1 /*
   2  * Copyright (c) 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 
  25 #ifndef SHARE_VM_ARENA_HPP
  26 #define SHARE_VM_ARENA_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 #include "runtime/globals.hpp"
  30 #include "utilities/globalDefinitions.hpp"
  31 
  32 #include <new>
  33 
  34 // The byte alignment to be used by Arena::Amalloc.  See bugid 4169348.
  35 // Note: this value must be a power of 2
  36 
  37 #define ARENA_AMALLOC_ALIGNMENT (2*BytesPerWord)
  38 
  39 #define ARENA_ALIGN_M1 (((size_t)(ARENA_AMALLOC_ALIGNMENT)) - 1)
  40 #define ARENA_ALIGN_MASK (~((size_t)ARENA_ALIGN_M1))
  41 #define ARENA_ALIGN(x) ((((size_t)(x)) + ARENA_ALIGN_M1) & ARENA_ALIGN_MASK)
  42 
  43 //------------------------------Chunk------------------------------------------
  44 // Linked list of raw memory chunks
  45 class Chunk: CHeapObj<mtChunk> {
  46 
  47  private:
  48   Chunk*       _next;     // Next Chunk in list
  49   const size_t _len;      // Size of this Chunk
  50  public:
  51   void* operator new(size_t size, AllocFailType alloc_failmode, size_t length) throw();
  52   void  operator delete(void* p);
  53   Chunk(size_t length);
  54 
  55   enum {
  56     // default sizes; make them slightly smaller than 2**k to guard against
  57     // buddy-system style malloc implementations
  58 #ifdef _LP64
  59     slack      = 40,            // [RGV] Not sure if this is right, but make it
  60                                 //       a multiple of 8.
  61 #else
  62     slack      = 20,            // suspected sizeof(Chunk) + internal malloc headers
  63 #endif
  64 
  65     tiny_size  =  256  - slack, // Size of first chunk (tiny)
  66     init_size  =  1*K  - slack, // Size of first chunk (normal aka small)
  67     medium_size= 10*K  - slack, // Size of medium-sized chunk
  68     size       = 32*K  - slack, // Default size of an Arena chunk (following the first)
  69     non_pool_size = init_size + 32 // An initial size which is not one of above
  70   };
  71 
  72   void chop();                  // Chop this chunk
  73   void next_chop();             // Chop next chunk
  74   static size_t aligned_overhead_size(void) { return ARENA_ALIGN(sizeof(Chunk)); }
  75   static size_t aligned_overhead_size(size_t byte_size) { return ARENA_ALIGN(byte_size); }
  76 
  77   size_t length() const         { return _len;  }
  78   Chunk* next() const           { return _next;  }
  79   void set_next(Chunk* n)       { _next = n;  }
  80   // Boundaries of data area (possibly unused)
  81   char* bottom() const          { return ((char*) this) + aligned_overhead_size();  }
  82   char* top()    const          { return bottom() + _len; }
  83   bool contains(char* p) const  { return bottom() <= p && p <= top(); }
  84 
  85   // Start the chunk_pool cleaner task
  86   static void start_chunk_pool_cleaner_task();
  87 
  88   static void clean_chunk_pool();
  89 };
  90 
  91 //------------------------------Arena------------------------------------------
  92 // Fast allocation of memory
  93 class Arena : public CHeapObj<mtNone> {
  94 protected:
  95   friend class ResourceMark;
  96   friend class HandleMark;
  97   friend class NoHandleMark;
  98   friend class VMStructs;
  99 
 100   MEMFLAGS    _flags;           // Memory tracking flags
 101 
 102   Chunk *_first;                // First chunk
 103   Chunk *_chunk;                // current chunk
 104   char *_hwm, *_max;            // High water mark and max in current chunk
 105   // Get a new Chunk of at least size x
 106   void* grow(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
 107   size_t _size_in_bytes;        // Size of arena (used for native memory tracking)
 108 
 109   NOT_PRODUCT(static julong _bytes_allocated;) // total #bytes allocated since start
 110   friend class AllocStats;
 111   debug_only(void* malloc(size_t size);)
 112   debug_only(void* internal_malloc_4(size_t x);)
 113   NOT_PRODUCT(void inc_bytes_allocated(size_t x);)
 114 
 115   void signal_out_of_memory(size_t request, const char* whence) const;
 116 
 117   bool check_for_overflow(size_t request, const char* whence,
 118       AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) const {
 119     if (UINTPTR_MAX - request < (uintptr_t)_hwm) {
 120       if (alloc_failmode == AllocFailStrategy::RETURN_NULL) {
 121         return false;
 122       }
 123       signal_out_of_memory(request, whence);
 124     }
 125     return true;
 126  }
 127 
 128  public:
 129   Arena(MEMFLAGS memflag);
 130   Arena(MEMFLAGS memflag, size_t init_size);
 131   ~Arena();
 132   void  destruct_contents();
 133   char* hwm() const             { return _hwm; }
 134 
 135   // new operators
 136   void* operator new (size_t size) throw();
 137   void* operator new (size_t size, const std::nothrow_t& nothrow_constant) throw();
 138 
 139   // dynamic memory type tagging
 140   void* operator new(size_t size, MEMFLAGS flags) throw();
 141   void* operator new(size_t size, const std::nothrow_t& nothrow_constant, MEMFLAGS flags) throw();
 142   void  operator delete(void* p);
 143 
 144   // Fast allocate in the arena.  Common case is: pointer test + increment.
