Integrated: Enforce max regions

[Kelvin Nilsen]

On Tue, 6 Dec 2022 17:57:18 GMT, Kelvin Nilsen <kdnilsen at openjdk.org> wrote:

> This commit enforces upper bounds on the number of ShenandoahHeapRegions affiliated with each generation.  Prior to this change, enforcement of generation sizes was by usage alone.  This allowed situations in which so many sparsely populated regions were affiliated with old-gen that there were insufficient FREE regions available to satisfy legitimate young-gen allocation requests.  This was resulting in excessive TLAB allocation failures and degenerated collections.

This pull request has now been integrated.

Changeset: 25469283
Author:    Kelvin Nilsen <kdnilsen at openjdk.org>
URL:       https://git.openjdk.org/shenandoah/commit/25469283fbe14e85adeaf0e3a21d40faea5f7288
Stats:     202 lines in 10 files changed: 150 ins; 17 del; 35 mod

Enforce max regions

Reviewed-by: wkemper, ysr

-------------

PR: https://git.openjdk.org/shenandoah/pull/179