Question about bailout list in concurrent marking

[Salt Fish]

Hello everyone,

I read the official blog about concurrent marking (Concurrent marking in V8 · V8).

I am confused about the implementation of the bailout worklist. The bailout list is markingworklist on_hold_  in the c++ code.

I noticed that v8 will move object whose address is between new_space_top and new_space_limit

src/heap/concurrent-marking.cc - v8/v8 - Git at Google (googlesource.com)

I don't understand this.  I found that the page of a semispace can be not contiguous, how to avoid page of old space being between this range?