RFR: 8315884: New Object to ObjectMonitor mapping [v9]

[Axel Boldt-Christmas]

On Tue, 23 Jul 2024 13:19:02 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> src/hotspot/share/runtime/lightweightSynchronizer.cpp line 62:
>> 
>>> 60: class ObjectMonitorWorld : public CHeapObj<MEMFLAGS::mtObjectMonitor> {
>>> 61:   struct Config {
>>> 62:     using Value = ObjectMonitor*;
>> 
>> Does this alias really help? We don't state the type that many times and it looks odd to end up with a mix of `Value` and `ObjectMonitor*` in the same code.
>
> This alias is present in the other CHT implementations, alas as a typedef in StringTable and SymbolTable so this follows the pattern and allows cut/paste of the allocate_node, get_hash, and other functions.

It is required by the `ConcurrentHashTable` implementation.
https://github.com/openjdk/jdk/blob/ebf1154292aa5e78c9eb9ddb26a1a3f9885c2ef8/src/hotspot/share/utilities/concurrentHashTable.hpp#L43-L45

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PR Review Comment: https://git.openjdk.org/jdk/pull/20067#discussion_r1715304376