1 /* 2 * Copyright (c) 1997, 2022, 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 "memory/allStatic.hpp" 29 #include "utilities/globalDefinitions.hpp" 30 #include "utilities/macros.hpp" 31 32 #include <new> 33 34 class outputStream; 35 class Thread; 36 class JavaThread; 37 38 class AllocFailStrategy { 39 public: 40 enum AllocFailEnum { EXIT_OOM, RETURN_NULL }; 41 }; 42 typedef AllocFailStrategy::AllocFailEnum AllocFailType; 43 44 // The virtual machine must never call one of the implicitly declared 45 // global allocation or deletion functions. (Such calls may result in 46 // link-time or run-time errors.) For convenience and documentation of 47 // intended use, classes in the virtual machine may be derived from one 48 // of the following allocation classes, some of which define allocation 49 // and deletion functions. 50 // Note: std::malloc and std::free should never called directly. 51 52 // 53 // For objects allocated in the resource area (see resourceArea.hpp). 54 // - ResourceObj 55 // 56 // For objects allocated in the C-heap (managed by: free & malloc and tracked with NMT) 57 // - CHeapObj 58 // 59 // For objects allocated on the stack. 60 // - StackObj 61 // 62 // For classes used as name spaces. 63 // - AllStatic 64 // 65 // For classes in Metaspace (class data) 66 // - MetaspaceObj 67 // 68 // The printable subclasses are used for debugging and define virtual 69 // member functions for printing. Classes that avoid allocating the 70 // vtbl entries in the objects should therefore not be the printable 71 // subclasses. 72 // 73 // The following macros and function should be used to allocate memory 74 // directly in the resource area or in the C-heap, The _OBJ variants 75 // of the NEW/FREE_C_HEAP macros are used for alloc/dealloc simple 76 // objects which are not inherited from CHeapObj, note constructor and 77 // destructor are not called. The preferable way to allocate objects 78 // is using the new operator. 79 // 80 // WARNING: The array variant must only be used for a homogenous array 81 // where all objects are of the exact type specified. If subtypes are 82 // stored in the array then must pay attention to calling destructors 83 // at needed. 84 // 85 // NEW_RESOURCE_ARRAY* 86 // REALLOC_RESOURCE_ARRAY* 87 // FREE_RESOURCE_ARRAY* 88 // NEW_RESOURCE_OBJ* 89 // NEW_C_HEAP_ARRAY* 90 // REALLOC_C_HEAP_ARRAY* 91 // FREE_C_HEAP_ARRAY* 92 // NEW_C_HEAP_OBJ* 93 // FREE_C_HEAP_OBJ 94 // 95 // char* AllocateHeap(size_t size, MEMFLAGS flags, const NativeCallStack& stack, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM); 96 // char* AllocateHeap(size_t size, MEMFLAGS flags, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM); 97 // char* ReallocateHeap(char *old, size_t size, MEMFLAGS flag, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM); 98 // void FreeHeap(void* p); 99 // 100 // In non product mode we introduce a super class for all allocation classes 101 // that supports printing. 102 // We avoid the superclass in product mode to save space. 103 104 #ifdef PRODUCT 105 #define ALLOCATION_SUPER_CLASS_SPEC 106 #else 107 #define ALLOCATION_SUPER_CLASS_SPEC : public AllocatedObj 108 class AllocatedObj { 109 public: 110 // Printing support 111 void print() const; 112 void print_value() const; 113 114 virtual void print_on(outputStream* st) const; 115 virtual void print_value_on(outputStream* st) const; 116 }; 117 #endif 118 119 #define MEMORY_TYPES_DO(f) \ 120 /* Memory type by sub systems. It occupies lower byte. */ \ 121 f(mtJavaHeap, "Java Heap") /* Java heap */ \ 122 