gh-103059: Clarify gc.freeze documentation (#103058)

Doc/library/gc.rst

@@ -206,12 +206,17 @@ The :mod:`gc` module provides the following functions:
 
 .. function:: freeze()
 
- Freeze all the objects tracked by gc - move them to a permanent generation
- and ignore all the future collections. This can be used before a POSIX
- fork() call to make the gc copy-on-write friendly or to speed up collection.
- Also collection before a POSIX fork() call may free pages for future
- allocation which can cause copy-on-write too so it's advised to disable gc
- in parent process and freeze before fork and enable gc in child process.
+ Freeze all the objects tracked by the garbage collector; move them to a
+ permanent generation and ignore them in all the future collections.
+
+ If a process will ``fork()`` without ``exec()``, avoiding unnecessary
+ copy-on-write in child processes will maximize memory sharing and reduce
+ overall memory usage. This requires both avoiding creation of freed "holes"
+ in memory pages in the parent process and ensuring that GC collections in
+ child processes won't touch the ``gc_refs`` counter of long-lived objects
+ originating in the parent process. To accomplish both, call ``gc.disable()``
+ early in the parent process, ``gc.freeze()`` right before ``fork()``, and
+ ``gc.enable()`` early in child processes.
 
  .. versionadded:: 3.7
 

Misc/ACKS

@@ -1115,6 +1115,7 @@ Jason Lowe
 Tony Lownds
 Ray Loyzaga
 Kang-Hao (Kenny) Lu
+Raymond Lu
 Lukas Lueg
 Loren Luke
 Fredrik Lundh