src/share/vm/gc_implementation/shared/vmGCOperations.cpp

@@ -193,18 +193,19 @@
   GenCollectedHeap* gch = GenCollectedHeap::heap();
   GCCauseSetter gccs(gch, _gc_cause);
   gch->do_full_collection(gch->must_clear_all_soft_refs(), _max_level);
 }
 
+// Returns true iff concurrent GCs unloads metadata.
 bool VM_CollectForMetadataAllocation::initiate_concurrent_GC() {
 #if INCLUDE_ALL_GCS
   if (UseConcMarkSweepGC && CMSClassUnloadingEnabled) {
     MetaspaceGC::set_should_concurrent_collect(true);
     return true;
   }
 
-  if (UseG1GC) {
+  if (UseG1GC && G1ClassUnloadingEnabled) {
     G1CollectedHeap* g1h = G1CollectedHeap::heap();
     g1h->g1_policy()->set_initiate_conc_mark_if_possible();
 
     GCCauseSetter x(g1h, _gc_cause);