view src/hotspot/share/gc/cms/cmsOopClosures.hpp @ 54526:ee29b516a36a

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author jlaskey
date Wed, 23 Jan 2019 16:09:20 -0400
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/*
 * Copyright (c) 2007, 2019, 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.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 */

#ifndef SHARE_GC_CMS_CMSOOPCLOSURES_HPP
#define SHARE_GC_CMS_CMSOOPCLOSURES_HPP

#include "gc/shared/genOopClosures.hpp"
#include "gc/shared/taskqueue.hpp"
#include "memory/iterator.hpp"

/////////////////////////////////////////////////////////////////
// Closures used by ConcurrentMarkSweepGeneration's collector
/////////////////////////////////////////////////////////////////
class ConcurrentMarkSweepGeneration;
class CMSBitMap;
class CMSMarkStack;
class CMSCollector;
class MarkFromRootsClosure;
class ParMarkFromRootsClosure;

class Mutex;

// Decode the oop and call do_oop on it.
#define DO_OOP_WORK_DEFN                             \
  void do_oop(oop obj);                              \
  template <class T> inline void do_oop_work(T* p);

// TODO: This duplication of the MetadataVisitingOopIterateClosure class is only needed
//       because some CMS OopClosures derive from OopsInGenClosure. It would be
//       good to get rid of them completely.
class MetadataVisitingOopsInGenClosure: public OopsInGenClosure {
 public:
  virtual bool do_metadata() { return true; }
  virtual void do_klass(Klass* k);
  virtual void do_cld(ClassLoaderData* cld);
};

class MarkRefsIntoClosure: public MetadataVisitingOopsInGenClosure {
 private:
  const MemRegion _span;
  CMSBitMap*      _bitMap;
 protected:
  DO_OOP_WORK_DEFN
 public:
  MarkRefsIntoClosure(MemRegion span, CMSBitMap* bitMap);
  virtual void do_oop(oop* p);
  virtual void do_oop(narrowOop* p);
};

class ParMarkRefsIntoClosure: public MetadataVisitingOopsInGenClosure {
 private:
  const MemRegion _span;
  CMSBitMap*      _bitMap;
 protected:
  DO_OOP_WORK_DEFN
 public:
  ParMarkRefsIntoClosure(MemRegion span, CMSBitMap* bitMap);
  virtual void do_oop(oop* p);
  virtual void do_oop(narrowOop* p);
};

// A variant of the above used in certain kinds of CMS
// marking verification.
class MarkRefsIntoVerifyClosure: public MetadataVisitingOopsInGenClosure {
 private:
  const MemRegion _span;
  CMSBitMap*      _verification_bm;
  CMSBitMap*      _cms_bm;
 protected:
  DO_OOP_WORK_DEFN
 public:
  MarkRefsIntoVerifyClosure(MemRegion span, CMSBitMap* verification_bm,
                            CMSBitMap* cms_bm);
  virtual void do_oop(oop* p);
  virtual void do_oop(narrowOop* p);
};

// The non-parallel version (the parallel version appears further below).
class PushAndMarkClosure: public MetadataVisitingOopIterateClosure {
 private:
  CMSCollector* _collector;
  MemRegion     _span;
  CMSBitMap*    _bit_map;
  CMSBitMap*    _mod_union_table;
  CMSMarkStack* _mark_stack;
  bool          _concurrent_precleaning;
 protected:
  DO_OOP_WORK_DEFN
 public:
  PushAndMarkClosure(CMSCollector* collector,
                     MemRegion span,
                     ReferenceDiscoverer* rd,
                     CMSBitMap* bit_map,
                     CMSBitMap* mod_union_table,
                     CMSMarkStack* mark_stack,
                     bool concurrent_precleaning);
  virtual void do_oop(oop* p);
  virtual void do_oop(narrowOop* p);
};

