RFR: Cleanup UseShenandoahOWST blocks

[Zhengyu Gu]

On 07/09/2018 05:12 AM, Roman Kennke wrote:
> Looks good, thank you!
> 
> We should soon consider to go for OWST by default. It's baked long
> enough. The only thing to wait for is current upstreaming efforts by
> Zhengyu, at which point we can just use upstreams TQ stuff.

Looks like that Thomas Schatzl is playing it. He mentioned that he ran 
into unexplainable hung with source code we probably don't know about.

-Zhengyu

> 
> Roman
> 
> 
>> This applies a few trivial cleanups around UseShenandoahOWST blocks. Mostly renames "*_task" ->
>> task, and cleaning up useless UseShenandoahOWST in ShenandoahTraversalGC::init_traversal_collection:
>>
>> diff -r fde9a873d896 src/hotspot/share/gc/shenandoah/shenandoahConcurrentMark.cpp
>> --- a/src/hotspot/share/gc/shenandoah/shenandoahConcurrentMark.cpp	Mon Jul 09 10:29:38 2018 +0200
>> +++ b/src/hotspot/share/gc/shenandoah/shenandoahConcurrentMark.cpp	Mon Jul 09 10:34:32 2018 +0200
>> @@ -419,16 +419,16 @@
>>
>>     task_queues()->reserve(nworkers);
>>
>>     if (UseShenandoahOWST) {
>>       ShenandoahTaskTerminator terminator(nworkers, task_queues());
>> -    ShenandoahConcurrentMarkingTask markingTask = ShenandoahConcurrentMarkingTask(this,
>> &terminator, update_refs);
>> -    workers->run_task(&markingTask);
>> +    ShenandoahConcurrentMarkingTask task(this, &terminator, update_refs);
>> +    workers->run_task(&task);
>>     } else {
>>       ParallelTaskTerminator terminator(nworkers, task_queues());
>> -    ShenandoahConcurrentMarkingTask markingTask = ShenandoahConcurrentMarkingTask(this,
>> &terminator, update_refs);
>> -    workers->run_task(&markingTask);
>> +    ShenandoahConcurrentMarkingTask task(this, &terminator, update_refs);
>> +    workers->run_task(&task);
>>     }
>>
>>     assert(task_queues()->is_empty() || sh->cancelled_gc(), "Should be empty when not cancelled");
>>   }
>>
>> diff -r fde9a873d896 src/hotspot/share/gc/shenandoah/shenandoahTraversalGC.cpp
>> --- a/src/hotspot/share/gc/shenandoah/shenandoahTraversalGC.cpp	Mon Jul 09 10:29:38 2018 +0200
>> +++ b/src/hotspot/share/gc/shenandoah/shenandoahTraversalGC.cpp	Mon Jul 09 10:34:32 2018 +0200
>> @@ -417,19 +417,12 @@
>>       {
>>         uint nworkers = _heap->workers()->active_workers();
>>         task_queues()->reserve(nworkers);
>>         ShenandoahRootProcessor rp(_heap, nworkers, ShenandoahPhaseTimings::init_traversal_gc_work);
>>
>> -      if (UseShenandoahOWST) {
>> -        ShenandoahTaskTerminator terminator(nworkers, task_queues());
>> -        ShenandoahInitTraversalCollectionTask traversal_task(&rp);
>> -        _heap->workers()->run_task(&traversal_task);
>> -      } else {
>> -        ParallelTaskTerminator terminator(nworkers, task_queues());
>> -        ShenandoahInitTraversalCollectionTask traversal_task(&rp);
>> -        _heap->workers()->run_task(&traversal_task);
>> -      }
>> +      ShenandoahInitTraversalCollectionTask traversal_task(&rp);
>> +      _heap->workers()->run_task(&traversal_task);
>>       }
>>
>>   #if defined(COMPILER2) || INCLUDE_JVMCI
>>       DerivedPointerTable::update_pointers();
>>   #endif
>> @@ -641,16 +634,16 @@
>>     if (!_heap->cancelled_gc()) {
>>       uint nworkers = _heap->workers()->active_workers();
>>       task_queues()->reserve(nworkers);
>>       if (UseShenandoahOWST) {
>>         ShenandoahTaskTerminator terminator(nworkers, task_queues());
>> -      ShenandoahConcurrentTraversalCollectionTask traversal_task(&terminator);
>> -      _heap->workers()->run_task(&traversal_task);
>> +      ShenandoahConcurrentTraversalCollectionTask task(&terminator);
>> +      _heap->workers()->run_task(&task);
>>       } else {
>>         ParallelTaskTerminator terminator(nworkers, task_queues());
>> -      ShenandoahConcurrentTraversalCollectionTask traversal_task(&terminator);
>> -      _heap->workers()->run_task(&traversal_task);
>> +      ShenandoahConcurrentTraversalCollectionTask task(&terminator);
>> +      _heap->workers()->run_task(&task);
>>       }
>>     }
>>
>>     if (!_heap->cancelled_gc() && ShenandoahPreclean && _heap->process_references()) {
>>       ShenandoahEvacOOMScope oom_evac_scope;
>> @@ -672,16 +665,16 @@
>>
>>       // Finish traversal
>>       ShenandoahRootProcessor rp(_heap, nworkers, ShenandoahPhaseTimings::final_traversal_gc_work);
>>       if (UseShenandoahOWST) {
>>         ShenandoahTaskTerminator terminator(nworkers, task_queues());
>> -      ShenandoahFinalTraversalCollectionTask traversal_task(&rp, &terminator);
>> -      _heap->workers()->run_task(&traversal_task);
>> +      ShenandoahFinalTraversalCollectionTask task(&rp, &terminator);
>> +      _heap->workers()->run_task(&task);
>>       } else {
>>         ParallelTaskTerminator terminator(nworkers, task_queues());
>> -      ShenandoahFinalTraversalCollectionTask traversal_task(&rp, &terminator);
>> -      _heap->workers()->run_task(&traversal_task);
>> +      ShenandoahFinalTraversalCollectionTask task(&rp, &terminator);
>> +      _heap->workers()->run_task(&task);
>>       }
>>   #if defined(COMPILER2) || INCLUDE_JVMCI
>>       DerivedPointerTable::update_pointers();
>>   #endif
>>     }
>>
>>
>> Testing: tier1_gc_shenandoah
>>
>> Thanks,
>> -Aleksey
>>
> 
>