1 /*
  2  * Copyright (c) 1997, 2021, 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(mtNone,           "Unknown")                                                     \
150   //end
151 
152 #define MEMORY_TYPE_DECLARE_ENUM(type, human_readable) \
153   type,
154 
155 /*
156  * Memory types
157  */
158 enum class MEMFLAGS {
159   MEMORY_TYPES_DO(MEMORY_TYPE_DECLARE_ENUM)
160   mtValueTypes,        // memory for buffered value types
161   mt_number_of_types   // number of memory types (mtDontTrack
162                        // is not included as validate type)
163 };
164 
165 #define MEMORY_TYPE_SHORTNAME(type, human_readable) \
166   constexpr MEMFLAGS type = MEMFLAGS::type;
167 
168 // Generate short aliases for the enum values. E.g. mtGC instead of MEMFLAGS::mtGC.
169 MEMORY_TYPES_DO(MEMORY_TYPE_SHORTNAME)
170 
171 // Make an int version of the sentinel end value.
172 constexpr int mt_number_of_types = static_cast<int>(MEMFLAGS::mt_number_of_types);
173 
174 #if INCLUDE_NMT
175 
176 extern bool NMT_track_callsite;
177 
178 #else
179 
180 const bool NMT_track_callsite = false;
181 
182 #endif // INCLUDE_NMT
183 
184 class NativeCallStack;
185 
186 
187 char* AllocateHeap(size_t size,
188                    MEMFLAGS flags,
189                    const NativeCallStack& stack,
190                    AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
191 char* AllocateHeap(size_t size,
192                    MEMFLAGS flags,
193                    AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
194 
195 char* ReallocateHeap(char *old,
196                      size_t size,
197                      MEMFLAGS flag,
198                      AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
199 
200 // handles NULL pointers
201 void FreeHeap(void* p);
202 
203 template <MEMFLAGS F> class CHeapObj ALLOCATION_SUPER_CLASS_SPEC {
204  public:
205   ALWAYSINLINE void* operator new(size_t size) throw() {
206     return (void*)AllocateHeap(size, F);
207   }
208 
209   ALWAYSINLINE void* operator new(size_t size,
210                                   const NativeCallStack& stack) throw() {
211     return (void*)AllocateHeap(size, F, stack);
212   }
213 
214   ALWAYSINLINE void* operator new(size_t size, const std::nothrow_t&,
215                                   const NativeCallStack& stack) throw() {
216     return (void*)AllocateHeap(size, F, stack, AllocFailStrategy::RETURN_NULL);
217   }
218 
219   ALWAYSINLINE void* operator new(size_t size, const std::nothrow_t&) throw() {
220     return (void*)AllocateHeap(size, F, AllocFailStrategy::RETURN_NULL);
221   }
222 
223   ALWAYSINLINE void* operator new[](size_t size) throw() {
224     return (void*)AllocateHeap(size, F);
225   }
226 
227   ALWAYSINLINE void* operator new[](size_t size,
228                                   const NativeCallStack& stack) throw() {
229     return (void*)AllocateHeap(size, F, stack);
230   }
231 
232   ALWAYSINLINE void* operator new[](size_t size, const std::nothrow_t&,
233                                     const NativeCallStack& stack) throw() {
234     return (void*)AllocateHeap(size, F, stack, AllocFailStrategy::RETURN_NULL);
235   }
236 
237   ALWAYSINLINE void* operator new[](size_t size, const std::nothrow_t&) throw() {
238     return (void*)AllocateHeap(size, F, AllocFailStrategy::RETURN_NULL);
239   }
240 
241   void  operator delete(void* p)     { FreeHeap(p); }
242   void  operator delete [] (void* p) { FreeHeap(p); }
243 };
244 
245 // Base class for objects allocated on the stack only.
246 // Calling new or delete will result in fatal error.
