> You'll eventually sweep That's the key here. Eventually. When it is convenient to do so. You have a very fine grained control over when sweeper process may d

> You'll eventually sweep That's the key here. Eventually. When it is convenient to do so. You have a very fine grained control over when sweeper process may do its dirty job. It's far more complicated with RC to ensure that it only does a certain small amount of work once in a while. And with a loop detection, you have to do everything at once. Also, with mark&sweep you can keep your tags somewhere else altogether and avoid touching (and invalidating) the actual data at all, at no additional cost.