1 /*
   2  * Copyright (c) 1997, 2019, 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_MEMORY_ALLOCATION_HPP
  26 #define SHARE_MEMORY_ALLOCATION_HPP
  27 
  28 #include "runtime/globals.hpp"
  29 #include "utilities/globalDefinitions.hpp"
  30 #include "utilities/macros.hpp"
  31 
  32 #include <new>
  33 
  34 class Thread;
  35 
  36 class AllocFailStrategy {
  37 public:
  38   enum AllocFailEnum { EXIT_OOM, RETURN_NULL };
  39 };
  40 typedef AllocFailStrategy::AllocFailEnum AllocFailType;
  41 
  42 // The virtual machine must never call one of the implicitly declared
  43 // global allocation or deletion functions.  (Such calls may result in
  44 // link-time or run-time errors.)  For convenience and documentation of
  45 // intended use, classes in the virtual machine may be derived from one
  46 // of the following allocation classes, some of which define allocation
  47 // and deletion functions.
  48 // Note: std::malloc and std::free should never called directly.
  49 
  50 //
  51 // For objects allocated in the resource area (see resourceArea.hpp).
  52 // - ResourceObj
  53 //
  54 // For objects allocated in the C-heap (managed by: free & malloc and tracked with NMT)
  55 // - CHeapObj
  56 //
  57 // For objects allocated on the stack.
  58 // - StackObj
  59 //
  60 // For classes used as name spaces.
  61 // - AllStatic
  62 //
  63 // For classes in Metaspace (class data)
  64 // - MetaspaceObj
  65 //
  66 // The printable subclasses are used for debugging and define virtual
  67 // member functions for printing. Classes that avoid allocating the
  68 // vtbl entries in the objects should therefore not be the printable
  69 // subclasses.
  70 //
  71 // The following macros and function should be used to allocate memory
  72 // directly in the resource area or in the C-heap, The _OBJ variants
  73 // of the NEW/FREE_C_HEAP macros are used for alloc/dealloc simple
  74 // objects which are not inherited from CHeapObj, note constructor and
  75 // destructor are not called. The preferable way to allocate objects
  76 // is using the new operator.
  77 //
  78 // WARNING: The array variant must only be used for a homogenous array
  79 // where all objects are of the exact type specified. If subtypes are
  80 // stored in the array then must pay attention to calling destructors
  81 // at needed.
  82 //
  83 //   NEW_RESOURCE_ARRAY(type, size)
  84 //   NEW_RESOURCE_OBJ(type)
  85 //   NEW_C_HEAP_ARRAY(type, size)
  86 //   NEW_C_HEAP_OBJ(type, memflags)
  87 //   FREE_C_HEAP_ARRAY(type, old)
  88 //   FREE_C_HEAP_OBJ(objname, type, memflags)
  89 //   char* AllocateHeap(size_t size, const char* name);
  90 //   void  FreeHeap(void* p);
  91 //
  92 
  93 // In non product mode we introduce a super class for all allocation classes
  94 // that supports printing.
  95 // We avoid the superclass in product mode to save space.
