/* * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #ifndef SHARE_VM_MEMORY_ALLOCATION_HPP #define SHARE_VM_MEMORY_ALLOCATION_HPP #include "runtime/globals.hpp" #include "utilities/globalDefinitions.hpp" #include "utilities/macros.hpp" #ifdef COMPILER1 #include "c1/c1_globals.hpp" #endif #ifdef COMPILER2 #include "opto/c2_globals.hpp" #endif #include // The byte alignment to be used by Arena::Amalloc. See bugid 4169348. // Note: this value must be a power of 2 #define ARENA_AMALLOC_ALIGNMENT (2*BytesPerWord) #define ARENA_ALIGN_M1 (((size_t)(ARENA_AMALLOC_ALIGNMENT)) - 1) #define ARENA_ALIGN_MASK (~((size_t)ARENA_ALIGN_M1)) #define ARENA_ALIGN(x) ((((size_t)(x)) + ARENA_ALIGN_M1) & ARENA_ALIGN_MASK) class AllocFailStrategy { public: enum AllocFailEnum { EXIT_OOM, RETURN_NULL }; }; typedef AllocFailStrategy::AllocFailEnum AllocFailType; // All classes in the virtual machine must be subclassed // by one of the following allocation classes: // // For objects allocated in the resource area (see resourceArea.hpp). // - ResourceObj // // For objects allocated in the C-heap (managed by: free & malloc). // - CHeapObj // // For objects allocated on the stack. // - StackObj // // For embedded objects. // - ValueObj // // For classes used as name spaces. // - AllStatic // // For classes in Metaspace (class data) // - MetaspaceObj // // The printable subclasses are used for debugging and define virtual // member functions for printing. Classes that avoid allocating the // vtbl entries in the objects should therefore not be the printable // subclasses. // // The following macros and function should be used to allocate memory // directly in the resource area or in the C-heap, The _OBJ variants // of the NEW/FREE_C_HEAP macros are used for alloc/dealloc simple // objects which are not inherited from CHeapObj, note constructor and // destructor are not called. The preferable way to allocate objects // is using the new operator. // // WARNING: The array variant must only be used for a homogenous array // where all objects are of the exact type specified. If subtypes are // stored in the array then must pay attention to calling destructors // at needed. // // NEW_RESOURCE_ARRAY(type, size) // NEW_RESOURCE_OBJ(type) // NEW_C_HEAP_ARRAY(type, size) // NEW_C_HEAP_OBJ(type, memflags) // FREE_C_HEAP_ARRAY(type, old) // FREE_C_HEAP_OBJ(objname, type, memflags) // char* AllocateHeap(size_t size, const char* name); // void FreeHeap(void* p); // // C-heap allocation can be traced using +PrintHeapAllocation. // malloc and free should therefore never called directly. // Base class for objects allocated in the C-heap. // In non product mode we introduce a super class for all allocation classes // that supports printing. // We avoid the superclass in product mode since some C++ compilers add // a word overhead for empty super classes. #ifdef PRODUCT #define ALLOCATION_SUPER_CLASS_SPEC #else #define ALLOCATION_SUPER_CLASS_SPEC : public AllocatedObj class AllocatedObj { public: // Printing support void print() const; void print_value() const; virtual void print_on(outputStream* st) const; virtual void print_value_on(outputStream* st) const; }; #endif /* * Memory types */ enum MemoryType { // Memory type by sub systems. It occupies lower byte. mtJavaHeap = 0x00, // Java heap mtClass = 0x01, // memory class for Java classes mtThread = 0x02, // memory for thread objects mtThreadStack = 0x03, mtCode = 0x04, // memory for generated code mtGC = 0x05, // memory for GC mtCompiler = 0x06, // memory for compiler mtInternal = 0x07, // memory used by VM, but does not belong to // any of above categories, and not used for // native memory tracking mtOther = 0x08, // memory not used by VM mtSymbol = 0x09, // symbol mtNMT = 0x0A, // memory used by native memory tracking mtClassShared = 0x0B, // class data sharing mtChunk = 0x0C, // chunk that holds content of arenas mtTest = 0x0D, // Test type for verifying NMT mtTracing = 0x0E, // memory used for Tracing mtLogging = 0x0F, // memory for logging mtArguments = 0x10, // memory for argument processing mtModule = 0x11, // memory for module processing mtNone = 0x12, // undefined mt_number_of_types = 0x13 // number of memory types (mtDontTrack // is not included as validate type) }; typedef MemoryType