6711316: Open source the Garbage-First garbage collector

First mercurial integration of the code for the Garbage-First garbage collector.

Reviewed-by: apetrusenko, iveresov, jmasa, sgoldman, tonyp, ysr

hotspot/src/share/vm/utilities/taskqueue.hpp

@@ -120,6 +120,11 @@ public:
     return dirty_size(_bottom, get_top());
   }
 
+  void set_empty() {
+    _bottom = 0;
+    _age = Age();
+  }
+
   // Maximum number of elements allowed in the queue.  This is two less
   // than the actual queue size, for somewhat complicated reasons.
   juint max_elems() { return n() - 2; }
@@ -155,6 +160,9 @@ public:
   // Delete any resource associated with the queue.
   ~GenericTaskQueue();
 
+  // apply the closure to all elements in the task queue
+  void oops_do(OopClosure* f);
+
 private:
   // Element array.
   volatile E* _elems;
@@ -171,6 +179,24 @@ void GenericTaskQueue<E>::initialize() {
   guarantee(_elems != NULL, "Allocation failed.");
 }
 
+template<class E>
+void GenericTaskQueue<E>::oops_do(OopClosure* f) {
+  // tty->print_cr("START OopTaskQueue::oops_do");
+  int iters = size();
+  juint index = _bottom;
+  for (int i = 0; i < iters; ++i) {
+    index = decrement_index(index);
+    // tty->print_cr("  doing entry %d," INTPTR_T " -> " INTPTR_T,
+    //            index, &_elems[index], _elems[index]);
+    E* t = (E*)&_elems[index];      // cast away volatility
+    oop* p = (oop*)t;
+    assert((*t)->is_oop_or_null(), "Not an oop or null");
+    f->do_oop(p);
+  }
+  // tty->print_cr("END OopTaskQueue::oops_do");
+}
+
+
 template<class E>
 bool GenericTaskQueue<E>::push_slow(E t, juint dirty_n_elems) {
   if (dirty_n_elems == n() - 1) {
@@ -383,6 +409,12 @@ bool GenericTaskQueueSet<E>::peek() {
   return false;
 }
 
+// When to terminate from the termination protocol.
+class TerminatorTerminator: public CHeapObj {
+public:
+  virtual bool should_exit_termination() = 0;
+};
+
 // A class to aid in the termination of a set of parallel tasks using
 // TaskQueueSet's for work stealing.
 
@@ -407,7 +439,14 @@ public:
   // else is.  If returns "true", all threads are terminated.  If returns
   // "false", available work has been observed in one of the task queues,
   // so the global task is not complete.
-  bool offer_termination();
+  bool offer_termination() {
+    return offer_termination(NULL);
+  }
+
+  // As above, but it also terminates of the should_exit_termination()
+  // method of the terminator parameter returns true. If terminator is
+  // NULL, then it is ignored.
+  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