  96 
  97 #ifdef PRODUCT
  98 #define ALLOCATION_SUPER_CLASS_SPEC
  99 #else
 100 #define ALLOCATION_SUPER_CLASS_SPEC : public AllocatedObj
 101 class AllocatedObj {
 102  public:
 103   // Printing support
 104   void print() const;
 105   void print_value() const;
 106 
 107   virtual void print_on(outputStream* st) const;
 108   virtual void print_value_on(outputStream* st) const;
 109 };
 110 #endif
 111 
 112 #define MEMORY_TYPES_DO(f) \
 113   /* Memory type by sub systems. It occupies lower byte. */  \
 114   f(mtJavaHeap,      "Java Heap")   /* Java heap                                 */ \
 115   f(mtClass,         "Class")       /* Java classes                              */ \
 116   f(mtThread,        "Thread")      /* thread objects                            */ \
 117   f(mtThreadStack,   "Thread Stack")                                                \
 118   f(mtCode,          "Code")        /* generated code                            */ \
 119   f(mtGC,            "GC")                                                          \
 120   f(mtCompiler,      "Compiler")                                                    \
 121   f(mtJVMCI,         "JVMCI")                                                       \
 122   f(mtInternal,      "Internal")    /* memory used by VM, but does not belong to */ \
 123                                     /* any of above categories, and not used by  */ \
 124                                     /* NMT                                       */ \
 125   f(mtOther,         "Other")       /* memory not used by VM                     */ \
 126   f(mtSymbol,        "Symbol")                                                      \
 127   f(mtNMT,           "Native Memory Tracking")  /* memory used by NMT            */ \
 128   f(mtClassShared,   "Shared class space")      /* class data sharing            */ \
 129   f(mtChunk,         "Arena Chunk") /* chunk that holds content of arenas        */ \
 130   f(mtTest,          "Test")        /* Test type for verifying NMT               */ \
 131   f(mtTracing,       "Tracing")                                                     \
 132   f(mtLogging,       "Logging")                                                     \
 133   f(mtStatistics,    "Statistics")                                                  \
 134   f(mtArguments,     "Arguments")                                                   \
 135   f(mtModule,        "Module")                                                      \
 136   f(mtSafepoint,     "Safepoint")                                                   \
 137   f(mtSynchronizer,  "Synchronization")                                             \
 138   f(mtNone,          "Unknown")                                                     \
 139   //end
 140 
 141 #define MEMORY_TYPE_DECLARE_ENUM(type, human_readable) \
 142   type,
 143 
 144 /*
 145  * Memory types
 146  */
 147 enum MemoryType {
 148   MEMORY_TYPES_DO(MEMORY_TYPE_DECLARE_ENUM)
 149   mt_number_of_types   // number of memory types (mtDontTrack
 150                        // is not included as validate type)
 151 };
 152 
 153 typedef MemoryType MEMFLAGS;
 154 
 155 
 156 #if INCLUDE_NMT
 157 
 158 extern bool NMT_track_callsite;
 159 
 160 #else
 161 
 162 const bool NMT_track_callsite = false;
 163 
 164 #endif // INCLUDE_NMT
 165 
 166 class NativeCallStack;
 167 
 168 
 169 char* AllocateHeap(size_t size,
 170                    MEMFLAGS flags,
 171                    const NativeCallStack& stack,
 172                    AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
 173 char* AllocateHeap(size_t size,
 174                    MEMFLAGS flags,
 175                    AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
 176 
 177 char* ReallocateHeap(char *old,
 178                      size_t size,
 179                      MEMFLAGS flag,
 180                      AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
 181 
 182 void FreeHeap(void* p);
 183 
 184 template <MEMFLAGS F> class CHeapObj ALLOCATION_SUPER_CLASS_SPEC {
 185  public:
 186   ALWAYSINLINE void* operator new(size_t size) throw() {
 187     return (void*)AllocateHeap(size, F);
 188   }
 189 
 190   ALWAYSINLINE void* operator new(size_t size,
 191                                   const NativeCallStack& stack) throw() {
 192     return (void*)AllocateHeap(size, F, stack);
 193   }
 194 
 195   ALWAYSINLINE void* operator new(size_t size, const std::nothrow_t&,
 196                                   const NativeCallStack& stack) throw() {
 197     return (void*)AllocateHeap(size, F, stack, AllocFailStrategy::RETURN_NULL);
 198   }
 199 
 200   ALWAYSINLINE void* operator new(size_t size, const std::nothrow_t&) throw() {
 201     return (void*)AllocateHeap(size, F, AllocFailStrategy::RETURN_NULL);
 202   }
 203 
 204   ALWAYSINLINE void* operator new[](size_t size) throw() {
 205     return (void*)AllocateHeap(size, F);
 206   }
 207 
 208   ALWAYSINLINE void* operator new[](size_t size,
 209                                   const NativeCallStack& stack) throw() {
 210     return (void*)AllocateHeap(size, F, stack);
 211   }
 212 
 213   ALWAYSINLINE void* operator new[](size_t size, const std::nothrow_t&,
 214                                     const NativeCallStack& stack) throw() {
 215     return (void*)AllocateHeap(size, F, stack, AllocFailStrategy::RETURN_NULL);
 216   }
 217 
 218   ALWAYSINLINE void* operator new[](size_t size, const std::nothrow_t&) throw() {
 219     return (void*)AllocateHeap(size, F, AllocFailStrategy::RETURN_NULL);
 220   }
 221 
 222   void  operator delete(void* p)     { FreeHeap(p); }
 223   void  operator delete [] (void* p) { FreeHeap(p); }
 224 };
 225 
 226 // Base class for objects allocated on the stack only.
