/*

 * Copyright 2002-2008 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/_psPromotionManager.cpp.incl"

PSPromotionManager**         PSPromotionManager::_manager_array = NULL;

OopStarTaskQueueSet*         PSPromotionManager::_stack_array_depth = NULL;

OopTaskQueueSet*             PSPromotionManager::_stack_array_breadth = NULL;

PSOldGen*                    PSPromotionManager::_old_gen = NULL;

MutableSpace*                PSPromotionManager::_young_space = NULL;

void PSPromotionManager::initialize() {

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

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

  _old_gen = heap->old_gen();

  _young_space = heap->young_gen()->to_space();

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

  _manager_array = NEW_C_HEAP_ARRAY(PSPromotionManager*, ParallelGCThreads+1 );

  guarantee(_manager_array != NULL, "Could not initialize promotion manager");

  if (UseDepthFirstScavengeOrder) {

    _stack_array_depth = new OopStarTaskQueueSet(ParallelGCThreads);

    guarantee(_stack_array_depth != NULL, "Count not initialize promotion manager");

  } else {

    _stack_array_breadth = new OopTaskQueueSet(ParallelGCThreads);

    guarantee(_stack_array_breadth != NULL, "Count not initialize promotion manager");

  }

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

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

    _manager_array[i] = new PSPromotionManager();

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

    if (UseDepthFirstScavengeOrder) {

      stack_array_depth()->register_queue(i, _manager_array[i]->claimed_stack_depth());

    } else {

      stack_array_breadth()->register_queue(i, _manager_array[i]->claimed_stack_breadth());

    }

  }

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

  // for work stealing.

  _manager_array[ParallelGCThreads] = new PSPromotionManager();

  guarantee(_manager_array[ParallelGCThreads] != NULL, "Could not create PSPromotionManager");

}

PSPromotionManager* PSPromotionManager::gc_thread_promotion_manager(int index) {

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

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

  return _manager_array[index];

}

PSPromotionManager* PSPromotionManager::vm_thread_promotion_manager() {

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

  return _manager_array[ParallelGCThreads];

}

void PSPromotionManager::pre_scavenge() {

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

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

  _young_space = heap->young_gen()->to_space();

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

    manager_array(i)->reset();

  }

}

void PSPromotionManager::post_scavenge() {

#if PS_PM_STATS

  print_stats();

#endif // PS_PM_STATS

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

    PSPromotionManager* manager = manager_array(i);

    // the guarantees are a bit gratuitous but, if one fires, we'll

    // have a better idea of what went wrong

    if (i < ParallelGCThreads) {

      guarantee((!UseDepthFirstScavengeOrder ||

                 manager->overflow_stack_depth()->length() <= 0),

                "promotion manager overflow stack must be empty");

      guarantee((UseDepthFirstScavengeOrder ||

                 manager->overflow_stack_breadth()->length() <= 0),

                "promotion manager overflow stack must be empty");

      guarantee((!UseDepthFirstScavengeOrder ||

                 manager->claimed_stack_depth()->size() <= 0),

                "promotion manager claimed stack must be empty");

      guarantee((UseDepthFirstScavengeOrder ||

                 manager->claimed_stack_breadth()->size() <= 0),

                "promotion manager claimed stack must be empty");

    } else {

      guarantee((!UseDepthFirstScavengeOrder ||

                 manager->overflow_stack_depth()->length() <= 0),

                "VM Thread promotion manager overflow stack "

                "must be empty");

      guarantee((UseDepthFirstScavengeOrder ||

                 manager->overflow_stack_breadth()->length() <= 0),

                "VM Thread promotion manager overflow stack "

                "must be empty");

      guarantee((!UseDepthFirstScavengeOrder ||

                 manager->claimed_stack_depth()->size() <= 0),

                "VM Thread promotion manager claimed stack "

                "must be empty");

      guarantee((UseDepthFirstScavengeOrder ||

                 manager->claimed_stack_breadth()->size() <= 0),

                "VM Thread promotion manager claimed stack "

                "must be empty");

    }

    manager->flush_labs();

