/*

 * Copyright 2001-2009 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 AdjoiningGenerations;

class GCTaskManager;

class PSAdaptiveSizePolicy;

class ParallelScavengeHeap : public CollectedHeap {

  friend class VMStructs;

 private:

  static PSYoungGen* _young_gen;

  static PSOldGen*   _old_gen;

  static PSPermGen*  _perm_gen;

  // Sizing policy for entire heap

  static PSAdaptiveSizePolicy* _size_policy;

  static PSGCAdaptivePolicyCounters*   _gc_policy_counters;

  static ParallelScavengeHeap* _psh;

  size_t _perm_gen_alignment;

  size_t _young_gen_alignment;

  size_t _old_gen_alignment;

  inline size_t set_alignment(size_t& var, size_t val);

  // Collection of generations that are adjacent in the

  // space reserved for the heap.

  AdjoiningGenerations* _gens;

  static GCTaskManager*          _gc_task_manager;      // The task manager.

 protected:

  static inline size_t total_invocations();

  HeapWord* allocate_new_tlab(size_t size);

 public:

  ParallelScavengeHeap() : CollectedHeap() {

    set_alignment(_perm_gen_alignment, intra_heap_alignment());

    set_alignment(_young_gen_alignment, intra_heap_alignment());

    set_alignment(_old_gen_alignment, intra_heap_alignment());

  }

  // For use by VM operations

  enum CollectionType {

    Scavenge,

    MarkSweep

  };

  ParallelScavengeHeap::Name kind() const {

    return CollectedHeap::ParallelScavengeHeap;

  }

  static PSYoungGen* young_gen()     { return _young_gen; }

  static PSOldGen* old_gen()         { return _old_gen; }

  static PSPermGen* perm_gen()       { return _perm_gen; }

  virtual PSAdaptiveSizePolicy* size_policy() { return _size_policy; }

  static PSGCAdaptivePolicyCounters* gc_policy_counters() { return _gc_policy_counters; }

  static ParallelScavengeHeap* heap();

  static GCTaskManager* const gc_task_manager() { return _gc_task_manager; }

  AdjoiningGenerations* gens() { return _gens; }

  // Returns JNI_OK on success

  virtual jint initialize();

  void post_initialize();

  void update_counters();

  // The alignment used for the various generations.

  size_t perm_gen_alignment()  const { return _perm_gen_alignment; }

  size_t young_gen_alignment() const { return _young_gen_alignment; }

  size_t old_gen_alignment()  const { return _old_gen_alignment; }

  // The alignment used for eden and survivors within the young gen

  // and for boundary between young gen and old gen.

  size_t intra_heap_alignment() const { return 64 * K; }

  size_t capacity() const;

  size_t used() const;

  // Return "true" if all generations (but perm) have reached the

  // maximal committed limit that they can reach, without a garbage

  // collection.

  virtual bool is_maximal_no_gc() const;

  // Does this heap support heap inspection? (+PrintClassHistogram)

  bool supports_heap_inspection() const { return true; }

  size_t permanent_capacity() const;

  size_t permanent_used() const;

  size_t max_capacity() const;

  // Whether p is in the allocated part of the heap

  bool is_in(const void* p) const;

  bool is_in_reserved(const void* p) const;

  bool is_in_permanent(const void *p) const {    // reserved part

    return perm_gen()->reserved().contains(p);

  }

  bool is_permanent(const void *p) const {    // committed part

    return perm_gen()->is_in(p);

  }

  inline bool is_in_young(oop p);        // reserved part

  inline bool is_in_old_or_perm(oop p);  // reserved part

  // Memory allocation.   "gc_time_limit_was_exceeded" will

  // be set to true if the adaptive size policy determine that

  // an excessive amount of time is being spent doing collections

  // and caused a NULL to be returned.  If a NULL is not returned,

  // "gc_time_limit_was_exceeded" has an undefined meaning.

