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Java example source code file (markSweep.cpp)

This example Java source code file (markSweep.cpp) 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

marksweep::adjust_pointer_closure, marksweep::mark_and_push_closure, marksweep\:\:_gc_timer, marksweep\:\:_gc_tracer, marksweep\:\:adjustpointerclosure\:\:do_oop, marksweep\:\:follow_klass_closure, marksweep\:\:follow_root_closure, marksweep\:\:followrootclosure\:\:do_oop, marksweep\:\:keepaliveclosure\:\:do_oop, marksweep\:\:markandpushclosure\:\:do_oop, null, serialoldtracer, stack, stwgctimer

The markSweep.cpp Java example source code

/*
 * Copyright (c) 1997, 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.
 *
 */

#include "precompiled.hpp"
#include "compiler/compileBroker.hpp"
#include "gc_implementation/shared/gcTimer.hpp"
#include "gc_implementation/shared/gcTrace.hpp"
#include "gc_implementation/shared/markSweep.inline.hpp"
#include "gc_interface/collectedHeap.inline.hpp"
#include "oops/methodData.hpp"
#include "oops/objArrayKlass.inline.hpp"
#include "oops/oop.inline.hpp"

uint                    MarkSweep::_total_invocations = 0;

Stack<oop, mtGC>              MarkSweep::_marking_stack;
Stack<ObjArrayTask, mtGC>     MarkSweep::_objarray_stack;

Stack<oop, mtGC>              MarkSweep::_preserved_oop_stack;
Stack<markOop, mtGC>          MarkSweep::_preserved_mark_stack;
size_t                  MarkSweep::_preserved_count = 0;
size_t                  MarkSweep::_preserved_count_max = 0;
PreservedMark*          MarkSweep::_preserved_marks = NULL;
ReferenceProcessor*     MarkSweep::_ref_processor   = NULL;
STWGCTimer*             MarkSweep::_gc_timer        = NULL;
SerialOldTracer*        MarkSweep::_gc_tracer       = NULL;

MarkSweep::FollowRootClosure  MarkSweep::follow_root_closure;
CodeBlobToOopClosure MarkSweep::follow_code_root_closure(&MarkSweep::follow_root_closure, /*do_marking=*/ true);

void MarkSweep::FollowRootClosure::do_oop(oop* p)       { follow_root(p); }
void MarkSweep::FollowRootClosure::do_oop(narrowOop* p) { follow_root(p); }

MarkSweep::MarkAndPushClosure MarkSweep::mark_and_push_closure;
MarkSweep::FollowKlassClosure MarkSweep::follow_klass_closure;
MarkSweep::AdjustKlassClosure MarkSweep::adjust_klass_closure;

void MarkSweep::MarkAndPushClosure::do_oop(oop* p)       { mark_and_push(p); }
void MarkSweep::MarkAndPushClosure::do_oop(narrowOop* p) { mark_and_push(p); }

void MarkSweep::FollowKlassClosure::do_klass(Klass* klass) {
  klass->oops_do(&MarkSweep::mark_and_push_closure);
}
void MarkSweep::AdjustKlassClosure::do_klass(Klass* klass) {
  klass->oops_do(&MarkSweep::adjust_pointer_closure);
}

void MarkSweep::follow_class_loader(ClassLoaderData* cld) {
  cld->oops_do(&MarkSweep::mark_and_push_closure, &MarkSweep::follow_klass_closure, true);
}

void MarkSweep::follow_stack() {
  do {
    while (!_marking_stack.is_empty()) {
      oop obj = _marking_stack.pop();
      assert (obj->is_gc_marked(), "p must be marked");
      obj->follow_contents();
    }
    // Process ObjArrays one at a time to avoid marking stack bloat.
    if (!_objarray_stack.is_empty()) {
      ObjArrayTask task = _objarray_stack.pop();
      ObjArrayKlass* k = (ObjArrayKlass*)task.obj()->klass();
      k->oop_follow_contents(task.obj(), task.index());
    }
  } while (!_marking_stack.is_empty() || !_objarray_stack.is_empty());
}

MarkSweep::FollowStackClosure MarkSweep::follow_stack_closure;

void MarkSweep::FollowStackClosure::do_void() { follow_stack(); }

// We preserve the mark which should be replaced at the end and the location
// that it will go.  Note that the object that this markOop belongs to isn't
// currently at that address but it will be after phase4
void MarkSweep::preserve_mark(oop obj, markOop mark) {
  // We try to store preserved marks in the to space of the new generation since
  // this is storage which should be available.  Most of the time this should be
  // sufficient space for the marks we need to preserve but if it isn't we fall
  // back to using Stacks to keep track of the overflow.
  if (_preserved_count < _preserved_count_max) {
    _preserved_marks[_preserved_count++].init(obj, mark);
  } else {
    _preserved_mark_stack.push(mark);
    _preserved_oop_stack.push(obj);
  }
}

MarkSweep::AdjustPointerClosure MarkSweep::adjust_pointer_closure;

void MarkSweep::AdjustPointerClosure::do_oop(oop* p)       { adjust_pointer(p); }
void MarkSweep::AdjustPointerClosure::do_oop(narrowOop* p) { adjust_pointer(p); }

void MarkSweep::adjust_marks() {
  assert( _preserved_oop_stack.size() == _preserved_mark_stack.size(),
         "inconsistent preserved oop stacks");

  // adjust the oops we saved earlier
  for (size_t i = 0; i < _preserved_count; i++) {
    _preserved_marks[i].adjust_pointer();
  }

  // deal with the overflow stack
  StackIterator<oop, mtGC> iter(_preserved_oop_stack);
  while (!iter.is_empty()) {
    oop* p = iter.next_addr();
    adjust_pointer(p);
  }
}

void MarkSweep::restore_marks() {
  assert(_preserved_oop_stack.size() == _preserved_mark_stack.size(),
         "inconsistent preserved oop stacks");
  if (PrintGC && Verbose) {
    gclog_or_tty->print_cr("Restoring %d marks",
                           _preserved_count + _preserved_oop_stack.size());
  }

  // restore the marks we saved earlier
  for (size_t i = 0; i < _preserved_count; i++) {
    _preserved_marks[i].restore();
  }

  // deal with the overflow
  while (!_preserved_oop_stack.is_empty()) {
    oop obj       = _preserved_oop_stack.pop();
    markOop mark  = _preserved_mark_stack.pop();
    obj->set_mark(mark);
  }
}

MarkSweep::IsAliveClosure   MarkSweep::is_alive;

bool MarkSweep::IsAliveClosure::do_object_b(oop p) { return p->is_gc_marked(); }

MarkSweep::KeepAliveClosure MarkSweep::keep_alive;

void MarkSweep::KeepAliveClosure::do_oop(oop* p)       { MarkSweep::KeepAliveClosure::do_oop_work(p); }
void MarkSweep::KeepAliveClosure::do_oop(narrowOop* p) { MarkSweep::KeepAliveClosure::do_oop_work(p); }

void marksweep_init() {
  MarkSweep::_gc_timer = new (ResourceObj::C_HEAP, mtGC) STWGCTimer();
  MarkSweep::_gc_tracer = new (ResourceObj::C_HEAP, mtGC) SerialOldTracer();
}

#ifndef PRODUCT

void MarkSweep::trace(const char* msg) {
  if (TraceMarkSweep)
    gclog_or_tty->print("%s", msg);
}

#endif

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