RFR: 8263915: runtime/cds/appcds/MismatchedPathTriggerMemoryRelease.java fails when UseCompressedClassPointers is off [v2]

[Jie Fu]

On Mon, 22 Mar 2021 20:50:25 GMT, Yumin Qi <minqi at openjdk.org> wrote:

>> Hi Jie,
>> 
>> I think it would be better to couple this not to bitness but directly to UseCompressedClassPointers. The test should also work if we run it with a 64bit VM with compressed class pointers off.
>> 
>> To keep matters simple, I think one could even match either pattern always instead of making it dependent on CompressedClassPointers, but I leave this up to the CDS guys.
>> 
>> Thanks, Thomas
>
>> Hi Jie,
>> 
>> I think it would be better to couple this not to bitness but directly to UseCompressedClassPointers. The test should also work if we run it with a 64bit VM with compressed class pointers off.
>> 
>> To keep matters simple, I think one could even match either pattern always instead of making it dependent on CompressedClassPointers, but I leave this up to the CDS guys.
>> 
>> Thanks, Thomas
> 
> Hi, Thomas, Jie
>   On 32bit platform, UseCompressedOops/UseCompressedClassPointers do not exist. So checking for that flag is a little different I think. @DamonFool , could you try to use WhiteBox.getBooleanVMFlag("UseCompressedClassPointers") to check this flag? If it does not exists, it should return null, or it is true/false.  This way, you can have two patterns to check again the result.
> 
> Thanks
> Yumin

Thanks @yminqi and @iklam for your review and comments.

I think @iklam 's suggestion is reasonable and simple enough.
Updated and testing on x64/x86 passed.
Thanks.

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PR: https://git.openjdk.java.net/jdk/pull/3110