1 /*
   2  * Copyright (c) 1997, 2015, 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
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  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
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  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  protected:
  35   char*  _base;
  36   size_t _size;
  37   size_t _noaccess_prefix;
  38   size_t _alignment;
  39   bool   _special;
  40  private:
  41   bool   _executable;
  42 
  43   // ReservedSpace
  44   ReservedSpace(char* base, size_t size, size_t alignment, bool special,
  45                 bool executable);
  46  protected:
  47   void initialize(size_t size, size_t alignment, bool large,
  48                   char* requested_address,
  49                   bool executable);
  50 
  51  public:
  52   // Constructor
  53   ReservedSpace();
  54   // Initialize the reserved space with the given size. If prefer_large_pages is
  55   // set, if the given size warrants use of large pages, try to force them by
  56   // passing an alignment restriction further down. This may waste some space
  57   // if the given size is not aligned, as the reservation will be aligned up
  58   // to large page alignment.
  59   ReservedSpace(size_t size, bool prefer_large_pages = false);
  60   ReservedSpace(size_t size, size_t alignment, bool large,
  61                 char* requested_address = NULL);
  62   ReservedSpace(size_t size, size_t alignment, bool large, bool executable);
  63 
  64   // Accessors
  65   char*  base()            const { return _base;      }
  66   size_t size()            const { return _size;      }
  67   size_t alignment()       const { return _alignment; }
  68   bool   special()         const { return _special;   }
  69   bool   executable()      const { return _executable;   }
  70   size_t noaccess_prefix() const { return _noaccess_prefix;   }
  71   bool is_reserved()       const { return _base != NULL; }
  72   void release();
  73 
  74   // Splitting
  75   ReservedSpace first_part(size_t partition_size, size_t alignment,
  76                            bool split = false, bool realloc = true);
  77   ReservedSpace last_part (size_t partition_size, size_t alignment);
  78 
  79   // These simply call the above using the default alignment.
  80   inline ReservedSpace first_part(size_t partition_size,
  81                                   bool split = false, bool realloc = true);
  82   inline ReservedSpace last_part (size_t partition_size);
  83 
  84   // Alignment
  85   static size_t page_align_size_up(size_t size);
  86   static size_t page_align_size_down(size_t size);
  87   static size_t allocation_align_size_up(size_t size);
  88   static size_t allocation_align_size_down(size_t size);
  89 };
  90 
  91 ReservedSpace
  92 ReservedSpace::first_part(size_t partition_size, bool split, bool realloc)
  93 {
  94   return first_part(partition_size, alignment(), split, realloc);
  95 }
  96 
  97 ReservedSpace ReservedSpace::last_part(size_t partition_size)
  98 {
  99   return last_part(partition_size, alignment());
 100 }
 101 
 102 // Class encapsulating behavior specific of memory space reserved for Java heap.
 103 class ReservedHeapSpace : public ReservedSpace {
 104  private:
 105   void try_reserve_heap(size_t size, size_t alignment, bool large,
 106                         char *requested_address);
 107   void try_reserve_range(char *highest_start, char *lowest_start,
 108                          size_t attach_point_alignment, char *aligned_HBMA,
 109                          char *upper_bound, size_t size, size_t alignment, bool large);
 110   void initialize_compressed_heap(const size_t size, size_t alignment, bool large);
 111   // Create protection page at the beginning of the space.
 112   void establish_noaccess_prefix();
 113  public:
 114   // Constructor. Tries to find a heap that is good for compressed oops.
 115   ReservedHeapSpace(size_t size, size_t forced_base_alignment, bool large);
 116   // Returns the base to be used for compression, i.e. so that null can be
 117   // encoded safely and implicit null checks can work.
 118   char *compressed_oop_base() { return _base - _noaccess_prefix; }
 119 };
 120 
 121 // Class encapsulating behavior specific memory space for Code
 122 class ReservedCodeSpace : public ReservedSpace {
 123  public:
 124   // Constructor
 125   ReservedCodeSpace(size_t r_size, size_t rs_align, bool large);
 126 };
 127 
 128 // VirtualSpace is data structure for committing a previously reserved address range in smaller chunks.
 129 
 130 class VirtualSpace VALUE_OBJ_CLASS_SPEC {
 131   friend class VMStructs;
 132  private:
 133   // Reserved area
 134   char* _low_boundary;
 135   char* _high_boundary;
 136 
 137   // Committed area
 138   char* _low;
 139   char* _high;
 140 
 141   // The entire space has been committed and pinned in memory, no
 142   // os::commit_memory() or os::uncommit_memory().
 143   bool _special;
 144 
 145   // Need to know if commit should be executable.
 146   bool   _executable;
 147 
 148   // MPSS Support
 149   // Each virtualspace region has a lower, middle, and upper region.
 150   // Each region has an end boundary and a high pointer which is the
 151   // high water mark for the last allocated byte.
 152   // The lower and upper unaligned to LargePageSizeInBytes uses default page.
 153   // size.  The middle region uses large page size.
 154   char* _lower_high;
 155   char* _middle_high;
 156   char* _upper_high;
 157 
 158   char* _lower_high_boundary;
 159   char* _middle_high_boundary;
 160   char* _upper_high_boundary;
 161 
 162   size_t _lower_alignment;
 163   size_t _middle_alignment;
 164   size_t _upper_alignment;
 165 
 166   // MPSS Accessors
 167   char* lower_high() const { return _lower_high; }
 168   char* middle_high() const { return _middle_high; }
 169   char* upper_high() const { return _upper_high; }
 170 
 171   char* lower_high_boundary() const { return _lower_high_boundary; }
 172   char* middle_high_boundary() const { return _middle_high_boundary; }
 173   char* upper_high_boundary() const { return _upper_high_boundary; }
 174 
 175   size_t lower_alignment() const { return _lower_alignment; }
 176   size_t middle_alignment() const { return _middle_alignment; }
 177   size_t upper_alignment() const { return _upper_alignment; }
 178 
 179  public:
 180   // Committed area
 181   char* low()  const { return _low; }
 182   char* high() const { return _high; }
 183 
 184   // Reserved area
 185   char* low_boundary()  const { return _low_boundary; }
 186   char* high_boundary() const { return _high_boundary; }
 187 
 188   bool special() const { return _special; }
 189 
 190  public:
 191   // Initialization
 192   VirtualSpace();
 193   bool initialize_with_granularity(ReservedSpace rs, size_t committed_byte_size, size_t max_commit_ganularity);
 194   bool initialize(ReservedSpace rs, size_t committed_byte_size);
 195 
 196   // Destruction
 197   ~VirtualSpace();
 198 
 199   // Reserved memory
 200   size_t reserved_size() const;
 201   // Actually committed OS memory
 202   size_t actual_committed_size() const;
 203   // Memory used/expanded in this virtual space
 204   size_t committed_size() const;
 205   // Memory left to use/expand in this virtual space
 206   size_t uncommitted_size() const;
 207 
 208   bool   contains(const void* p) const;
 209 
 210   // Operations
 211   // returns true on success, false otherwise
 212   bool expand_by(size_t bytes, bool pre_touch = false);
 213   void shrink_by(size_t bytes);
 214   void release();
 215 
 216   void check_for_contiguity() PRODUCT_RETURN;
 217 
 218   // Debugging
 219   void print_on(outputStream* out) PRODUCT_RETURN;
 220   void print();
 221 };
 222 
 223 #endif // SHARE_VM_RUNTIME_VIRTUALSPACE_HPP