/*

 * Copyright (c) 2015, 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/z/zPhysicalMemory.inline.hpp"

#include "logging/log.hpp"

#include "memory/allocation.inline.hpp"

#include "services/memTracker.hpp"

#include "utilities/debug.hpp"

#include "utilities/globalDefinitions.hpp"

ZPhysicalMemory::ZPhysicalMemory() :

    _nsegments(0),

    _segments(NULL) {}

ZPhysicalMemory::ZPhysicalMemory(size_t size) :

    _nsegments(0),

    _segments(NULL) {

  add_segment(ZPhysicalMemorySegment(0, size));

}

ZPhysicalMemory::ZPhysicalMemory(const ZPhysicalMemorySegment& segment) :

    _nsegments(0),

    _segments(NULL) {

  add_segment(segment);

}

size_t ZPhysicalMemory::size() const {

  size_t size = 0;

  for (size_t i = 0; i < _nsegments; i++) {

    size += _segments[i].size();

  }

  return size;

}

void ZPhysicalMemory::add_segment(ZPhysicalMemorySegment segment) {

  // Try merge with last segment

  if (_nsegments > 0) {

    ZPhysicalMemorySegment& last = _segments[_nsegments - 1];

    assert(last.end() <= segment.start(), "Segments added out of order");

    if (last.end() == segment.start()) {

      // Merge

      last.expand(segment.size());

      return;

    }

  }

  // Make room for a new segment

  const size_t size = sizeof(ZPhysicalMemorySegment) * (_nsegments + 1);

  _segments = (ZPhysicalMemorySegment*)ReallocateHeap((char*)_segments, size, mtGC);

  // Add new segment

  _segments[_nsegments] = segment;

  _nsegments++;

}

ZPhysicalMemory ZPhysicalMemory::split(size_t split_size) {

  // Only splitting of single-segment instances have been implemented.

  assert(nsegments() == 1, "Can only have one segment");

  assert(split_size <= size(), "Invalid size");

  return ZPhysicalMemory(_segments[0].split(split_size));

}

void ZPhysicalMemory::clear() {

  if (_segments != NULL) {

    FreeHeap(_segments);

    _segments = NULL;

    _nsegments = 0;

  }

}

ZPhysicalMemoryManager::ZPhysicalMemoryManager(size_t max_capacity) :

    _backing(max_capacity),

    _max_capacity(max_capacity),

    _current_max_capacity(max_capacity),

    _capacity(0),

    _used(0) {}

bool ZPhysicalMemoryManager::is_initialized() const {

  return _backing.is_initialized();

}

void ZPhysicalMemoryManager::try_ensure_unused_capacity(size_t size) {

  const size_t unused = unused_capacity();

  if (unused >= size) {

    // Don't try to expand, enough unused capacity available

    return;

  }

  const size_t current_max = current_max_capacity();

  if (_capacity == current_max) {

    // Don't try to expand, current max capacity reached

    return;

  }

  // Try to expand

  const size_t old_capacity = capacity();

  const size_t new_capacity = MIN2(old_capacity + size - unused, current_max);

  _capacity = _backing.try_expand(old_capacity, new_capacity);

  if (_capacity != new_capacity) {

    // Failed, or partly failed, to expand

    log_error(gc, init)("Not enough space available on the backing filesystem to hold the current max");

    log_error(gc, init)("Java heap size (" SIZE_FORMAT "M). Forcefully lowering max Java heap size to "

                        SIZE_FORMAT "M (%.0lf%%).", current_max / M, _capacity / M,

                        percent_of(_capacity, current_max));

    // Adjust current max capacity to avoid further expand attempts

    _current_max_capacity = _capacity;

  }

}

void ZPhysicalMemoryManager::nmt_commit(ZPhysicalMemory pmem, uintptr_t offset) {

  const uintptr_t addr = _backing.nmt_address(offset);

  const size_t size = pmem.size();

  MemTracker::record_virtual_memory_commit((void*)addr, size, CALLER_PC);

}

void ZPhysicalMemoryManager::nmt_uncommit(ZPhysicalMemory pmem, uintptr_t offset) {

  if (MemTracker::tracking_level() > NMT_minimal) {

    const uintptr_t addr = _backing.nmt_address(offset);

    const size_t size = pmem.size();

    Tracker tracker(Tracker::uncommit);

    tracker.record((address)addr, size);

  }

}

ZPhysicalMemory ZPhysicalMemoryManager::alloc(size_t size) {

  if (unused_capacity() < size) {

    // Not enough memory available

    return ZPhysicalMemory();

  }

  _used += size;

  return _backing.alloc(size);

}

void ZPhysicalMemoryManager::free(ZPhysicalMemory pmem) {

  _backing.free(pmem);

  _used -= pmem.size();

}

void ZPhysicalMemoryManager::map(ZPhysicalMemory pmem, uintptr_t offset) {

  // Map page

  _backing.map(pmem, offset);

  // Update native memory tracker

  nmt_commit(pmem, offset);

}

void ZPhysicalMemoryManager::unmap(ZPhysicalMemory pmem, uintptr_t offset) {

  // Update native memory tracker

  nmt_uncommit(pmem, offset);

  // Unmap page

  _backing.unmap(pmem, offset);

}

void ZPhysicalMemoryManager::debug_map(ZPhysicalMemory pmem, uintptr_t offset) {

  _backing.debug_map(pmem, offset);

}

void ZPhysicalMemoryManager::debug_unmap(ZPhysicalMemory pmem, uintptr_t offset) {

  _backing.debug_unmap(pmem, offset);

}