MEMFLAGS; #if INCLUDE_NMT extern bool NMT_track_callsite; #else const bool NMT_track_callsite = false; #endif // INCLUDE_NMT class NativeCallStack; template class CHeapObj ALLOCATION_SUPER_CLASS_SPEC { public: NOINLINE void* operator new(size_t size, const NativeCallStack& stack) throw(); NOINLINE void* operator new(size_t size) throw(); NOINLINE void* operator new (size_t size, const std::nothrow_t& nothrow_constant, const NativeCallStack& stack) throw(); NOINLINE void* operator new (size_t size, const std::nothrow_t& nothrow_constant) throw(); NOINLINE void* operator new [](size_t size, const NativeCallStack& stack) throw(); NOINLINE void* operator new [](size_t size) throw(); NOINLINE void* operator new [](size_t size, const std::nothrow_t& nothrow_constant, const NativeCallStack& stack) throw(); NOINLINE void* operator new [](size_t size, const std::nothrow_t& nothrow_constant) throw(); void operator delete(void* p); void operator delete [] (void* p); }; // Base class for objects allocated on the stack only. // Calling new or delete will result in fatal error. class StackObj ALLOCATION_SUPER_CLASS_SPEC { private: void* operator new(size_t size) throw(); void* operator new [](size_t size) throw(); #ifdef __IBMCPP__ public: #endif void operator delete(void* p); void operator delete [](void* p); }; // Base class for objects used as value objects. // Calling new or delete will result in fatal error. // // Portability note: Certain compilers (e.g. gcc) will // always make classes bigger if it has a superclass, even // if the superclass does not have any virtual methods or // instance fields. The HotSpot implementation relies on this // not to happen. So never make a ValueObj class a direct subclass // of this object, but use the VALUE_OBJ_CLASS_SPEC class instead, e.g., // like this: // // class A VALUE_OBJ_CLASS_SPEC { // ... // } // // With gcc and possible other compilers the VALUE_OBJ_CLASS_SPEC can // be defined as a an empty string "". // class _ValueObj { private: void* operator new(size_t size) throw(); void operator delete(void* p); void* operator new [](size_t size) throw(); void operator delete [](void* p); }; // Base class for objects stored in Metaspace. // Calling delete will result in fatal error. // // Do not inherit from something with a vptr because this class does // not introduce one. This class is used to allocate both shared read-only // and shared read-write classes. // class ClassLoaderData; class MetaspaceObj { public: bool is_metaspace_object() const; bool is_shared() const; void print_address_on(outputStream* st) const; // nonvirtual address printing #define METASPACE_OBJ_TYPES_DO(f) \ f(Unknown) \ f(Class) \ f(Symbol) \ f(TypeArrayU1) \ f(TypeArrayU2) \ f(TypeArrayU4) \ f(TypeArrayU8) \ f(TypeArrayOther) \ f(Method) \ f(ConstMethod) \ f(MethodData) \ f(ConstantPool) \ f(ConstantPoolCache) \ f(Annotation) \ f(MethodCounters) \ f(Deallocated) #define METASPACE_OBJ_TYPE_DECLARE(name) name ## Type, #define METASPACE_OBJ_TYPE_NAME_CASE(name) case name ## Type: return #name; enum Type { // Types are MetaspaceObj::ClassType, MetaspaceObj::SymbolType, etc METASPACE_OBJ_TYPES_DO(METASPACE_OBJ_TYPE_DECLARE) _number_of_types }; static const char * type_name(Type type) { switch(type) { METASPACE_OBJ_TYPES_DO(METASPACE_OBJ_TYPE_NAME_CASE) default: ShouldNotReachHere(); return NULL; } } static MetaspaceObj::Type array_type(size_t elem_size) { switch (elem_size) { case 1: return TypeArrayU1Type; case 2: return TypeArrayU2Type; case 4: return TypeArrayU4Type; case 8: return TypeArrayU8Type; default: return TypeArrayOtherType; } } void* operator new(size_t size, ClassLoaderData* loader_data, size_t word_size, bool read_only, Type type, Thread* thread) throw(); // can't use TRAPS from this header file. void operator delete(void* p) { ShouldNotCallThis(); } }; // Base class for classes that constitute name spaces. class AllStatic { public: AllStatic() { ShouldNotCallThis(); } ~AllStatic() { ShouldNotCallThis(); } }; //------------------------------Chunk------------------------------------------ // Linked list of raw memory chunks class Chunk: CHeapObj { friend class VMStructs; protected: Chunk* _next; // Next Chunk in list const size_t _len; // Size of this Chunk public: void* operator new(size_t