Java example source code file (cmsOopClosures.hpp)

This example Java source code file (cmsOopClosures.hpp) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

cmklassclosure, cmsbitmap, cmscollector, cmsmarkstack, cmsoopclosure, cmsoopsingenclosure, do_oop_work_defn, heapword, memregion, ooptaskqueue, prefetch\:\:do_read, prefetch\:\:style, referenceprocessor, share_vm_gc_implementation_concurrentmarksweep_cmsoopclosures_hpp

The cmsOopClosures.hpp Java example source code

/*
 * Copyright (c) 2007, 2013, 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_VM_GC_IMPLEMENTATION_CONCURRENTMARKSWEEP_CMSOOPCLOSURES_HPP
#define SHARE_VM_GC_IMPLEMENTATION_CONCURRENTMARKSWEEP_CMSOOPCLOSURES_HPP

#include "memory/genOopClosures.hpp"

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

// 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) {      \
    T heap_oop = oopDesc::load_heap_oop(p);               \
    if (!oopDesc::is_null(heap_oop)) {                    \
      oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);       \
      do_oop(obj);                                        \
    }                                                     \
  }

// Applies the given oop closure to all oops in all klasses visited.
class CMKlassClosure : public KlassClosure {
  friend class CMSOopClosure;
  friend class CMSOopsInGenClosure;

  OopClosure* _oop_closure;

  // Used when _oop_closure couldn't be set in an initialization list.
  void initialize(OopClosure* oop_closure) {
    assert(_oop_closure == NULL, "Should only be called once");
    _oop_closure = oop_closure;
  }
 public:
  CMKlassClosure(OopClosure* oop_closure = NULL) : _oop_closure(oop_closure) { }

  void do_klass(Klass* k);
};

// The base class for all CMS marking closures.
// It's used to proxy through the metadata to the oops defined in them.
class CMSOopClosure: public ExtendedOopClosure {
  CMKlassClosure      _klass_closure;
 public:
  CMSOopClosure() : ExtendedOopClosure() {
    _klass_closure.initialize(this);
  }
  CMSOopClosure(ReferenceProcessor* rp) : ExtendedOopClosure(rp) {
    _klass_closure.initialize(this);
  }

  virtual bool do_metadata()    { return do_metadata_nv(); }
  inline  bool do_metadata_nv() { return true; }

  virtual void do_klass(Klass* k);
  void do_klass_nv(Klass* k);

  virtual void do_class_loader_data(ClassLoaderData* cld);
};

// TODO: This duplication of the CMSOopClosure class is only needed because
//       some CMS OopClosures derive from OopsInGenClosure. It would be good
//       to get rid of them completely.
class CMSOopsInGenClosure: public OopsInGenClosure {
  CMKlassClosure _klass_closure;
 public:
  CMSOopsInGenClosure() {
    _klass_closure.initialize(this);
  }

  virtual bool do_metadata()    { return do_metadata_nv(); }
  inline  bool do_metadata_nv() { return true; }

  virtual void do_klass(Klass* k);
  void do_klass_nv(Klass* k);

  virtual void do_class_loader_data(ClassLoaderData* cld);
};

class MarkRefsIntoClosure: public CMSOopsInGenClosure {
 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);

  Prefetch::style prefetch_style() {
    return Prefetch::do_read;
  }
};

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

  Prefetch::style prefetch_style() {
    return Prefetch::do_read;
  }
};

// A variant of the above used in certain kinds of CMS
// marking verification.
class MarkRefsIntoVerifyClosure: public CMSOopsInGenClosure {
 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);

  Prefetch::style prefetch_style() {
    return Prefetch::do_read;
  }
};

// The non-parallel version (the parallel version appears further below).
class PushAndMarkClosure: public CMSOopClosure {
 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,
                     ReferenceProcessor* rp,
                     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);
  inline void do_oop_nv(oop* p)       { PushAndMarkClosure::do_oop_work(p); }
  inline void do_oop_nv(narrowOop* p) { PushAndMarkClosure::do_oop_work(p); }

  Prefetch::style prefetch_style() {
    return Prefetch::do_read;
  }
};

// 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 Par_PushAndMarkClosure: public CMSOopClosure {
 private:
  CMSCollector* _collector;
  MemRegion     _span;
  CMSBitMap*    _bit_map;
  OopTaskQueue* _work_queue;
 protected:
  DO_OOP_WORK_DEFN
 public:
  Par_PushAndMarkClosure(CMSCollector* collector,
                         MemRegion span,
                         ReferenceProcessor* rp,
                         CMSBitMap* bit_map,
                         OopTaskQueue* work_queue);
  virtual void do_oop(oop* p);
  virtual void do_oop(narrowOop* p);
  inline void do_oop_nv(oop* p)       { Par_PushAndMarkClosure::do_oop_work(p); }
  inline void do_oop_nv(narrowOop* p) { Par_PushAndMarkClosure::do_oop_work(p); }