// In the parallel case, the bit map and the
// reference processor are currently all shared. Access to
// these shared mutable structures must use appropriate
// synchronization (for instance, via CAS). The marking stack
// used in the non-parallel case above is here replaced with
// an OopTaskQueue structure to allow efficient work stealing.
class ParPushAndMarkClosure: public MetadataVisitingOopIterateClosure {
 private:
  CMSCollector* _collector;
  MemRegion     _span;
  CMSBitMap*    _bit_map;
  OopTaskQueue* _work_queue;
 protected:
  DO_OOP_WORK_DEFN
 public:
  ParPushAndMarkClosure(CMSCollector* collector,
                        MemRegion span,
                        ReferenceDiscoverer* rd,
                        CMSBitMap* bit_map,
                        OopTaskQueue* work_queue);
  virtual void do_oop(oop* p);
  virtual void do_oop(narrowOop* p);
};

// The non-parallel version (the parallel version appears further below).
class MarkRefsIntoAndScanClosure: public MetadataVisitingOopsInGenClosure {
 private:
  MemRegion          _span;
  CMSBitMap*         _bit_map;
  CMSMarkStack*      _mark_stack;
  PushAndMarkClosure _pushAndMarkClosure;
  CMSCollector*      _collector;
  Mutex*             _freelistLock;
  bool               _yield;
  // Whether closure is being used for concurrent precleaning
  bool               _concurrent_precleaning;
 protected:
  DO_OOP_WORK_DEFN
 public:
  MarkRefsIntoAndScanClosure(MemRegion span,
                             ReferenceDiscoverer* rd,
                             CMSBitMap* bit_map,
                             CMSBitMap* mod_union_table,
                             CMSMarkStack* mark_stack,
                             CMSCollector* collector,
                             bool should_yield,
                             bool concurrent_precleaning);
  virtual void do_oop(oop* p);
  virtual void do_oop(narrowOop* p);

  void set_freelistLock(Mutex* m) {
    _freelistLock = m;
  }

 private:
  inline void do_yield_check();
  void do_yield_work();
  bool take_from_overflow_list();
};

// In this, the parallel avatar of MarkRefsIntoAndScanClosure, the revisit
// stack and the bitMap are shared, so access needs to be suitably
// synchronized. An OopTaskQueue structure, supporting efficient
// work stealing, replaces a CMSMarkStack for storing grey objects.
class ParMarkRefsIntoAndScanClosure: public MetadataVisitingOopsInGenClosure {
 private:
  MemRegion             _span;
  CMSBitMap*            _bit_map;
  OopTaskQueue*         _work_queue;
  const uint            _low_water_mark;
  ParPushAndMarkClosure _parPushAndMarkClosure;
 protected:
  DO_OOP_WORK_DEFN
 public:
  ParMarkRefsIntoAndScanClosure(CMSCollector* collector,
                                 MemRegion span,
                                 ReferenceDiscoverer* rd,
                                 CMSBitMap* bit_map,
                                 OopTaskQueue* work_queue);
  virtual void do_oop(oop* p);
  virtual void do_oop(narrowOop* p);

  void trim_queue(uint size);
};

// This closure is used during the concurrent marking phase
// following the first checkpoint. Its use is buried in
// the closure MarkFromRootsClosure.
class PushOrMarkClosure: public MetadataVisitingOopIterateClosure {
 private:
  CMSCollector*   _collector;
  MemRegion       _span;
  CMSBitMap*      _bitMap;
  CMSMarkStack*   _markStack;
  HeapWord* const _finger;
  MarkFromRootsClosure* const
                  _parent;
 protected:
  DO_OOP_WORK_DEFN
 public:
  PushOrMarkClosure(CMSCollector* cms_collector,
                    MemRegion span,
                    CMSBitMap* bitMap,
                    CMSMarkStack* markStack,
                    HeapWord* finger,
                    MarkFromRootsClosure* parent);
  virtual void do_oop(oop* p);
  virtual void do_oop(narrowOop* p);

