/*

 * 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#include "precompiled.hpp"

#include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"

#include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp"

#include "gc_implementation/parallelScavenge/psMarkSweepDecorator.hpp"

#include "gc_implementation/parallelScavenge/psOldGen.hpp"

#include "gc_implementation/shared/spaceDecorator.hpp"

#include "memory/cardTableModRefBS.hpp"

#include "memory/gcLocker.inline.hpp"

#include "oops/oop.inline.hpp"

#include "runtime/java.hpp"

inline const char* PSOldGen::select_name() {

  return UseParallelOldGC ? "ParOldGen" : "PSOldGen";

}

PSOldGen::PSOldGen(ReservedSpace rs, size_t alignment,

                   size_t initial_size, size_t min_size, size_t max_size,

                   const char* perf_data_name, int level):

  _name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size),

  _max_gen_size(max_size)

{

  initialize(rs, alignment, perf_data_name, level);

}

PSOldGen::PSOldGen(size_t initial_size,

                   size_t min_size, size_t max_size,

                   const char* perf_data_name, int level):

  _name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size),

  _max_gen_size(max_size)

{}

void PSOldGen::initialize(ReservedSpace rs, size_t alignment,

                          const char* perf_data_name, int level) {

  initialize_virtual_space(rs, alignment);

  initialize_work(perf_data_name, level);

  // The old gen can grow to gen_size_limit().  _reserve reflects only

  // the current maximum that can be committed.

  assert(_reserved.byte_size() <= gen_size_limit(), "Consistency check");

}

void PSOldGen::initialize_virtual_space(ReservedSpace rs, size_t alignment) {

  _virtual_space = new PSVirtualSpace(rs, alignment);

  if (!_virtual_space->expand_by(_init_gen_size)) {

    vm_exit_during_initialization("Could not reserve enough space for "

                                  "object heap");

  }

}

void PSOldGen::initialize_work(const char* perf_data_name, int level) {

  //

  // Basic memory initialization

  //

  MemRegion limit_reserved((HeapWord*)virtual_space()->low_boundary(),

    heap_word_size(_max_gen_size));

  assert(limit_reserved.byte_size() == _max_gen_size,

    "word vs bytes confusion");

  //

  // Object start stuff

  //

  start_array()->initialize(limit_reserved);

  _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),

                        (HeapWord*)virtual_space()->high_boundary());

  //

  // Card table stuff

  //

  MemRegion cmr((HeapWord*)virtual_space()->low(),

                (HeapWord*)virtual_space()->high());

  if (ZapUnusedHeapArea) {

    // Mangle newly committed space immediately rather than

    // waiting for the initialization of the space even though

    // mangling is related to spaces.  Doing it here eliminates

    // the need to carry along information that a complete mangling

    // (bottom to end) needs to be done.

    SpaceMangler::mangle_region(cmr);

  }

  Universe::heap()->barrier_set()->resize_covered_region(cmr);

  CardTableModRefBS* _ct = (CardTableModRefBS*)Universe::heap()->barrier_set();

  assert (_ct->kind() == BarrierSet::CardTableModRef, "Sanity");

  // Verify that the start and end of this generation is the start of a card.

  // If this wasn't true, a single card could span more than one generation,

  // which would cause problems when we commit/uncommit memory, and when we

  // clear and dirty cards.

  guarantee(_ct->is_card_aligned(_reserved.start()), "generation must be card aligned");

  if (_reserved.end() != Universe::heap()->reserved_region().end()) {

    // Don't check at the very end of the heap as we'll assert that we're probing off

    // the end if we try.

    guarantee(_ct->is_card_aligned(_reserved.end()), "generation must be card aligned");

  }

  //

  // ObjectSpace stuff

  //

  _object_space = new MutableSpace(virtual_space()->alignment());

  if (_object_space == NULL)

    vm_exit_during_initialization("Could not allocate an old gen space");

  object_space()->initialize(cmr,

                             SpaceDecorator::Clear,

                             SpaceDecorator::Mangle);

  _object_mark_sweep = new PSMarkSweepDecorator(_object_space, start_array(), MarkSweepDeadRatio);

  if (_object_mark_sweep == NULL)

    vm_exit_during_initialization("Could not complete allocation of old generation");

