RFR: 8337658: ZGC: Move soft reference handling out of the driver loop function

[Guoxiong Li]

On Thu, 1 Aug 2024 12:19:04 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

> The ZDriver code is written to be neat and have a clear outline. The soft reference handling distracts when reading this code. I propose that we hide it a bit.
> 
> I've also clarified in comments and names that the code is dealing with clearing of *all* references.

I don't know whether `_uses_clear_all_soft_references_policy` is a good name. I may be confused by the name if I read the code first time.

One nit shown below.

src/hotspot/share/gc/z/zReferenceProcessor.hpp line 73:

> 71: 
> 72:   void set_soft_reference_policy(bool clear_all_soft_references);
> 73:   bool uses_clear_all_soft_reference_policy() const;

The method name should be `uses_clear_all_soft_references_policy`. Please note the letter `s` after the `reference`.

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Changes requested by gli (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/20418#pullrequestreview-2247312576
PR Review Comment: https://git.openjdk.org/jdk/pull/20418#discussion_r1722903702