size, AllocFailType alloc_failmode, size_t length) throw(); void operator delete(void* p); Chunk(size_t length); enum { // default sizes; make them slightly smaller than 2**k to guard against // buddy-system style malloc implementations #ifdef _LP64 slack = 40, // [RGV] Not sure if this is right, but make it // a multiple of 8. #else slack = 20, // suspected sizeof(Chunk) + internal malloc headers #endif tiny_size = 256 - slack, // Size of first chunk (tiny) init_size = 1*K - slack, // Size of first chunk (normal aka small) medium_size= 10*K - slack, // Size of medium-sized chunk size = 32*K - slack, // Default size of an Arena chunk (following the first) non_pool_size = init_size + 32 // An initial size which is not one of above }; void chop(); // Chop this chunk void next_chop(); // Chop next chunk static size_t aligned_overhead_size(void) { return ARENA_ALIGN(sizeof(Chunk)); } static size_t aligned_overhead_size(size_t byte_size) { return ARENA_ALIGN(byte_size); } size_t length() const { return _len; } Chunk* next() const { return _next; } void set_next(Chunk* n) { _next = n; } // Boundaries of data area (possibly unused) char* bottom() const { return ((char*) this) + aligned_overhead_size(); } char* top() const { return bottom() + _len; } bool contains(char* p) const { return bottom() <= p && p <= top(); } // Start the chunk_pool cleaner task static void start_chunk_pool_cleaner_task(); static void clean_chunk_pool(); }; //------------------------------Arena------------------------------------------ // Fast allocation of memory class Arena : public CHeapObj { protected: friend class ResourceMark; friend class HandleMark; friend class NoHandleMark; friend class VMStructs; MEMFLAGS _flags; // Memory tracking flags Chunk *_first; // First chunk Chunk *_chunk; // current chunk char *_hwm, *_max; // High water mark and max in current chunk // Get a new Chunk of at least size x void* grow(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM); size_t _size_in_bytes; // Size of arena (used for native memory tracking) NOT_PRODUCT(static julong _bytes_allocated;) // total #bytes allocated since start friend class AllocStats; debug_only(void* malloc(size_t size);) debug_only(void* internal_malloc_4(size_t x);) NOT_PRODUCT(void inc_bytes_allocated(size_t x);) void signal_out_of_memory(size_t request, const char* whence) const; bool check_for_overflow(size_t request, const char* whence, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) const { if (UINTPTR_MAX - request < (uintptr_t)_hwm) { if (alloc_failmode == AllocFailStrategy::RETURN_NULL) { return false; } signal_out_of_memory(request, whence); } return true; } public: Arena(MEMFLAGS memflag); Arena(MEMFLAGS memflag, size_t init_size); ~Arena(); void destruct_contents(); char* hwm() const { return _hwm; } // new operators void* operator new (size_t size) throw(); void* operator new (size_t size, const std::nothrow_t& nothrow_constant) throw(); // dynamic memory type tagging void* operator new(size_t size, MEMFLAGS flags) throw(); void* operator new(size_t size, const std::nothrow_t& nothrow_constant, MEMFLAGS flags) throw(); void operator delete(void* p); // Fast allocate in the arena. Common case is: pointer test + increment. void* Amalloc(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) { assert(is_power_of_2(ARENA_AMALLOC_ALIGNMENT) , "should be a power of 2"); x = ARENA_ALIGN(x); debug_only(if (UseMallocOnly) return malloc(x);) if (!check_for_overflow(x, "Arena::Amalloc", alloc_failmode)) return NULL; NOT_PRODUCT(inc_bytes_allocated(x);) if (_hwm + x > _max) { return grow(x, alloc_failmode); } else { char *old = _hwm; _hwm += x; return old; } } // Further assume size is padded out to words void *Amalloc_4(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) { assert( (x&(sizeof(char*)-1)) == 0, "misaligned size" ); debug_only(if (UseMallocOnly) return malloc(x);) if (!check_for_overflow(x, "Arena::Amalloc_4", alloc_failmode)) return NULL; NOT_PRODUCT(inc_bytes_allocated(x);) if (_hwm + x > _max) { return grow(x, alloc_failmode); } else { char *old = _hwm; _hwm += x; return old; } } // Allocate with 'double' alignment. It is 8 bytes on sparc. // In other cases Amalloc_D() should be the same as Amalloc_4(). void* Amalloc_D(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) { assert( (x&(sizeof(char*)-1)) == 