RFR: JDK-8266802: Shenandoah: Round up region size to page size unconditionally [v2]

[Zhengyu Gu]

On Mon, 10 May 2021 15:04:27 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> Since JDK-8265239, runtime/os/TestTracePageSizes.java fails with Shenandoah like this:
>> 
>> 
>> # Internal Error (/home/buildbot/worker/test-jdkX-linux/build/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp:156), pid=55712, tid=55720
>> # assert(_num_regions == (max_byte_size / reg_size_bytes)) failed: Must match
>> 
>> 
>> This is because Shenandoah region sizes are rounded up to page size only when `ShenandoahUncommit` is true. In the failing test configuration, `ShenandoahUncommit` is false, because Xmx == Xms.
>> 
>> Additional testing:
>>  - [x] New regression test, now passes
>>  - [x] `tier1` with Shenandoah
>
> Aleksey Shipilev has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:
> 
>  - Merge branch 'master' into JDK-8266802-shenandoah-region-size
>  - Minor whitespace
>  - Fix and regression tests

Looks good

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Marked as reviewed by zgu (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/3945