  // Update the start_array

  start_array()->set_covered_region(cmr);

  // Generation Counters, generation 'level', 1 subspace

  _gen_counters = new PSGenerationCounters(perf_data_name, level, 1,

                                           virtual_space());

  _space_counters = new SpaceCounters(perf_data_name, 0,

                                      virtual_space()->reserved_size(),

                                      _object_space, _gen_counters);

}

// Assume that the generation has been allocated if its

// reserved size is not 0.

bool  PSOldGen::is_allocated() {

  return virtual_space()->reserved_size() != 0;

}

void PSOldGen::precompact() {

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

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

  // Reset start array first.

  start_array()->reset();

  object_mark_sweep()->precompact();

  // Now compact the young gen

  heap->young_gen()->precompact();

}

void PSOldGen::adjust_pointers() {

  object_mark_sweep()->adjust_pointers();

}

void PSOldGen::compact() {

  object_mark_sweep()->compact(ZapUnusedHeapArea);

}

size_t PSOldGen::contiguous_available() const {

  return object_space()->free_in_bytes() + virtual_space()->uncommitted_size();

}

// Allocation. We report all successful allocations to the size policy

// Note that the perm gen does not use this method, and should not!

HeapWord* PSOldGen::allocate(size_t word_size, bool is_tlab) {

  assert_locked_or_safepoint(Heap_lock);

  HeapWord* res = allocate_noexpand(word_size, is_tlab);

  if (res == NULL) {

    res = expand_and_allocate(word_size, is_tlab);

  }

  // Allocations in the old generation need to be reported

  if (res != NULL) {

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

    heap->size_policy()->tenured_allocation(word_size);

  }

  return res;

}

HeapWord* PSOldGen::expand_and_allocate(size_t word_size, bool is_tlab) {

  assert(!is_tlab, "TLAB's are not supported in PSOldGen");

  expand(word_size*HeapWordSize);

  if (GCExpandToAllocateDelayMillis > 0) {

    os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false);

  }

  return allocate_noexpand(word_size, is_tlab);

}

HeapWord* PSOldGen::expand_and_cas_allocate(size_t word_size) {

  expand(word_size*HeapWordSize);

  if (GCExpandToAllocateDelayMillis > 0) {

    os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false);

  }

  return cas_allocate_noexpand(word_size);

}

void PSOldGen::expand(size_t bytes) {

  if (bytes == 0) {

    return;

  }

  MutexLocker x(ExpandHeap_lock);

  const size_t alignment = virtual_space()->alignment();

  size_t aligned_bytes  = align_size_up(bytes, alignment);

  size_t aligned_expand_bytes = align_size_up(MinHeapDeltaBytes, alignment);

  if (aligned_bytes == 0){

    // The alignment caused the number of bytes to wrap.  An expand_by(0) will

    // return true with the implication that and expansion was done when it

    // was not.  A call to expand implies a best effort to expand by "bytes"

    // but not a guarantee.  Align down to give a best effort.  This is likely

    // the most that the generation can expand since it has some capacity to

    // start with.

    aligned_bytes = align_size_down(bytes, alignment);

  }

  bool success = false;

  if (aligned_expand_bytes > aligned_bytes) {

    success = expand_by(aligned_expand_bytes);

  }

  if (!success) {

    success = expand_by(aligned_bytes);

  }

  if (!success) {

    success = expand_to_reserved();

  }

  if (PrintGC && Verbose) {

    if (success && GC_locker::is_active()) {

      gclog_or_tty->print_cr("Garbage collection disabled, expanded heap instead");

    }

  }

}

bool PSOldGen::expand_by(size_t bytes) {

  assert_lock_strong(ExpandHeap_lock);

  assert_locked_or_safepoint(Heap_lock);

  if (bytes == 0) {

    return true;  // That's what virtual_space()->expand_by(0) would return

  }

  bool result = virtual_space()->expand_by(bytes);

  if (result) {

    if (ZapUnusedHeapArea) {

      // We need to mangle the newly expanded area. The memregion spans

      // end -> new_end, we assume that top -> end is already mangled.

