/*

 * 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

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 */

#include "gc/parallel/parallelScavengeHeap.hpp"

#include "gc/parallel/parMarkBitMap.inline.hpp"

#include "gc/parallel/psOldGen.hpp"

#include "gc/parallel/psPromotionLAB.inline.hpp"

#include "gc/parallel/psPromotionManager.hpp"

#include "gc/parallel/psScavenge.inline.hpp"

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

#include "logging/log.hpp"

#include "memory/iterator.inline.hpp"

#include "oops/access.inline.hpp"

#include "oops/oop.inline.hpp"

inline PSPromotionManager* PSPromotionManager::manager_array(uint index) {

  assert(_manager_array != NULL, "access of NULL manager_array");

  assert(index <= ParallelGCThreads, "out of range manager_array access");

  return &_manager_array[index];

}

template <class T>

inline void PSPromotionManager::push_depth(T* p) {

  claimed_stack_depth()->push(p);

}

template <class T>

inline void PSPromotionManager::claim_or_forward_internal_depth(T* p) {

  if (p != NULL) { // XXX: error if p != NULL here

    oop o = RawAccess<IS_NOT_NULL>::oop_load(p);

    if (o->is_forwarded()) {

      o = o->forwardee();

      // Card mark

      if (PSScavenge::is_obj_in_young(o)) {

        PSScavenge::card_table()->inline_write_ref_field_gc(p, o);

      }

      RawAccess<IS_NOT_NULL>::oop_store(p, o);

    } else {

      push_depth(p);

    }

  }

}

template <class T>

inline void PSPromotionManager::claim_or_forward_depth(T* p) {

  assert(should_scavenge(p, true), "revisiting object?");

  assert(ParallelScavengeHeap::heap()->is_in(p), "pointer outside heap");

  claim_or_forward_internal_depth(p);

}

inline void PSPromotionManager::promotion_trace_event(oop new_obj, oop old_obj,

                                                      size_t obj_size,

                                                      uint age, bool tenured,

                                                      const PSPromotionLAB* lab) {

  // Skip if memory allocation failed

  if (new_obj != NULL) {

    const ParallelScavengeTracer* gc_tracer = PSScavenge::gc_tracer();

    if (lab != NULL) {

      // Promotion of object through newly allocated PLAB

      if (gc_tracer->should_report_promotion_in_new_plab_event()) {

        size_t obj_bytes = obj_size * HeapWordSize;

        size_t lab_size = lab->capacity();

        gc_tracer->report_promotion_in_new_plab_event(old_obj->klass(), obj_bytes,

                                                      age, tenured, lab_size);

      }

    } else {

      // Promotion of object directly to heap

      if (gc_tracer->should_report_promotion_outside_plab_event()) {

        size_t obj_bytes = obj_size * HeapWordSize;

        gc_tracer->report_promotion_outside_plab_event(old_obj->klass(), obj_bytes,

                                                       age, tenured);

      }

    }

  }

}

class PSPushContentsClosure: public BasicOopIterateClosure {

  PSPromotionManager* _pm;

 public:

  PSPushContentsClosure(PSPromotionManager* pm) : BasicOopIterateClosure(PSScavenge::reference_processor()), _pm(pm) {}

  template <typename T> void do_oop_nv(T* p) {

    if (PSScavenge::should_scavenge(p)) {

      _pm->claim_or_forward_depth(p);

    }

  }

  virtual void do_oop(oop* p)       { do_oop_nv(p); }

  virtual void do_oop(narrowOop* p) { do_oop_nv(p); }

  // Don't use the oop verification code in the oop_oop_iterate framework.

  debug_only(virtual bool should_verify_oops() { return false; })

};

//

// This closure specialization will override the one that is defined in

// instanceRefKlass.inline.cpp. It swaps the order of oop_oop_iterate and

// oop_oop_iterate_ref_processing. Unfortunately G1 and Parallel behaves

// significantly better (especially in the Derby benchmark) using opposite

// order of these function calls.

//

template <>

inline void InstanceRefKlass::oop_oop_iterate_reverse<oop, PSPushContentsClosure>(oop obj, PSPushContentsClosure* closure) {

  oop_oop_iterate_ref_processing<oop>(obj, closure);

  InstanceKlass::oop_oop_iterate_reverse<oop>(obj, closure);

}

template <>

inline void InstanceRefKlass::oop_oop_iterate_reverse<narrowOop, PSPushContentsClosure>(oop obj, PSPushContentsClosure* closure) {

  oop_oop_iterate_ref_processing<narrowOop>(obj, closure);

  InstanceKlass::oop_oop_iterate_reverse<narrowOop>(obj, closure);

}

inline void PSPromotionManager::push_contents(oop obj) {

  if (!obj->klass()->is_typeArray_klass()) {

    PSPushContentsClosure pcc(this);

    obj->oop_iterate_backwards(&pcc);

  }

}

//

// 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.

//

template<bool promote_immediately>

inline oop PSPromotionManager::copy_to_survivor_space(oop o) {

  assert(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_raw();

  // 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.

