--- old/src/share/vm/gc/shared/workgroup.cpp	2015-11-11 14:22:34.257579219 -0500
+++ new/src/share/vm/gc/shared/workgroup.cpp	2015-11-11 14:22:32.933504414 -0500
@@ -505,11 +505,12 @@
 FreeIdSet* FreeIdSet::_sets[NSets];
 bool FreeIdSet::_safepoint;
 
-FreeIdSet::FreeIdSet(int sz, Monitor* mon) :
+FreeIdSet::FreeIdSet(uint sz, Monitor* mon) :
   _sz(sz), _mon(mon), _hd(0), _waiters(0), _index(-1), _claimed(0)
 {
-  _ids = NEW_C_HEAP_ARRAY(int, sz, mtInternal);
-  for (int i = 0; i < sz; i++) _ids[i] = i+1;
+  guarantee(sz != 0, "must be");
+  _ids = NEW_C_HEAP_ARRAY(uint, sz, mtInternal);
+  for (uint i = 0; i < sz - 1; i++) _ids[i] = i+1;
   _ids[sz-1] = end_of_list; // end of list.
   if (_stat_init) {
     for (int j = 0; j < NSets; j++) _sets[j] = NULL;
@@ -528,7 +529,7 @@
 
 FreeIdSet::~FreeIdSet() {
   _sets[_index] = NULL;
-  FREE_C_HEAP_ARRAY(int, _ids);
+  FREE_C_HEAP_ARRAY(uint, _ids);
 }
 
 void FreeIdSet::set_safepoint(bool b) {
@@ -550,7 +551,7 @@
 int FreeIdSet::claim_par_id() {
 #if FID_STATS
   thread_t tslf = thr_self();
-  tty->print("claim_par_id[%d]: sz = %d, claimed = %d\n", tslf, _sz, _claimed);
+  tty->print("claim_par_id[%d]: sz = %u, claimed = %u\n", tslf, _sz, _claimed);
 #endif
   MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag);
   while (!_safepoint && _hd == end_of_list) {
@@ -568,52 +569,28 @@
 #if FID_STATS
     tty->print("claim_par_id[%d]: returning EOL.\n", tslf);
 #endif
-    return -1;
+    return UINT_MAX;
   } else {
     int res = _hd;
     _hd = _ids[res];
     _ids[res] = claimed;  // For debugging.
     _claimed++;
 #if FID_STATS
-    tty->print("claim_par_id[%d]: returning %d, claimed = %d.\n",
+    tty->print("claim_par_id[%d]: returning %d, claimed = %u.\n",
                tslf, res, _claimed);
 #endif
     return res;
   }
 }
 
-bool FreeIdSet::claim_perm_id(int i) {
-  assert(0 <= i && i < _sz, "Out of range.");
-  MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag);
-  int prev = end_of_list;
-  int cur = _hd;
-  while (cur != end_of_list) {
-    if (cur == i) {
-      if (prev == end_of_list) {
-        _hd = _ids[cur];
-      } else {
-        _ids[prev] = _ids[cur];
-      }
-      _ids[cur] = claimed;
-      _claimed++;
-      return true;
-    } else {
-      prev = cur;
-      cur = _ids[cur];
-    }
-  }
-  return false;
-
-}
-
-void FreeIdSet::release_par_id(int id) {
+void FreeIdSet::release_par_id(uint id) {
   MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag);
   assert(_ids[id] == claimed, "Precondition.");
   _ids[id] = _hd;
   _hd = id;
   _claimed--;
 #if FID_STATS
-  tty->print("[%d] release_par_id(%d), waiters =%d,  claimed = %d.\n",
+  tty->print("[%d] release_par_id(%u), waiters =%u,  claimed = %u.\n",
              thr_self(), id, _waiters, _claimed);
 #endif
   if (_waiters > 0)