RFR: 8292170: Convert CodeRootSetTable to use ResourceHashtable [v2]

[Coleen Phillimore]

On Thu, 15 Dec 2022 13:56:27 GMT, Leo Korinth <lkorinth at openjdk.org> wrote:

>> I am replacing the old hash table with ResourceHashtable. In the process I am also removing the redundant `_length` field. By removing the `_length` field, a lot of asserts can be removed as the length will trivially match the length of the underlying table.
>> 
>> I would like to have feedback on the addition of `unlink_destruct(Function&& should_remove)`. I added it because I prefer to use a functor object that can be used by lambdas instead of an iterator object. However, I did add code to "destruct" resource objects when they are removed instead of just letting them be to reflect that we use `delete` on c-heap objects. Maybe I should remove this "improvement" and then maybe implement the function by calling the existing unlink?
>
> Leo Korinth has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - copyrights
>  - use iter function interface instead, make closure NONCOPYABLE

Well this looks A LOT better than the old hashtable and I'm hitting approve but I don't know this code so take that with a grain of salt.  Thank you.

src/hotspot/share/gc/g1/g1CodeCacheRemSet.cpp line 73:

> 71:   _table.iterate_all([&](nmethod* nm, nmethod* _) {
> 72:     blk->do_code_blob(nm);
> 73:   });

cool use of lambdas.

src/hotspot/share/gc/g1/g1CodeCacheRemSet.cpp line 222:

> 220:   CleanCallback should_clean(owner);
> 221:   if (_table != NULL) {
> 222:     _table->remove_if(should_clean);

remove_if is a template function but it's only called here.  Does it need to be a template function?

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Marked as reviewed by coleenp (Reviewer).

PR: https://git.openjdk.org/jdk/pull/11675