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

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

    if (!promote_immediately) {

      // 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);

            promotion_trace_event(new_obj, o, new_obj_size, age, false, NULL);

          } 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);

              promotion_trace_event(new_obj, o, new_obj_size, age, false, &_young_lab);

            } else {

              _young_gen_is_full = true;

            }

          }

        }

      }

    }

    // Otherwise try allocating obj tenured

    if (new_obj == NULL) {

#ifndef PRODUCT

      if (ParallelScavengeHeap::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);

            promotion_trace_event(new_obj, o, new_obj_size, age, true, NULL);

          } else {

            // Flush and fill

            _old_lab.flush();

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

            if(lab_base != NULL) {

#ifdef ASSERT

              // Delay the initialization of the promotion lab (plab).

              // This exposes uninitialized plabs to card table processing.

              if (GCWorkerDelayMillis > 0) {

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

              }

#endif

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

              // Try the old lab allocation again.

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

              promotion_trace_event(new_obj, o, new_obj_size, age, true, &_old_lab);

            }

          }

        }

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

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

        // different than 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.

    // Make copy visible to threads reading the forwardee.

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

      // 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");

      }

      // 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

        oop* const masked_o = mask_chunked_array_oop(o);

        push_depth(masked_o);

        TASKQUEUE_STATS_ONLY(++_arrays_chunked; ++_masked_pushes);

      } else {

        // we'll just push its contents

        push_contents(new_obj);

      }

    }  else {

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

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

      // Try to deallocate the space.  If it was directly allocated we cannot

      // deallocate it, so we have to test.  If the deallocation fails,

      // overwrite with a filler object.

      if (new_obj_is_tenured) {

        if (!_old_lab.unallocate_object((HeapWord*) new_obj, new_obj_size)) {

          CollectedHeap::fill_with_object((HeapWord*) new_obj, new_obj_size);

        }

      } else if (!_young_lab.unallocate_object((HeapWord*) new_obj, new_obj_size)) {

        CollectedHeap::fill_with_object((HeapWord*) new_obj, new_obj_size);

      }

      // don't update this before the unallocation!

      // Using acquire though consume would be accurate for accessing new_obj.

      new_obj = o->forwardee_acquire();

    }

  } else {

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

    new_obj = o->forwardee_acquire();

  }

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

  // information.

  log_develop_trace(gc, scavenge)("{%s %s " PTR_FORMAT " -> " PTR_FORMAT " (%d)}",

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

                                  new_obj->klass()->internal_name(), p2i((void *)o), p2i((void *)new_obj), new_obj->size());

  return new_obj;

}

// Attempt to "claim" oop at p via CAS, push the new obj if successful

// This version tests the oop* to make sure it is within the heap before

// attempting marking.

template <class T, bool promote_immediately>

inline void PSPromotionManager::copy_and_push_safe_barrier(T* p) {

  assert(should_scavenge(p, true), "revisiting object?");

  oop o = RawAccess<IS_NOT_NULL>::oop_load(p);

  oop new_obj = o->is_forwarded()

        ? o->forwardee()

        : copy_to_survivor_space<promote_immediately>(o);

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

  // information.

  if (log_develop_is_enabled(Trace, gc, scavenge) && o->is_forwarded()) {

    log_develop_trace(gc, scavenge)("{%s %s " PTR_FORMAT " -> " PTR_FORMAT " (%d)}",

                      "forwarding",

                      new_obj->klass()->internal_name(), p2i((void *)o), p2i((void *)new_obj), new_obj->size());

  }

  RawAccess<IS_NOT_NULL>::oop_store(p, new_obj);

  // We cannot mark without test, as some code passes us pointers

  // that are outside the heap. These pointers are either from roots

  // or from metadata.

  if ((!PSScavenge::is_obj_in_young((HeapWord*)p)) &&

      ParallelScavengeHeap::heap()->is_in_reserved(p)) {

    if (PSScavenge::is_obj_in_young(new_obj)) {

      PSScavenge::card_table()->inline_write_ref_field_gc(p, new_obj);

    }

  }

}

inline void PSPromotionManager::process_popped_location_depth(StarTask p) {

  if (is_oop_masked(p)) {

    assert(PSChunkLargeArrays, "invariant");

    oop const old = unmask_chunked_array_oop(p);

    process_array_chunk(old);

  } else {

    if (p.is_narrow()) {

      assert(UseCompressedOops, "Error");

      copy_and_push_safe_barrier<narrowOop, /*promote_immediately=*/false>(p);

    } else {

      copy_and_push_safe_barrier<oop, /*promote_immediately=*/false>(p);

    }

  }

}

inline bool PSPromotionManager::steal_depth(int queue_num, StarTask& t) {

  return stack_array_depth()->steal(queue_num, t);

}

#if TASKQUEUE_STATS

void PSPromotionManager::record_steal(StarTask& p) {

  if (is_oop_masked(p)) {

    ++_masked_steals;

  }

}

#endif // TASKQUEUE_STATS