RFR: 8286066: FillerObject_klass should be loaded as early as possible [v4]

[Jie Fu]

On Wed, 4 May 2022 02:10:35 GMT, Jie Fu <jiefu at openjdk.org> wrote:

>> For the x64 case (thanks for that reproducer!) it crashes after loading ` java.lang.Thread$UncaughtExceptionHandler` - so somewhat later than the x86 case.
>> I thought the underlying problem was the TLAB size but at least with EpsilonGC it is acting very counterintuitively - any size > 6K crashes, while less does not. But logging also seems to show that the requested size is not being honoured in those cases but the Ergo size of 2K is being selected! This is all very odd, but perhaps specific to Epsilon.
>> With G1 I can crash with a TLABSize of 4K (or less), but it occurs much later after loading `jdk.internal.reflect.UnsafeStaticFieldAccessorImpl` (for 4K). With 2K minimum TLABSize it is after `java.lang.Boolean`.
>> So I guess after Error is a reasonable compromise.
>> Thanks.
>
>> So I guess after Error is a reasonable compromise.
> 
> 
> Updated.
> `runtime/cds/appcds/TestEpsilonGCWithCDS.java runtime/cds/FillerObjectLoadTest.java` passed on Linux/x86_32.
> More testing is in progress.
> Thanks.

> With G1 I can crash with a TLABSize of 4K (or less), but it occurs much later after loading

The jtreg test had been updated to also test the default GC.
Thanks.

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PR: https://git.openjdk.java.net/jdk/pull/8519