Integrated: 8364212: Shenandoah: Rework archived objects loading

[Aleksey Shipilev]

On Mon, 28 Jul 2025 15:36:22 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> As continuation of [JDK-8293650](https://bugs.openjdk.org/browse/JDK-8293650), we would want to avoid allocating CDS archives as humongous regions and then flipping them back to regular state. This already complicates the region accounting significantly, and was a source a few bugs. We can rework the CDS archive load to cleanly ask collector for a contiguous set of regular regions.
> 
> Additional testing:
>  - [x] Linux x86_64 server fastdebug, `hotspot_gc_shenandoah`
>  - [x] Linux x86_64 server fastdebug, `runtime/cds`
>  - [x] Linux x86_64 server fastdebug, `runtime/cds` with `-XX:+UseShenandoahGC`
>  - [x] Linux x86_64 server fastdebug, `all`

This pull request has now been integrated.

Changeset: 68a35511
Author:    Aleksey Shipilev <shade at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/68a35511ebd3fd77716242db973104657bc7b541
Stats:     115 lines in 6 files changed: 42 ins; 39 del; 34 mod

8364212: Shenandoah: Rework archived objects loading

Reviewed-by: wkemper, kdnilsen

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PR: https://git.openjdk.org/jdk/pull/26510