--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/gc_implementation/parNew/parNewGeneration.hpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,388 @@
+/*
+ * Copyright 2001-2007 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+class ChunkArray;
+class ParScanWithoutBarrierClosure;
+class ParScanWithBarrierClosure;
+class ParRootScanWithoutBarrierClosure;
+class ParRootScanWithBarrierTwoGensClosure;
+class ParEvacuateFollowersClosure;
+
+// It would be better if these types could be kept local to the .cpp file,
+// but they must be here to allow ParScanClosure::do_oop_work to be defined
+// in genOopClosures.inline.hpp.
+
+
+typedef OopTaskQueue    ObjToScanQueue;
+typedef OopTaskQueueSet ObjToScanQueueSet;
+
+// Enable this to get push/pop/steal stats.
+const int PAR_STATS_ENABLED = 0;
+
+class ParKeepAliveClosure: public DefNewGeneration::KeepAliveClosure {
+  ParScanWeakRefClosure* _par_cl;
+ public:
+  ParKeepAliveClosure(ParScanWeakRefClosure* cl);
+  void do_oop(oop* p);
+};
+
+// The state needed by thread performing parallel young-gen collection.
+class ParScanThreadState {
+  friend class ParScanThreadStateSet;
+  ObjToScanQueue *_work_queue;
+
+  ParGCAllocBuffer _to_space_alloc_buffer;
+
+  ParScanWithoutBarrierClosure         _to_space_closure; // scan_without_gc_barrier
+  ParScanWithBarrierClosure            _old_gen_closure; // scan_with_gc_barrier
+  ParRootScanWithoutBarrierClosure     _to_space_root_closure; // scan_root_without_gc_barrier
+  // One of these two will be passed to process_strong_roots, which will
+  // set its generation.  The first is for two-gen configs where the
+  // old gen collects the perm gen; the second is for arbitrary configs.
+  // The second isn't used right now (it used to be used for the train, an
+  // incremental collector) but the declaration has been left as a reminder.
+  ParRootScanWithBarrierTwoGensClosure _older_gen_closure;
+  // This closure will always be bound to the old gen; it will be used
+  // in evacuate_followers.
+  ParRootScanWithBarrierTwoGensClosure _old_gen_root_closure; // scan_old_root_with_gc_barrier
+  ParEvacuateFollowersClosure          _evacuate_followers;
+  DefNewGeneration::IsAliveClosure     _is_alive_closure;
+  ParScanWeakRefClosure                _scan_weak_ref_closure;
+  ParKeepAliveClosure                  _keep_alive_closure;
+
+
+  Space* _to_space;
+  Space* to_space() { return _to_space; }
+
+  Generation* _old_gen;
+  Generation* old_gen() { return _old_gen; }
+
+  HeapWord *_young_old_boundary;
+
+  int _hash_seed;
+  int _thread_num;
+  ageTable _ageTable;
+
+  bool _to_space_full;
+
+  int _pushes, _pops, _steals, _steal_attempts, _term_attempts;
+  int _overflow_pushes, _overflow_refills, _overflow_refill_objs;
+
+  // Timing numbers.
+  double _start;
+  double _start_strong_roots;
+  double _strong_roots_time;
+  double _start_term;
+  double _term_time;
+
+  // Helper for trim_queues. Scans subset of an array and makes
+  // remainder available for work stealing.
+  void scan_partial_array_and_push_remainder(oop obj);
+
+  // In support of CMS' parallel rescan of survivor space.
+  ChunkArray* _survivor_chunk_array;
+  ChunkArray* survivor_chunk_array() { return _survivor_chunk_array; }
+
+  void record_survivor_plab(HeapWord* plab_start, size_t plab_word_size);
+
+  ParScanThreadState(Space* to_space_, ParNewGeneration* gen_,
+                     Generation* old_gen_, int thread_num_,
+                     ObjToScanQueueSet* work_queue_set_, size_t desired_plab_sz_,
+                     ParallelTaskTerminator& term_);
+
+public:
+  ageTable* age_table() {return &_ageTable;}
+
+  ObjToScanQueue* work_queue() { return _work_queue; }
+
+  ParGCAllocBuffer* to_space_alloc_buffer() {
+    return &_to_space_alloc_buffer;
+  }
+
+  ParEvacuateFollowersClosure&      evacuate_followers_closure() { return _evacuate_followers; }
+  DefNewGeneration::IsAliveClosure& is_alive_closure() { return _is_alive_closure; }
+  ParScanWeakRefClosure&            scan_weak_ref_closure() { return _scan_weak_ref_closure; }
+  ParKeepAliveClosure&              keep_alive_closure() { return _keep_alive_closure; }
+  ParScanClosure&                   older_gen_closure() { return _older_gen_closure; }
+  ParRootScanWithoutBarrierClosure& to_space_root_closure() { return _to_space_root_closure; };
+
+  // Decrease queue size below "max_size".
