RFR: 8294954: Remove superfluous ResourceMarks when using LogStream

[David Holmes]

On Fri, 21 Mar 2025 15:38:21 GMT, Casper Norrbin <cnorrbin at openjdk.org> wrote:

> Hi everyone,
> 
> This PR removes redundant `ResourceMark` instances where `LogStream` is used. Previously, `LogStream` inherited from `ResourceObj`, which required a `ResourceMark`, but this is no longer the case, making these instances unnecessary.
> 
> Process:
> 1. I added assertions to check for resource unwinding in places where `ResourceMark`s were used with `LogStream`s.
> 2. Ran tests up to tier7 to confirm no unwinding was happening. This helped filter out cases where `ResourceMark`s were still required for other reasons.
> 3. Manually verified the remaining cases by tracing function calls to ensure the `ResourceMark`s were truly unnecessary.
> 4. Removed the redundant `ResourceMark` instances.

Did you determine that the deleted RM's were put in to be used by the LogStream rather than the things being printed to the LogStream? It is quite difficult to be sure you have exercised all of the logging code that was modified. It is quite likely many of these log outputs are not actually being tested anywhere (and very difficult to verify one way or another). Have you tested by enabling all logging in some simple tests on all platforms? (Of course that is nowhere near sufficient in terms of coverage as you would need to test with numerous permutations of VM features.)

Thanks

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PR Review: https://git.openjdk.org/jdk/pull/24162#pullrequestreview-2709241848