3 ms·

At least in NetBSD, M:N was abandoned not for performance reasons but because it was too complex and could not be fully debugged. I don't know the details, but

• nickpsecurity 11y ago
  It's something that, if it could be optimal, would only be optimal in specific situations. A lot of tactics CompSci discovers are like that. So, we experiment with them, stash them, whatever. Mainstream and crowd effects in academia both have a tendency to occasionally jump on something like a crusade. Many promises are made, much money thrown at it, and it never delivers. Inability to integrate with models of legacy systems, either at all or with desired attributes, is often one result of this. I knew the moment I saw the activity that it couldn't be trusted without further review. It was at least useful in security kernel model but most of those are gone now. So, we stash it in case it benefits another problem one day or someone has a use for it likely in a clean-slate system. That's how these things go. I wouldn't expect it to work on NetBSD or any UNIX. Even the good ideas often fail to integrate into UNIX. Half-ass ones like M:N more so. UNIX model is just too broken. Hence, my opposing it here.