f(mtClass, "Class") /* Java classes */ \ 123 f(mtThread, "Thread") /* thread objects */ \ 124 f(mtThreadStack, "Thread Stack") \ 125 f(mtCode, "Code") /* generated code */ \ 126 f(mtGC, "GC") \ 127 f(mtGCCardSet, "GCCardSet") /* G1 card set remembered set */ \ 128 f(mtCompiler, "Compiler") \ 129 f(mtJVMCI, "JVMCI") \ 130 f(mtInternal, "Internal") /* memory used by VM, but does not belong to */ \ 131 /* any of above categories, and not used by */ \ 132 /* NMT */ \ 133 f(mtOther, "Other") /* memory not used by VM */ \ 134 f(mtSymbol, "Symbol") \ 135 f(mtNMT, "Native Memory Tracking") /* memory used by NMT */ \ 136 f(mtClassShared, "Shared class space") /* class data sharing */ \ 137 f(mtChunk, "Arena Chunk") /* chunk that holds content of arenas */ \ 138 f(mtTest, "Test") /* Test type for verifying NMT */ \ 139 f(mtTracing, "Tracing") \ 140 f(mtLogging, "Logging") \ 141 f(mtStatistics, "Statistics") \ 142 f(mtArguments, "Arguments") \ 143 f(mtModule, "Module") \ 144 f(mtSafepoint, "Safepoint") \ 145 f(mtSynchronizer, "Synchronization") \ 146 f(mtServiceability, "Serviceability") \ 147 f(mtMetaspace, "Metaspace") \ 148 f(mtStringDedup, "String Deduplication") \ 149 f(mtObjectMonitor, "Object Monitors") \ 150 f(mtNone, "Unknown") \ 151 //end 152 153 #define MEMORY_TYPE_DECLARE_ENUM(type, human_readable) \ 154 type, 155 156 /* 157 * Memory types 158 */ 159 enum class MEMFLAGS { 160 MEMORY_TYPES_DO(MEMORY_TYPE_DECLARE_ENUM) 161 mtValueTypes, // memory for buffered value types 162 mt_number_of_types // number of memory types (mtDontTrack 163 // is not included as validate type) 164 }; 165 166 #define MEMORY_TYPE_SHORTNAME(type, human_readable) \ 167 constexpr MEMFLAGS type = MEMFLAGS::type; 168 169 // Generate short aliases for the enum values. E.g. mtGC instead of MEMFLAGS::mtGC. 170 MEMORY_TYPES_DO(MEMORY_TYPE_SHORTNAME) 171 172 // Make an int version of the sentinel end value. 173 constexpr int mt_number_of_types = static_cast<int>(MEMFLAGS::mt_number_of_types); 174 175 extern bool NMT_track_callsite; 176 177 class NativeCallStack; 178 179 180 char* AllocateHeap(size_t size, 181 MEMFLAGS flags, 182 const NativeCallStack& stack, 183 AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM); 184 char* AllocateHeap(size_t size, 185 MEMFLAGS flags, 186 AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM); 187 188 char* ReallocateHeap(char *old, 189 size_t size, 190 MEMFLAGS flag, 191 AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM); 192 193 // handles NULL pointers 194 void FreeHeap(void* p); 195 196 template <MEMFLAGS F> class CHeapObj ALLOCATION_SUPER_CLASS_SPEC { 197 public: 198 ALWAYSINLINE void* operator new(size_t size) throw() { 199 return (void*)AllocateHeap(size, F); 200 } 201 202 ALWAYSINLINE void* operator new(size_t size, 203 const NativeCallStack& stack) throw() { 204 return (void*)AllocateHeap(size, F, stack); 205 } 206 207 ALWAYSINLINE void* operator new(size_t size, const std::nothrow_t&, 208 const NativeCallStack& stack) throw() { 209 return (void*)AllocateHeap(size, F, stack, AllocFailStrategy::RETURN_NULL); 210 } 211 212 ALWAYSINLINE void* operator new(size_t size, const std::nothrow_t&) throw() { 213 return (void*)AllocateHeap(size, F, AllocFailStrategy::RETURN_NULL); 214 } 215 216 ALWAYSINLINE void* operator new[](size_t size) throw() { 217 return (void*)AllocateHeap(size, F); 218 } 219 220 ALWAYSINLINE void* operator new[](size_t size, 221 const NativeCallStack& stack) throw() { 222 return (void*)AllocateHeap(size, F, stack); 223 } 224 225 ALWAYSINLINE void* operator new[](size_t size, const