src/share/vm/utilities/workgroup.cpp

rev 6345 : 8040803: G1: Concurrent mark hangs when mark stack overflows
Reviewed-by: TDB

@@ -374,25 +374,26 @@
 
 // *** WorkGangBarrierSync
 
 WorkGangBarrierSync::WorkGangBarrierSync()
   : _monitor(Mutex::safepoint, "work gang barrier sync", true),
-    _n_workers(0), _n_completed(0), _should_reset(false) {
+    _n_workers(0), _n_completed(0), _should_reset(false), _aborted(false) {
 }
 
 WorkGangBarrierSync::WorkGangBarrierSync(uint n_workers, const char* name)
   : _monitor(Mutex::safepoint, name, true),
-    _n_workers(n_workers), _n_completed(0), _should_reset(false) {
+    _n_workers(n_workers), _n_completed(0), _should_reset(false), _aborted(false) {
 }
 
 void WorkGangBarrierSync::set_n_workers(uint n_workers) {
   _n_workers   = n_workers;
   _n_completed = 0;
   _should_reset = false;
+  _aborted      = false;
 }
 
-void WorkGangBarrierSync::enter() {
+bool WorkGangBarrierSync::enter() {
   MutexLockerEx x(monitor(), Mutex::_no_safepoint_check_flag);
   if (should_reset()) {
     // The should_reset() was set and we are the first worker to enter
     // the sync barrier. We will zero the n_completed() count which
     // effectively resets the barrier.

@@ -411,14 +412,21 @@
     // should_reset() flag and the barrier will be reset the first
     // time a worker enters it again.
     set_should_reset(true);
     monitor()->notify_all();
   } else {
-    while (n_completed() != n_workers()) {
+    while (n_completed() != n_workers() && !aborted()) {
       monitor()->wait(/* no_safepoint_check */ true);
     }
   }
+  return !aborted();
+}
+
+void WorkGangBarrierSync::abort() {
+  MutexLockerEx x(monitor(), Mutex::_no_safepoint_check_flag);
+  set_aborted();
+  monitor()->notify_all();
 }
 
 // SubTasksDone functions.
 
 SubTasksDone::SubTasksDone(uint n) :