/*

 * Copyright (c) 1997, 2017, 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

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 */

#include "precompiled.hpp"

#include "gc/serial/genMarkSweep.hpp"

#include "gc/shared/blockOffsetTable.inline.hpp"

#include "gc/shared/cardTableRS.hpp"

#include "gc/shared/collectedHeap.inline.hpp"

#include "gc/shared/gcLocker.hpp"

#include "gc/shared/gcTimer.hpp"

#include "gc/shared/gcTrace.hpp"

#include "gc/shared/genCollectedHeap.hpp"

#include "gc/shared/genOopClosures.hpp"

#include "gc/shared/genOopClosures.inline.hpp"

#include "gc/shared/generation.hpp"

#include "gc/shared/space.inline.hpp"

#include "gc/shared/spaceDecorator.hpp"

#include "logging/log.hpp"

#include "memory/allocation.inline.hpp"

#include "oops/oop.inline.hpp"

#include "runtime/java.hpp"

#include "utilities/copy.hpp"

#include "utilities/events.hpp"

Generation::Generation(ReservedSpace rs, size_t initial_size) :

  _ref_processor(NULL),

  _gc_manager(NULL) {

  if (!_virtual_space.initialize(rs, initial_size)) {

    vm_exit_during_initialization("Could not reserve enough space for "

                    "object heap");

  }

  // Mangle all of the the initial generation.

  if (ZapUnusedHeapArea) {

    MemRegion mangle_region((HeapWord*)_virtual_space.low(),

      (HeapWord*)_virtual_space.high());

    SpaceMangler::mangle_region(mangle_region);

  }

  _reserved = MemRegion((HeapWord*)_virtual_space.low_boundary(),

          (HeapWord*)_virtual_space.high_boundary());

}

size_t Generation::initial_size() {

  GenCollectedHeap* gch = GenCollectedHeap::heap();

  if (gch->is_young_gen(this)) {

    return gch->young_gen_spec()->init_size();

  }

  return gch->old_gen_spec()->init_size();

}

size_t Generation::max_capacity() const {

  return reserved().byte_size();

}

// By default we get a single threaded default reference processor;

// generations needing multi-threaded refs processing or discovery override this method.

void Generation::ref_processor_init() {

  assert(_ref_processor == NULL, "a reference processor already exists");

  assert(!_reserved.is_empty(), "empty generation?");

  if (_ref_processor == NULL) {

    vm_exit_during_initialization("Could not allocate ReferenceProcessor object");

  }

}

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

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

  st->print(" %-20s", name());

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

             capacity()/K, used()/K);

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

              p2i(_virtual_space.low_boundary()),

              p2i(_virtual_space.high()),

              p2i(_virtual_space.high_boundary()));

}

void Generation::print_summary_info_on(outputStream* st) {

  StatRecord* sr = stat_record();

  double time = sr->accumulated_time.seconds();

  st->print_cr("Accumulated %s generation GC time %3.7f secs, "

               "%u GC's, avg GC time %3.7f",

               GenCollectedHeap::heap()->is_young_gen(this) ? "young" : "old" ,

               time,

               sr->invocations,

               sr->invocations > 0 ? time / sr->invocations : 0.0);

}

// Utility iterator classes

class GenerationIsInReservedClosure : public SpaceClosure {

 public:

  const void* _p;

  Space* sp;

  virtual void do_space(Space* s) {

    if (sp == NULL) {

      if (s->is_in_reserved(_p)) sp = s;

    }

  }

  GenerationIsInReservedClosure(const void* p) : _p(p), sp(NULL) {}

};

class GenerationIsInClosure : public SpaceClosure {

 public:

  const void* _p;

  Space* sp;

  virtual void do_space(Space* s) {

    if (sp == NULL) {

      if (s->is_in(_p)) sp = s;

    }

  }

  GenerationIsInClosure(const void* p) : _p(p), sp(NULL) {}

};

bool Generation::is_in(const void* p) const {

  GenerationIsInClosure blk(p);

  ((Generation*)this)->space_iterate(&blk);

  return blk.sp != NULL;

}

size_t Generation::max_contiguous_available() const {

  // The largest number of contiguous free words in this or any higher generation.

  size_t avail = contiguous_available();

  size_t old_avail = 0;

  if (GenCollectedHeap::heap()->is_young_gen(this)) {

    old_avail = GenCollectedHeap::heap()->old_gen()->contiguous_available();

  }

  return MAX2(avail, old_avail);

}

bool Generation::promotion_attempt_is_safe(size_t max_promotion_in_bytes) const {

  size_t available = max_contiguous_available();

  bool   res = (available >= max_promotion_in_bytes);

  log_trace(gc)("Generation: promo attempt is%s safe: available(" SIZE_FORMAT ") %s max_promo(" SIZE_FORMAT ")",

                res? "":" not", available, res? ">=":"<", max_promotion_in_bytes);

  return res;

}

// Ignores "ref" and calls allocate().

oop Generation::promote(oop obj, size_t obj_size) {

  assert(obj_size == (size_t)obj->size(), "bad obj_size passed in");

#ifndef PRODUCT

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

    return NULL;

  }

#endif  // #ifndef PRODUCT

  HeapWord* result = allocate(obj_size, false);

  if (result != NULL) {

    Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size);

    return oop(result);

  } else {

    GenCollectedHeap* gch = GenCollectedHeap::heap();

    return gch->handle_failed_promotion(this, obj, obj_size);

  }

}

oop Generation::par_promote(int thread_num,

                            oop obj, markOop m, size_t word_sz) {

  // Could do a bad general impl here that gets a lock.  But no.

