jdk-24/src/hotspot/share/gc/serial/tenuredGeneration.hpp

/*
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 * 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.
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#ifndef SHARE_GC_SERIAL_TENUREDGENERATION_HPP
#define SHARE_GC_SERIAL_TENUREDGENERATION_HPP

#include "gc/serial/cSpaceCounters.hpp"
#include "gc/shared/cardGeneration.hpp"
#include "gc/shared/gcStats.hpp"
#include "gc/shared/generationCounters.hpp"
#include "utilities/macros.hpp"

// TenuredGeneration models the heap containing old (promoted/tenured) objects
// contained in a single contiguous space.
//
// Garbage collection is performed using mark-compact.

class TenuredGeneration: public CardGeneration {
  friend class VMStructs;
  // Abstractly, this is a subtype that gets access to protected fields.
  friend class VM_PopulateDumpSharedSpace;

 protected:
  ContiguousSpace*    _the_space;       // Actual space holding objects

  GenerationCounters* _gen_counters;
  CSpaceCounters*     _space_counters;

  // Allocation failure
  virtual bool expand(size_t bytes, size_t expand_bytes);

  // Accessing spaces
  ContiguousSpace* space() const { return _the_space; }

  void assert_correct_size_change_locking();

 public:
  TenuredGeneration(ReservedSpace rs,
                    size_t initial_byte_size,
                    CardTableRS* remset);

  Generation::Name kind() { return Generation::MarkSweepCompact; }

  // Printing
  const char* name() const { return "tenured generation"; }
  const char* short_name() const { return "Tenured"; }

  size_t unsafe_max_alloc_nogc() const;
  size_t contiguous_available() const;

  // Iteration
  void object_iterate(ObjectClosure* blk);

  virtual inline HeapWord* allocate(size_t word_size, bool is_tlab);
  virtual inline HeapWord* par_allocate(size_t word_size, bool is_tlab);

  template <typename OopClosureType>
  void oop_since_save_marks_iterate(OopClosureType* cl);

  void save_marks();
  void reset_saved_marks();
  bool no_allocs_since_save_marks();

  inline size_t block_size(const HeapWord* addr) const;

  inline bool block_is_obj(const HeapWord* addr) const;

  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);

  virtual void prepare_for_verify();

  virtual void gc_prologue(bool full);
  virtual void gc_epilogue(bool full);

  bool should_collect(bool   full,
                      size_t word_size,
                      bool   is_tlab);

  virtual void compute_new_size();

  // Performance Counter support
  void update_counters();

  virtual void record_spaces_top();

  // Statistics

  virtual void update_gc_stats(Generation* current_generation, bool full);

  virtual bool promotion_attempt_is_safe(size_t max_promoted_in_bytes) const;

  virtual void verify();
  virtual void print_on(outputStream* st) const;
};

#endif // SHARE_GC_SERIAL_TENUREDGENERATION_HPP