diff -r 4101eab5f3f5 src/hotspot/share/gc/g1/g1CollectedHeap.cpp
--- a/src/hotspot/share/gc/g1/g1CollectedHeap.cpp	Thu Jul 19 17:22:15 2018 +0200
+++ b/src/hotspot/share/gc/g1/g1CollectedHeap.cpp	Thu Jul 19 17:23:44 2018 +0200
@@ -3106,7 +3106,6 @@
 }
 
 bool G1ParEvacuateFollowersClosure::offer_termination() {
-  G1ParScanThreadState* const pss = par_scan_state();
   start_term_time();
   const bool res = terminator()->offer_termination();
   end_term_time();
@@ -3116,8 +3115,11 @@
 void G1ParEvacuateFollowersClosure::do_void() {
   G1ParScanThreadState* const pss = par_scan_state();
   pss->trim_queue();
+  // Assume that initially all queues are active.
   do {
-    pss->steal_and_trim_queue(queues());
+    uint num_live_queues = terminator()->num_live_queues();
+      //log_debug(gc)("live queues %u", num_live_queues);
+    pss->steal_and_trim_queue(queues(), num_live_queues);
   } while (!offer_termination());
 }
 
diff -r 4101eab5f3f5 src/hotspot/share/gc/g1/g1ParScanThreadState.hpp
--- a/src/hotspot/share/gc/g1/g1ParScanThreadState.hpp	Thu Jul 19 17:22:15 2018 +0200
+++ b/src/hotspot/share/gc/g1/g1ParScanThreadState.hpp	Thu Jul 19 17:23:44 2018 +0200
@@ -203,7 +203,7 @@
   Tickspan trim_ticks() const;
   void reset_trim_ticks();
 
-  inline void steal_and_trim_queue(RefToScanQueueSet *task_queues);
+  inline void steal_and_trim_queue(RefToScanQueueSet *task_queues, uint live_queues);
 
   // An attempt to evacuate "obj" has failed; take necessary steps.
   oop handle_evacuation_failure_par(oop obj, markOop m);
diff -r 4101eab5f3f5 src/hotspot/share/gc/g1/g1ParScanThreadState.inline.hpp
--- a/src/hotspot/share/gc/g1/g1ParScanThreadState.inline.hpp	Thu Jul 19 17:22:15 2018 +0200
+++ b/src/hotspot/share/gc/g1/g1ParScanThreadState.inline.hpp	Thu Jul 19 17:23:44 2018 +0200
@@ -138,9 +138,9 @@
   }
 }
 
-void G1ParScanThreadState::steal_and_trim_queue(RefToScanQueueSet *task_queues) {
+void G1ParScanThreadState::steal_and_trim_queue(RefToScanQueueSet *task_queues, uint num_live_queues) {
   StarTask stolen_task;
-  while (task_queues->steal(_worker_id, stolen_task)) {
+  while (task_queues->steal(_worker_id, num_live_queues, stolen_task)) {
     assert(verify_task(stolen_task), "sanity");
     dispatch_reference(stolen_task);
 
diff -r 4101eab5f3f5 src/hotspot/share/gc/shared/taskqueue.cpp
--- a/src/hotspot/share/gc/shared/taskqueue.cpp	Thu Jul 19 17:22:15 2018 +0200
+++ b/src/hotspot/share/gc/shared/taskqueue.cpp	Thu Jul 19 17:23:44 2018 +0200
@@ -28,6 +28,7 @@
 #include "logging/log.hpp"
 #include "runtime/atomic.hpp"
 #include "runtime/os.hpp"
+#include "runtime/mutex.hpp"
 #include "runtime/thread.inline.hpp"
 #include "utilities/debug.hpp"
 #include "utilities/stack.inline.hpp"
@@ -131,8 +132,7 @@
   os::sleep(Thread::current(), millis, false);
 }
 
-bool
-ParallelTaskTerminator::offer_termination(TerminatorTerminator* terminator) {
+bool ParallelTaskTerminator::offer_termination(TerminatorTerminator* terminator) {
   assert(_n_threads > 0, "Initialization is incorrect");
   assert(_offered_termination < _n_threads, "Invariant");
   Atomic::inc(&_offered_termination);
diff -r 4101eab5f3f5 src/hotspot/share/gc/shared/taskqueue.hpp
--- a/src/hotspot/share/gc/shared/taskqueue.hpp	Thu Jul 19 17:22:15 2018 +0200
+++ b/src/hotspot/share/gc/shared/taskqueue.hpp	Thu Jul 19 17:23:44 2018 +0200
@@ -398,8 +398,12 @@
   // Returns if stealing succeeds, and sets "t" to the stolen task.
   bool steal(uint queue_num, E& t);
 
+  // Same as above, but takes an estimation of current number of queues that are currently
+  // active. This is used to improve the number of attempts made for stealing.
+  bool steal(uint queue_num, uint num_live_queues, E& t);
+
   bool peek();
-
+  
   uint size() const { return _n; }
 };
 
@@ -469,7 +473,7 @@
   // As above, but it also terminates if the should_exit_termination()
   // method of the terminator parameter returns true. If terminator is
   // NULL, then it is ignored.
-  bool offer_termination(TerminatorTerminator* terminator);
+  virtual bool offer_termination(TerminatorTerminator* terminator);
 
   // Reset the terminator, so that it may be reused again.
   // The caller is responsible for ensuring that this is done
@@ -480,6 +484,8 @@
   // given number.
   void reset_for_reuse(uint n_threads);
 
+  // An *estimate* on how many active queues are currently running.
+  uint num_live_queues() const { return _n_threads - _offered_termination; }
 #ifdef TRACESPINNING
   static uint total_yields() { return _total_yields; }
   static uint total_spins() { return _total_spins; }
diff -r 4101eab5f3f5 src/hotspot/share/gc/shared/taskqueue.inline.hpp
--- a/src/hotspot/share/gc/shared/taskqueue.inline.hpp	Thu Jul 19 17:22:15 2018 +0200
+++ b/src/hotspot/share/gc/shared/taskqueue.inline.hpp	Thu Jul 19 17:23:44 2018 +0200
@@ -302,9 +302,14 @@
   }
 }
 
-template<class T, MEMFLAGS F> bool
-GenericTaskQueueSet<T, F>::steal(uint queue_num, E& t) {
-  for (uint i = 0; i < 2 * _n; i++) {
+template<class T, MEMFLAGS F>
+bool GenericTaskQueueSet<T, F>::steal(uint queue_num, E& t) {
+  return steal(queue_num, _n, t);
+}
+
+template<class T, MEMFLAGS F>
+bool GenericTaskQueueSet<T, F>::steal(uint queue_num, uint num_live_queues, E& t) {
+  for (uint i = 0; i < 2 * num_live_queues; i++) {
     TASKQUEUE_STATS_ONLY(queue(queue_num)->stats.record_steal_attempt());
     if (steal_best_of_2(queue_num, t)) {
       TASKQUEUE_STATS_ONLY(queue(queue_num)->stats.record_steal());