RFR: 8300915: G1: incomplete SATB because nmethod entry barriers don't get armed [v5]

[Richard Reingruber]

On Thu, 26 Jan 2023 21:07:34 GMT, Erik Österlund <eosterlund at openjdk.org> wrote:

>> Richard Reingruber has updated the pull request incrementally with two additional commits since the last revision:
>> 
>>  - Remark: only finish codecache cycle if marking was finished
>>  - Conservative fix: arm nmethods unconditionally at marking start
>
> src/hotspot/share/gc/g1/g1CollectedHeap.cpp line 3389:
> 
>> 3387:     CodeCache::on_gc_marking_cycle_start();
>> 3388:   }
>> 3389:   if (!full_gc) {
> 
> Should this be else if?

No, `!full_gc` means we reach here because concurrent marking is about to start and we want to arm unconditionally then. Never arm for the start of a full gc on the other hand.

Would it be clearer if I renamed `full_gc` to `concurrent_marking_start`?

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PR: https://git.openjdk.org/jdk/pull/12194