/*

 * Copyright (c) 2001, 2019, 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/g1/g1BiasedArray.hpp"

#include "gc/g1/g1RegionToSpaceMapper.hpp"

#include "logging/log.hpp"

#include "memory/allocation.inline.hpp"

#include "memory/virtualspace.hpp"

#include "runtime/java.hpp"

#include "runtime/os.inline.hpp"

#include "services/memTracker.hpp"

#include "utilities/align.hpp"

#include "utilities/bitMap.inline.hpp"

#include "utilities/formatBuffer.hpp"

G1RegionToSpaceMapper::G1RegionToSpaceMapper(ReservedSpace rs,

                                             size_t used_size,

                                             size_t page_size,

                                             size_t region_granularity,

                                             size_t commit_factor,

                                             MemoryType type) :

  _listener(NULL),

  _storage(rs, used_size, page_size),

  _region_granularity(region_granularity),

  _commit_map(rs.size() * commit_factor / region_granularity, mtGC) {

  guarantee(is_power_of_2(page_size), "must be");

  guarantee(is_power_of_2(region_granularity), "must be");

  MemTracker::record_virtual_memory_type((address)rs.base(), type);

}

// G1RegionToSpaceMapper implementation where the region granularity is larger than

// or the same as the commit granularity.

// Basically, the space corresponding to one region region spans several OS pages.

class G1RegionsLargerThanCommitSizeMapper : public G1RegionToSpaceMapper {

 private:

  size_t _pages_per_region;

 public:

  G1RegionsLargerThanCommitSizeMapper(ReservedSpace rs,

                                      size_t actual_size,

                                      size_t page_size,

                                      size_t alloc_granularity,

                                      size_t commit_factor,

                                      MemoryType type) :

    G1RegionToSpaceMapper(rs, actual_size, page_size, alloc_granularity, commit_factor, type),

    _pages_per_region(alloc_granularity / (page_size * commit_factor)) {

    guarantee(alloc_granularity >= page_size, "allocation granularity smaller than commit granularity");

  }

  virtual void commit_regions(uint start_idx, size_t num_regions, WorkGang* pretouch_gang) {

    size_t const start_page = (size_t)start_idx * _pages_per_region;

    bool zero_filled = _storage.commit(start_page, num_regions * _pages_per_region);

    if (AlwaysPreTouch) {

      _storage.pretouch(start_page, num_regions * _pages_per_region, pretouch_gang);

    }

    _commit_map.set_range(start_idx, start_idx + num_regions);

    fire_on_commit(start_idx, num_regions, zero_filled);

  }

  virtual void uncommit_regions(uint start_idx, size_t num_regions) {

    _storage.uncommit((size_t)start_idx * _pages_per_region, num_regions * _pages_per_region);

    _commit_map.clear_range(start_idx, start_idx + num_regions);

  }

};

// G1RegionToSpaceMapper implementation where the region granularity is smaller

// than the commit granularity.

// Basically, the contents of one OS page span several regions.

class G1RegionsSmallerThanCommitSizeMapper : public G1RegionToSpaceMapper {

 private:

  class CommitRefcountArray : public G1BiasedMappedArray<uint> {

   protected:

     virtual uint default_value() const { return 0; }

  };

  size_t _regions_per_page;

  CommitRefcountArray _refcounts;

  uintptr_t region_idx_to_page_idx(uint region) const {

    return region / _regions_per_page;

  }

 public:

  G1RegionsSmallerThanCommitSizeMapper(ReservedSpace rs,

                                       size_t actual_size,

                                       size_t page_size,

                                       size_t alloc_granularity,

                                       size_t commit_factor,

                                       MemoryType type) :

    G1RegionToSpaceMapper(rs, actual_size, page_size, alloc_granularity, commit_factor, type),

    _regions_per_page((page_size * commit_factor) / alloc_granularity), _refcounts() {

    guarantee((page_size * commit_factor) >= alloc_granularity, "allocation granularity smaller than commit granularity");

    _refcounts.initialize((HeapWord*)rs.base(), (HeapWord*)(rs.base() + align_up(rs.size(), page_size)), page_size);