      // Do the mangling before post_resize() is called because

      // the space is available for allocation after post_resize();

      HeapWord* const virtual_space_high = (HeapWord*) virtual_space()->high();

      assert(object_space()->end() < virtual_space_high,

        "Should be true before post_resize()");

      MemRegion mangle_region(object_space()->end(), virtual_space_high);

      // Note that the object space has not yet been updated to

      // coincede with the new underlying virtual space.

      SpaceMangler::mangle_region(mangle_region);

    }

    post_resize();

    if (UsePerfData) {

      _space_counters->update_capacity();

      _gen_counters->update_all();

    }

  }

  if (result && Verbose && PrintGC) {

    size_t new_mem_size = virtual_space()->committed_size();

    size_t old_mem_size = new_mem_size - bytes;

    gclog_or_tty->print_cr("Expanding %s from " SIZE_FORMAT "K by "

                                       SIZE_FORMAT "K to "

                                       SIZE_FORMAT "K",

                    name(), old_mem_size/K, bytes/K, new_mem_size/K);

  }

  return result;

}

bool PSOldGen::expand_to_reserved() {

  assert_lock_strong(ExpandHeap_lock);

  assert_locked_or_safepoint(Heap_lock);

  bool result = true;

  const size_t remaining_bytes = virtual_space()->uncommitted_size();

  if (remaining_bytes > 0) {

    result = expand_by(remaining_bytes);

    DEBUG_ONLY(if (!result) warning("grow to reserve failed"));

  }

  return result;

}

void PSOldGen::shrink(size_t bytes) {

  assert_lock_strong(ExpandHeap_lock);

  assert_locked_or_safepoint(Heap_lock);

  size_t size = align_size_down(bytes, virtual_space()->alignment());

  if (size > 0) {

    assert_lock_strong(ExpandHeap_lock);

    virtual_space()->shrink_by(bytes);

    post_resize();

    if (Verbose && PrintGC) {

      size_t new_mem_size = virtual_space()->committed_size();

      size_t old_mem_size = new_mem_size + bytes;

      gclog_or_tty->print_cr("Shrinking %s from " SIZE_FORMAT "K by "

                                         SIZE_FORMAT "K to "

                                         SIZE_FORMAT "K",

                      name(), old_mem_size/K, bytes/K, new_mem_size/K);

    }

  }

}

void PSOldGen::resize(size_t desired_free_space) {

  const size_t alignment = virtual_space()->alignment();

  const size_t size_before = virtual_space()->committed_size();

  size_t new_size = used_in_bytes() + desired_free_space;

  if (new_size < used_in_bytes()) {

    // Overflowed the addition.

    new_size = gen_size_limit();

  }

  // Adjust according to our min and max

  new_size = MAX2(MIN2(new_size, gen_size_limit()), min_gen_size());

  assert(gen_size_limit() >= reserved().byte_size(), "max new size problem?");

  new_size = align_size_up(new_size, alignment);

  const size_t current_size = capacity_in_bytes();

  if (PrintAdaptiveSizePolicy && Verbose) {

    gclog_or_tty->print_cr("AdaptiveSizePolicy::old generation size: "

      "desired free: " SIZE_FORMAT " used: " SIZE_FORMAT

      " new size: " SIZE_FORMAT " current size " SIZE_FORMAT

      " gen limits: " SIZE_FORMAT " / " SIZE_FORMAT,

      desired_free_space, used_in_bytes(), new_size, current_size,

      gen_size_limit(), min_gen_size());

  }

  if (new_size == current_size) {

    // No change requested

    return;

  }

  if (new_size > current_size) {

    size_t change_bytes = new_size - current_size;

    expand(change_bytes);

  } else {

    size_t change_bytes = current_size - new_size;

    // shrink doesn't grab this lock, expand does. Is that right?

