1 /*
   2  * Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 #include "precompiled.hpp"
  25 #include "gc/z/zGlobals.hpp"
  26 #include "gc/z/zVirtualMemory.inline.hpp"
  27 
  28 ZVirtualMemoryManager::ZVirtualMemoryManager() :
  29     _manager(),
  30     _initialized(false) {
  31   // Reserve address space
  32   if (!reserve(ZAddressSpaceStart, ZAddressSpaceSize)) {
  33     return;
  34   }
  35 
  36   // Make the complete address view free
  37   _manager.free(0, ZAddressOffsetMax);
  38 
  39   // Successfully initialized
  40   _initialized = true;
  41 }
  42 
  43 bool ZVirtualMemoryManager::is_initialized() const {
  44   return _initialized;
  45 }
  46 
  47 ZVirtualMemory ZVirtualMemoryManager::alloc(size_t size, bool alloc_from_front) {
  48   uintptr_t start;
  49 
  50   if (alloc_from_front || size <= ZPageSizeSmall) {
  51     // Small page
  52     start = _manager.alloc_from_front(size);
  53   } else {
  54     // Medium/Large page
  55     start = _manager.alloc_from_back(size);
  56   }
  57 
  58   return ZVirtualMemory(start, size);
  59 }
  60 
  61 void ZVirtualMemoryManager::free(ZVirtualMemory vmem) {
  62   _manager.free(vmem.start(), vmem.size());
  63 }