/*

 * Copyright (c) 2014, 2015, 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.

 *

 */

class EvacuationInfo;

// Base class for G1 allocators.

class G1Allocator : public CHeapObj<mtGC> {

  friend class VMStructs;

protected:

  G1CollectedHeap* _g1h;

  // Outside of GC pauses, the number of bytes used in all regions other

  // than the current allocation region.

  size_t _summary_bytes_used;

public:

   G1Allocator(G1CollectedHeap* heap) :

     _g1h(heap), _summary_bytes_used(0) { }

   static G1Allocator* create_allocator(G1CollectedHeap* g1h);

   virtual void init_mutator_alloc_region() = 0;

   virtual void release_mutator_alloc_region() = 0;

   virtual void init_gc_alloc_regions(EvacuationInfo& evacuation_info) = 0;

   virtual void release_gc_alloc_regions(uint no_of_gc_workers, EvacuationInfo& evacuation_info) = 0;

   virtual void abandon_gc_alloc_regions() = 0;

   virtual MutatorAllocRegion*    mutator_alloc_region(AllocationContext_t context) = 0;

   virtual SurvivorGCAllocRegion* survivor_gc_alloc_region(AllocationContext_t context) = 0;

   virtual OldGCAllocRegion*      old_gc_alloc_region(AllocationContext_t context) = 0;

   virtual size_t                 used() = 0;

   virtual bool                   is_retained_old_region(HeapRegion* hr) = 0;

   void                           reuse_retained_old_region(EvacuationInfo& evacuation_info,

                                                            OldGCAllocRegion* old,

                                                            HeapRegion** retained);

   size_t used_unlocked() const {

     return _summary_bytes_used;

   }

   void increase_used(size_t bytes) {

     _summary_bytes_used += bytes;

   }

   void decrease_used(size_t bytes) {

     assert(_summary_bytes_used >= bytes,

            err_msg("invariant: _summary_bytes_used: "SIZE_FORMAT" should be >= bytes: "SIZE_FORMAT,

                _summary_bytes_used, bytes));

     _summary_bytes_used -= bytes;

   }

   void set_used(size_t bytes) {

     _summary_bytes_used = bytes;

   }

   virtual HeapRegion* new_heap_region(uint hrs_index,

                                       G1BlockOffsetSharedArray* sharedOffsetArray,

                                       MemRegion mr) {

     return new HeapRegion(hrs_index, sharedOffsetArray, mr);

   }

};

// The default allocator for G1.

class G1DefaultAllocator : public G1Allocator {

protected:

  // Alloc region used to satisfy mutator allocation requests.

  MutatorAllocRegion _mutator_alloc_region;

  // Alloc region used to satisfy allocation requests by the GC for

  // survivor objects.

  SurvivorGCAllocRegion _survivor_gc_alloc_region;

  // Alloc region used to satisfy allocation requests by the GC for

  // old objects.

  OldGCAllocRegion _old_gc_alloc_region;

  HeapRegion* _retained_old_gc_alloc_region;

public:

  G1DefaultAllocator(G1CollectedHeap* heap) : G1Allocator(heap), _retained_old_gc_alloc_region(NULL) { }

  virtual void init_mutator_alloc_region();

  virtual void release_mutator_alloc_region();

  virtual void init_gc_alloc_regions(EvacuationInfo& evacuation_info);

  virtual void release_gc_alloc_regions(uint no_of_gc_workers, EvacuationInfo& evacuation_info);

  virtual void abandon_gc_alloc_regions();

  virtual bool is_retained_old_region(HeapRegion* hr) {

    return _retained_old_gc_alloc_region == hr;

  }

  virtual MutatorAllocRegion* mutator_alloc_region(AllocationContext_t context) {

    return &_mutator_alloc_region;

  }

  virtual SurvivorGCAllocRegion* survivor_gc_alloc_region(AllocationContext_t context) {

    return &_survivor_gc_alloc_region;

  }

  virtual OldGCAllocRegion* old_gc_alloc_region(AllocationContext_t context) {

    return &_old_gc_alloc_region;

  }

  virtual size_t used() {

    assert(Heap_lock->owner() != NULL,

           "Should be owned on this thread's behalf.");

    size_t result = _summary_bytes_used;

    // Read only once in case it is set to NULL concurrently

    HeapRegion* hr = mutator_alloc_region(AllocationContext::current())->get();

    if (hr != NULL) {

      result += hr->used();

    }

    return result;

