RFR: 8174986: CDS archived java heap region may not compatible with AOT

[Jiangli Zhou]

Thank for the review, Ioi! I’ll fix the typo.

Jiangli

> On Oct 5, 2017, at 9:30 AM, Ioi Lam <ioi.lam at oracle.com> wrote:
> 
> Hi Jiangli:
> 
> The changes look good, and thank you for doing the clean up. I agree that MetaspaceShared::initialize_runtime_shared_and_meta_spaces() is a better location for this functionality that inside metaspace.cpp.
> 
> Just a small typo:
> 
> 306   // Set narrow_klass_shift to be LogKlassAlignmentInBytes. This is consisten
> 
> -> consistent
> 
> Thanks
> 
> - Ioi
> 
> 
> On 10/4/17 4:12 PM, Jiangli Zhou wrote:
>> Hi,
>> 
>> Please review the following enhancement that always sets the narrow klass encoding shift to be LogKlassAlignmentInBytes when CDS is enabled. This is done so the archived java heap regions (the shared string space and adjustable archive heap space) can coexist with AOT code, because AOT uses LogKlassAlignmentInBytes for narrow klass encode shift when generating the precompiled code.
>> 
>> I also took the opportunity to clean up Meatspace::global_initialize(). I moved the block of code that initializes the shared spaces and meatspace at CDS runtime into a new function, MetaspaceShared::initialize_runtime_shared_and_meta_spaces(). I also added more comments so it is easier to understand the logic.
>> 
>> webrev: http://cr.openjdk.java.net/~jiangli/8174986/webrev.00/ <http://cr.openjdk.java.net/~jiangli/8174986/webrev.00/><http://cr.openjdk.java.net/~jiangli/8174986/webrev.00/ <http://cr.openjdk.java.net/~jiangli/8174986/webrev.00/>>
>> RFE: https://bugs.openjdk.java.net/browse/JDK-8174986?filter=14921 <https://bugs.openjdk.java.net/browse/JDK-8174986?filter=14921><https://bugs.openjdk.java.net/browse/JDK-8174986?filter=14921 <https://bugs.openjdk.java.net/browse/JDK-8174986?filter=14921>>
>> 
>> Tested with all CDS/AppCDS tests on linux x64.
>> 
>> Thanks,
>> Jiangli