Request for review (S): 8005489: VM hangs during GC with ParallelGC and ParallelGCThreads=0

[Bengt Rutisson]

Hi all,

Could I have a couple of reviews for this change. The parallel collector 
needs at least one GC worker thread to function properly . Setting 
ParallelGCThreads=0 on the command line causes the parallel collector to 
hang in product builds and assert in debug builds. This has been the 
case back to JDK6u14.

The fix will instead print an error message and exit the VM if 
ParallelGCThreads=0 is used with UseParallelGC. This is similar to what 
we recently did for the ParNew collector.

http://cr.openjdk.java.net/~brutisso/8005489/webrev.00/

Thanks,
Bengt