  }

  virtual void commit_regions(uint start_idx, size_t num_regions, WorkGang* pretouch_gang) {

    size_t const NoPage = ~(size_t)0;

    size_t first_committed = NoPage;

    size_t num_committed = 0;

    bool all_zero_filled = true;

    for (uint i = start_idx; i < start_idx + num_regions; i++) {

      assert(!_commit_map.at(i), "Trying to commit storage at region %u that is already committed", i);

      size_t idx = region_idx_to_page_idx(i);

      uint old_refcount = _refcounts.get_by_index(idx);

      bool zero_filled = false;

      if (old_refcount == 0) {

        if (first_committed == NoPage) {

          first_committed = idx;

          num_committed = 1;

        } else {

          num_committed++;

        }

        zero_filled = _storage.commit(idx, 1);

      }

      all_zero_filled &= zero_filled;

      _refcounts.set_by_index(idx, old_refcount + 1);

      _commit_map.set_bit(i);

    }

    if (AlwaysPreTouch && num_committed > 0) {

      _storage.pretouch(first_committed, num_committed, pretouch_gang);

    }

    fire_on_commit(start_idx, num_regions, all_zero_filled);

  }

  virtual void uncommit_regions(uint start_idx, size_t num_regions) {

    for (uint i = start_idx; i < start_idx + num_regions; i++) {

      assert(_commit_map.at(i), "Trying to uncommit storage at region %u that is not committed", i);

      size_t idx = region_idx_to_page_idx(i);

      uint old_refcount = _refcounts.get_by_index(idx);

      assert(old_refcount > 0, "must be");

      if (old_refcount == 1) {

        _storage.uncommit(idx, 1);

      }

      _refcounts.set_by_index(idx, old_refcount - 1);

      _commit_map.clear_bit(i);

    }

  }

};

void G1RegionToSpaceMapper::fire_on_commit(uint start_idx, size_t num_regions, bool zero_filled) {

  if (_listener != NULL) {

    _listener->on_commit(start_idx, num_regions, zero_filled);

  }

}

static bool map_nvdimm_space(ReservedSpace rs) {

  assert(AllocateOldGenAt != NULL, "");

  int _backing_fd = os::create_file_for_heap(AllocateOldGenAt);

  if (_backing_fd == -1) {

    log_error(gc, init)("Could not create file for Old generation at location %s", AllocateOldGenAt);

    return false;

  }

  // commit this memory in nv-dimm

  char* ret = os::attempt_reserve_memory_at(rs.size(), rs.base(), _backing_fd);

  if (ret != rs.base()) {

    if (ret != NULL) {

      os::unmap_memory(rs.base(), rs.size());

    }

    log_error(gc, init)("Error in mapping Old Gen to given AllocateOldGenAt = %s", AllocateOldGenAt);

    os::close(_backing_fd);

    return false;

  }

  os::close(_backing_fd);

  return true;

}

G1RegionToHeteroSpaceMapper::G1RegionToHeteroSpaceMapper(ReservedSpace rs,

                                                         size_t actual_size,

                                                         size_t page_size,

                                                         size_t alloc_granularity,

                                                         size_t commit_factor,

                                                         MemoryType type) :

  G1RegionToSpaceMapper(rs, actual_size, page_size, alloc_granularity, commit_factor, type),

  _rs(rs),

  _dram_mapper(NULL),

  _num_committed_dram(0),

  _num_committed_nvdimm(0),

  _start_index_of_dram(0),

  _page_size(page_size),

  _commit_factor(commit_factor),

  _type(type) {

  assert(actual_size == 2 * MaxHeapSize, "For 2-way heterogenuous heap, reserved space is two times MaxHeapSize");

}

bool G1RegionToHeteroSpaceMapper::initialize() {

  // Since we need to re-map the reserved space - 'Xmx' to nv-dimm and 'Xmx' to dram, we need to release the reserved memory first.

  // Because on some OSes (e.g. Windows) you cannot do a file mapping on memory reserved with regular mapping.

  os::release_memory(_rs.base(), _rs.size());

  // First half of size Xmx is for nv-dimm.

  ReservedSpace rs_nvdimm = _rs.first_part(MaxHeapSize);

  assert(rs_nvdimm.base() == _rs.base(), "We should get the same base address");

  // Second half of reserved memory is mapped to dram.

