RFR: 8373295: Wrong log tag for UseCompressedOops ergo setting

[Ioi Lam]

On Tue, 9 Dec 2025 06:42:47 GMT, David Holmes <dholmes at openjdk.org> wrote:

> The CDS logging line was put in for JDK-8226462, and as referenced by Yasumasa it was there for CDS users to be informed (or perhaps more accurately for one of our CDS tests to check it). Does that test no longer exist, or check this condition?

This log is used only by the SysDictCras.java test .

CDS dumping requires `UseCompressedClassPointers==true`. In the time of JDK-8226462, when running on a host with lot of RAM, `UseCompressedOops` would be disabled, which causes `UseCompressedClassPointers` to be disabled, which caused the CDS dump to fail.

This is no longer the case -- `UseCompressedClassPointers` is now independent of `UseCompressedOops`


$ java -XX:MaxRAM=512g -XX:MaxRAMPercentage=12.5 -XX:+PrintFlagsFinal --version | grep UseCompressedClassPointers
     bool UseCompressedClassPointers   = true   {product} {default}


Also, the test is kind of pointless now. The only significant VM flags are

- `-XX:SharedBaseAddress=0`: this is covered by other test cases such as test/hotspot/jtreg/runtime/cds/appcds/ArchiveRelocationTest.java
- `-XX:MaxRAMPercentage=12.5`: this might have been useful in reproducing the original crash but it's no longer relevant.

So I removed this test altogether.

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PR Comment: https://git.openjdk.org/jdk/pull/28716#issuecomment-3630781054