 227 // Calling new or delete will result in fatal error.
 228 
 229 class StackObj ALLOCATION_SUPER_CLASS_SPEC {
 230  private:
 231   void* operator new(size_t size) throw();
 232   void* operator new [](size_t size) throw();
 233 #ifdef __IBMCPP__
 234  public:
 235 #endif
 236   void  operator delete(void* p);
 237   void  operator delete [](void* p);
 238 };
 239 
 240 // Base class for objects stored in Metaspace.
 241 // Calling delete will result in fatal error.
 242 //
 243 // Do not inherit from something with a vptr because this class does
 244 // not introduce one.  This class is used to allocate both shared read-only
 245 // and shared read-write classes.
 246 //
 247 
 248 class ClassLoaderData;
 249 class MetaspaceClosure;
 250 
 251 class MetaspaceObj {
 252   friend class VMStructs;
 253   // When CDS is enabled, all shared metaspace objects are mapped
 254   // into a single contiguous memory block, so we can use these
 255   // two pointers to quickly determine if something is in the
 256   // shared metaspace.
 257   // When CDS is not enabled, both pointers are set to NULL.
 258   static void* _shared_metaspace_base;  // (inclusive) low address
 259   static void* _shared_metaspace_top;   // (exclusive) high address
 260 
 261  public:
 262 
 263   // Returns true if the pointer points to a valid MetaspaceObj. A valid
 264   // MetaspaceObj is MetaWord-aligned and contained within either
 265   // non-shared or shared metaspace.
 266   static bool is_valid(const MetaspaceObj* p);
 267 
 268   static bool is_shared(const MetaspaceObj* p) {
 269     // If no shared metaspace regions are mapped, _shared_metaspace_{base,top} will
 270     // both be NULL and all values of p will be rejected quickly.
 271     return (((void*)p) < _shared_metaspace_top &&
 272             ((void*)p) >= _shared_metaspace_base);
 273   }
 274   bool is_shared() const { return MetaspaceObj::is_shared(this); }
 275 
 276   void print_address_on(outputStream* st) const;  // nonvirtual address printing
 277 
 278   static void set_shared_metaspace_range(void* base, void* top) {
 279     _shared_metaspace_base = base;
 280     _shared_metaspace_top = top;
 281   }
 282 
 283   static void expand_shared_metaspace_range(void* top) {
 284     assert(top >= _shared_metaspace_top, "must be");
 285     _shared_metaspace_top = top;
 286   }
 287 
 288   static void* shared_metaspace_base() { return _shared_metaspace_base; }
 289   static void* shared_metaspace_top()  { return _shared_metaspace_top;  }
 290 
 291 #define METASPACE_OBJ_TYPES_DO(f) \
 292   f(Class) \
 293   f(Symbol) \
 294   f(TypeArrayU1) \
 295   f(TypeArrayU2) \
 296   f(TypeArrayU4) \
 297   f(TypeArrayU8) \
 298   f(TypeArrayOther) \
 299   f(Method) \
 300   f(ConstMethod) \
 301   f(MethodData) \
 302   f(ConstantPool) \
 303   f(ConstantPoolCache) \
 304   f(Annotations) \
 305   f(MethodCounters)
 306 
 307 #define METASPACE_OBJ_TYPE_DECLARE(name) name ## Type,
 308 #define METASPACE_OBJ_TYPE_NAME_CASE(name) case name ## Type: return #name;
 309 
 310   enum Type {
 311     // Types are MetaspaceObj::ClassType, MetaspaceObj::SymbolType, etc
 312     METASPACE_OBJ_TYPES_DO(METASPACE_OBJ_TYPE_DECLARE)
 313     _number_of_types
 314   };
 315 
 316   static const char * type_name(Type type) {
 317     switch(type) {
 318     METASPACE_OBJ_TYPES_DO(METASPACE_OBJ_TYPE_NAME_CASE)
 319     default:
 320       ShouldNotReachHere();
 321       return NULL;
 322     }
 323   }
 324 
 325   static MetaspaceObj::Type array_type(size_t elem_size) {
 326     switch (elem_size) {
 327     case 1: return TypeArrayU1Type;
 328     case 2: return TypeArrayU2Type;
 329     case 4: return TypeArrayU4Type;
 330     case 8: return TypeArrayU8Type;
 331     default:
 332       return TypeArrayOtherType;
 333     }
 334   }
 335 
 336   void* operator new(size_t size, ClassLoaderData* loader_data,
 337                      size_t word_size,
 338                      Type type, Thread* thread) throw();
 339                      // can't use TRAPS from this header file.
