Integrated: 8318057: GenShen: investigate small refactor of remset swap code

[Y. Srinivas Ramakrishna]

On Tue, 17 Oct 2023 23:26:31 GMT, Y. Srinivas Ramakrishna <ysr at openjdk.org> wrote:

> Some closures were being unnecessarily applied to free regions rather than just to allocated old and young regions. Restrict the closure application to old and young regions as appropriate, eliminating extra generation affiliation checks in some closures. Also fixed a slightly incorrect documentation comment.
> 
> Replaced use of integer division with right shifts. Added a few useful assertions associated with these operations.
> 
> However, neither of these made any measurable difference to the performance of the bulk operations on the card table.
> 
> **Testing:**
> 
> - [x] jtreg and stress tests in test pipeline helper
> - [x] locally tested with jtreg hotsot_gc tests and with specjbb with and without heap verification
> - [x] no performance improvements noted; see ticket

This pull request has now been integrated.

Changeset: 05b7a3c5
Author:    Y. Srinivas Ramakrishna <ysr at openjdk.org>
URL:       https://git.openjdk.org/shenandoah/commit/05b7a3c5d59173c9f7c9db4ee7a7bca642c3d4a9
Stats:     103 lines in 4 files changed: 61 ins; 25 del; 17 mod

8318057: GenShen: investigate small refactor of remset swap code

Reviewed-by: kdnilsen, wkemper

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

PR: https://git.openjdk.org/shenandoah/pull/342