src/share/vm/gc_implementation/g1/concurrentMark.cpp

rev 4029 : 8005875: G1: Kitchensink fails with ParallelGCThreads=0
Summary: Check that the concurrent marking worker gang exists in ConcurrentMark::print_worker_threads_on(). Code changes were also reviewed by Vitaly Davidovich <vitalyd@gmail.com>.
Reviewed-by: brutisso

@@ -1188,11 +1188,11 @@
     assert(parallel_marking_threads() <= max_parallel_marking_threads(),
            "Maximum number of marking threads exceeded");
     uint active_workers = MAX2(1U, parallel_marking_threads());
 
     CMRootRegionScanTask task(this);
-    if (parallel_marking_threads() > 0) {
+    if (use_parallel_marking_threads()) {
       _parallel_workers->set_active_workers((int) active_workers);
       _parallel_workers->run_task(&task);
     } else {
       task.work(0);
     }

@@ -1224,11 +1224,11 @@
 
   // Parallel task terminator is set in "set_phase()"
   set_phase(active_workers, true /* concurrent */);
 
   CMConcurrentMarkingTask markingTask(this, cmThread());
-  if (parallel_marking_threads() > 0) {
+  if (use_parallel_marking_threads()) {
     _parallel_workers->set_active_workers((int)active_workers);
     // Don't set _n_par_threads because it affects MT in proceess_strong_roots()
     // and the decisions on that MT processing is made elsewhere.
     assert(_parallel_workers->active_workers() > 0, "Should have been set");
     _parallel_workers->run_task(&markingTask);

@@ -3240,11 +3240,13 @@
                 cmThread()->vtime_accum(),
                 cmThread()->vtime_mark_accum());
 }
 
 void ConcurrentMark::print_worker_threads_on(outputStream* st) const {
+  if (use_parallel_marking_threads()) {
   _parallel_workers->print_worker_threads_on(st);
+  }
 }
 
 // We take a break if someone is trying to stop the world.
 bool ConcurrentMark::do_yield_check(uint worker_id) {
   if (should_yield()) {