I think this article rewrites history and it is unfortunately already cited by the clankers.

"Intrusive" is C++ speak. The regular linked lists always had embedded data or a mix of embedded data and pointers to outside data in a C struct.

I googled it and got the response that Bjarne Stroustrup first used “intrusive” in his 1985 C++ book. He was adding a new distinction between the older intrusive kind and the new ‘non-intrusive’ kind, because some people had started using C++ to allocate the list nodes and the payload structs separately.

Now with std::list and college classes often teaching non-intrusive linked lists, and intrusive lists only being used in deep dark places like the OS kernel, maybe it’s easy to assume the ‘regular’ kind is non-intrusive.

What Stroustrup called ‘intrusive’ had been the default understanding of linked lists since around 1955, and what people used most often. A ‘regular’ linked list to most people back then was the intrusive kind, and the term ‘non-intrusive’ might have been an attempt to sell people on the benefits of abstracting and separating node types from payloads, but that maybe papers over the disadvantages a little.

The only kind of linked list I’ve ever used in my professional career is the intrusive kind. There are very few good reasons to ever use non-intrusive lists outside of the classroom. At least, not if you care about performance at all. They might be convenient & easy, but it’s usually the case that either an array or an intrusive list would be a better engineering choice.

"Intrusive" may be a C++ speak, but I wouldn't say that one or the other type of lists is necessarily much older or more "normal". After all, a cons cell embeds data and not the other way around and lisp is one of the oldest programming languages in existence

Back in the day what is being called out here as an "intrusive" linked list was just a linked list, since you didn't have the luxury of having memory and CPU cycles to waste with extra allocations and indirection.

In the C++ world the STL introduced generic data types such as linked lists, which became the default, but "instrusive" linked lists still have their place in specialized list-heavy use cases where performance matters. In a previous job I wrote a widely adopted XML/JSON library using instrusive lists to link child elements, and the performance benefit was considerable, with my DOM API basically hiding this implementation detail from the user.

You have it backwards, an intrusive linked list is a linked list that is embedded in another data structure. The classic example is a linked list whose elements live on the stack.

The article is wrong too, or at least using the term over-specifically.

It's not really tied to C++isms at all.

This was my reaction exactly. I was surprised by the diagram of a "normal" linked list.

I came to this relatively late (2013-ish, windows kernel development, scouring OSDev, etc) so I thought that was always the right name for them. Prior experience was mostly... higher-level langs.

I concur. I recall being a student and when implementing LL for the first time, you did it this way (mix your data and ptr to next node). It is baby's first linked list.