std::nothrow_t&, 226 const NativeCallStack& stack) throw() { 227 return (void*)AllocateHeap(size, F, stack, AllocFailStrategy::RETURN_NULL); 228 } 229 230 ALWAYSINLINE void* operator new[](size_t size, const std::nothrow_t&) throw() { 231 return (void*)AllocateHeap(size, F, AllocFailStrategy::RETURN_NULL); 232 } 233 234 void operator delete(void* p) { FreeHeap(p); } 235 void operator delete [] (void* p) { FreeHeap(p); } 236 }; 237 238 // Base class for objects allocated on the stack only. 239 // Calling new or delete will result in fatal error. 240 241 class StackObj ALLOCATION_SUPER_CLASS_SPEC { 242 private: 243 void* operator new(size_t size) throw(); 244 void* operator new [](size_t size) throw(); 245 void operator delete(void* p); 246 void operator delete [](void* p); 247 }; 248 249 // Base class for objects stored in Metaspace. 250 // Calling delete will result in fatal error. 251 // 252 // Do not inherit from something with a vptr because this class does 253 // not introduce one. This class is used to allocate both shared read-only 254 // and shared read-write classes. 255 // 256 257 class ClassLoaderData; 258 class MetaspaceClosure; 259 260 class MetaspaceObj { 261 // There are functions that all subtypes of MetaspaceObj are expected 262 // to implement, so that templates which are defined for this class hierarchy 263 // can work uniformly. Within the sub-hierarchy of Metadata, these are virtuals. 264 // Elsewhere in the hierarchy of MetaspaceObj, type(), size(), and/or on_stack() 265 // can be static if constant. 266 // 267 // The following functions are required by MetaspaceClosure: 268 // void metaspace_pointers_do(MetaspaceClosure* it) { <walk my refs> } 269 // int size() const { return align_up(sizeof(<This>), wordSize) / wordSize; } 270 // MetaspaceObj::Type type() const { return <This>Type; } 271 // 272 // The following functions are required by MetadataFactory::free_metadata(): 273 // bool on_stack() { return false; } 274 // void deallocate_contents(ClassLoaderData* loader_data); 275 276 friend class VMStructs; 277 // When CDS is enabled, all shared metaspace objects are mapped 278 // into a single contiguous memory block, so we can use these 279 // two pointers to quickly determine if something is in the 280 // shared metaspace. 281 // When CDS is not enabled, both pointers are set to NULL. 282 static void* _shared_metaspace_base; // (inclusive) low address 283 static void* _shared_metaspace_top; // (exclusive) high address 284 285 public: 286 287 // Returns true if the pointer points to a valid MetaspaceObj. A valid 288 // MetaspaceObj is MetaWord-aligned and contained within either 289 // non-shared or shared metaspace. 290 static bool is_valid(const MetaspaceObj* p); 291 292 static bool is_shared(const MetaspaceObj* p) { 293 // If no shared metaspace regions are mapped, _shared_metaspace_{base,top} will 294 // both be NULL and all values of p will be rejected quickly. 295 return (((void*)p) < _shared_metaspace_top && 296 ((void*)p) >= _shared_metaspace_base); 297 } 298 bool is_shared() const { return MetaspaceObj::is_shared(this); } 299 300 void print_address_on(outputStream* st) const; // nonvirtual address printing 301 302 static void set_shared_metaspace_range(void* base, void* top) { 303 _shared_metaspace_base = base; 304 _shared_metaspace_top = top; 305 } 306 307 static void* shared_metaspace_base() { return _shared_metaspace_base; } 308 static void* shared_metaspace_top() { return _shared_metaspace_top; } 309 310 #define METASPACE_OBJ_TYPES_DO(f) \ 311 f(Class) \ 312 f(Symbol) \ 313 