RFR: 8305895: Implement JEP 450: Compact Object Headers (Experimental) [v6]

[Roman Kennke]

On Mon, 9 Sep 2024 14:47:28 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

>> src/hotspot/share/cds/filemap.cpp line 2508:
>> 
>>> 2506: 
>>> 2507:   if (compact_headers() != UseCompactObjectHeaders) {
>>> 2508:     log_info(cds)("The shared archive file's UseCompactObjectHeaders setting (%s)"
>> 
>> Printing on the `info` level mimics what we do when there's a mismatch for compressed classes (and oops), but I wonder if that one is intentional or if it is accidentally printing to 'info' instead of 'warning'.
>
> @iklam informed me that some of the info levels (including this line) should be converted to warning.

Yeah that looks inconsistent with other places where we print a warning instead. I'll change it to warning for the UCOH check.

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PR Review Comment: https://git.openjdk.org/jdk/pull/20677#discussion_r1750430001