--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/memory/defNewGeneration.hpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,332 @@
+/*
+ * 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 EdenSpace;
+class ContiguousSpace;
+
+// DefNewGeneration is a young generation containing eden, from- and
+// to-space.
+
+class DefNewGeneration: public Generation {
+  friend class VMStructs;
+
+protected:
+  Generation* _next_gen;
+  int         _tenuring_threshold;   // Tenuring threshold for next collection.
+  ageTable    _age_table;
+  // Size of object to pretenure in words; command line provides bytes
+  size_t        _pretenure_size_threshold_words;
+
+  ageTable*   age_table() { return &_age_table; }
+  // Initialize state to optimistically assume no promotion failure will
+  // happen.
+  void   init_assuming_no_promotion_failure();
+  // True iff a promotion has failed in the current collection.
+  bool   _promotion_failed;
+  bool   promotion_failed() { return _promotion_failed; }
+
+  // Handling promotion failure.  A young generation collection
+  // can fail if a live object cannot be copied out of its
+  // location in eden or from-space during the collection.  If
+  // a collection fails, the young generation is left in a
+  // consistent state such that it can be collected by a
+  // full collection.
+  //   Before the collection
+  //     Objects are in eden or from-space
+  //     All roots into the young generation point into eden or from-space.
+  //
+  //   After a failed collection
+  //     Objects may be in eden, from-space, or to-space
+  //     An object A in eden or from-space may have a copy B
+  //       in to-space.  If B exists, all roots that once pointed
+  //       to A must now point to B.
+  //     All objects in the young generation are unmarked.
+  //     Eden, from-space, and to-space will all be collected by
+  //       the full collection.
+  void handle_promotion_failure(oop);
+
+  // In the absence of promotion failure, we wouldn't look at "from-space"
+  // objects after a young-gen collection.  When promotion fails, however,
+  // the subsequent full collection will look at from-space objects:
+  // therefore we must remove their forwarding pointers.
+  void remove_forwarding_pointers();
+
+  // 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);
+
+  // When one is non-null, so is the other.  Together, they each pair is
+  // an object with a preserved mark, and its mark value.
+  GrowableArray<oop>*     _objs_with_preserved_marks;
+  GrowableArray<markOop>* _preserved_marks_of_objs;
+
+  // Returns true if the collection can be safely attempted.
+  // If this method returns false, a collection is not
+  // guaranteed to fail but the system may not be able
+  // to recover from the failure.
+  bool collection_attempt_is_safe();
+
+  // Promotion failure handling
+  OopClosure *_promo_failure_scan_stack_closure;
+  void set_promo_failure_scan_stack_closure(OopClosure *scan_stack_closure) {
+    _promo_failure_scan_stack_closure = scan_stack_closure;
+  }
+
+  GrowableArray<oop>* _promo_failure_scan_stack;
+  GrowableArray<oop>* promo_failure_scan_stack() const {
+    return _promo_failure_scan_stack;
+  }
+  void push_on_promo_failure_scan_stack(oop);
+  void drain_promo_failure_scan_stack(void);
+  bool _promo_failure_drain_in_progress;
+
+  // Performance Counters
+  GenerationCounters*  _gen_counters;
+  CSpaceCounters*      _eden_counters;
+  CSpaceCounters*      _from_counters;
+  CSpaceCounters*      _to_counters;
+
+  // sizing information
+  size_t               _max_eden_size;
+  size_t               _max_survivor_size;
+
+  // Allocation support
+  bool _should_allocate_from_space;
+  bool should_allocate_from_space() const {
+    return _should_allocate_from_space;
+  }
+  void clear_should_allocate_from_space() {
+    _should_allocate_from_space = false;
+  }
+  void set_should_allocate_from_space() {
+    _should_allocate_from_space = true;
+  }
+
+ protected:
+  // Spaces
+  EdenSpace*       _eden_space;
+  ContiguousSpace* _from_space;
+  ContiguousSpace* _to_space;
+
+  enum SomeProtectedConstants {
+    // Generations are GenGrain-aligned and have size that are multiples of
+    // GenGrain.
+    MinFreeScratchWords = 100
+  };
+
+  // Return the size of a survivor space if this generation were of size
+  // gen_size.