247 
248 class StackObj ALLOCATION_SUPER_CLASS_SPEC {
249  private:
250   void* operator new(size_t size) throw();
251   void* operator new [](size_t size) throw();
252   void  operator delete(void* p);
253   void  operator delete [](void* p);
254 };
255 
256 // Base class for objects stored in Metaspace.
257 // Calling delete will result in fatal error.
258 //
259 // Do not inherit from something with a vptr because this class does
260 // not introduce one.  This class is used to allocate both shared read-only
261 // and shared read-write classes.
262 //
263 
264 class ClassLoaderData;
265 class MetaspaceClosure;
266 
267 class MetaspaceObj {
268   // There are functions that all subtypes of MetaspaceObj are expected
269   // to implement, so that templates which are defined for this class hierarchy
270   // can work uniformly. Within the sub-hierarchy of Metadata, these are virtuals.
271   // Elsewhere in the hierarchy of MetaspaceObj, type(), size(), and/or on_stack()
272   // can be static if constant.
273   //
274   // The following functions are required by MetaspaceClosure:
275   //   void metaspace_pointers_do(MetaspaceClosure* it) { <walk my refs> }
276   //   int size() const { return align_up(sizeof(<This>), wordSize) / wordSize; }
277   //   MetaspaceObj::Type type() const { return <This>Type; }
278   //
279   // The following functions are required by MetadataFactory::free_metadata():
280   //   bool on_stack() { return false; }
281   //   void deallocate_contents(ClassLoaderData* loader_data);
282 
283   friend class VMStructs;
284   // When CDS is enabled, all shared metaspace objects are mapped
285   // into a single contiguous memory block, so we can use these
286   // two pointers to quickly determine if something is in the
287   // shared metaspace.
288   // When CDS is not enabled, both pointers are set to NULL.
289   static void* _shared_metaspace_base;  // (inclusive) low address
290   static void* _shared_metaspace_top;   // (exclusive) high address
291 
292  public:
293 
294   // Returns true if the pointer points to a valid MetaspaceObj. A valid
295   // MetaspaceObj is MetaWord-aligned and contained within either
296   // non-shared or shared metaspace.
297   static bool is_valid(const MetaspaceObj* p);
298 
299   static bool is_shared(const MetaspaceObj* p) {
300     // If no shared metaspace regions are mapped, _shared_metaspace_{base,top} will
301     // both be NULL and all values of p will be rejected quickly.
302     return (((void*)p) < _shared_metaspace_top &&
303             ((void*)p) >= _shared_metaspace_base);
304   }
305   bool is_shared() const { return MetaspaceObj::is_shared(this); }
306 
307   void print_address_on(outputStream* st) const;  // nonvirtual address printing
308 
309   static void set_shared_metaspace_range(void* base, void* top) {
310     _shared_metaspace_base = base;
311     _shared_metaspace_top = top;
312   }
313 
314   static void* shared_metaspace_base() { return _shared_metaspace_base; }
315   static void* shared_metaspace_top()  { return _shared_metaspace_top;  }
316 
317 #define METASPACE_OBJ_TYPES_DO(f) \
318   f(Class) \
319   f(Symbol) \
320   f(TypeArrayU1) \
321   f(TypeArrayU2) \
322   f(TypeArrayU4) \
323   f(TypeArrayU8) \
324   f(TypeArrayOther) \
325   f(Method) \
326   f(ConstMethod) \
327   f(MethodData) \
328   f(ConstantPool) \
329   f(ConstantPoolCache) \
330   f(Annotations) \
331   f(MethodCounters) \
332   f(RecordComponent)
333 
334 #define METASPACE_OBJ_TYPE_DECLARE(name) name ## Type,
335 #define METASPACE_OBJ_TYPE_NAME_CASE(name) case name ## Type: return #name;
336 
337   enum Type {
338     // Types are MetaspaceObj::ClassType, MetaspaceObj::SymbolType, etc
339     METASPACE_OBJ_TYPES_DO(METASPACE_OBJ_TYPE_DECLARE)
340     _number_of_types
341   };
342 
343   static const char * type_name(Type type) {
344     switch(type) {
345     METASPACE_OBJ_TYPES_DO(METASPACE_OBJ_TYPE_NAME_CASE)
346     default:
347       ShouldNotReachHere();
348       return NULL;
349     }
350   }
351 
352   static MetaspaceObj::Type array_type(size_t elem_size) {
353     switch (elem_size) {
354     case 1: return TypeArrayU1Type;
355     case 2: return TypeArrayU2Type;
356     case 4: return TypeArrayU4Type;
357     case 8: return TypeArrayU8Type;
358     default:
359       return TypeArrayOtherType;
360     }
361   }
362 
363   void* operator new(size_t size, ClassLoaderData* loader_data,
364                      size_t word_size,
365                      Type type, JavaThread* thread) throw();
366                      // can't use TRAPS from this header file.