+  void trim_queues(int max_size);
+
+  // Is new_obj a candidate for scan_partial_array_and_push_remainder method.
+  inline bool should_be_partially_scanned(oop new_obj, oop old_obj) const;
+
+  int* hash_seed()  { return &_hash_seed; }
+  int  thread_num() { return _thread_num; }
+
+  // Allocate a to-space block of size "sz", or else return NULL.
+  HeapWord* alloc_in_to_space_slow(size_t word_sz);
+
+  HeapWord* alloc_in_to_space(size_t word_sz) {
+    HeapWord* obj = to_space_alloc_buffer()->allocate(word_sz);
+    if (obj != NULL) return obj;
+    else return alloc_in_to_space_slow(word_sz);
+  }
+
+  HeapWord* young_old_boundary() { return _young_old_boundary; }
+
+  void set_young_old_boundary(HeapWord *boundary) {
+    _young_old_boundary = boundary;
+  }
+
+  // Undo the most recent allocation ("obj", of "word_sz").
+  void undo_alloc_in_to_space(HeapWord* obj, size_t word_sz);
+
+  int pushes() { return _pushes; }
+  int pops()   { return _pops; }
+  int steals() { return _steals; }
+  int steal_attempts() { return _steal_attempts; }
+  int term_attempts()  { return _term_attempts; }
+  int overflow_pushes() { return _overflow_pushes; }
+  int overflow_refills() { return _overflow_refills; }
+  int overflow_refill_objs() { return _overflow_refill_objs; }
+
+  void note_push()  { if (PAR_STATS_ENABLED) _pushes++; }
+  void note_pop()   { if (PAR_STATS_ENABLED) _pops++; }
+  void note_steal() { if (PAR_STATS_ENABLED) _steals++; }
+  void note_steal_attempt() { if (PAR_STATS_ENABLED) _steal_attempts++; }
+  void note_term_attempt()  { if (PAR_STATS_ENABLED) _term_attempts++; }
+  void note_overflow_push() { if (PAR_STATS_ENABLED) _overflow_pushes++; }
+  void note_overflow_refill(int objs) {
+    if (PAR_STATS_ENABLED) {
+      _overflow_refills++;
+      _overflow_refill_objs += objs;
+    }
+  }
+
+  void start_strong_roots() {
+    _start_strong_roots = os::elapsedTime();
+  }
+  void end_strong_roots() {
+    _strong_roots_time += (os::elapsedTime() - _start_strong_roots);
+  }
+  double strong_roots_time() { return _strong_roots_time; }
+  void start_term_time() {
+    note_term_attempt();
+    _start_term = os::elapsedTime();
+  }
+  void end_term_time() {
+    _term_time += (os::elapsedTime() - _start_term);
+  }
+  double term_time() { return _term_time; }
+
+  double elapsed() {
+    return os::elapsedTime() - _start;
+  }
+
+};
+
+class ParNewGenTask: public AbstractGangTask {
+  ParNewGeneration* _gen;
+  Generation* _next_gen;
+  HeapWord* _young_old_boundary;
+  class ParScanThreadStateSet* _state_set;
+
+public:
+  ParNewGenTask(ParNewGeneration*      gen,
+                Generation*            next_gen,
+                HeapWord*              young_old_boundary,
+                ParScanThreadStateSet* state_set);
+
+  HeapWord* young_old_boundary() { return _young_old_boundary; }
+
+  void work(int i);
+};
+
+class KeepAliveClosure: public DefNewGeneration::KeepAliveClosure {
+ public:
+  KeepAliveClosure(ScanWeakRefClosure* cl);
+  void do_oop(oop* p);
+};
+
+class EvacuateFollowersClosureGeneral: public VoidClosure {
+    GenCollectedHeap* _gch;
+    int _level;
+    OopsInGenClosure* _scan_cur_or_nonheap;
+    OopsInGenClosure* _scan_older;
+  public:
+    EvacuateFollowersClosureGeneral(GenCollectedHeap* gch, int level,
+                                    OopsInGenClosure* cur,
+                                    OopsInGenClosure* older);
+    void do_void();
+};
+
+// Closure for scanning ParNewGeneration.
+// Same as ScanClosure, except does parallel GC barrier.
+class ScanClosureWithParBarrier: public ScanClosure {
+public:
+  ScanClosureWithParBarrier(ParNewGeneration* g, bool gc_barrier);
+  void do_oop(oop* p);
+};
+
+// Implements AbstractRefProcTaskExecutor for ParNew.
+class ParNewRefProcTaskExecutor: public AbstractRefProcTaskExecutor {
+public:
+
+  ParNewRefProcTaskExecutor(ParNewGeneration& generation,
+                            ParScanThreadStateSet& state_set)
+    : _generation(generation), _state_set(state_set)
+  { }
+
+  // Executes a task using worker threads.
+  virtual void execute(ProcessTask& task);
+  virtual void execute(EnqueueTask& task);
+  // Switch to single threaded mode.
