RFR: 8272773: Investigate making card table size configurable

[Vishal Chand]

On Thu, 7 Oct 2021 11:20:37 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

>> Hi,
>> 
>> Please review the changes to make CardTable entry size configurable. The changes primarily consists of:
>> 
>> 1. Addition of a cmdline flag **GCCardSizeInBytes** to make the card size startup time configurable.
>> 2. Setting the card size based on the flag in G1, Parallel and Serial GC memory initialization paths.
>> 3. Setting BlockOffsetTable size and ObjectStartArray size based on the card size.
>
> src/hotspot/share/gc/parallel/objectStartArray.hpp line 57:
> 
>> 55:   static uint block_shift;
>> 56:   static uint block_size;
>> 57:   static uint block_size_in_words;
> 
> I *think* the naming guideline for static members is the same as for regular class members, i.e. use an underscore in front. Maybe wait on changing this for another person to comment on (I did not look up the style guide).
> We do not use public static members too often :)

Actually I've kept the names of all the pre-existing constants (which are now variables) same as before. Otherwise we have to change all the references also.

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PR: https://git.openjdk.java.net/jdk/pull/5838