--- old/src/share/vm/gc/shared/workgroup.cpp	2016-07-20 13:16:02.708290512 -0700
+++ new/src/share/vm/gc/shared/workgroup.cpp	2016-07-20 13:16:02.580290516 -0700
@@ -271,11 +271,13 @@
             "Trying to execute task %s with %u workers which is more than the amount of total workers %u.",
             task->name(), num_workers, total_workers());
   guarantee(num_workers > 0, "Trying to execute task %s with zero workers", task->name());
-  // num_workers may have been calculated based on different criteria
-  // than _active_workers so use num_workers limited by the number of
-  // created workers.
-  uint active_workers = MIN2(_created_workers, num_workers);
-  _dispatcher->coordinator_execute_on_workers(task, active_workers);
+  uint old_num_workers = _active_workers;
+  log_debug(gc)("run_task: updating active workers for %s from %u to %u", task->name(), old_num_workers, num_workers);
+  update_active_workers(num_workers);
+  guarantee(_active_workers == num_workers, "active workers %u num_workers %u", _active_workers, num_workers);
+  _dispatcher->coordinator_execute_on_workers(task, num_workers);
+  log_debug(gc)("run_task: restoring active workers from %u to %u", num_workers, old_num_workers);
+  update_active_workers(old_num_workers);
 }
 
 AbstractGangWorker::AbstractGangWorker(AbstractWorkGang* gang, uint id) {