367   void* operator new(size_t size, ClassLoaderData* loader_data,
368                      size_t word_size,
369                      Type type) throw();
370   void operator delete(void* p) { ShouldNotCallThis(); }
371 
372   // Declare a *static* method with the same signature in any subclass of MetaspaceObj
373   // that should be read-only by default. See symbol.hpp for an example. This function
374   // is used by the templates in metaspaceClosure.hpp
375   static bool is_read_only_by_default() { return false; }
376 };
377 
378 // Base class for classes that constitute name spaces.
379 
380 class Arena;
381 
382 extern char* resource_allocate_bytes(size_t size,
383     AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
384 extern char* resource_allocate_bytes(Thread* thread, size_t size,
385     AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
386 extern char* resource_reallocate_bytes( char *old, size_t old_size, size_t new_size,
387     AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
388 extern void resource_free_bytes( char *old, size_t size );
389 
390 //----------------------------------------------------------------------
391 // Base class for objects allocated in the resource area per default.
392 // Optionally, objects may be allocated on the C heap with
393 // new(ResourceObj::C_HEAP) Foo(...) or in an Arena with new (&arena)
394 // ResourceObj's can be allocated within other objects, but don't use
395 // new or delete (allocation_type is unknown).  If new is used to allocate,
396 // use delete to deallocate.
397 class ResourceObj ALLOCATION_SUPER_CLASS_SPEC {
398  public:
399   enum allocation_type { STACK_OR_EMBEDDED = 0, RESOURCE_AREA, C_HEAP, ARENA, allocation_mask = 0x3 };
400   static void set_allocation_type(address res, allocation_type type) NOT_DEBUG_RETURN;
401 #ifdef ASSERT
402  private:
403   // When this object is allocated on stack the new() operator is not
404   // called but garbage on stack may look like a valid allocation_type.
405   // Store negated 'this' pointer when new() is called to distinguish cases.
406   // Use second array's element for verification value to distinguish garbage.
