1 /*
   2  * Copyright (c) 1997, 2012, 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 
  25 #ifndef SHARE_VM_RUNTIME_VIRTUALSPACE_HPP
  26 #define SHARE_VM_RUNTIME_VIRTUALSPACE_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 
  30 // ReservedSpace is a data structure for reserving a contiguous address range.
  31 
  32 class ReservedSpace VALUE_OBJ_CLASS_SPEC {
  33   friend class VMStructs;
  34  private:
  35   char*  _base;
  36   size_t _size;
  37   size_t _noaccess_prefix;
  38   size_t _alignment;
  39   bool   _special;
  40   bool   _executable;
  41 
  42   // ReservedSpace
  43   ReservedSpace(char* base, size_t size, size_t alignment, bool special,
  44                 bool executable);
  45   void initialize(size_t size, size_t alignment, bool large,
  46                   char* requested_address,
  47                   const size_t noaccess_prefix,
  48                   bool executable);
  49 
  50  protected:
  51   // Create protection page at the beginning of the space.
  52   void protect_noaccess_prefix(const size_t size);
  53 
  54  public:
  55   // Constructor
  56   ReservedSpace();
  57   ReservedSpace(size_t size);
  58   ReservedSpace(size_t size, size_t alignment, bool large,
  59                 char* requested_address = NULL,
  60                 const size_t noaccess_prefix = 0);
  61   ReservedSpace(size_t size, size_t alignment, bool large, bool executable);
  62 
  63   // Accessors
  64   char*  base()            const { return _base;      }
  65   size_t size()            const { return _size;      }
  66   size_t alignment()       const { return _alignment; }
  67   bool   special()         const { return _special;   }
  68   bool   executable()      const { return _executable;   }
  69   size_t noaccess_prefix() const { return _noaccess_prefix;   }
  70   bool is_reserved()       const { return _base != NULL; }
  71   void release();
  72 
  73   // Splitting
  74   ReservedSpace first_part(size_t partition_size, size_t alignment,
  75                            bool split = false, bool realloc = true);
  76   ReservedSpace last_part (size_t partition_size, size_t alignment);
  77 
  78   // These simply call the above using the default alignment.
  79   inline ReservedSpace first_part(size_t partition_size,
  80                                   bool split = false, bool realloc = true);
  81   inline ReservedSpace last_part (size_t partition_size);
  82 
  83   // Alignment
  84   static size_t page_align_size_up(size_t size);
  85   static size_t page_align_size_down(size_t size);
  86   static size_t allocation_align_size_up(size_t size);
  87   static size_t allocation_align_size_down(size_t size);
  88 };
  89 
  90 ReservedSpace
  91 ReservedSpace::first_part(size_t partition_size, bool split, bool realloc)
  92 {
  93   return first_part(partition_size, alignment(), split, realloc);
  94 }
  95 
  96 ReservedSpace ReservedSpace::last_part(size_t partition_size)
  97 {
  98   return last_part(partition_size, alignment());
  99 }
 100 
 101 // Class encapsulating behavior specific of memory space reserved for Java heap
 102 class ReservedHeapSpace : public ReservedSpace {
 103 public:
 104   // Constructor
 105   ReservedHeapSpace(size_t size, size_t forced_base_alignment,
 106                     bool large, char* requested_address);
 107 };
 108 
 109 // Class encapsulating behavior specific memory space for Code
 110 class ReservedCodeSpace : public ReservedSpace {
 111  public:
 112   // Constructor
 113   ReservedCodeSpace(size_t r_size, size_t rs_align, bool large);
 114 };
 115 
 116 // VirtualSpace is data structure for committing a previously reserved address range in smaller chunks.
 117 
 118 class VirtualSpace VALUE_OBJ_CLASS_SPEC {
 119   friend class VMStructs;
 120  private:
 121   // Reserved area
 122   char* _low_boundary;
 123   char* _high_boundary;
 124 
 125   // Committed area
 126   char* _low;
 127   char* _high;
 128 
 129   // The entire space has been committed and pinned in memory, no
 130   // os::commit_memory() or os::uncommit_memory().
 131   bool _special;
 132 
 133   // Need to know if commit should be executable.
 134   bool   _executable;
 135 
 136   // MPSS Support
 137   // Each virtualspace region has a lower, middle, and upper region.
 138   // Each region has an end boundary and a high pointer which is the
 139   // high water mark for the last allocated byte.
 140   // The lower and upper unaligned to LargePageSizeInBytes uses default page.
 141   // size.  The middle region uses large page size.
 142   char* _lower_high;
 143   char* _middle_high;
 144   char* _upper_high;
 145 
 146   char* _lower_high_boundary;
 147   char* _middle_high_boundary;
 148   char* _upper_high_boundary;
 149 
 150   size_t _lower_alignment;
 151   size_t _middle_alignment;
 152   size_t _upper_alignment;
 153 
 154   // MPSS Accessors
 155   char* lower_high() const { return _lower_high; }
 156   char* middle_high() const { return _middle_high; }
 157   char* upper_high() const { return _upper_high; }
 158 
 159   char* lower_high_boundary() const { return _lower_high_boundary; }
 160   char* middle_high_boundary() const { return _middle_high_boundary; }
 161   char* upper_high_boundary() const { return _upper_high_boundary; }
 162 
 163   size_t lower_alignment() const { return _lower_alignment; }
 164   size_t middle_alignment() const { return _middle_alignment; }
 165   size_t upper_alignment() const { return _upper_alignment; }
 166 
 167  public:
 168   // Committed area
 169   char* low()  const { return _low; }
 170   char* high() const { return _high; }
 171 
 172   // Reserved area
 173   char* low_boundary()  const { return _low_boundary; }
 174   char* high_boundary() const { return _high_boundary; }
 175 
 176   bool special() const { return _special; }
 177 
 178  public:
 179   // Initialization
 180   VirtualSpace();
 181   bool initialize(ReservedSpace rs, size_t committed_byte_size);
 182 
 183   // Destruction
 184   ~VirtualSpace();
 185 
 186   // Testers (all sizes are byte sizes)
 187   size_t committed_size()   const;
 188   size_t reserved_size()    const;
 189   size_t uncommitted_size() const;
 190   bool   contains(const void* p)  const;
 191 
 192   // Operations
 193   // returns true on success, false otherwise
 194   bool expand_by(size_t bytes, bool pre_touch = false);
 195   void shrink_by(size_t bytes);
 196   void release();
 197 
 198   void check_for_contiguity() PRODUCT_RETURN;
 199 
 200   // Debugging
 201   void print() PRODUCT_RETURN;
 202 };
 203 
 204 #endif // SHARE_VM_RUNTIME_VIRTUALSPACE_HPP