+  virtual void set_single_threaded_mode();
+private:
+  ParNewGeneration&      _generation;
+  ParScanThreadStateSet& _state_set;
+};
+
+
+// A Generation that does parallel young-gen collection.
+
+class ParNewGeneration: public DefNewGeneration {
+  friend class ParNewGenTask;
+  friend class ParNewRefProcTask;
+  friend class ParNewRefProcTaskExecutor;
+  friend class ParScanThreadStateSet;
+
+  // XXX use a global constant instead of 64!
+  struct ObjToScanQueuePadded {
+        ObjToScanQueue work_queue;
+        char pad[64 - sizeof(ObjToScanQueue)];  // prevent false sharing
+  };
+
+  // The per-thread work queues, available here for stealing.
+  ObjToScanQueueSet* _task_queues;
+
+  // Desired size of survivor space plab's
+  PLABStats _plab_stats;
+
+  // A list of from-space images of to-be-scanned objects, threaded through
+  // klass-pointers (klass information already copied to the forwarded
+  // image.)  Manipulated with CAS.
+  oop _overflow_list;
+
+  // If true, older generation does not support promotion undo, so avoid.
+  static bool _avoid_promotion_undo;
+
+  // This closure is used by the reference processor to filter out
+  // references to live referent.
+  DefNewGeneration::IsAliveClosure _is_alive_closure;
+
+  static oop real_forwardee_slow(oop obj);
+  static void waste_some_time();
+
+  // Preserve the mark of "obj", if necessary, in preparation for its mark
+  // word being overwritten with a self-forwarding-pointer.
+  void preserve_mark_if_necessary(oop obj, markOop m);
+
+ protected:
+
+  bool _survivor_overflow;
+
+  bool avoid_promotion_undo() { return _avoid_promotion_undo; }
+  void set_avoid_promotion_undo(bool v) { _avoid_promotion_undo = v; }
+
+  bool survivor_overflow() { return _survivor_overflow; }
+  void set_survivor_overflow(bool v) { _survivor_overflow = v; }
+
+  // Adjust the tenuring threshold.  See the implementation for
+  // the details of the policy.
+  virtual void adjust_desired_tenuring_threshold();
+
+public:
+  ParNewGeneration(ReservedSpace rs, size_t initial_byte_size, int level);
+
+  ~ParNewGeneration() {
+    for (uint i = 0; i < ParallelGCThreads; i++)
+        delete _task_queues->queue(i);
+
+    delete _task_queues;
+  }
+
+  virtual void ref_processor_init();
+  virtual Generation::Name kind()        { return Generation::ParNew; }
+  virtual const char* name() const;
+  virtual const char* short_name() const { return "ParNew"; }
+
+  // override
+  virtual bool refs_discovery_is_mt()     const {
+    assert(UseParNewGC, "ParNewGeneration only when UseParNewGC");
+    return ParallelGCThreads > 1;
+  }
+
+  // Make the collection virtual.
+  virtual void collect(bool   full,
+                       bool   clear_all_soft_refs,
+                       size_t size,
+                       bool   is_tlab);
+
+  // This needs to be visible to the closure function.
+  // "obj" is the object to be copied, "m" is a recent value of its mark
+  // that must not contain a forwarding pointer (though one might be
+  // inserted in "obj"s mark word by a parallel thread).
+  inline oop copy_to_survivor_space(ParScanThreadState* par_scan_state,
+                             oop obj, size_t obj_sz, markOop m) {
+    if (_avoid_promotion_undo) {
+       return copy_to_survivor_space_avoiding_promotion_undo(par_scan_state,
+                                                             obj, obj_sz, m);
+    }
+
+    return copy_to_survivor_space_with_undo(par_scan_state, obj, obj_sz, m);
+  }
+
+  oop copy_to_survivor_space_avoiding_promotion_undo(ParScanThreadState* par_scan_state,
+                             oop obj, size_t obj_sz, markOop m);
+
+  oop copy_to_survivor_space_with_undo(ParScanThreadState* par_scan_state,
+                             oop obj, size_t obj_sz, markOop m);
+
+  // Push the given (from-space) object on the global overflow list.
+  void push_on_overflow_list(oop from_space_obj);
+
+  // If the global overflow list is non-empty, move some tasks from it
+  // onto "work_q" (which must be empty).  No more than 1/4 of the
+  // max_elems of "work_q" are moved.
+  bool take_from_overflow_list(ParScanThreadState* par_scan_state);
+
+  // The task queues to be used by parallel GC threads.
+  ObjToScanQueueSet* task_queues() {
+    return _task_queues;
+  }
+
+  PLABStats* plab_stats() {
+    return &_plab_stats;
+  }
+
+  size_t desired_plab_sz() {
+    return _plab_stats.desired_plab_sz();
+  }
+
+  static oop real_forwardee(oop obj);
+
+  DEBUG_ONLY(static bool is_legal_forward_ptr(oop p);)
+};