407   uintptr_t _allocation_t[2];
408   bool is_type_set() const;
409   void initialize_allocation_info();
410  public:
411   allocation_type get_allocation_type() const;
412   bool allocated_on_stack()    const { return get_allocation_type() == STACK_OR_EMBEDDED; }
413   bool allocated_on_res_area() const { return get_allocation_type() == RESOURCE_AREA; }
414   bool allocated_on_C_heap()   const { return get_allocation_type() == C_HEAP; }
415   bool allocated_on_arena()    const { return get_allocation_type() == ARENA; }
416 protected:
417   ResourceObj(); // default constructor
418   ResourceObj(const ResourceObj& r); // default copy constructor
419   ResourceObj& operator=(const ResourceObj& r); // default copy assignment
420   ~ResourceObj();
421 #endif // ASSERT
422 
423  public:
424   void* operator new(size_t size, allocation_type type, MEMFLAGS flags) throw();
425   void* operator new [](size_t size, allocation_type type, MEMFLAGS flags) throw() = delete;
426   void* operator new(size_t size, const std::nothrow_t&  nothrow_constant,
427       allocation_type type, MEMFLAGS flags) throw();
428   void* operator new [](size_t size, const std::nothrow_t&  nothrow_constant,
429       allocation_type type, MEMFLAGS flags) throw() = delete;
430   void* operator new(size_t size, Arena *arena) throw();
431   void* operator new [](size_t size, Arena *arena) throw() = delete;
432 
433   void* operator new(size_t size) throw() {
434       address res = (address)resource_allocate_bytes(size);
435       DEBUG_ONLY(set_allocation_type(res, RESOURCE_AREA);)
436       return res;
437   }
438 
439   void* operator new(size_t size, const std::nothrow_t& nothrow_constant) throw() {
440       address res = (address)resource_allocate_bytes(size, AllocFailStrategy::RETURN_NULL);
441       DEBUG_ONLY(if (res != NULL) set_allocation_type(res, RESOURCE_AREA);)
442       return res;
443   }
444 
445   void* operator new [](size_t size) throw() = delete;
446   void* operator new [](size_t size, const std::nothrow_t& nothrow_constant) throw() = delete;
447   void  operator delete(void* p);
448   void  operator delete [](void* p) = delete;
449 };
450 
451 // One of the following macros must be used when allocating an array
452 // or object to determine whether it should reside in the C heap on in
453 // the resource area.
454 
455 #define NEW_RESOURCE_ARRAY(type, size)\
456   (type*) resource_allocate_bytes((size) * sizeof(type))
457 
458 #define NEW_RESOURCE_ARRAY_RETURN_NULL(type, size)\
459   (type*) resource_allocate_bytes((size) * sizeof(type), AllocFailStrategy::RETURN_NULL)
460 
461 #define NEW_RESOURCE_ARRAY_IN_THREAD(thread, type, size)\
462   (type*) resource_allocate_bytes(thread, (size) * sizeof(type))
463 
464 #define NEW_RESOURCE_ARRAY_IN_THREAD_RETURN_NULL(thread, type, size)\
465   (type*) resource_allocate_bytes(thread, (size) * sizeof(type), AllocFailStrategy::RETURN_NULL)
466 
467 #define REALLOC_RESOURCE_ARRAY(type, old, old_size, new_size)\
468   (type*) resource_reallocate_bytes((char*)(old), (old_size) * sizeof(type), (new_size) * sizeof(type))
469 
470 #define REALLOC_RESOURCE_ARRAY_RETURN_NULL(type, old, old_size, new_size)\
471   (type*) resource_reallocate_bytes((char*)(old), (old_size) * sizeof(type),\
472                                     (new_size) * sizeof(type), AllocFailStrategy::RETURN_NULL)
473 
474 #define FREE_RESOURCE_ARRAY(type, old, size)\
475   resource_free_bytes((char*)(old), (size) * sizeof(type))
476 
477 #define FREE_FAST(old)\
478     /* nop */
479 
480 #define NEW_RESOURCE_OBJ(type)\
481   NEW_RESOURCE_ARRAY(type, 1)
482 
483 #define NEW_RESOURCE_OBJ_RETURN_NULL(type)\
484   NEW_RESOURCE_ARRAY_RETURN_NULL(type, 1)
485 
486 #define NEW_C_HEAP_ARRAY3(type, size, memflags, pc, allocfail)\