 145   void* Amalloc(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) {
 146     assert(is_power_of_2(ARENA_AMALLOC_ALIGNMENT) , "should be a power of 2");
 147     x = ARENA_ALIGN(x);
 148     debug_only(if (UseMallocOnly) return malloc(x);)
 149     if (!check_for_overflow(x, "Arena::Amalloc", alloc_failmode))
 150       return NULL;
 151     NOT_PRODUCT(inc_bytes_allocated(x);)
 152     if (_hwm + x > _max) {
 153       return grow(x, alloc_failmode);
 154     } else {
 155       char *old = _hwm;
 156       _hwm += x;
 157       return old;
 158     }
 159   }
 160   // Further assume size is padded out to words
 161   void *Amalloc_4(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) {
 162     assert( (x&(sizeof(char*)-1)) == 0, "misaligned size" );
 163     debug_only(if (UseMallocOnly) return malloc(x);)
 164     if (!check_for_overflow(x, "Arena::Amalloc_4", alloc_failmode))
 165       return NULL;
 166     NOT_PRODUCT(inc_bytes_allocated(x);)
 167     if (_hwm + x > _max) {
 168       return grow(x, alloc_failmode);
 169     } else {
 170       char *old = _hwm;
 171       _hwm += x;
 172       return old;
 173     }
 174   }
 175 
 176   // Allocate with 'double' alignment. It is 8 bytes on sparc.
 177   // In other cases Amalloc_D() should be the same as Amalloc_4().
 178   void* Amalloc_D(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) {
 179     assert( (x&(sizeof(char*)-1)) == 0, "misaligned size" );
 180     debug_only(if (UseMallocOnly) return malloc(x);)
 181 #if defined(SPARC) && !defined(_LP64)
 182 #define DALIGN_M1 7
 183     size_t delta = (((size_t)_hwm + DALIGN_M1) & ~DALIGN_M1) - (size_t)_hwm;
 184     x += delta;
 185 #endif
 186     if (!check_for_overflow(x, "Arena::Amalloc_D", alloc_failmode))
 187       return NULL;
 188     NOT_PRODUCT(inc_bytes_allocated(x);)
 189     if (_hwm + x > _max) {
 190       return grow(x, alloc_failmode); // grow() returns a result aligned >= 8 bytes.
 191     } else {
 192       char *old = _hwm;
 193       _hwm += x;
 194 #if defined(SPARC) && !defined(_LP64)
 195       old += delta; // align to 8-bytes
 196 #endif
 197       return old;
 198     }
 199   }
 200 
 201   // Fast delete in area.  Common case is: NOP (except for storage reclaimed)
 202   void Afree(void *ptr, size_t size) {
 203 #ifdef ASSERT
 204     if (ZapResourceArea) memset(ptr, badResourceValue, size); // zap freed memory
 205     if (UseMallocOnly) return;
 206 #endif
 207     if (((char*)ptr) + size == _hwm) _hwm = (char*)ptr;
 208   }
 209 
 210   void *Arealloc( void *old_ptr, size_t old_size, size_t new_size,
 211       AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
 212 
 213   // Move contents of this arena into an empty arena
 214   Arena *move_contents(Arena *empty_arena);
 215 
 216   // Determine if pointer belongs to this Arena or not.
 217   bool contains( const void *ptr ) const;
 218 
 219   // Total of all chunks in use (not thread-safe)
 220   size_t used() const;
 221 
 222   // Total # of bytes used
 223   size_t size_in_bytes() const         {  return _size_in_bytes; };
 224   void set_size_in_bytes(size_t size);
 225 
 226   static void free_malloced_objects(Chunk* chunk, char* hwm, char* max, char* hwm2)  PRODUCT_RETURN;
 227   static void free_all(char** start, char** end)                                     PRODUCT_RETURN;
 228 
 229 private:
 230   // Reset this Arena to empty, access will trigger grow if necessary
 231   void   reset(void) {
 232     _first = _chunk = NULL;
 233     _hwm = _max = NULL;
 234     set_size_in_bytes(0);
 235   }
 236 };
 237 
 238 // One of the following macros must be used when allocating
 239 // an array or object from an arena
 240 #define NEW_ARENA_ARRAY(arena, type, size) \
 241   (type*) (arena)->Amalloc((size) * sizeof(type))
 242 
 243 #define REALLOC_ARENA_ARRAY(arena, type, old, old_size, new_size)    \
 244   (type*) (arena)->Arealloc((char*)(old), (old_size) * sizeof(type), \
 245                             (new_size) * sizeof(type) )
 246 
 247 #define FREE_ARENA_ARRAY(arena, type, old, size) \
 248   (arena)->Afree((char*)(old), (size) * sizeof(type))
 249 
 250 #define NEW_ARENA_OBJ(arena, type) \
 251   NEW_ARENA_ARRAY(arena, type, 1)
 252 
 253 #endif // SHARE_VM_ARENA_HPP