Integrated: 8371381: [Shenandoah] Setting ergo flags should use FLAG_SET_ERGO

[Rui Li]

On Tue, 11 Nov 2025 18:24:25 GMT, Rui Li <duke at openjdk.org> wrote:

> Setting ergo flags using `FLAG_SET_ERGO`, instead of `FLAG_SET_DEFAULT`, so we can have the right origin info.
> 
> 
> For `ShenandoahEvacReserve` change: when we use shenandoah passive mode and degen is also turned off (`-XX:ShenandoahGCMode=passive -XX:-ShenandoahDegeneratedGC`), we set the ShenandoahEvacReserve to 0:  https://github.com/openjdk/jdk/blob/c6a8027b94bbcbde5f7dcabd0bff48b93bbb5a7f/src/hotspot/share/gc/shenandoah/mode/shenandoahPassiveMode.cpp#L40-L42
> 
> `FLAG_SET_DEFAULT` doesn't check the range but `FLAG_SET_ERGO` does so some of the jtreg would fail because of this change. Had to move this ergo setting to regular `FLAG_SET_DEFAULT`.
> 
> Testing: jtreg gc. GHA pending.

This pull request has now been integrated.

Changeset: 2199b5fe
Author:    Rui Li <ruiamzn at amazon.com>
Committer: Xiaolong Peng <xpeng at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/2199b5fef4540ae8da77c5c4feafc8822a3d9d3d
Stats:     8 lines in 2 files changed: 4 ins; 0 del; 4 mod

8371381: [Shenandoah] Setting ergo flags should use FLAG_SET_ERGO

Reviewed-by: xpeng, wkemper, ysr, cslucas

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PR: https://git.openjdk.org/jdk/pull/28242