RFR: 8302215: G1: Last-ditch Full GC should do serial compaction for tail regions in per thread compaction points. [v3]

[Albert Mingkun Yang]

On Thu, 16 Feb 2023 16:39:58 GMT, Ivan Walulya <iwalulya at openjdk.org> wrote:

>> Hi all, 
>> 
>> Please review this change to call `G1FullCollector::phase2c_prepare_serial_compaction` when `do_maximal_compaction`. For maximum compaction, we re-prepare all objects in the "tail" regions of the per thread compaction points.
>> 
>> Testing: Tier 1-3.
>> 
>> Thanks
>
> Ivan Walulya has updated the pull request incrementally with one additional commit since the last revision:
> 
>   reviews

src/hotspot/share/gc/g1/g1FullCollector.cpp line 382:

> 380:   for (uint i = lowest_current; i < _heap->max_reserved_regions(); i++) {
> 381:     if (_region_attr_table.is_free(i) || _region_attr_table.is_compacting(i)) {
> 382:       serial_cp->add(_heap->region_at(i));

Could `G1SerialRePrepareClosure` be used here, instead of having another loop iterating over the same set of regions in next step?

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PR: https://git.openjdk.org/jdk/pull/12529