f(TypeArrayU1) \ 314 f(TypeArrayU2) \ 315 f(TypeArrayU4) \ 316 f(TypeArrayU8) \ 317 f(TypeArrayOther) \ 318 f(Method) \ 319 f(ConstMethod) \ 320 f(MethodData) \ 321 f(ConstantPool) \ 322 f(ConstantPoolCache) \ 323 f(Annotations) \ 324 f(MethodCounters) \ 325 f(RecordComponent) 326 327 #define METASPACE_OBJ_TYPE_DECLARE(name) name ## Type, 328 #define METASPACE_OBJ_TYPE_NAME_CASE(name) case name ## Type: return #name; 329 330 enum Type { 331 // Types are MetaspaceObj::ClassType, MetaspaceObj::SymbolType, etc 332 METASPACE_OBJ_TYPES_DO(METASPACE_OBJ_TYPE_DECLARE) 333 _number_of_types 334 }; 335 336 static const char * type_name(Type type) { 337 switch(type) { 338 METASPACE_OBJ_TYPES_DO(METASPACE_OBJ_TYPE_NAME_CASE) 339 default: 340 ShouldNotReachHere(); 341 return NULL; 342 } 343 } 344 345 static MetaspaceObj::Type array_type(size_t elem_size) { 346 switch (elem_size) { 347 case 1: return TypeArrayU1Type; 348 case 2: return TypeArrayU2Type; 349 case 4: return TypeArrayU4Type; 350 case 8: return TypeArrayU8Type; 351 default: 352 return TypeArrayOtherType; 353 } 354 } 355 356 void* operator new(size_t size, ClassLoaderData* loader_data, 357 size_t word_size, 358 Type type, JavaThread* thread) throw(); 359 // can't use TRAPS from this header file. 360 void* operator new(size_t size, ClassLoaderData* loader_data, 361 size_t word_size, 362 Type type) throw(); 363 void operator delete(void* p) { ShouldNotCallThis(); } 364 365 // Declare a *static* method with the same signature in any subclass of MetaspaceObj 366 // that should be read-only by default. See symbol.hpp for an example. This function 367 // is used by the templates in metaspaceClosure.hpp 368 static bool is_read_only_by_default() { return false; } 369 }; 370 371 // Base class for classes that constitute name spaces. 372 373 class Arena; 374 375 extern char* resource_allocate_bytes(size_t size, 376 AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM); 377 extern char* resource_allocate_bytes(Thread* thread, size_t size, 378 AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM); 379 extern char* resource_reallocate_bytes( char *old, size_t old_size, size_t new_size, 380 AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM); 381 extern void resource_free_bytes( char *old, size_t size ); 382 383 //---------------------------------------------------------------------- 384 // Base class for objects allocated in the resource area per default. 385 // Optionally, objects may be allocated on the C heap with 386 // new(ResourceObj::C_HEAP) Foo(...) or in an Arena with new (&arena) 387 // ResourceObj's can be allocated within other objects, but don't use 388 // new or delete (allocation_type is unknown). If new is used to allocate, 389 // use delete to deallocate. 390 class ResourceObj ALLOCATION_SUPER_CLASS_SPEC { 391 public: 392 enum allocation_type { STACK_OR_EMBEDDED = 0, RESOURCE_AREA, C_HEAP, ARENA, allocation_mask = 0x3 }; 393 static void set_allocation_type(address res, allocation_type type) NOT_DEBUG_RETURN; 394 #ifdef ASSERT 395 private: 396 // When this object is allocated on stack the new() operator is not 397 // called but garbage on stack may look like a valid allocation_type. 398 // Store negated 'this' pointer when new() is called to distinguish cases. 399 // Use second array's element for verification value to distinguish garbage. 