RFR: 8189088: Add intrusive doubly-linked list utility [v7]

[Stefan Johansson]

On Mon, 16 Oct 2023 07:56:14 GMT, Kim Barrett <kbarrett at openjdk.org> wrote:

>> Kim Barrett has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   const-element nomenclature, other review comments
>
> src/hotspot/share/utilities/intrusiveList.hpp line 87:
> 
>> 85:  * * Base is the base class for the list.  This is typically
>> 86:  * used to specify the allocation class, such as CHeapObj<>.  The default
>> 87:  * is void, indicating the list is not derived from an allocation class.
> 
> I'm not certain this Base class for allocation support is actually needed.  I remember one of the alternatives had
> (or used to have?) allocation base class support, but haven't found it when I looked recently.  But we have a lot
> of these doubly-linked-lists in HotSpot.  Do we have a use-case for a "heap" allocated bare (as in not
> embedded in some other object) list?  Removing it would save ~25 lines of code/comments.

Did a quick skim as well and yes, quite a few ad-hoc lists in the code base. Did not see a case needing this and I think removing this makes sense if we don't see an obvious use-case.

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PR Review Comment: https://git.openjdk.org/jdk/pull/15896#discussion_r1361667266