By "pretty much", I meant that the bucket lists are already allocation free thanks to intrusive lists; of course the hash table itself can uses allocation when

By "pretty much", I meant that the bucket lists are already allocation free thanks to intrusive lists; of course the hash table itself can uses allocation when it's resized, or not, depending on user choice. It's trivial to preallocate it or use an arena or whatever, since it's just a flat array.