  }

}

#if PS_PM_STATS

void

PSPromotionManager::print_stats(uint i) {

  tty->print_cr("---- GC Worker %2d Stats", i);

  tty->print_cr("    total pushes            %8d", _total_pushes);

  tty->print_cr("    masked pushes           %8d", _masked_pushes);

  tty->print_cr("    overflow pushes         %8d", _overflow_pushes);

  tty->print_cr("    max overflow length     %8d", _max_overflow_length);

  tty->print_cr("");

  tty->print_cr("    arrays chunked          %8d", _arrays_chunked);

  tty->print_cr("    array chunks processed  %8d", _array_chunks_processed);

  tty->print_cr("");

  tty->print_cr("    total steals            %8d", _total_steals);

  tty->print_cr("    masked steals           %8d", _masked_steals);

  tty->print_cr("");

}

void

PSPromotionManager::print_stats() {

  tty->print_cr("== GC Tasks Stats (%s), GC %3d",

                (UseDepthFirstScavengeOrder) ? "Depth-First" : "Breadth-First",

                Universe::heap()->total_collections());

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

    PSPromotionManager* manager = manager_array(i);

    manager->print_stats(i);

  }

}

#endif // PS_PM_STATS

PSPromotionManager::PSPromotionManager() {

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

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

  _depth_first = UseDepthFirstScavengeOrder;

  // We set the old lab's start array.

  _old_lab.set_start_array(old_gen()->start_array());

  uint queue_size;

  if (depth_first()) {

    claimed_stack_depth()->initialize();

    queue_size = claimed_stack_depth()->max_elems();

    // We want the overflow stack to be permanent

    _overflow_stack_depth = new (ResourceObj::C_HEAP) GrowableArray<StarTask>(10, true);

    _overflow_stack_breadth = NULL;

  } else {

    claimed_stack_breadth()->initialize();

    queue_size = claimed_stack_breadth()->max_elems();

    // We want the overflow stack to be permanent

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

    _overflow_stack_depth = NULL;

  }

  _totally_drain = (ParallelGCThreads == 1) || (GCDrainStackTargetSize == 0);

  if (_totally_drain) {

    _target_stack_size = 0;

  } else {

    // don't let the target stack size to be more than 1/4 of the entries

    _target_stack_size = (uint) MIN2((uint) GCDrainStackTargetSize,

                                     (uint) (queue_size / 4));

  }

  _array_chunk_size = ParGCArrayScanChunk;

  // let's choose 1.5x the chunk size

  _min_array_size_for_chunking = 3 * _array_chunk_size / 2;

  reset();

}

void PSPromotionManager::reset() {

  assert(claimed_stack_empty(), "reset of non-empty claimed stack");

  assert(overflow_stack_empty(), "reset of non-empty overflow stack");

  // We need to get an assert in here to make sure the labs are always flushed.

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

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

  // Do not prefill the LAB's, save heap wastage!

  HeapWord* lab_base = young_space()->top();

  _young_lab.initialize(MemRegion(lab_base, (size_t)0));

  _young_gen_is_full = false;

  lab_base = old_gen()->object_space()->top();

  _old_lab.initialize(MemRegion(lab_base, (size_t)0));

  _old_gen_is_full = false;

  _prefetch_queue.clear();

#if PS_PM_STATS

  _total_pushes = 0;

  _masked_pushes = 0;

  _overflow_pushes = 0;

  _max_overflow_length = 0;

  _arrays_chunked = 0;

  _array_chunks_processed = 0;

  _total_steals = 0;

  _masked_steals = 0;

#endif // PS_PM_STATS

}

void PSPromotionManager::drain_stacks_depth(bool totally_drain) {

  assert(depth_first(), "invariant");

  assert(overflow_stack_depth() != NULL, "invariant");

  totally_drain = totally_drain || _totally_drain;

#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 */

  do {

    StarTask p;

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

    // claimed stack while we work.

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

      // linux compiler wants different overloaded operator= in taskqueue to

      // assign to p that the other compilers don't like.