400 uintptr_t _allocation_t[2]; 401 bool is_type_set() const; 402 void initialize_allocation_info(); 403 public: 404 allocation_type get_allocation_type() const; 405 bool allocated_on_stack_or_embedded() const { return get_allocation_type() == STACK_OR_EMBEDDED; } 406 bool allocated_on_res_area() const { return get_allocation_type() == RESOURCE_AREA; } 407 bool allocated_on_C_heap() const { return get_allocation_type() == C_HEAP; } 408 bool allocated_on_arena() const { return get_allocation_type() == ARENA; } 409 protected: 410 ResourceObj(); // default constructor 411 ResourceObj(const ResourceObj& r); // default copy constructor 412 ResourceObj& operator=(const ResourceObj& r); // default copy assignment 413 ~ResourceObj(); 414 #endif // ASSERT 415 416 public: 417 void* operator new(size_t size, allocation_type type, MEMFLAGS flags) throw(); 418 void* operator new [](size_t size, allocation_type type, MEMFLAGS flags) throw() = delete; 419 void* operator new(size_t size, const std::nothrow_t& nothrow_constant, 420 allocation_type type, MEMFLAGS flags) throw(); 421 void* operator new [](size_t size, const std::nothrow_t& nothrow_constant, 422 allocation_type type, MEMFLAGS flags) throw() = delete; 423 void* operator new(size_t size, Arena *arena) throw(); 424 void* operator new [](size_t size, Arena *arena) throw() = delete; 425 426 void* operator new(size_t size) throw() { 427 address res = (address)resource_allocate_bytes(size); 428 DEBUG_ONLY(set_allocation_type(res, RESOURCE_AREA);) 429 return res; 430 } 431 432 void* operator new(size_t size, const std::nothrow_t& nothrow_constant) throw() { 433 address res = (address)resource_allocate_bytes(size, AllocFailStrategy::RETURN_NULL); 434 DEBUG_ONLY(if (res != NULL) set_allocation_type(res, RESOURCE_AREA);) 435 return res; 436 } 437 438 void* operator new [](size_t size) throw() = delete; 439 void* operator new [](size_t size, const std::nothrow_t& nothrow_constant) throw() = delete; 440 void operator delete(void* p); 441 void operator delete [](void* p) = delete; 442 }; 443 444 // One of the following macros must be used when allocating an array 445 // or object to determine whether it should reside in the C heap on in 446 // the resource area. 447 448 #define NEW_RESOURCE_ARRAY(type, size)\ 449 (type*) resource_allocate_bytes((size) * sizeof(type)) 450 451 #define NEW_RESOURCE_ARRAY_RETURN_NULL(type, size)\ 452 (type*) resource_allocate_bytes((size) * sizeof(type), AllocFailStrategy::RETURN_NULL) 453 454 #define NEW_RESOURCE_ARRAY_IN_THREAD(thread, type, size)\ 455 (type*) resource_allocate_bytes(thread, (size) * sizeof(type)) 456 457 #define NEW_RESOURCE_ARRAY_IN_THREAD_RETURN_NULL(thread, type, size)\ 458 (type*) resource_allocate_bytes(thread, (size) * sizeof(type), AllocFailStrategy::RETURN_NULL) 459 460 #define REALLOC_RESOURCE_ARRAY(type, old, old_size, new_size)\ 461 (type*) resource_reallocate_bytes((char*)(old), (old_size) * sizeof(type), (new_size) * sizeof(type)) 462 463 #define REALLOC_RESOURCE_ARRAY_RETURN_NULL(type, old, old_size, new_size)\ 464 (type*) resource_reallocate_bytes((char*)(old), (old_size) * sizeof(type),\ 465 (new_size) * sizeof(type), AllocFailStrategy::RETURN_NULL) 466 467 #define FREE_RESOURCE_ARRAY(type, old, size)\ 468 resource_free_bytes((char*)(old), (size) * sizeof(type)) 469 470 #define FREE_FAST(old)\ 471 /* nop */ 472 473 #define NEW_RESOURCE_OBJ(type)\ 474 NEW_RESOURCE_ARRAY(type, 1) 475 476 #define NEW_RESOURCE_OBJ_RETURN_NULL(type)\ 477 NEW_RESOURCE_ARRAY_RETURN_NULL(type, 1) 478 479 #define NEW_C_HEAP_ARRAY3(type, size, memflags, pc, allocfail)\ 480 (type*) AllocateHeap((size) * sizeof(type), memflags, pc, allocfail) 481 482 #define NEW_C_HEAP_ARRAY2(type, size, memflags, pc)\ 483 (type*) (AllocateHeap((size) * sizeof(type), memflags, pc)) 