 340   void operator delete(void* p) { ShouldNotCallThis(); }
 341 
 342   // Declare a *static* method with the same signature in any subclass of MetaspaceObj
 343   // that should be read-only by default. See symbol.hpp for an example. This function
 344   // is used by the templates in metaspaceClosure.hpp
 345   static bool is_read_only_by_default() { return false; }
 346 };
 347 
 348 // Base class for classes that constitute name spaces.
 349 
 350 class Arena;
 351 
 352 class AllStatic {
 353  public:
 354   AllStatic()  { ShouldNotCallThis(); }
 355   ~AllStatic() { ShouldNotCallThis(); }
 356 };
 357 
 358 
 359 extern char* resource_allocate_bytes(size_t size,
 360     AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
 361 extern char* resource_allocate_bytes(Thread* thread, size_t size,
 362     AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
 363 extern char* resource_reallocate_bytes( char *old, size_t old_size, size_t new_size,
 364     AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
 365 extern void resource_free_bytes( char *old, size_t size );
 366 
 367 //----------------------------------------------------------------------
 368 // Base class for objects allocated in the resource area per default.
 369 // Optionally, objects may be allocated on the C heap with
 370 // new(ResourceObj::C_HEAP) Foo(...) or in an Arena with new (&arena)
 371 // ResourceObj's can be allocated within other objects, but don't use
 372 // new or delete (allocation_type is unknown).  If new is used to allocate,
 373 // use delete to deallocate.
 374 class ResourceObj ALLOCATION_SUPER_CLASS_SPEC {
 375  public:
 376   enum allocation_type { STACK_OR_EMBEDDED = 0, RESOURCE_AREA, C_HEAP, ARENA, allocation_mask = 0x3 };
 377   static void set_allocation_type(address res, allocation_type type) NOT_DEBUG_RETURN;
 378 #ifdef ASSERT
 379  private:
 380   // When this object is allocated on stack the new() operator is not
 381   // called but garbage on stack may look like a valid allocation_type.
 382   // Store negated 'this' pointer when new() is called to distinguish cases.
 383   // Use second array's element for verification value to distinguish garbage.
 384   uintptr_t _allocation_t[2];
 385   bool is_type_set() const;
 386   void initialize_allocation_info();
 387  public:
 388   allocation_type get_allocation_type() const;
 389   bool allocated_on_stack()    const { return get_allocation_type() == STACK_OR_EMBEDDED; }
 390   bool allocated_on_res_area() const { return get_allocation_type() == RESOURCE_AREA; }
 391   bool allocated_on_C_heap()   const { return get_allocation_type() == C_HEAP; }
 392   bool allocated_on_arena()    const { return get_allocation_type() == ARENA; }
 393 protected:
 394   ResourceObj(); // default constructor
 395   ResourceObj(const ResourceObj& r); // default copy constructor
 396   ResourceObj& operator=(const ResourceObj& r); // default copy assignment
 397   ~ResourceObj();
 398 #endif // ASSERT
 399 
 400  public:
 401   void* operator new(size_t size, allocation_type type, MEMFLAGS flags) throw();
 402   void* operator new [](size_t size, allocation_type type, MEMFLAGS flags) throw();
 403   void* operator new(size_t size, const std::nothrow_t&  nothrow_constant,
 404       allocation_type type, MEMFLAGS flags) throw();
 405   void* operator new [](size_t size, const std::nothrow_t&  nothrow_constant,
 406       allocation_type type, MEMFLAGS flags) throw();
 407 
 408   void* operator new(size_t size, Arena *arena) throw();
 409 
 410   void* operator new [](size_t size, Arena *arena) throw();
 411 
 412   void* operator new(size_t size) throw() {
 413       address res = (address)resource_allocate_bytes(size);
 414       DEBUG_ONLY(set_allocation_type(res, RESOURCE_AREA);)
 415       return res;
 416   }
 417 
 418   void* operator new(size_t size, const std::nothrow_t& nothrow_constant) throw() {
 419       address res = (address)resource_allocate_bytes(size, AllocFailStrategy::RETURN_NULL);
 420       DEBUG_ONLY(if (res != NULL) set_allocation_type(res, RESOURCE_AREA);)
 421       return res;
 422   }
 423 
 424   void* operator new [](size_t size) throw() {
 425       address res = (address)resource_allocate_bytes(size);
 426       DEBUG_ONLY(set_allocation_type(res, RESOURCE_AREA);)
 427       return res;
 428   }
 429 
 430   void* operator new [](size_t size, const std::nothrow_t& nothrow_constant) throw() {
 431       address res = (address)resource_allocate_bytes(size, AllocFailStrategy::RETURN_NULL);
 432       DEBUG_ONLY(if (res != NULL) set_allocation_type(res, RESOURCE_AREA);)
 433       return res;
 434   }
 435 
 436   void  operator delete(void* p);
 437   void  operator delete [](void* p);
 438 };
 439 
 440 // One of the following macros must be used when allocating an array
 441 // or object to determine whether it should reside in the C heap on in
 442 // the resource area.
