[gclist] Are the traces sequential?

[Rick Hudson]

Interesting stuff and my brain is still trying to figure it all out.
I do have a few questions that might help me out. 

Point 1.

Is it true that after an initial trace is done and a suspected garbage train
is discovered then a second confirming trace is done to insure that nothing
has changed since the first trace. Just to clarify this point when I say
nothing has changed I mean that no pointers have been passed out (read barrier
protection) and no pointers to an object have arrived (write barrier
protection) since the first trace.

Point 2. 

The length of the trace is not bounded.

- Rick Hudson