view src/share/vm/gc_implementation/g1/g1OopClosures.hpp @ 2740:4dfb2df418f2

6484982: G1: process references during evacuation pauses Summary: G1 now uses two reference processors - one is used by concurrent marking and the other is used by STW GCs (both full and incremental evacuation pauses). In an evacuation pause, the reference processor is embedded into the closures used to scan objects. Doing so causes causes reference objects to be 'discovered' by the reference processor. At the end of the evacuation pause, these discovered reference objects are processed - preserving (and copying) referent objects (and their reachable graphs) as appropriate. Reviewed-by: ysr, jwilhelm, brutisso, stefank, tonyp
author johnc
date Thu, 22 Sep 2011 10:57:37 -0700
parents 663cb89032b1
children 811ec3d0833b
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/*
 * Copyright (c) 2001, 2011, 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
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 * questions.
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 */

#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1OOPCLOSURES_HPP
#define SHARE_VM_GC_IMPLEMENTATION_G1_G1OOPCLOSURES_HPP

class HeapRegion;
class G1CollectedHeap;
class G1RemSet;
class ConcurrentMark;
class DirtyCardToOopClosure;
class CMBitMap;
class CMMarkStack;
class G1ParScanThreadState;
class CMTask;
class ReferenceProcessor;

// A class that scans oops in a given heap region (much as OopsInGenClosure
// scans oops in a generation.)
class OopsInHeapRegionClosure: public OopsInGenClosure {
protected:
  HeapRegion* _from;
public:
  void set_region(HeapRegion* from) { _from = from; }
};

class G1ParClosureSuper : public OopsInHeapRegionClosure {
protected:
  G1CollectedHeap* _g1;
  G1RemSet* _g1_rem;
  ConcurrentMark* _cm;
  G1ParScanThreadState* _par_scan_state;
  bool _during_initial_mark;
  bool _mark_in_progress;
public:
  G1ParClosureSuper(G1CollectedHeap* g1, G1ParScanThreadState* par_scan_state);
  bool apply_to_weak_ref_discovered_field() { return true; }
};

class G1ParPushHeapRSClosure : public G1ParClosureSuper {
public:
  G1ParPushHeapRSClosure(G1CollectedHeap* g1,
                         G1ParScanThreadState* par_scan_state,
                         ReferenceProcessor* rp) :
    G1ParClosureSuper(g1, par_scan_state)
  {
    assert(_ref_processor == NULL, "sanity");
    _ref_processor = rp;
  }

  template <class T> void do_oop_nv(T* p);
  virtual void do_oop(oop* p)          { do_oop_nv(p); }
  virtual void do_oop(narrowOop* p)    { do_oop_nv(p); }
};

class G1ParScanClosure : public G1ParClosureSuper {
public:
  G1ParScanClosure(G1CollectedHeap* g1, G1ParScanThreadState* par_scan_state, ReferenceProcessor* rp) :
    G1ParClosureSuper(g1, par_scan_state)
  {
    assert(_ref_processor == NULL, "sanity");
    _ref_processor = rp;
  }

  template <class T> void do_oop_nv(T* p);
  virtual void do_oop(oop* p)          { do_oop_nv(p); }
  virtual void do_oop(narrowOop* p)    { do_oop_nv(p); }
};

#define G1_PARTIAL_ARRAY_MASK 0x2

template <class T> inline bool has_partial_array_mask(T* ref) {
  return ((uintptr_t)ref & G1_PARTIAL_ARRAY_MASK) == G1_PARTIAL_ARRAY_MASK;
}

template <class T> inline T* set_partial_array_mask(T obj) {
  assert(((uintptr_t)obj & G1_PARTIAL_ARRAY_MASK) == 0, "Information loss!");
  return (T*) ((uintptr_t)obj | G1_PARTIAL_ARRAY_MASK);
}

template <class T> inline oop clear_partial_array_mask(T* ref) {
  return oop((intptr_t)ref & ~G1_PARTIAL_ARRAY_MASK);
}

class G1ParScanPartialArrayClosure : public G1ParClosureSuper {
  G1ParScanClosure _scanner;

public:
  G1ParScanPartialArrayClosure(G1CollectedHeap* g1, G1ParScanThreadState* par_scan_state, ReferenceProcessor* rp) :
    G1ParClosureSuper(g1, par_scan_state), _scanner(g1, par_scan_state, rp)
  {
    assert(_ref_processor == NULL, "sanity");
  }

