view src/share/vm/gc_implementation/g1/g1OopClosures.hpp @ 2981:2ace1c4ee8da

6888336: G1: avoid explicitly marking and pushing objects in survivor spaces Summary: This change simplifies the interaction between GC and concurrent marking. By disabling survivor spaces during the initial-mark pause we don't need to propagate marks of objects we copy during each GC (since we never need to copy an explicitly marked object). Reviewed-by: johnc, brutisso
author tonyp
date Tue, 10 Jan 2012 18:58:13 -0500
parents 811ec3d0833b
children d30fa85f9994
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/*
 * Copyright (c) 2001, 2012, 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_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):
    G1ParClosureSuper(g1, par_scan_state) { }

  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:
  // Mark the object if it's not already marked. This is used to mark
  // objects pointed to by roots that are guaranteed not to move
  // during the GC (i.e., non-CSet objects). It is MT-safe.
  void mark_object(oop obj);

  // Mark the object if it's not already marked. This is used to mark
  // objects pointed to by roots that have been forwarded during a
  // GC. It is MT-safe.
  void mark_forwarded_object(oop from_obj, oop to_obj);

  oop copy_to_survivor_space(oop obj);

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) :
    _dcto_cl(dcto_cl), _g1(g1), _oc(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; }
};

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