Integrated: 8295657: SA: Allow larger object alignments

[Aleksey Shipilev]

On Wed, 19 Oct 2022 12:04:49 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> Found this when working on JOL support ([CODETOOLS-7903364](https://bugs.openjdk.org/browse/CODETOOLS-7903364)). If you try to attach to VM running with -XX:ObjectAlignmentInBytes=32, then SA would fail with:
> 
> 
> Caused by: java.lang.RuntimeException: Object alignment 32 not yet supported
> at jdk.hotspot.agent/sun.jvm.hotspot.runtime.VM.<init>(VM.java:510)
> at jdk.hotspot.agent/sun.jvm.hotspot.runtime.VM.initialize(VM.java:544)
> at jdk.hotspot.agent/sun.jvm.hotspot.HotSpotAgent.setupVM(HotSpotAgent.java:444)
> 
> 
> This code was added by [JDK-6916623](https://bugs.openjdk.org/browse/JDK-6916623), but I don't see a reason why it should only handle 8 and 16 byte alignment.
> 
> Additional testing:
>  - [x] New regression test
>  - [x] Linux x86_64 fastdebug `serviceability/sa`, with the combination of:
>     - different `-XX:ObjectAlignmentInBytes=`: 8, 16, 32, 64, 128, 256
>     - different GCs: Serial, Parallel, G1
>  - [x] Linux x86_64 fastdebug `sun/tools/jhsdb`, with the combination of:
>     - different `-XX:ObjectAlignmentInBytes=`: 8, 16, 32, 64, 128, 256
>     - different GCs: Parallel, G1

This pull request has now been integrated.

Changeset: dfd2d831
Author:    Aleksey Shipilev <shade at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/dfd2d83144fe4d78a7144acda6d9cb3e0045ea70
Stats:     105 lines in 2 files changed: 99 ins; 4 del; 2 mod

8295657: SA: Allow larger object alignments

Reviewed-by: stuefe, cjplummer

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PR: https://git.openjdk.org/jdk/pull/10762