RFR: 8368006: Parallel: Skip full regions in dense prefix during Full GC [v2]

[Albert Mingkun Yang]

On Wed, 24 Sep 2025 14:49:00 GMT, Francesco Andreuzzi <fandreuzzi at openjdk.org> wrote:

>> Albert Mingkun Yang has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:
>> 
>>  - review
>>  - Merge branch 'master' into pgc-skip-full-region
>>  - pgc-skip-full-region
>
> src/hotspot/share/gc/parallel/psParallelCompact.cpp line 1721:
> 
>> 1719:   for (HeapWord* cur_addr = start_addr; cur_addr < end_addr; /* empty */) {
>> 1720:     RegionData* cur_region_ptr = _summary_data.addr_to_region_ptr(cur_addr);
>> 1721:     if (cur_region_ptr->data_size() == region_size) {
> 
> The next lines up to `cur_addr += cur_region_ptr->partial_obj_size()` could possibly be extracted to a common function? Then you could check again if `cur_region_ptr->data_size() == region_size` to decide if you should `continue`.

Can you provide a snippet? I don't get what you are suggesting. Just fyi, `cur_addr += cur_region_ptr->partial_obj_size()` is needed to make sure `cur_addr` is live-obj-end.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27369#discussion_r2376098764