      StarTask ptr = overflow_stack_depth()->pop();

      process_popped_location_depth(ptr);

    }

    if (totally_drain) {

      while (claimed_stack_depth()->pop_local(p)) {

        process_popped_location_depth(p);

      }

    } else {

      while (claimed_stack_depth()->size() > _target_stack_size &&

             claimed_stack_depth()->pop_local(p)) {

        process_popped_location_depth(p);

      }

    }

  } while( (totally_drain && claimed_stack_depth()->size() > 0) ||

           (overflow_stack_depth()->length() > 0) );

  assert(!totally_drain || claimed_stack_empty(), "Sanity");

  assert(totally_drain ||

         claimed_stack_depth()->size() <= _target_stack_size,

         "Sanity");

  assert(overflow_stack_empty(), "Sanity");

}

void PSPromotionManager::drain_stacks_breadth(bool totally_drain) {

  assert(!depth_first(), "invariant");

  assert(overflow_stack_breadth() != NULL, "invariant");

  totally_drain = totally_drain || _totally_drain;

#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 */

  do {

    oop obj;

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

    // claimed stack while we work.

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

      obj = overflow_stack_breadth()->pop();

      obj->copy_contents(this);

    }

    if (totally_drain) {

      // obj is a reference!!!

      while (claimed_stack_breadth()->pop_local(obj)) {

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

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

        obj->copy_contents(this);

      }

    } else {

      // obj is a reference!!!

      while (claimed_stack_breadth()->size() > _target_stack_size &&

             claimed_stack_breadth()->pop_local(obj)) {

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

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

        obj->copy_contents(this);

      }

    }

    // If we could not find any other work, flush the prefetch queue

    if (claimed_stack_breadth()->size() == 0 &&

        (overflow_stack_breadth()->length() == 0)) {

      flush_prefetch_queue();

    }

  } while((totally_drain && claimed_stack_breadth()->size() > 0) ||

          (overflow_stack_breadth()->length() > 0));

  assert(!totally_drain || claimed_stack_empty(), "Sanity");

  assert(totally_drain ||

         claimed_stack_breadth()->size() <= _target_stack_size,

         "Sanity");

  assert(overflow_stack_empty(), "Sanity");

}

void PSPromotionManager::flush_labs() {

  assert(claimed_stack_empty(), "Attempt to flush lab with live stack");

  assert(overflow_stack_empty(), "Attempt to flush lab with live overflow stack");

  // If either promotion lab fills up, we can flush the

  // lab but not refill it, so check first.

  assert(!_young_lab.is_flushed() || _young_gen_is_full, "Sanity");

  if (!_young_lab.is_flushed())

    _young_lab.flush();

  assert(!_old_lab.is_flushed() || _old_gen_is_full, "Sanity");

  if (!_old_lab.is_flushed())

    _old_lab.flush();

  // Let PSScavenge know if we overflowed

  if (_young_gen_is_full) {

    PSScavenge::set_survivor_overflow(true);

  }

}

//

// This method is pretty bulky. It would be nice to split it up

// into smaller submethods, but we need to be careful not to hurt

// performance.

//

oop PSPromotionManager::copy_to_survivor_space(oop o, bool depth_first) {

  assert(PSScavenge::should_scavenge(&o), "Sanity");

  oop new_obj = NULL;

  // NOTE! We must be very careful with any methods that access the mark

  // in o. There may be multiple threads racing on it, and it may be forwarded

  // at any time. Do not use oop methods for accessing the mark!

  markOop test_mark = o->mark();

  // The same test as "o->is_forwarded()"

  if (!test_mark->is_marked()) {

    bool new_obj_is_tenured = false;

    size_t new_obj_size = o->size();

    // Find the objects age, MT safe.

    int age = (test_mark->has_displaced_mark_helper() /* o->has_displaced_mark() */) ?

      test_mark->displaced_mark_helper()->age() : test_mark->age();

    // Try allocating obj in to-space (unless too old)

    if (age < PSScavenge::tenuring_threshold()) {

      new_obj = (oop) _young_lab.allocate(new_obj_size);

      if (new_obj == NULL && !_young_gen_is_full) {

        // Do we allocate directly, or flush and refill?

        if (new_obj_size > (YoungPLABSize / 2)) {

          // Allocate this object directly

          new_obj = (oop)young_space()->cas_allocate(new_obj_size);

        } else {

          // Flush and fill

          _young_lab.flush();