  ReservedSpace rs_dram = _rs.last_part(MaxHeapSize);

  assert(rs_dram.size() == rs_nvdimm.size() && rs_nvdimm.size() == MaxHeapSize, "They all should be same");

  // Reserve dram memory

  char* base = os::attempt_reserve_memory_at(rs_dram.size(), rs_dram.base());

  if (base != rs_dram.base()) {

    if (base != NULL) {

      os::release_memory(base, rs_dram.size());

    }

    log_error(gc, init)("Error in re-mapping memory on dram during G1 heterogenous memory initialization");

    return false;

  }

  // We reserve and commit this entire space to NV-DIMM.

  if (!map_nvdimm_space(rs_nvdimm)) {

    log_error(gc, init)("Error in re-mapping memory to nv-dimm during G1 heterogenous memory initialization");

    return false;

  }

  if (_region_granularity >= (_page_size * _commit_factor)) {

    _dram_mapper = new G1RegionsLargerThanCommitSizeMapper(rs_dram, rs_dram.size(), _page_size, _region_granularity, _commit_factor, _type);

  } else {

    _dram_mapper = new G1RegionsSmallerThanCommitSizeMapper(rs_dram, rs_dram.size(), _page_size, _region_granularity, _commit_factor, _type);

  }

  _start_index_of_dram = (uint)(rs_nvdimm.size() / _region_granularity);

  return true;

}

void G1RegionToHeteroSpaceMapper::commit_regions(uint start_idx, size_t num_regions, WorkGang* pretouch_gang) {

  uint end_idx = (start_idx + (uint)num_regions - 1);

  uint num_dram = end_idx >= _start_index_of_dram ? MIN2((end_idx - _start_index_of_dram + 1), (uint)num_regions) : 0;

  uint num_nvdimm = (uint)num_regions - num_dram;

  if (num_nvdimm > 0) {

    // We do not need to commit nv-dimm regions, since they are committed in the beginning.

    _num_committed_nvdimm += num_nvdimm;

  }

  if (num_dram > 0) {

    _dram_mapper->commit_regions(start_idx > _start_index_of_dram ? (start_idx - _start_index_of_dram) : 0, num_dram, pretouch_gang);

    _num_committed_dram += num_dram;

  }

}

void G1RegionToHeteroSpaceMapper::uncommit_regions(uint start_idx, size_t num_regions) {

  uint end_idx = (start_idx + (uint)num_regions - 1);

  uint num_dram = end_idx >= _start_index_of_dram ? MIN2((end_idx - _start_index_of_dram + 1), (uint)num_regions) : 0;

  uint num_nvdimm = (uint)num_regions - num_dram;

  if (num_nvdimm > 0) {

    // We do not uncommit memory for nv-dimm regions.

    _num_committed_nvdimm -= num_nvdimm;

  }

  if (num_dram > 0) {

    _dram_mapper->uncommit_regions(start_idx > _start_index_of_dram ? (start_idx - _start_index_of_dram) : 0, num_dram);

    _num_committed_dram -= num_dram;

  }

}

uint G1RegionToHeteroSpaceMapper::num_committed_dram() const {

  return _num_committed_dram;

}

uint G1RegionToHeteroSpaceMapper::num_committed_nvdimm() const {

  return _num_committed_nvdimm;

}

G1RegionToSpaceMapper* G1RegionToSpaceMapper::create_heap_mapper(ReservedSpace rs,

                                                                 size_t actual_size,

                                                                 size_t page_size,

                                                                 size_t region_granularity,

                                                                 size_t commit_factor,

                                                                 MemoryType type) {

  if (AllocateOldGenAt != NULL) {

    G1RegionToHeteroSpaceMapper* mapper = new G1RegionToHeteroSpaceMapper(rs, actual_size, page_size, region_granularity, commit_factor, type);

    if (!mapper->initialize()) {

      delete mapper;

      return NULL;

    }

    return (G1RegionToSpaceMapper*)mapper;

  } else {

    return create_mapper(rs, actual_size, page_size, region_granularity, commit_factor, type);

  }

}

G1RegionToSpaceMapper* G1RegionToSpaceMapper::create_mapper(ReservedSpace rs,

                                                            size_t actual_size,

                                                            size_t page_size,

                                                            size_t region_granularity,

                                                            size_t commit_factor,

                                                            MemoryType type) {

  if (region_granularity >= (page_size * commit_factor)) {

    return new G1RegionsLargerThanCommitSizeMapper(rs, actual_size, page_size, region_granularity, commit_factor, type);

  } else {

    return new G1RegionsSmallerThanCommitSizeMapper(rs, actual_size, page_size, region_granularity, commit_factor, type);

  }

}

void G1RegionToSpaceMapper::commit_and_set_special() {

  _storage.commit_and_set_special();

}