RFR: 8361726: Shenandoah: More detailed evacuation instrumentation [v3]

[Y. Srinivas Ramakrishna]

On Wed, 23 Jul 2025 23:16:42 GMT, William Kemper <wkemper at openjdk.org> wrote:

>> Shenandoah has `not product` instrumentation to track evacuation performance. This change introduces more detail by categorizing each evacuation as young, old or promotion.
>
> William Kemper has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fix merge error

src/hotspot/share/gc/shenandoah/shenandoahEvacTracker.hpp line 106:

> 104:   void begin_evacuation(Thread* thread, size_t bytes, ShenandoahAffiliation from, ShenandoahAffiliation to);
> 105: 
> 106:   // Multiple threads may attempt to evacuate the same object, but only the succeeding thread will end the evacuation.

Instead of `only the succeeding thread will end the evacuation`, I might say: `the unique thread that is successful will end the evacuation`. (Alternatively, replace "succeeding" with "successful"; the word "succeeding" as an adjective can be ambiguous in this context.)

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PR Review Comment: https://git.openjdk.org/jdk/pull/26222#discussion_r2227175181