RFR: 8327452: G1: Improve scalability of Merge Log Buffers [v5]

[Kim Barrett]

On Tue, 12 Mar 2024 11:47:01 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

>> Ivan Walulya has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Kim Review
>
> src/hotspot/share/gc/g1/g1RemSet.cpp line 1313:
> 
>> 1311:           count += tail->size();
>> 1312:           cur = tail->next();
>> 1313:         }
> 
> Still good. Looking at this balancing code again, maybe a comment about that part ("// Balance dirty card buffers for better work distribution.") or factoring this out into a helper method for documentation purposes would be nice.
> It just feels quite a bit of code in a constructor, but just a comment what this is doing is just fine. Or just ignore if you feel it is obvious.

To me, the balancing code seems pretty obvious in the context of avoiding the bottleneck of a single
list being processed by multiple threads.  But a comment about that bottleneck to explain all of this stuff
around `_dirty_card_buffers` might be nice.

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

PR Review Comment: https://git.openjdk.org/jdk/pull/18134#discussion_r1521508818