RFR: Cleanups, TODOs, asserts (part 1) [v2]

[Aleksey Shipilev]

On Thu, 6 Apr 2023 16:56:23 GMT, William Kemper <wkemper at openjdk.org> wrote:

>> Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   New assert fires, but instead of fixing it, remove useless live_memory completely
>
> src/hotspot/share/gc/shenandoah/c2/shenandoahBarrierSetC2.cpp line 943:
> 
>> 941:     int flags = ShenandoahHeap::HAS_FORWARDED;
>> 942:     if (ShenandoahIUBarrier) {
>> 943:       // TODO: Shouldn't this be OLD_MARKING too?
> 
> Generational mode requires SATB barriers right now - IU mode only has the young generation.

Ok, removed.

> src/hotspot/share/gc/shenandoah/shenandoahConcurrentGC.cpp line 125:
> 
>> 123:     // Concurrent remembered set scanning
>> 124:     entry_scan_remembered_set();
>> 125:     // TODO: When RS scanning yields, we will need a check_cancellation_and_abort() degeneration point here.
> 
> We need to be really careful when transitioning to a degenerated cycle after RS scan is complete. Logically, the RS scan is part of the concurrent root scan, but it didn't get implemented with that pattern.

Yes, I just converted this to TODO, because it looks like a TODO.

> src/hotspot/share/gc/shenandoah/shenandoahControlThread.cpp line 284:
> 
>> 282:           if (age_period-- == 0) {
>> 283:              heap->set_aging_cycle(true);
>> 284:             age_period = ShenandoahAgingCyclePeriod - 1;
> 
> Indentation looks inconsistent here

Fixed! Thanks.

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PR Review Comment: https://git.openjdk.org/shenandoah/pull/245#discussion_r1160079018
PR Review Comment: https://git.openjdk.org/shenandoah/pull/245#discussion_r1160078567
PR Review Comment: https://git.openjdk.org/shenandoah/pull/245#discussion_r1160077543