  // Deal with a stack overflow condition
  void handle_stack_overflow(HeapWord* lost);
 private:
  inline void do_yield_check();
};

// A parallel (MT) version of the above.
// This closure is used during the concurrent marking phase
// following the first checkpoint. Its use is buried in
// the closure ParMarkFromRootsClosure.
class ParPushOrMarkClosure: public MetadataVisitingOopIterateClosure {
 private:
  CMSCollector*                  _collector;
  MemRegion                      _whole_span;
  MemRegion                      _span;       // local chunk
  CMSBitMap*                     _bit_map;
  OopTaskQueue*                  _work_queue;
  CMSMarkStack*                  _overflow_stack;
  HeapWord*  const               _finger;
  HeapWord* volatile* const      _global_finger_addr;
  ParMarkFromRootsClosure* const _parent;
 protected:
  DO_OOP_WORK_DEFN
 public:
  ParPushOrMarkClosure(CMSCollector* cms_collector,
                       MemRegion span,
                       CMSBitMap* bit_map,
                       OopTaskQueue* work_queue,
                       CMSMarkStack* mark_stack,
                       HeapWord* finger,
                       HeapWord* volatile* global_finger_addr,
                       ParMarkFromRootsClosure* parent);
  virtual void do_oop(oop* p);
  virtual void do_oop(narrowOop* p);

  // Deal with a stack overflow condition
  void handle_stack_overflow(HeapWord* lost);
 private:
  inline void do_yield_check();
};

// For objects in CMS generation, this closure marks
// given objects (transitively) as being reachable/live.
// This is currently used during the (weak) reference object
// processing phase of the CMS final checkpoint step, as
// well as during the concurrent precleaning of the discovered
// reference lists.
class CMSKeepAliveClosure: public MetadataVisitingOopIterateClosure {
 private:
  CMSCollector* _collector;
  const MemRegion _span;
  CMSMarkStack* _mark_stack;
  CMSBitMap*    _bit_map;
  bool          _concurrent_precleaning;
 protected:
  DO_OOP_WORK_DEFN
 public:
  CMSKeepAliveClosure(CMSCollector* collector, MemRegion span,
                      CMSBitMap* bit_map, CMSMarkStack* mark_stack,
                      bool cpc);
  bool    concurrent_precleaning() const { return _concurrent_precleaning; }
  virtual void do_oop(oop* p);
  virtual void do_oop(narrowOop* p);
};

class CMSInnerParMarkAndPushClosure: public MetadataVisitingOopIterateClosure {
 private:
  CMSCollector* _collector;
  MemRegion     _span;
  OopTaskQueue* _work_queue;
  CMSBitMap*    _bit_map;
 protected:
  DO_OOP_WORK_DEFN
 public:
  CMSInnerParMarkAndPushClosure(CMSCollector* collector,
                                MemRegion span, CMSBitMap* bit_map,
                                OopTaskQueue* work_queue);
  virtual void do_oop(oop* p);
  virtual void do_oop(narrowOop* p);
};

// A parallel (MT) version of the above, used when
// reference processing is parallel; the only difference
// is in the do_oop method.
class CMSParKeepAliveClosure: public MetadataVisitingOopIterateClosure {
 private:
  MemRegion     _span;
  OopTaskQueue* _work_queue;
  CMSBitMap*    _bit_map;
  CMSInnerParMarkAndPushClosure
                _mark_and_push;
  const uint    _low_water_mark;
  void trim_queue(uint max);
 protected:
  DO_OOP_WORK_DEFN
 public:
  CMSParKeepAliveClosure(CMSCollector* collector, MemRegion span,
                         CMSBitMap* bit_map, OopTaskQueue* work_queue);
  virtual void do_oop(oop* p);
  virtual void do_oop(narrowOop* p);
};

#endif // SHARE_GC_CMS_CMSOOPCLOSURES_HPP