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 preferred_page_size
  55   // is set, use this as minimum page size/alignment. This may waste some space
  56   // if the given size is not aligned to that value, as the reservation will be
  57   // aligned up to the final alignment in this case.
  58   ReservedSpace(size_t size, size_t preferred_page_size = 0);
  59   ReservedSpace(size_t size, size_t alignment, bool large,
  60                 char* requested_address = NULL);
  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_up(size_t size);
  85   static size_t page_align_down(size_t size);
  86   static size_t allocation_align_up(size_t size);
  87   static size_t allocation_align_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  private:
 104   void try_reserve_heap(size_t size, size_t alignment, bool large,
 105                         char *requested_address);
 106   void try_reserve_range(char *highest_start, char *lowest_start,
 107                          size_t attach_point_alignment, char *aligned_HBMA,
 108                          char *upper_bound, size_t size, size_t alignment, bool large);
 109   void initialize_compressed_heap(const size_t size, size_t alignment, bool large);
 110   // Create protection page at the beginning of the space.
 111   void establish_noaccess_prefix();
 112  public:
 113   // Constructor. Tries to find a heap that is good for compressed oops.
 114   ReservedHeapSpace(size_t size, size_t forced_base_alignment, bool large);
 115   // Returns the base to be used for compression, i.e. so that null can be
 116   // encoded safely and implicit null checks can work.
 117   char *compressed_oop_base() { return _base - _noaccess_prefix; }
 118 };
 119 
 120 // Class encapsulating behavior specific memory space for Code
 121 class ReservedCodeSpace : public ReservedSpace {
 122  public:
 123   // Constructor
 124   ReservedCodeSpace(size_t r_size, size_t rs_align, bool large);
 125 };
 126 
 127 // VirtualSpace is data structure for committing a previously reserved address range in smaller chunks.
 128 
 129 class VirtualSpace VALUE_OBJ_CLASS_SPEC {
 130   friend class VMStructs;
 131  private:
 132   // Reserved area
 133   char* _low_boundary;
 134   char* _high_boundary;
 135 
 136   // Committed area
 137   char* _low;
 138   char* _high;
 139 
 140   // The entire space has been committed and pinned in memory, no
 141   // os::commit_memory() or os::uncommit_memory().
 142   bool _special;
 143 
 144   // Need to know if commit should be executable.
 145   bool   _executable;
 146 
 147   // MPSS Support
 148   // Each virtualspace region has a lower, middle, and upper region.
 149   // Each region has an end boundary and a high pointer which is the
 150   // high water mark for the last allocated byte.
 151   // The lower and upper unaligned to LargePageSizeInBytes uses default page.
 152   // size.  The middle region uses large page size.
 153   char* _lower_high;
 154   char* _middle_high;
 155   char* _upper_high;
 156 
 157   char* _lower_high_boundary;
 158   char* _middle_high_boundary;
 159   char* _upper_high_boundary;
 160 
 161   size_t _lower_alignment;
 162   size_t _middle_alignment;
 163   size_t _upper_alignment;
 164 
 165   // MPSS Accessors
 166   char* lower_high() const { return _lower_high; }
 167   char* middle_high() const { return _middle_high; }
 168   char* upper_high() const { return _upper_high; }
 169 
 170   char* lower_high_boundary() const { return _lower_high_boundary; }
 171   char* middle_high_boundary() const { return _middle_high_boundary; }
 172   char* upper_high_boundary() const { return _upper_high_boundary; }
 173 
 174   size_t lower_alignment() const { return _lower_alignment; }
 175   size_t middle_alignment() const { return _middle_alignment; }
 176   size_t upper_alignment() const { return _upper_alignment; }
 177 
 178  public:
 179   // Committed area
 180   char* low()  const { return _low; }
 181   char* high() const { return _high; }
 182 
 183   // Reserved area
 184   char* low_boundary()  const { return _low_boundary; }
 185   char* high_boundary() const { return _high_boundary; }
 186 
 187 #if INCLUDE_AOT
 188   // Set boundaries for code section in AOT library.
 189   void set_low_boundary(char *p)  { _low_boundary = p; }
 190   void set_high_boundary(char *p) { _high_boundary = p; }
 191   void set_low(char *p)           { _low = p; }
 192   void set_high(char *p)          { _high = p; }
 193 #endif
 194 
 195   bool special() const { return _special; }
 196 
 197  public:
 198   // Initialization
 199   VirtualSpace();
 200   bool initialize_with_granularity(ReservedSpace rs, size_t committed_byte_size, size_t max_commit_ganularity);
 201   bool initialize(ReservedSpace rs, size_t committed_byte_size);
 202 
 203   // Destruction
 204   ~VirtualSpace();
 205 
 206   // Reserved memory
 207   size_t reserved_size() const;
 208   // Actually committed OS memory
 209   size_t actual_committed_size() const;
 210   // Memory used/expanded in this virtual space
 211   size_t committed_size() const;
 212   // Memory left to use/expand in this virtual space
 213   size_t uncommitted_size() const;
 214 
 215   bool   contains(const void* p) const;
 216 
 217   // Operations
 218   // returns true on success, false otherwise
 219   bool expand_by(size_t bytes, bool pre_touch = false);
 220   void shrink_by(size_t bytes);
 221   void release();
 222 
 223   void check_for_contiguity() PRODUCT_RETURN;
 224 
 225   // Debugging
 226   void print_on(outputStream* out) PRODUCT_RETURN;
 227   void print();
 228 };
 229 
 230 #endif // SHARE_VM_RUNTIME_VIRTUALSPACE_HPP