/*

 * Copyright 2005-2009 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 *

 */

#include "incls/_precompiled.incl"

#include "incls/_psCompactionManager.cpp.incl"

PSOldGen*            ParCompactionManager::_old_gen = NULL;

ParCompactionManager**  ParCompactionManager::_manager_array = NULL;

OopTaskQueueSet*     ParCompactionManager::_stack_array = NULL;

ObjectStartArray*    ParCompactionManager::_start_array = NULL;

ParMarkBitMap*       ParCompactionManager::_mark_bitmap = NULL;

RegionTaskQueueSet*   ParCompactionManager::_region_array = NULL;

ParCompactionManager::ParCompactionManager() :

    _action(CopyAndUpdate) {

  ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();

  assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");

  _old_gen = heap->old_gen();

  _start_array = old_gen()->start_array();

  marking_stack()->initialize();

  // We want the overflow stack to be permanent

  _overflow_stack = new (ResourceObj::C_HEAP) GrowableArray<oop>(10, true);

#ifdef USE_RegionTaskQueueWithOverflow

  region_stack()->initialize();

#else

  region_stack()->initialize();

  // We want the overflow stack to be permanent

  _region_overflow_stack =

    new (ResourceObj::C_HEAP) GrowableArray<size_t>(10, true);

#endif

  // Note that _revisit_klass_stack is allocated out of the

  // C heap (as opposed to out of ResourceArena).

  int size =

    (SystemDictionary::number_of_classes() * 2) * 2 / ParallelGCThreads;

  _revisit_klass_stack = new (ResourceObj::C_HEAP) GrowableArray<Klass*>(size, true);

  // From some experiments (#klass/k)^2 for k = 10 seems a better fit, but this will

  // have to do for now until we are able to investigate a more optimal setting.

  _revisit_mdo_stack = new (ResourceObj::C_HEAP) GrowableArray<DataLayout*>(size*2, true);

}

ParCompactionManager::~ParCompactionManager() {

  delete _overflow_stack;

  delete _revisit_klass_stack;

  delete _revisit_mdo_stack;

  // _manager_array and _stack_array are statics

  // shared with all instances of ParCompactionManager

  // should not be deallocated.

}

void ParCompactionManager::initialize(ParMarkBitMap* mbm) {

  assert(PSParallelCompact::gc_task_manager() != NULL,

    "Needed for initialization");

  _mark_bitmap = mbm;

  uint parallel_gc_threads = PSParallelCompact::gc_task_manager()->workers();

  assert(_manager_array == NULL, "Attempt to initialize twice");

  _manager_array = NEW_C_HEAP_ARRAY(ParCompactionManager*, parallel_gc_threads+1 );

  _stack_array = new OopTaskQueueSet(parallel_gc_threads);

  _region_array = new RegionTaskQueueSet(parallel_gc_threads);

  // Create and register the ParCompactionManager(s) for the worker threads.

  for(uint i=0; i<parallel_gc_threads; i++) {

    _manager_array[i] = new ParCompactionManager();

    guarantee(_manager_array[i] != NULL, "Could not create ParCompactionManager");

    stack_array()->register_queue(i, _manager_array[i]->marking_stack());

#ifdef USE_RegionTaskQueueWithOverflow

    region_array()->register_queue(i, _manager_array[i]->region_stack()->task_queue());

#else

    region_array()->register_queue(i, _manager_array[i]->region_stack());

#endif

  }

  // The VMThread gets its own ParCompactionManager, which is not available

  // for work stealing.

  _manager_array[parallel_gc_threads] = new ParCompactionManager();

  guarantee(_manager_array[parallel_gc_threads] != NULL,

    "Could not create ParCompactionManager");

  assert(PSParallelCompact::gc_task_manager()->workers() != 0,

    "Not initialized?");

}

bool ParCompactionManager::should_update() {

  assert(action() != NotValid, "Action is not set");

  return (action() == ParCompactionManager::Update) ||

         (action() == ParCompactionManager::CopyAndUpdate) ||

         (action() == ParCompactionManager::UpdateAndCopy);

}

bool ParCompactionManager::should_copy() {

  assert(action() != NotValid, "Action is not set");

  return (action() == ParCompactionManager::Copy) ||

         (action() == ParCompactionManager::CopyAndUpdate) ||

         (action() == ParCompactionManager::UpdateAndCopy);

}

bool ParCompactionManager::should_verify_only() {

  assert(action() != NotValid, "Action is not set");

  return action() == ParCompactionManager::VerifyUpdate;

