<p>What does the allocation under "VM: Dispatch continuations" signify?</p> <p><img src="https://i.stack.imgur.com/4kuqz.png" alt="enter image description here"> (http://i.stack.imgur.com/4kuqz.png)</p>

Mark Generation: What is VM: Dispatch continuations

What does the allocation under "VM: Dispatch continuations" signify?

enter image description here (http://i.stack.imgur.com/4kuqz.png)

@InkGolem is on the right lines. This is a cache for dispatch blocks inside GCD.

@AbhiBeckert is off by a factor of 1000. 16MB is 2 million 64-bit pointers, not 2 billion.

This cache is allocated on a per-thread basis, and you're just seeing the allocation size of this cache, not what's actually in use. 16 MB is well within range, if you're doing lots of dispatching onto background threads (and since you're using RAC, I'm guessing that you are).

Don't worry about it, basically.