/*
 * 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/zAddress.inline.hpp"
#include "gc/z/zGlobals.hpp"
#include "gc/z/zVirtualMemory.inline.hpp"
#include "logging/log.hpp"
#include "services/memTracker.hpp"

bool ZVirtualMemoryManager::reserve_range(uintptr_t start, size_t size) {
  // Reserve address space
  char* const marked0_addr = (char*)ZAddress::marked0(start);
  char* const marked1_addr = (char*)ZAddress::marked1(start);
  char* const remapped_addr = (char*)ZAddress::remapped(start);

  if (!os::attempt_reserve_memory_at(size, marked0_addr)) {
    return false;
  }

  if (!os::attempt_reserve_memory_at(size, marked1_addr)) {
    os::release_memory(marked0_addr, size);
    return false;
  }

  if (!os::attempt_reserve_memory_at(size, remapped_addr)) {
    os::release_memory(marked0_addr, size);
    os::release_memory(marked1_addr, size);
    return false;
  }

  // Make the address view free
  _manager.free(start, size);
  return true;
}

size_t ZVirtualMemoryManager::reserve(uintptr_t start, size_t size) {
  if (reserve_range(start, size)) {
    return size;
  }

  if (size <= ZGranuleSize) {
    return 0;
  }

  const size_t range = size / 2;
  return reserve(start, range) + reserve(start + range, range);
}

ZVirtualMemoryManager::ZVirtualMemoryManager() :
    _manager(),
    _initialized(false) {

  log_info(gc, init)("Address Space: " PTR_FORMAT " - " PTR_FORMAT " (" SIZE_FORMAT "T)",
                     ZAddressSpaceStart, ZAddressSpaceEnd, ZAddressSpaceSize / K / G);

  // Reserve address space
  if (reserve(0, ZAddressOffsetMax) < MaxHeapSize) {
    log_error(gc)("Failed to reserve enough address space for Java heap");
    return;
  }

  // Successfully initialized
  _initialized = true;
}

bool ZVirtualMemoryManager::is_initialized() const {
  return _initialized;
}

ZVirtualMemory ZVirtualMemoryManager::alloc(size_t size, bool alloc_from_front) {
  uintptr_t start;

  if (alloc_from_front || size <= ZPageSizeSmall) {
    // Small page
    start = _manager.alloc_from_front(size);
  } else {
    // Medium/Large page
    start = _manager.alloc_from_back(size);
  }

  return ZVirtualMemory(start, size);
}

void ZVirtualMemoryManager::free(const ZVirtualMemory& vmem) {
  _manager.free(vmem.start(), vmem.size());
}