}

bool ParCompactionManager::should_reset_only() {

  assert(action() != NotValid, "Action is not set");

  return action() == ParCompactionManager::ResetObjects;

}

// For now save on a stack

void ParCompactionManager::save_for_scanning(oop m) {

  stack_push(m);

}

void ParCompactionManager::stack_push(oop obj) {

  if(!marking_stack()->push(obj)) {

    overflow_stack()->push(obj);

  }

}

oop ParCompactionManager::retrieve_for_scanning() {

  // Should not be used in the parallel case

  ShouldNotReachHere();

  return NULL;

}

// Save region on a stack

void ParCompactionManager::save_for_processing(size_t region_index) {

#ifdef ASSERT

  const ParallelCompactData& sd = PSParallelCompact::summary_data();

  ParallelCompactData::RegionData* const region_ptr = sd.region(region_index);

  assert(region_ptr->claimed(), "must be claimed");

  assert(region_ptr->_pushed++ == 0, "should only be pushed once");

#endif

  region_stack_push(region_index);

}

void ParCompactionManager::region_stack_push(size_t region_index) {

#ifdef USE_RegionTaskQueueWithOverflow

  region_stack()->save(region_index);

#else

  if(!region_stack()->push(region_index)) {

    region_overflow_stack()->push(region_index);

  }

#endif

}

bool ParCompactionManager::retrieve_for_processing(size_t& region_index) {

#ifdef USE_RegionTaskQueueWithOverflow

  return region_stack()->retrieve(region_index);

#else

  // Should not be used in the parallel case

  ShouldNotReachHere();

  return false;

#endif

}

ParCompactionManager*

ParCompactionManager::gc_thread_compaction_manager(int index) {

  assert(index >= 0 && index < (int)ParallelGCThreads, "index out of range");

  assert(_manager_array != NULL, "Sanity");

  return _manager_array[index];

}

void ParCompactionManager::reset() {

  for(uint i=0; i<ParallelGCThreads+1; i++) {

    manager_array(i)->revisit_klass_stack()->clear();

    manager_array(i)->revisit_mdo_stack()->clear();

  }

}

  do {

      obj->follow_contents(this);

    }

    }

}

void ParCompactionManager::drain_region_overflow_stack() {

  size_t region_index = (size_t) -1;

  while(region_stack()->retrieve_from_overflow(region_index)) {

    PSParallelCompact::fill_and_update_region(this, region_index);

  }

}

void ParCompactionManager::drain_region_stacks() {

#ifdef ASSERT

  ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();

  assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");

  MutableSpace* to_space = heap->young_gen()->to_space();

  MutableSpace* old_space = heap->old_gen()->object_space();

  MutableSpace* perm_space = heap->perm_gen()->object_space();

#endif /* ASSERT */

#if 1 // def DO_PARALLEL - the serial code hasn't been updated

  do {

#ifdef USE_RegionTaskQueueWithOverflow

    // Drain overflow stack first, so other threads can steal from

    // claimed stack while we work.

    size_t region_index = (size_t) -1;

    while(region_stack()->retrieve_from_overflow(region_index)) {

      PSParallelCompact::fill_and_update_region(this, region_index);

    }

    while (region_stack()->retrieve_from_stealable_queue(region_index)) {

      PSParallelCompact::fill_and_update_region(this, region_index);

    }

  } while (!region_stack()->is_empty());

#else

    // Drain overflow stack first, so other threads can steal from

    // claimed stack while we work.

    while(!region_overflow_stack()->is_empty()) {

      size_t region_index = region_overflow_stack()->pop();

      PSParallelCompact::fill_and_update_region(this, region_index);

    }

    size_t region_index = -1;

    // obj is a reference!!!

    while (region_stack()->pop_local(region_index)) {

      // It would be nice to assert about the type of objects we might

      // pop, but they can come from anywhere, unfortunately.

      PSParallelCompact::fill_and_update_region(this, region_index);

    }

  } while((region_stack()->size() != 0) ||

          (region_overflow_stack()->length() != 0));

#endif

#ifdef USE_RegionTaskQueueWithOverflow

  assert(region_stack()->is_empty(), "Sanity");

#else

  assert(region_stack()->size() == 0, "Sanity");

  assert(region_overflow_stack()->length() == 0, "Sanity");

#endif

#else

  oop obj;

  while (obj = retrieve_for_scanning()) {

    obj->follow_contents(this);

  }

#endif

}

#ifdef ASSERT

bool ParCompactionManager::stacks_have_been_allocated() {

  return (revisit_klass_stack()->data_addr() != NULL &&

          revisit_mdo_stack()->data_addr() != NULL);

}

#endif