    MutexLocker x(ExpandHeap_lock);

    shrink(change_bytes);

  }

  if (PrintAdaptiveSizePolicy) {

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

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

    gclog_or_tty->print_cr("AdaptiveSizePolicy::old generation size: "

                  "collection: %d "

                  "(" SIZE_FORMAT ") -> (" SIZE_FORMAT ") ",

                  heap->total_collections(),

                  size_before, virtual_space()->committed_size());

  }

}

// NOTE! We need to be careful about resizing. During a GC, multiple

// allocators may be active during heap expansion. If we allow the

// heap resizing to become visible before we have correctly resized

// all heap related data structures, we may cause program failures.

void PSOldGen::post_resize() {

  // First construct a memregion representing the new size

  MemRegion new_memregion((HeapWord*)virtual_space()->low(),

    (HeapWord*)virtual_space()->high());

  size_t new_word_size = new_memregion.word_size();

  start_array()->set_covered_region(new_memregion);

  Universe::heap()->barrier_set()->resize_covered_region(new_memregion);

  // ALWAYS do this last!!

  object_space()->initialize(new_memregion,

                             SpaceDecorator::DontClear,

                             SpaceDecorator::DontMangle);

  assert(new_word_size == heap_word_size(object_space()->capacity_in_bytes()),

    "Sanity");

}

size_t PSOldGen::gen_size_limit() {

  return _max_gen_size;

}

void PSOldGen::reset_after_change() {

  ShouldNotReachHere();

  return;

}

size_t PSOldGen::available_for_expansion() {

  ShouldNotReachHere();

  return 0;

}

size_t PSOldGen::available_for_contraction() {

  ShouldNotReachHere();

  return 0;

}

void PSOldGen::print() const { print_on(tty);}

void PSOldGen::print_on(outputStream* st) const {

  st->print(" %-15s", name());

  if (PrintGCDetails && Verbose) {

    st->print(" total " SIZE_FORMAT ", used " SIZE_FORMAT,

                capacity_in_bytes(), used_in_bytes());

  } else {

    st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K",

                capacity_in_bytes()/K, used_in_bytes()/K);

  }

  st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")",

                virtual_space()->low_boundary(),

                virtual_space()->high(),

                virtual_space()->high_boundary());

  st->print("  object"); object_space()->print_on(st);

}

void PSOldGen::print_used_change(size_t prev_used) const {

  gclog_or_tty->print(" [%s:", name());

  gclog_or_tty->print(" "  SIZE_FORMAT "K"

                      "->" SIZE_FORMAT "K"

                      "("  SIZE_FORMAT "K)",

                      prev_used / K, used_in_bytes() / K,

                      capacity_in_bytes() / K);

  gclog_or_tty->print("]");

}

void PSOldGen::update_counters() {

  if (UsePerfData) {

    _space_counters->update_all();

    _gen_counters->update_all();

  }

}

#ifndef PRODUCT

void PSOldGen::space_invariants() {

  assert(object_space()->end() == (HeapWord*) virtual_space()->high(),

    "Space invariant");

  assert(object_space()->bottom() == (HeapWord*) virtual_space()->low(),

    "Space invariant");

  assert(virtual_space()->low_boundary() <= virtual_space()->low(),

    "Space invariant");

  assert(virtual_space()->high_boundary() >= virtual_space()->high(),

    "Space invariant");

  assert(virtual_space()->low_boundary() == (char*) _reserved.start(),

    "Space invariant");

  assert(virtual_space()->high_boundary() == (char*) _reserved.end(),

    "Space invariant");

  assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(),

    "Space invariant");

}

#endif

void PSOldGen::verify(bool allow_dirty) {

  object_space()->verify(allow_dirty);

}

class VerifyObjectStartArrayClosure : public ObjectClosure {

  PSOldGen* _gen;

  ObjectStartArray* _start_array;

 public:

  VerifyObjectStartArrayClosure(PSOldGen* gen, ObjectStartArray* start_array) :

    _gen(gen), _start_array(start_array) { }

  virtual void do_object(oop obj) {

    HeapWord* test_addr = (HeapWord*)obj + 1;

    guarantee(_start_array->object_start(test_addr) == (HeapWord*)obj, "ObjectStartArray cannot find start of object");

    guarantee(_start_array->is_block_allocated((HeapWord*)obj), "ObjectStartArray missing block allocation");

  }

};

void PSOldGen::verify_object_start_array() {

  VerifyObjectStartArrayClosure check( this, &_start_array );

  object_iterate(&check);

}

#ifndef PRODUCT

void PSOldGen::record_spaces_top() {

  assert(ZapUnusedHeapArea, "Not mangling unused space");

  object_space()->set_top_for_allocations();

}

#endif