  G1ParScanClosure* scanner() {
    return &_scanner;
  }

  template <class T> void do_oop_nv(T* p);
  virtual void do_oop(oop* p)       { do_oop_nv(p); }
  virtual void do_oop(narrowOop* p) { do_oop_nv(p); }
};


class G1ParCopyHelper : public G1ParClosureSuper {
  G1ParScanClosure *_scanner;
protected:
  template <class T> void mark_object(T* p);
  oop copy_to_survivor_space(oop obj, bool should_mark_root,
                                      bool should_mark_copy);
public:
  G1ParCopyHelper(G1CollectedHeap* g1, G1ParScanThreadState* par_scan_state,
                  G1ParScanClosure *scanner) :
    G1ParClosureSuper(g1, par_scan_state), _scanner(scanner) { }
};

template<bool do_gen_barrier, G1Barrier barrier,
         bool do_mark_object>
class G1ParCopyClosure : public G1ParCopyHelper {
  G1ParScanClosure _scanner;

  template <class T> void do_oop_work(T* p);

public:
  G1ParCopyClosure(G1CollectedHeap* g1, G1ParScanThreadState* par_scan_state,
                   ReferenceProcessor* rp) :
    _scanner(g1, par_scan_state, rp),
    G1ParCopyHelper(g1, par_scan_state, &_scanner)
  {
    assert(_ref_processor == NULL, "sanity");
  }

  G1ParScanClosure* scanner() { return &_scanner; }

  template <class T> void do_oop_nv(T* p) {
    do_oop_work(p);
  }
  virtual void do_oop(oop* p)       { do_oop_nv(p); }
  virtual void do_oop(narrowOop* p) { do_oop_nv(p); }
};

typedef G1ParCopyClosure<false, G1BarrierNone, false> G1ParScanExtRootClosure;
typedef G1ParCopyClosure<true,  G1BarrierNone, false> G1ParScanPermClosure;

typedef G1ParCopyClosure<false, G1BarrierNone, true> G1ParScanAndMarkExtRootClosure;
typedef G1ParCopyClosure<true,  G1BarrierNone, true> G1ParScanAndMarkPermClosure;

// The following closure types are no longer used but are retained
// for historical reasons:
// typedef G1ParCopyClosure<false, G1BarrierRS,   false> G1ParScanHeapRSClosure;
// typedef G1ParCopyClosure<false, G1BarrierRS,   true> G1ParScanAndMarkHeapRSClosure;

// The following closure type is defined in g1_specialized_oop_closures.hpp:
//
// typedef G1ParCopyClosure<false, G1BarrierEvac, false> G1ParScanHeapEvacClosure;

// We use a separate closure to handle references during evacuation
// failure processing.
// We could have used another instance of G1ParScanHeapEvacClosure
// (since that closure no longer assumes that the references it
// handles point into the collection set).

typedef G1ParCopyClosure<false, G1BarrierEvac, false> G1ParScanHeapEvacFailureClosure;

class FilterIntoCSClosure: public OopClosure {
  G1CollectedHeap* _g1;
  OopClosure* _oc;
  DirtyCardToOopClosure* _dcto_cl;
public:
  FilterIntoCSClosure(  DirtyCardToOopClosure* dcto_cl,
                        G1CollectedHeap* g1,
                        OopClosure* oc,
                        ReferenceProcessor* rp) :
    _dcto_cl(dcto_cl), _g1(g1), _oc(oc)
  {
    assert(_ref_processor == NULL, "sanity");
    _ref_processor = rp;
  }

  template <class T> void do_oop_nv(T* p);
  virtual void do_oop(oop* p)        { do_oop_nv(p); }
  virtual void do_oop(narrowOop* p)  { do_oop_nv(p); }
  bool apply_to_weak_ref_discovered_field() { return true; }
  bool do_header() { return false; }
};

class FilterOutOfRegionClosure: public OopClosure {
  HeapWord* _r_bottom;
  HeapWord* _r_end;
  OopClosure* _oc;
  int _out_of_region;
public:
  FilterOutOfRegionClosure(HeapRegion* r, OopClosure* oc);
  template <class T> void do_oop_nv(T* p);
  virtual void do_oop(oop* p) { do_oop_nv(p); }
  virtual void do_oop(narrowOop* p) { do_oop_nv(p); }
  bool apply_to_weak_ref_discovered_field() { return true; }
  bool do_header() { return false; }
  int out_of_region() { return _out_of_region; }
};

// Closure for iterating over object fields during concurrent marking
class G1CMOopClosure : public OopClosure {
  G1CollectedHeap*   _g1h;
  ConcurrentMark*    _cm;
  CMTask*            _task;
public:
  G1CMOopClosure(G1CollectedHeap* g1h, ConcurrentMark* cm, CMTask* task);
  template <class T> void do_oop_nv(T* p);
  virtual void do_oop(      oop* p) { do_oop_nv(p); }
  virtual void do_oop(narrowOop* p) { do_oop_nv(p); }
};

#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1OOPCLOSURES_HPP