src/hotspot/share/gc/z/zForwarding.hpp

/*
 * Copyright (c) 2015, 2024, Oracle and/or its affiliates. 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.
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 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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#ifndef SHARE_GC_Z_ZFORWARDING_HPP
#define SHARE_GC_Z_ZFORWARDING_HPP

#include "gc/z/zArray.hpp"
#include "gc/z/zAttachedArray.hpp"
#include "gc/z/zForwardingEntry.hpp"
#include "gc/z/zGenerationId.hpp"
#include "gc/z/zLock.hpp"
#include "gc/z/zPageAge.hpp"
#include "gc/z/zPageType.hpp"
#include "gc/z/zVirtualMemory.hpp"

class ObjectClosure;
class ZForwardingAllocator;
class ZPage;
class ZRelocateQueue;

typedef size_t ZForwardingCursor;

class ZForwarding {
  friend class VMStructs;
  friend class ZForwardingTest;

  enum class ZPublishState : int8_t {
    none,      // No publishing done yet
    published, // OC published remset field info, which YC will reject or accept
    reject,    // YC remset scanning accepted OC published remset field info
    accept     // YC remset scanning rejected OC published remset field info
  };

private:
  typedef ZAttachedArray<ZForwarding, ZForwardingEntry> AttachedArray;
  typedef ZArray<volatile zpointer*> PointerArray;

  const ZVirtualMemory   _virtual;
  const size_t           _object_alignment_shift;
  const AttachedArray    _entries;
  ZPage* const           _page;
  const ZPageAge         _from_age;
  const ZPageAge         _to_age;
  volatile bool          _claimed;
  mutable ZConditionLock _ref_lock;
  volatile int32_t       _ref_count;
  volatile bool          _done;

  // Relocated remembered set fields support
  volatile ZPublishState _relocated_remembered_fields_state;
  PointerArray           _relocated_remembered_fields_array;
  uint32_t               _relocated_remembered_fields_publish_young_seqnum;

  // In-place relocation support
  bool                   _in_place;
  zoffset_end            _in_place_top_at_start;

  // Debugging
  volatile Thread*       _in_place_thread;

  ZForwardingEntry* entries() const;
  ZForwardingEntry at(ZForwardingCursor* cursor) const;
  ZForwardingEntry first(uintptr_t from_index, ZForwardingCursor* cursor) const;
  ZForwardingEntry next(ZForwardingCursor* cursor) const;

  uintptr_t index(zoffset from_offset);

  ZForwardingEntry find(uintptr_t from_index, ZForwardingCursor* cursor) const;
  zaddress find(zoffset from_offset, ZForwardingCursor* cursor);

  zoffset insert(uintptr_t from_index, zoffset to_offset, ZForwardingCursor* cursor);
  zaddress insert(zoffset from_offset, zaddress to_addr, ZForwardingCursor* cursor);

  template <typename Function>
  void object_iterate_forwarded_via_livemap(Function function);

  ZForwarding(ZPage* page, ZPageAge to_age, size_t nentries);

public:
  static uint32_t nentries(const ZPage* page);
  static ZForwarding* alloc(ZForwardingAllocator* allocator, ZPage* page, ZPageAge to_age);

  ZPageType type() const;
  ZPageAge from_age() const;
  ZPageAge to_age() const;
  zoffset start() const;
  zoffset_end end() const;
  size_t size() const;
  size_t object_alignment_shift() const;

  bool is_promotion() const;

  // Visit from-objects
  template <typename Function>
  void object_iterate(Function function);

  template <typename Function>
  void address_unsafe_iterate_via_table(Function function);

  // Visit to-objects
  template <typename Function>
  void object_iterate_forwarded(Function function);

  template <typename Function>
  void object_iterate_forwarded_via_table(Function function);

  template <typename Function>
  void oops_do_in_forwarded(Function function);

  template <typename Function>
  void oops_do_in_forwarded_via_table(Function function);

  bool claim();

  // In-place relocation support
  bool in_place_relocation() const;
  void in_place_relocation_claim_page();
  void in_place_relocation_start(zoffset relocated_watermark);
  void in_place_relocation_finish();
  bool in_place_relocation_is_below_top_at_start(zoffset addr) const;

  bool retain_page(ZRelocateQueue* queue);
  void release_page();

  ZPage* detach_page();
  ZPage* page();

  void mark_done();
  bool is_done() const;

  zaddress find(zaddress from_addr, ZForwardingCursor* cursor);
  zaddress find(zaddress_unsafe from_addr, ZForwardingCursor* cursor);
  zaddress find(zaddress_unsafe from_addr);

  zaddress insert(zaddress from_addr, zaddress to_addr, ZForwardingCursor* cursor);

  // Relocated remembered set fields support
  void relocated_remembered_fields_register(volatile zpointer* p);
  void relocated_remembered_fields_after_relocate();
  void relocated_remembered_fields_publish();
  void relocated_remembered_fields_notify_concurrent_scan_of();
  bool relocated_remembered_fields_is_concurrently_scanned() const;
  template <typename Function>
  void relocated_remembered_fields_apply_to_published(Function function);
  bool relocated_remembered_fields_published_contains(volatile zpointer* p);

  void verify() const;
};

#endif // SHARE_GC_Z_ZFORWARDING_HPP