+  size_t compute_survivor_size(size_t gen_size, size_t alignment) const {
+    size_t n = gen_size / (SurvivorRatio + 2);
+    return n > alignment ? align_size_down(n, alignment) : alignment;
+  }
+
+ public:  // was "protected" but caused compile error on win32
+  class IsAliveClosure: public BoolObjectClosure {
+    Generation* _g;
+  public:
+    IsAliveClosure(Generation* g);
+    void do_object(oop p);
+    bool do_object_b(oop p);
+  };
+
+  class KeepAliveClosure: public OopClosure {
+  protected:
+    ScanWeakRefClosure* _cl;
+    CardTableRS* _rs;
+  public:
+    KeepAliveClosure(ScanWeakRefClosure* cl);
+    void do_oop(oop* p);
+  };
+
+  class FastKeepAliveClosure: public KeepAliveClosure {
+  protected:
+    HeapWord* _boundary;
+  public:
+    FastKeepAliveClosure(DefNewGeneration* g, ScanWeakRefClosure* cl);
+    void do_oop(oop* p);
+  };
+
+  class EvacuateFollowersClosure: public VoidClosure {
+    GenCollectedHeap* _gch;
+    int _level;
+    ScanClosure* _scan_cur_or_nonheap;
+    ScanClosure* _scan_older;
+  public:
+    EvacuateFollowersClosure(GenCollectedHeap* gch, int level,
+                             ScanClosure* cur, ScanClosure* older);
+    void do_void();
+  };
+
+  class FastEvacuateFollowersClosure;
+  friend class FastEvacuateFollowersClosure;
+  class FastEvacuateFollowersClosure: public VoidClosure {
+    GenCollectedHeap* _gch;
+    int _level;
+    DefNewGeneration* _gen;
+    FastScanClosure* _scan_cur_or_nonheap;
+    FastScanClosure* _scan_older;
+  public:
+    FastEvacuateFollowersClosure(GenCollectedHeap* gch, int level,
+                                 DefNewGeneration* gen,
+                                 FastScanClosure* cur,
+                                 FastScanClosure* older);
+    void do_void();
+  };
+
+ public:
+  DefNewGeneration(ReservedSpace rs, size_t initial_byte_size, int level,
+                   const char* policy="Copy");
+
+  virtual Generation::Name kind() { return Generation::DefNew; }
+
+  // Accessing spaces
+  EdenSpace*       eden() const           { return _eden_space; }
+  ContiguousSpace* from() const           { return _from_space;  }
+  ContiguousSpace* to()   const           { return _to_space;    }
+
+  inline CompactibleSpace* first_compaction_space() const;
+
+  // Space enquiries
+  size_t capacity() const;
+  size_t used() const;
+  size_t free() const;
+  size_t max_capacity() const;
+  size_t capacity_before_gc() const;
+  size_t unsafe_max_alloc_nogc() const;
+  size_t contiguous_available() const;
+
+  size_t max_eden_size() const              { return _max_eden_size; }
+  size_t max_survivor_size() const          { return _max_survivor_size; }
+
+  bool supports_inline_contig_alloc() const { return true; }
+  HeapWord** top_addr() const;
+  HeapWord** end_addr() const;
+
+  // Thread-local allocation buffers
+  bool supports_tlab_allocation() const { return true; }
+  inline size_t tlab_capacity() const;
+  inline size_t unsafe_max_tlab_alloc() const;
+
+  // Grow the generation by the specified number of bytes.
+  // The size of bytes is assumed to be properly aligned.
+  // Return true if the expansion was successful.
+  bool expand(size_t bytes);
+
+  // DefNewGeneration cannot currently expand except at
+  // a GC.
+  virtual bool is_maximal_no_gc() const { return true; }
+
+  // Iteration
+  void object_iterate(ObjectClosure* blk);
+  void object_iterate_since_last_GC(ObjectClosure* cl);
+
+  void younger_refs_iterate(OopsInGenClosure* cl);
+
+  void space_iterate(SpaceClosure* blk, bool usedOnly = false);
+
+  // Allocation support
+  virtual bool should_allocate(size_t word_size, bool is_tlab) {
+    assert(UseTLAB || !is_tlab, "Should not allocate tlab");
+
+    size_t overflow_limit    = (size_t)1 << (BitsPerSize_t - LogHeapWordSize);
+
+    const bool non_zero      = word_size > 0;
+    const bool overflows     = word_size >= overflow_limit;
+    const bool check_too_big = _pretenure_size_threshold_words > 0;
+    const bool not_too_big   = word_size < _pretenure_size_threshold_words;
+    const bool size_ok       = is_tlab || !check_too_big || not_too_big;
+
+    bool result = !overflows &&
+                  non_zero   &&
+                  size_ok;
+
+    return result;
+  }
+
+  inline HeapWord* allocate(size_t word_size, bool is_tlab);
+  HeapWord* allocate_from_space(size_t word_size);
+
+  inline HeapWord* par_allocate(size_t word_size, bool is_tlab);
+
+  // Prologue & Epilogue
+  inline virtual void gc_prologue(bool full);
+  virtual void gc_epilogue(bool full);
+
+  // Doesn't require additional work during GC prologue and epilogue
+  virtual bool performs_in_place_marking() const { return false; }
+
+  // Accessing marks
+  void save_marks();
+  void reset_saved_marks();
+  bool no_allocs_since_save_marks();
+
+  // Need to declare the full complement of closures, whether we'll
+  // override them or not, or get message from the compiler:
+  //   oop_since_save_marks_iterate_nv hides virtual function...
+#define DefNew_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \
+  void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl);
+
+  ALL_SINCE_SAVE_MARKS_CLOSURES(DefNew_SINCE_SAVE_MARKS_DECL)
+
+#undef DefNew_SINCE_SAVE_MARKS_DECL
+
+  // For non-youngest collection, the DefNewGeneration can contribute
+  // "to-space".
+  void contribute_scratch(ScratchBlock*& list, Generation* requestor,
+                          size_t max_alloc_words);
+
+  // GC support
+  virtual void compute_new_size();
+  virtual void collect(bool   full,
+                       bool   clear_all_soft_refs,
+                       size_t size,
+                       bool   is_tlab);
+  HeapWord* expand_and_allocate(size_t size,
+                                bool is_tlab,
+                                bool parallel = false);
+
+  oop copy_to_survivor_space(oop old, oop* from);
+  int tenuring_threshold() { return _tenuring_threshold; }
+
+  // Performance Counter support
+  void update_counters();
+
+  // Printing
+  virtual const char* name() const;
+  virtual const char* short_name() const { return "DefNew"; }
+
+  bool must_be_youngest() const { return true; }
+  bool must_be_oldest() const { return false; }
+
+  // PrintHeapAtGC support.
+  void print_on(outputStream* st) const;
+
+  void verify(bool allow_dirty);
+
+ protected:
+  void compute_space_boundaries(uintx minimum_eden_size);
+  // Scavenge support
+  void swap_spaces();
+};