RFR: 8252103: Parallel heap inspection for ParallelScavengeHeap [v6]

[Stefan Johansson]

On Wed, 28 Oct 2020 11:31:01 GMT, Lin Zang <lzang at openjdk.org> wrote:

>> - Parallel heap iteration support for PSS
>> - JBS:  https://bugs.openjdk.java.net/browse/JDK-8252103
>
> Lin Zang has updated the pull request incrementally with one additional commit since the last revision:
> 
>   fix constant coding style and do code refine

The build testing caught an error. If you enable GitHub actions for openjdk, you will get basic testing like this automatically (if your branch is based on a recent master or merged recently).

src/hotspot/share/gc/parallel/psOldGen.hpp line 170:

> 168:   uint iterable_blocks() {
> 169:     return (object_space()->used_in_bytes() + IterateBlockSize - 1) / IterateBlockSize;
> 170:   }

This causes a build failure on windows:
hotspot\share\gc/parallel/psOldGen.hpp(169): error C2220: the following warning is treated as an error
hotspot\share\gc/parallel/psOldGen.hpp(169): warning C4267: 'return': conversion from 'size_t' to 'uint', possible loss of data
I suggest either changing the return here to `int` and make an explicit cast or `size_t` and then add the cast when used in `claim_and_get_block()`

-------------

Changes requested by sjohanss (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/25