 443 
 444 #define NEW_RESOURCE_ARRAY(type, size)\
 445   (type*) resource_allocate_bytes((size) * sizeof(type))
 446 
 447 #define NEW_RESOURCE_ARRAY_RETURN_NULL(type, size)\
 448   (type*) resource_allocate_bytes((size) * sizeof(type), AllocFailStrategy::RETURN_NULL)
 449 
 450 #define NEW_RESOURCE_ARRAY_IN_THREAD(thread, type, size)\
 451   (type*) resource_allocate_bytes(thread, (size) * sizeof(type))
 452 
 453 #define NEW_RESOURCE_ARRAY_IN_THREAD_RETURN_NULL(thread, type, size)\
 454   (type*) resource_allocate_bytes(thread, (size) * sizeof(type), AllocFailStrategy::RETURN_NULL)
 455 
 456 #define REALLOC_RESOURCE_ARRAY(type, old, old_size, new_size)\
 457   (type*) resource_reallocate_bytes((char*)(old), (old_size) * sizeof(type), (new_size) * sizeof(type))
 458 
 459 #define REALLOC_RESOURCE_ARRAY_RETURN_NULL(type, old, old_size, new_size)\
 460   (type*) resource_reallocate_bytes((char*)(old), (old_size) * sizeof(type),\
 461                                     (new_size) * sizeof(type), AllocFailStrategy::RETURN_NULL)
 462 
 463 #define FREE_RESOURCE_ARRAY(type, old, size)\
 464   resource_free_bytes((char*)(old), (size) * sizeof(type))
 465 
 466 #define FREE_FAST(old)\
 467     /* nop */
 468 
 469 #define NEW_RESOURCE_OBJ(type)\
 470   NEW_RESOURCE_ARRAY(type, 1)
 471 
 472 #define NEW_RESOURCE_OBJ_RETURN_NULL(type)\
 473   NEW_RESOURCE_ARRAY_RETURN_NULL(type, 1)
 474 
 475 #define NEW_C_HEAP_ARRAY3(type, size, memflags, pc, allocfail)\
 476   (type*) AllocateHeap((size) * sizeof(type), memflags, pc, allocfail)
 477 
 478 #define NEW_C_HEAP_ARRAY2(type, size, memflags, pc)\
 479   (type*) (AllocateHeap((size) * sizeof(type), memflags, pc))
 480 
 481 #define NEW_C_HEAP_ARRAY(type, size, memflags)\
 482   (type*) (AllocateHeap((size) * sizeof(type), memflags))
 483 
 484 #define NEW_C_HEAP_ARRAY2_RETURN_NULL(type, size, memflags, pc)\
 485   NEW_C_HEAP_ARRAY3(type, (size), memflags, pc, AllocFailStrategy::RETURN_NULL)
 486 
 487 #define NEW_C_HEAP_ARRAY_RETURN_NULL(type, size, memflags)\
 488   NEW_C_HEAP_ARRAY3(type, (size), memflags, CURRENT_PC, AllocFailStrategy::RETURN_NULL)
 489 
 490 #define REALLOC_C_HEAP_ARRAY(type, old, size, memflags)\
 491   (type*) (ReallocateHeap((char*)(old), (size) * sizeof(type), memflags))
 492 
 493 #define REALLOC_C_HEAP_ARRAY_RETURN_NULL(type, old, size, memflags)\
 494   (type*) (ReallocateHeap((char*)(old), (size) * sizeof(type), memflags, AllocFailStrategy::RETURN_NULL))
 495 
 496 #define FREE_C_HEAP_ARRAY(type, old) \
 497   FreeHeap((char*)(old))
 498 
 499 // allocate type in heap without calling ctor
 500 #define NEW_C_HEAP_OBJ(type, memflags)\
 501   NEW_C_HEAP_ARRAY(type, 1, memflags)
 502 
 503 #define NEW_C_HEAP_OBJ_RETURN_NULL(type, memflags)\
 504   NEW_C_HEAP_ARRAY_RETURN_NULL(type, 1, memflags)
 505 
 506 // deallocate obj of type in heap without calling dtor
 507 #define FREE_C_HEAP_OBJ(objname)\
 508   FreeHeap((char*)objname);
