

[OneMoreIdol]

Indeed we agree. Using any ffi for that matter.