RFR: 8256172: Clean up CDS handling of i2i_entry [v2]

[Ioi Lam]

On Wed, 18 Nov 2020 18:26:44 GMT, Yumin Qi <minqi at openjdk.org> wrote:

>> Ioi Lam has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains three commits:
>> 
>>  - fixed merge
>>  - Merge branch 'master' into 8256172-cleanup-cds-i2i-entry
>>  - 8256172: Clean up CDS handling of i2i_entry
>
> src/hotspot/share/memory/metaspaceShared.cpp line 513:
> 
>> 511:   // We don't want any valid object to be at the very bottom of the archive.
>> 512:   // See ArchivePtrMarker::mark_pointer().
>> 513:   MetaspaceShared::misc_code_space_alloc(16);
> 
> 16 looks arbitrary number though we know it is minimal object alignment --- maybe we we can use object_alignment instead? up to you.

`16` is just an arbitrary small number. `MetaspaceShared::misc_code_space_alloc(16)` will round up the size to the appropriate alignment. So I think I'll keep the existing code.

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PR: https://git.openjdk.java.net/jdk/pull/1280