  }

};

class G1PLAB: public PLAB {

private:

  bool _retired;

public:

  G1PLAB(size_t gclab_word_size);

  virtual ~G1PLAB() {

    guarantee(_retired, "Allocation buffer has not been retired");

  }

  virtual void set_buf(HeapWord* buf) {

    PLAB::set_buf(buf);

    _retired = false;

  }

  virtual void retire() {

    if (_retired) {

      return;

    }

    PLAB::retire();

    _retired = true;

  }

  virtual void flush_and_retire_stats(PLABStats* stats) {

    PLAB::flush_and_retire_stats(stats);

    _retired = true;

  }

};

class G1ParGCAllocator : public CHeapObj<mtGC> {

  friend class G1ParScanThreadState;

protected:

  G1CollectedHeap* _g1h;

  // The survivor alignment in effect in bytes.

  // == 0 : don't align survivors

  // != 0 : align survivors to that alignment

  // These values were chosen to favor the non-alignment case since some

  // architectures have a special compare against zero instructions.

  const uint _survivor_alignment_bytes;

  virtual void retire_alloc_buffers() = 0;

  virtual G1PLAB* alloc_buffer(InCSetState dest, AllocationContext_t context) = 0;

  // Calculate the survivor space object alignment in bytes. Returns that or 0 if

  // there are no restrictions on survivor alignment.

  static uint calc_survivor_alignment_bytes() {

    assert(SurvivorAlignmentInBytes >= ObjectAlignmentInBytes, "sanity");

    if (SurvivorAlignmentInBytes == ObjectAlignmentInBytes) {

      // No need to align objects in the survivors differently, return 0

      // which means "survivor alignment is not used".

      return 0;

    } else {

      assert(SurvivorAlignmentInBytes > 0, "sanity");

      return SurvivorAlignmentInBytes;

    }

  }

public:

  G1ParGCAllocator(G1CollectedHeap* g1h) :

    _g1h(g1h), _survivor_alignment_bytes(calc_survivor_alignment_bytes()) { }

  virtual ~G1ParGCAllocator() { }

  static G1ParGCAllocator* create_allocator(G1CollectedHeap* g1h);

  virtual void waste(size_t& wasted, size_t& undo_wasted) = 0;

  // Allocate word_sz words in dest, either directly into the regions or by

  // allocating a new PLAB. Returns the address of the allocated memory, NULL if

  // not successful.

  HeapWord* allocate_direct_or_new_plab(InCSetState dest,

                                        size_t word_sz,

                                        AllocationContext_t context);

  // Allocate word_sz words in the PLAB of dest.  Returns the address of the

  // allocated memory, NULL if not successful.

  HeapWord* plab_allocate(InCSetState dest,

                          size_t word_sz,

                          AllocationContext_t context) {

    G1PLAB* buffer = alloc_buffer(dest, context);

    if (_survivor_alignment_bytes == 0) {

      return buffer->allocate(word_sz);

    } else {

      return buffer->allocate_aligned(word_sz, _survivor_alignment_bytes);

    }

  }

  HeapWord* allocate(InCSetState dest, size_t word_sz,

                     AllocationContext_t context) {

    HeapWord* const obj = plab_allocate(dest, word_sz, context);

    if (obj != NULL) {

      return obj;

    }

    return allocate_direct_or_new_plab(dest, word_sz, context);

  }

  void undo_allocation(InCSetState dest, HeapWord* obj, size_t word_sz, AllocationContext_t context) {

    alloc_buffer(dest, context)->undo_allocation(obj, word_sz);

  }

};

class G1DefaultParGCAllocator : public G1ParGCAllocator {

  G1PLAB  _surviving_alloc_buffer;

  G1PLAB  _tenured_alloc_buffer;

  G1PLAB* _alloc_buffers[InCSetState::Num];

public:

  G1DefaultParGCAllocator(G1CollectedHeap* g1h);

  virtual G1PLAB* alloc_buffer(InCSetState dest, AllocationContext_t context) {

    assert(dest.is_valid(),

           err_msg("Allocation buffer index out-of-bounds: " CSETSTATE_FORMAT, dest.value()));

    assert(_alloc_buffers[dest.value()] != NULL,

           err_msg("Allocation buffer is NULL: " CSETSTATE_FORMAT, dest.value()));

    return _alloc_buffers[dest.value()];

  }

  virtual void retire_alloc_buffers();

  virtual void waste(size_t& wasted, size_t& undo_wasted);

};