  HeapWord* mem_allocate(size_t size,

                         bool is_noref,

                         bool is_tlab,

                         bool* gc_overhead_limit_was_exceeded);

  HeapWord* failed_mem_allocate(size_t size, bool is_tlab);

  HeapWord* permanent_mem_allocate(size_t size);

  HeapWord* failed_permanent_mem_allocate(size_t size);

  // Support for System.gc()

  void collect(GCCause::Cause cause);

  // This interface assumes that it's being called by the

  // vm thread. It collects the heap assuming that the

  // heap lock is already held and that we are executing in

  // the context of the vm thread.

  void collect_as_vm_thread(GCCause::Cause cause);

  // These also should be called by the vm thread at a safepoint (e.g., from a

  // VM operation).

  //

  // The first collects the young generation only, unless the scavenge fails; it

  // will then attempt a full gc.  The second collects the entire heap; if

  // maximum_compaction is true, it will compact everything and clear all soft

  // references.

  inline void invoke_scavenge();

  inline void invoke_full_gc(bool maximum_compaction);

  size_t large_typearray_limit() { return FastAllocateSizeLimit; }

  bool supports_inline_contig_alloc() const { return !UseNUMA; }

  HeapWord** top_addr() const { return !UseNUMA ? young_gen()->top_addr() : (HeapWord**)-1; }

  HeapWord** end_addr() const { return !UseNUMA ? young_gen()->end_addr() : (HeapWord**)-1; }

  void ensure_parsability(bool retire_tlabs);

  void accumulate_statistics_all_tlabs();

  void resize_all_tlabs();

  size_t unsafe_max_alloc();

  bool supports_tlab_allocation() const { return true; }

  size_t tlab_capacity(Thread* thr) const;

  size_t unsafe_max_tlab_alloc(Thread* thr) const;

  // Can a compiler initialize a new object without store barriers?

  // This permission only extends from the creation of a new object

  // via a TLAB up to the first subsequent safepoint.

  virtual bool can_elide_tlab_store_barriers() const {

    return true;

  }

  // Return true if we don't we need a store barrier for

  // initializing stores to an object at this address.

  virtual bool can_elide_initializing_store_barrier(oop new_obj);

  // Can a compiler elide a store barrier when it writes

  // a permanent oop into the heap?  Applies when the compiler

  // is storing x to the heap, where x->is_perm() is true.

  virtual bool can_elide_permanent_oop_store_barriers() const {

    return true;

  }

  void oop_iterate(OopClosure* cl);

  void object_iterate(ObjectClosure* cl);

  void safe_object_iterate(ObjectClosure* cl) { object_iterate(cl); }

  void permanent_oop_iterate(OopClosure* cl);

  void permanent_object_iterate(ObjectClosure* cl);

  HeapWord* block_start(const void* addr) const;

  size_t block_size(const HeapWord* addr) const;

  bool block_is_obj(const HeapWord* addr) const;

  jlong millis_since_last_gc();

  void prepare_for_verify();

  void print() const;

  void print_on(outputStream* st) const;

  virtual void print_gc_threads_on(outputStream* st) const;

  virtual void gc_threads_do(ThreadClosure* tc) const;

  virtual void print_tracing_info() const;

  void verify(bool allow_dirty, bool silent, bool /* option */);

  void print_heap_change(size_t prev_used);

  // Resize the young generation.  The reserved space for the

  // generation may be expanded in preparation for the resize.

  void resize_young_gen(size_t eden_size, size_t survivor_size);

  // Resize the old generation.  The reserved space for the

  // generation may be expanded in preparation for the resize.

  void resize_old_gen(size_t desired_free_space);

  // Save the tops of the spaces in all generations

  void record_gen_tops_before_GC() PRODUCT_RETURN;

  // Mangle the unused parts of all spaces in the heap

  void gen_mangle_unused_area() PRODUCT_RETURN;

  // Call these in sequential code around the processing of strong roots.

  class ParStrongRootsScope : public MarkingCodeBlobClosure::MarkScope {

  public:

    ParStrongRootsScope();

    ~ParStrongRootsScope();

  };

};

inline size_t ParallelScavengeHeap::set_alignment(size_t& var, size_t val)

{

  assert(is_power_of_2((intptr_t)val), "must be a power of 2");

  var = round_to(val, intra_heap_alignment());

  return var;

}