  Prefetch::style prefetch_style() {
    return Prefetch::do_read;
  }
};

// The non-parallel version (the parallel version appears further below).
class MarkRefsIntoAndScanClosure: public CMSOopsInGenClosure {
 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,
                             ReferenceProcessor* rp,
                             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);
  inline void do_oop_nv(oop* p)       { MarkRefsIntoAndScanClosure::do_oop_work(p); }
  inline void do_oop_nv(narrowOop* p) { MarkRefsIntoAndScanClosure::do_oop_work(p); }

  Prefetch::style prefetch_style() {
    return Prefetch::do_read;
  }
  void set_freelistLock(Mutex* m) {
    _freelistLock = m;
  }

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

// Tn this, the parallel avatar of MarkRefsIntoAndScanClosure, the revisit
// stack and the bitMap are shared, so access needs to be suitably
// sycnhronized. An OopTaskQueue structure, supporting efficient
// workstealing, replaces a CMSMarkStack for storing grey objects.
class Par_MarkRefsIntoAndScanClosure: public CMSOopsInGenClosure {
 private:
  MemRegion              _span;
  CMSBitMap*             _bit_map;
  OopTaskQueue*          _work_queue;
  const uint             _low_water_mark;
  Par_PushAndMarkClosure _par_pushAndMarkClosure;
 protected:
  DO_OOP_WORK_DEFN
 public:
  Par_MarkRefsIntoAndScanClosure(CMSCollector* collector,
                                 MemRegion span,
                                 ReferenceProcessor* rp,
                                 CMSBitMap* bit_map,
                                 OopTaskQueue* work_queue);
  virtual void do_oop(oop* p);
  virtual void do_oop(narrowOop* p);
  inline void do_oop_nv(oop* p)       { Par_MarkRefsIntoAndScanClosure::do_oop_work(p); }
  inline void do_oop_nv(narrowOop* p) { Par_MarkRefsIntoAndScanClosure::do_oop_work(p); }

  Prefetch::style prefetch_style() {
    return Prefetch::do_read;
  }
  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 CMSOopClosure {
 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);
  inline void do_oop_nv(oop* p)       { PushOrMarkClosure::do_oop_work(p); }
  inline void do_oop_nv(narrowOop* p) { PushOrMarkClosure::do_oop_work(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 Par_MarkFromRootsClosure.
class Par_PushOrMarkClosure: public CMSOopClosure {
 private:
  CMSCollector*    _collector;
  MemRegion        _whole_span;
  MemRegion        _span;        // local chunk
  CMSBitMap*       _bit_map;
  OopTaskQueue*    _work_queue;
  CMSMarkStack*    _overflow_stack;
  HeapWord*  const _finger;
  HeapWord** const _global_finger_addr;
  Par_MarkFromRootsClosure* const
                   _parent;
 protected:
  DO_OOP_WORK_DEFN
 public:
  Par_PushOrMarkClosure(CMSCollector* cms_collector,
                        MemRegion span,
                        CMSBitMap* bit_map,
                        OopTaskQueue* work_queue,
                        CMSMarkStack* mark_stack,
                        HeapWord* finger,
                        HeapWord** global_finger_addr,
                        Par_MarkFromRootsClosure* parent);
  virtual void do_oop(oop* p);
  virtual void do_oop(narrowOop* p);
  inline void do_oop_nv(oop* p)       { Par_PushOrMarkClosure::do_oop_work(p); }
  inline void do_oop_nv(narrowOop* p) { Par_PushOrMarkClosure::do_oop_work(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 CMSOopClosure {
 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);
  inline void do_oop_nv(oop* p)       { CMSKeepAliveClosure::do_oop_work(p); }
  inline void do_oop_nv(narrowOop* p) { CMSKeepAliveClosure::do_oop_work(p); }
};

class CMSInnerParMarkAndPushClosure: public CMSOopClosure {
 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);
  inline void do_oop_nv(oop* p)       { CMSInnerParMarkAndPushClosure::do_oop_work(p); }
  inline void do_oop_nv(narrowOop* p) { CMSInnerParMarkAndPushClosure::do_oop_work(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 CMSOopClosure {
 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_VM_GC_IMPLEMENTATION_CONCURRENTMARKSWEEP_CMSOOPCLOSURES_HPP