484 485 #define NEW_C_HEAP_ARRAY(type, size, memflags)\ 486 (type*) (AllocateHeap((size) * sizeof(type), memflags)) 487 488 #define NEW_C_HEAP_ARRAY2_RETURN_NULL(type, size, memflags, pc)\ 489 NEW_C_HEAP_ARRAY3(type, (size), memflags, pc, AllocFailStrategy::RETURN_NULL) 490 491 #define NEW_C_HEAP_ARRAY_RETURN_NULL(type, size, memflags)\ 492 NEW_C_HEAP_ARRAY2(type, (size), memflags, AllocFailStrategy::RETURN_NULL) 493 494 #define REALLOC_C_HEAP_ARRAY(type, old, size, memflags)\ 495 (type*) (ReallocateHeap((char*)(old), (size) * sizeof(type), memflags)) 496 497 #define REALLOC_C_HEAP_ARRAY_RETURN_NULL(type, old, size, memflags)\ 498 (type*) (ReallocateHeap((char*)(old), (size) * sizeof(type), memflags, AllocFailStrategy::RETURN_NULL)) 499 500 #define FREE_C_HEAP_ARRAY(type, old) \ 501 FreeHeap((char*)(old)) 502 503 // allocate type in heap without calling ctor 504 #define NEW_C_HEAP_OBJ(type, memflags)\ 505 NEW_C_HEAP_ARRAY(type, 1, memflags) 506 507 #define NEW_C_HEAP_OBJ_RETURN_NULL(type, memflags)\ 508 NEW_C_HEAP_ARRAY_RETURN_NULL(type, 1, memflags) 509 510 // deallocate obj of type in heap without calling dtor 511 #define FREE_C_HEAP_OBJ(objname)\ 512 FreeHeap((char*)objname); 513 514 515 //------------------------------ReallocMark--------------------------------- 516 // Code which uses REALLOC_RESOURCE_ARRAY should check an associated 517 // ReallocMark, which is declared in the same scope as the reallocated 518 // pointer. Any operation that could __potentially__ cause a reallocation 519 // should check the ReallocMark. 520 class ReallocMark: public StackObj { 521 protected: 522 NOT_PRODUCT(int _nesting;) 523 524 public: 525 ReallocMark() PRODUCT_RETURN; 526 void check() PRODUCT_RETURN; 527 }; 528 529 // Helper class to allocate arrays that may become large. 530 // Uses the OS malloc for allocations smaller than ArrayAllocatorMallocLimit 531 // and uses mapped memory for larger allocations. 532 // Most OS mallocs do something similar but Solaris malloc does not revert 533 // to mapped memory for large allocations. By default ArrayAllocatorMallocLimit 534 // is set so that we always use malloc except for Solaris where we set the 535 // limit to get mapped memory. 536 template <class E> 537 class ArrayAllocator : public AllStatic { 538 private: 539 static bool should_use_malloc(size_t length); 540 541 static E* allocate_malloc(size_t length, MEMFLAGS flags); 542 static E* allocate_mmap(size_t length, MEMFLAGS flags); 543 544 static void free_malloc(E* addr, size_t length); 545 static void free_mmap(E* addr, size_t length); 546 547 public: 548 static E* allocate(size_t length, MEMFLAGS flags); 549 static E* reallocate(E* old_addr, size_t old_length, size_t new_length, MEMFLAGS flags); 550 static void free(E* addr, size_t length); 551 }; 552 553 // Uses mmaped memory for all allocations. All allocations are initially 554 // zero-filled. No pre-touching. 555 template <class E> 556 class MmapArrayAllocator : public AllStatic { 557 private: 558 static size_t size_for(size_t length); 559 560 public: 561 static E* allocate_or_null(size_t length, MEMFLAGS flags); 562 static E* allocate(size_t length, MEMFLAGS flags); 563 static void free(E* addr, size_t length); 564 }; 565 566 // Uses malloc:ed memory for all allocations. 567 template <class E> 568 class MallocArrayAllocator : public AllStatic { 569 public: 570 static size_t size_for(size_t length); 571 572 static E* allocate(size_t length, MEMFLAGS flags); 573 static void free(E* addr); 574 }; 575 576 #endif // SHARE_MEMORY_ALLOCATION_HPP