          HeapWord* lab_base = young_space()->cas_allocate(YoungPLABSize);

          if (lab_base != NULL) {

            _young_lab.initialize(MemRegion(lab_base, YoungPLABSize));

            // Try the young lab allocation again.

            new_obj = (oop) _young_lab.allocate(new_obj_size);

          } else {

            _young_gen_is_full = true;

          }

        }

      }

    }

    // Otherwise try allocating obj tenured

    if (new_obj == NULL) {

#ifndef PRODUCT

      if (Universe::heap()->promotion_should_fail()) {

        return oop_promotion_failed(o, test_mark);

      }

#endif  // #ifndef PRODUCT

      new_obj = (oop) _old_lab.allocate(new_obj_size);

      new_obj_is_tenured = true;

      if (new_obj == NULL) {

        if (!_old_gen_is_full) {

          // Do we allocate directly, or flush and refill?

          if (new_obj_size > (OldPLABSize / 2)) {

            // Allocate this object directly

            new_obj = (oop)old_gen()->cas_allocate(new_obj_size);

          } else {

            // Flush and fill

            _old_lab.flush();

            HeapWord* lab_base = old_gen()->cas_allocate(OldPLABSize);

            if(lab_base != NULL) {

              _old_lab.initialize(MemRegion(lab_base, OldPLABSize));

              // Try the old lab allocation again.

              new_obj = (oop) _old_lab.allocate(new_obj_size);

            }

          }

        }

        // This is the promotion failed test, and code handling.

        // The code belongs here for two reasons. It is slightly

        // different thatn the code below, and cannot share the

        // CAS testing code. Keeping the code here also minimizes

        // the impact on the common case fast path code.

        if (new_obj == NULL) {

          _old_gen_is_full = true;

          return oop_promotion_failed(o, test_mark);

        }

      }

    }

    assert(new_obj != NULL, "allocation should have succeeded");

    // Copy obj

    Copy::aligned_disjoint_words((HeapWord*)o, (HeapWord*)new_obj, new_obj_size);

    // Now we have to CAS in the header.

    if (o->cas_forward_to(new_obj, test_mark)) {

      // We won any races, we "own" this object.

      assert(new_obj == o->forwardee(), "Sanity");

      // Increment age if obj still in new generation. Now that

      // we're dealing with a markOop that cannot change, it is

      // okay to use the non mt safe oop methods.

      if (!new_obj_is_tenured) {

        new_obj->incr_age();

        assert(young_space()->contains(new_obj), "Attempt to push non-promoted obj");

      }

      if (depth_first) {

        // Do the size comparison first with new_obj_size, which we

        // already have. Hopefully, only a few objects are larger than

        // _min_array_size_for_chunking, and most of them will be arrays.

        // So, the is->objArray() test would be very infrequent.

        if (new_obj_size > _min_array_size_for_chunking &&

            new_obj->is_objArray() &&

            PSChunkLargeArrays) {

          // we'll chunk it

#if PS_PM_STATS

          ++_arrays_chunked;

#endif // PS_PM_STATS

          oop* const masked_o = mask_chunked_array_oop(o);

          push_depth(masked_o);

#if PS_PM_STATS

          ++_masked_pushes;

#endif // PS_PM_STATS

        } else {

          // we'll just push its contents

          new_obj->push_contents(this);

        }

      } else {

        push_breadth(new_obj);

      }

    }  else {

      // We lost, someone else "owns" this object

      guarantee(o->is_forwarded(), "Object must be forwarded if the cas failed.");

      if (new_obj_is_tenured) {

        if (!_old_lab.unallocate_object(new_obj)) {

        }

      }

      // don't update this before the unallocation!

      new_obj = o->forwardee();

    }

  } else {

    assert(o->is_forwarded(), "Sanity");

    new_obj = o->forwardee();

  }

#ifdef DEBUG

  // This code must come after the CAS test, or it will print incorrect

  // information.

  if (TraceScavenge) {

    gclog_or_tty->print_cr("{%s %s " PTR_FORMAT " -> " PTR_FORMAT " (" SIZE_FORMAT ")}",

       PSScavenge::should_scavenge(&new_obj) ? "copying" : "tenuring",