  ShouldNotCallThis();

  return NULL;

}

Space* Generation::space_containing(const void* p) const {

  GenerationIsInReservedClosure blk(p);

  // Cast away const

  ((Generation*)this)->space_iterate(&blk);

  return blk.sp;

}

// Some of these are mediocre general implementations.  Should be

// overridden to get better performance.

class GenerationBlockStartClosure : public SpaceClosure {

 public:

  const void* _p;

  HeapWord* _start;

  virtual void do_space(Space* s) {

    if (_start == NULL && s->is_in_reserved(_p)) {

      _start = s->block_start(_p);

    }

  }

  GenerationBlockStartClosure(const void* p) { _p = p; _start = NULL; }

};

HeapWord* Generation::block_start(const void* p) const {

  GenerationBlockStartClosure blk(p);

  // Cast away const

  ((Generation*)this)->space_iterate(&blk);

  return blk._start;

}

class GenerationBlockSizeClosure : public SpaceClosure {

 public:

  const HeapWord* _p;

  size_t size;

  virtual void do_space(Space* s) {

    if (size == 0 && s->is_in_reserved(_p)) {

      size = s->block_size(_p);

    }

  }

  GenerationBlockSizeClosure(const HeapWord* p) { _p = p; size = 0; }

};

size_t Generation::block_size(const HeapWord* p) const {

  GenerationBlockSizeClosure blk(p);

  // Cast away const

  ((Generation*)this)->space_iterate(&blk);

  assert(blk.size > 0, "seems reasonable");

  return blk.size;

}

class GenerationBlockIsObjClosure : public SpaceClosure {

 public:

  const HeapWord* _p;

  bool is_obj;

  virtual void do_space(Space* s) {

    if (!is_obj && s->is_in_reserved(_p)) {

      is_obj |= s->block_is_obj(_p);

    }

  }

  GenerationBlockIsObjClosure(const HeapWord* p) { _p = p; is_obj = false; }

};

bool Generation::block_is_obj(const HeapWord* p) const {

  GenerationBlockIsObjClosure blk(p);

  // Cast away const

  ((Generation*)this)->space_iterate(&blk);

  return blk.is_obj;

}

class GenerationOopIterateClosure : public SpaceClosure {

 public:

  ExtendedOopClosure* _cl;

  virtual void do_space(Space* s) {

    s->oop_iterate(_cl);

  }

  GenerationOopIterateClosure(ExtendedOopClosure* cl) :

    _cl(cl) {}

};

void Generation::oop_iterate(ExtendedOopClosure* cl) {

  GenerationOopIterateClosure blk(cl);

  space_iterate(&blk);

}

void Generation::younger_refs_in_space_iterate(Space* sp,

                                               OopsInGenClosure* cl,

                                               uint n_threads) {

  CardTableRS* rs = GenCollectedHeap::heap()->rem_set();

  rs->younger_refs_in_space_iterate(sp, cl, n_threads);

}

class GenerationObjIterateClosure : public SpaceClosure {

 private:

  ObjectClosure* _cl;

 public:

  virtual void do_space(Space* s) {

    s->object_iterate(_cl);

  }

  GenerationObjIterateClosure(ObjectClosure* cl) : _cl(cl) {}

};

void Generation::object_iterate(ObjectClosure* cl) {

  GenerationObjIterateClosure blk(cl);

  space_iterate(&blk);

}

class GenerationSafeObjIterateClosure : public SpaceClosure {

 private:

  ObjectClosure* _cl;

 public:

  virtual void do_space(Space* s) {

    s->safe_object_iterate(_cl);

  }

  GenerationSafeObjIterateClosure(ObjectClosure* cl) : _cl(cl) {}

};

void Generation::safe_object_iterate(ObjectClosure* cl) {

  GenerationSafeObjIterateClosure blk(cl);

  space_iterate(&blk);

}

void Generation::prepare_for_compaction(CompactPoint* cp) {

  // Generic implementation, can be specialized

  CompactibleSpace* space = first_compaction_space();

  while (space != NULL) {

    space->prepare_for_compaction(cp);

    space = space->next_compaction_space();

  }

}

class AdjustPointersClosure: public SpaceClosure {

 public:

  void do_space(Space* sp) {

    sp->adjust_pointers();

  }

};

void Generation::adjust_pointers() {

  // Note that this is done over all spaces, not just the compactible

  // ones.

  AdjustPointersClosure blk;

  space_iterate(&blk, true);

}

void Generation::compact() {

  CompactibleSpace* sp = first_compaction_space();

  while (sp != NULL) {

    sp->compact();

    sp = sp->next_compaction_space();

  }

}