 509 
 510 // for statistics
 511 #ifndef PRODUCT
 512 class AllocStats : StackObj {
 513   julong start_mallocs, start_frees;
 514   julong start_malloc_bytes, start_mfree_bytes, start_res_bytes;
 515  public:
 516   AllocStats();
 517 
 518   julong num_mallocs();    // since creation of receiver
 519   julong alloc_bytes();
 520   julong num_frees();
 521   julong free_bytes();
 522   julong resource_bytes();
 523   void   print();
 524 };
 525 #endif
 526 
 527 
 528 //------------------------------ReallocMark---------------------------------
 529 // Code which uses REALLOC_RESOURCE_ARRAY should check an associated
 530 // ReallocMark, which is declared in the same scope as the reallocated
 531 // pointer.  Any operation that could __potentially__ cause a reallocation
 532 // should check the ReallocMark.
 533 class ReallocMark: public StackObj {
 534 protected:
 535   NOT_PRODUCT(int _nesting;)
 536 
 537 public:
 538   ReallocMark()   PRODUCT_RETURN;
 539   void check()    PRODUCT_RETURN;
 540 };
 541 
 542 // Helper class to allocate arrays that may become large.
 543 // Uses the OS malloc for allocations smaller than ArrayAllocatorMallocLimit
 544 // and uses mapped memory for larger allocations.
 545 // Most OS mallocs do something similar but Solaris malloc does not revert
 546 // to mapped memory for large allocations. By default ArrayAllocatorMallocLimit
 547 // is set so that we always use malloc except for Solaris where we set the
 548 // limit to get mapped memory.
 549 template <class E>
 550 class ArrayAllocator : public AllStatic {
 551  private:
 552   static bool should_use_malloc(size_t length);
 553 
 554   static E* allocate_malloc(size_t length, MEMFLAGS flags);
 555   static E* allocate_mmap(size_t length, MEMFLAGS flags);
 556 
 557   static void free_malloc(E* addr, size_t length);
 558   static void free_mmap(E* addr, size_t length);
 559 
 560  public:
 561   static E* allocate(size_t length, MEMFLAGS flags);
 562   static E* reallocate(E* old_addr, size_t old_length, size_t new_length, MEMFLAGS flags);
 563   static void free(E* addr, size_t length);
 564 };
 565 
 566 // Uses mmaped memory for all allocations. All allocations are initially
 567 // zero-filled. No pre-touching.
 568 template <class E>
 569 class MmapArrayAllocator : public AllStatic {
 570  private:
 571   static size_t size_for(size_t length);
 572 
 573  public:
 574   static E* allocate_or_null(size_t length, MEMFLAGS flags);
 575   static E* allocate(size_t length, MEMFLAGS flags);
 576   static void free(E* addr, size_t length);
 577 };
 578 
 579 // Uses malloc:ed memory for all allocations.
 580 template <class E>
 581 class MallocArrayAllocator : public AllStatic {
 582  public:
 583   static size_t size_for(size_t length);
 584 
 585   static E* allocate(size_t length, MEMFLAGS flags);
 586   static void free(E* addr);
 587 };
 588 
 589 #endif // SHARE_MEMORY_ALLOCATION_HPP