487   (type*) AllocateHeap((size) * sizeof(type), memflags, pc, allocfail)
488 
489 #define NEW_C_HEAP_ARRAY2(type, size, memflags, pc)\
490   (type*) (AllocateHeap((size) * sizeof(type), memflags, pc))
491 
492 #define NEW_C_HEAP_ARRAY(type, size, memflags)\
493   (type*) (AllocateHeap((size) * sizeof(type), memflags))
494 
495 #define NEW_C_HEAP_ARRAY2_RETURN_NULL(type, size, memflags, pc)\
496   NEW_C_HEAP_ARRAY3(type, (size), memflags, pc, AllocFailStrategy::RETURN_NULL)
497 
498 #define NEW_C_HEAP_ARRAY_RETURN_NULL(type, size, memflags)\
499   NEW_C_HEAP_ARRAY2(type, (size), memflags, AllocFailStrategy::RETURN_NULL)
500 
501 #define REALLOC_C_HEAP_ARRAY(type, old, size, memflags)\
502   (type*) (ReallocateHeap((char*)(old), (size) * sizeof(type), memflags))
503 
504 #define REALLOC_C_HEAP_ARRAY_RETURN_NULL(type, old, size, memflags)\
505   (type*) (ReallocateHeap((char*)(old), (size) * sizeof(type), memflags, AllocFailStrategy::RETURN_NULL))
506 
507 #define FREE_C_HEAP_ARRAY(type, old) \
508   FreeHeap((char*)(old))
509 
510 // allocate type in heap without calling ctor
511 #define NEW_C_HEAP_OBJ(type, memflags)\
512   NEW_C_HEAP_ARRAY(type, 1, memflags)
513 
514 #define NEW_C_HEAP_OBJ_RETURN_NULL(type, memflags)\
515   NEW_C_HEAP_ARRAY_RETURN_NULL(type, 1, memflags)
516 
517 // deallocate obj of type in heap without calling dtor
518 #define FREE_C_HEAP_OBJ(objname)\
519   FreeHeap((char*)objname);
520 
521 
522 //------------------------------ReallocMark---------------------------------
523 // Code which uses REALLOC_RESOURCE_ARRAY should check an associated
524 // ReallocMark, which is declared in the same scope as the reallocated
525 // pointer.  Any operation that could __potentially__ cause a reallocation
526 // should check the ReallocMark.
527 class ReallocMark: public StackObj {
528 protected:
529   NOT_PRODUCT(int _nesting;)
530 
531 public:
532   ReallocMark()   PRODUCT_RETURN;
533   void check()    PRODUCT_RETURN;
534 };
535 
536 // Helper class to allocate arrays that may become large.
537 // Uses the OS malloc for allocations smaller than ArrayAllocatorMallocLimit
538 // and uses mapped memory for larger allocations.
539 // Most OS mallocs do something similar but Solaris malloc does not revert
540 // to mapped memory for large allocations. By default ArrayAllocatorMallocLimit
541 // is set so that we always use malloc except for Solaris where we set the
542 // limit to get mapped memory.
543 template <class E>
544 class ArrayAllocator : public AllStatic {
545  private:
546   static bool should_use_malloc(size_t length);
547 
548   static E* allocate_malloc(size_t length, MEMFLAGS flags);
549   static E* allocate_mmap(size_t length, MEMFLAGS flags);
550 
551   static void free_malloc(E* addr, size_t length);
552   static void free_mmap(E* addr, size_t length);
553 
554  public:
555   static E* allocate(size_t length, MEMFLAGS flags);
556   static E* reallocate(E* old_addr, size_t old_length, size_t new_length, MEMFLAGS flags);
557   static void free(E* addr, size_t length);
558 };
559 
560 // Uses mmaped memory for all allocations. All allocations are initially
561 // zero-filled. No pre-touching.
562 template <class E>
563 class MmapArrayAllocator : public AllStatic {
564  private:
565   static size_t size_for(size_t length);
566 
567  public:
568   static E* allocate_or_null(size_t length, MEMFLAGS flags);
569   static E* allocate(size_t length, MEMFLAGS flags);
570   static void free(E* addr, size_t length);
571 };
572 
573 // Uses malloc:ed memory for all allocations.
574 template <class E>
575 class MallocArrayAllocator : public AllStatic {
576  public:
577   static size_t size_for(size_t length);
578 
579   static E* allocate(size_t length, MEMFLAGS flags);
580   static void free(E* addr);
581 };
582 
583 #endif // SHARE_MEMORY_ALLOCATION_HPP