0, "misaligned size" ); debug_only(if (UseMallocOnly) return malloc(x);) #if defined(SPARC) && !defined(_LP64) #define DALIGN_M1 7 size_t delta = (((size_t)_hwm + DALIGN_M1) & ~DALIGN_M1) - (size_t)_hwm; x += delta; #endif if (!check_for_overflow(x, "Arena::Amalloc_D", alloc_failmode)) return NULL; NOT_PRODUCT(inc_bytes_allocated(x);) if (_hwm + x > _max) { return grow(x, alloc_failmode); // grow() returns a result aligned >= 8 bytes. } else { char *old = _hwm; _hwm += x; #if defined(SPARC) && !defined(_LP64) old += delta; // align to 8-bytes #endif return old; } } // Fast delete in area. Common case is: NOP (except for storage reclaimed) void Afree(void *ptr, size_t size) { #ifdef ASSERT if (ZapResourceArea) memset(ptr, badResourceValue, size); // zap freed memory if (UseMallocOnly) return; #endif if (((char*)ptr) + size == _hwm) _hwm = (char*)ptr; } void *Arealloc( void *old_ptr, size_t old_size, size_t new_size, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM); // Move contents of this arena into an empty arena Arena *move_contents(Arena *empty_arena); // Determine if pointer belongs to this Arena or not. bool contains( const void *ptr ) const; // Total of all chunks in use (not thread-safe) size_t used() const; // Total # of bytes used size_t size_in_bytes() const { return _size_in_bytes; }; void set_size_in_bytes(size_t size); static void free_malloced_objects(Chunk* chunk, char* hwm, char* max, char* hwm2) PRODUCT_RETURN; static void free_all(char** start, char** end) PRODUCT_RETURN; private: // Reset this Arena to empty, access will trigger grow if necessary void reset(void) { _first = _chunk = NULL; _hwm = _max = NULL; set_size_in_bytes(0); } }; // One of the following macros must be used when allocating // an array or object from an arena #define NEW_ARENA_ARRAY(arena, type, size) \ (type*) (arena)->Amalloc((size) * sizeof(type)) #define REALLOC_ARENA_ARRAY(arena, type, old, old_size, new_size) \ (type*) (arena)->Arealloc((char*)(old), (old_size) * sizeof(type), \ (new_size) * sizeof(type) ) #define FREE_ARENA_ARRAY(arena, type, old, size) \ (arena)->Afree((char*)(old), (size) * sizeof(type)) #define NEW_ARENA_OBJ(arena, type) \ NEW_ARENA_ARRAY(arena, type, 1) //%note allocation_1 extern char* resource_allocate_bytes(size_t size, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM); extern char* resource_allocate_bytes(Thread* thread, size_t size, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM); extern char* resource_reallocate_bytes( char *old, size_t old_size, size_t new_size, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM); extern void resource_free_bytes( char *old, size_t size ); //---------------------------------------------------------------------- // Base class for objects allocated in the resource area per default. // Optionally, objects may be allocated on the C heap with // new(ResourceObj::C_HEAP) Foo(...) or in an Arena with new (&arena) // ResourceObj's can be allocated within other objects, but don't use // new or delete (allocation_type is unknown). If new is used to allocate, // use delete to deallocate. class ResourceObj ALLOCATION_SUPER_CLASS_SPEC { public: enum allocation_type { STACK_OR_EMBEDDED = 0, RESOURCE_AREA, C_HEAP, ARENA, allocation_mask = 0x3 }; static void set_allocation_type(address res, allocation_type type) NOT_DEBUG_RETURN; #ifdef ASSERT private: // When this object is allocated on stack the new() operator is not // called but garbage on stack may look like a valid allocation_type. // Store negated 'this' pointer when new() is called to distinguish cases. // Use second array's element for verification value to distinguish garbage. uintptr_t _allocation_t[2]; bool is_type_set() const; public: allocation_type get_allocation_type() const; bool allocated_on_stack() const { return get_allocation_type() == STACK_OR_EMBEDDED; } bool allocated_on_res_area() const { return get_allocation_type() == RESOURCE_AREA; } bool allocated_on_C_heap() const { return get_allocation_type() == C_HEAP; } bool allocated_on_arena() const { return get_allocation_type() == ARENA; } ResourceObj(); // default constructor ResourceObj(const ResourceObj& r); // default copy constructor ResourceObj& operator=(const ResourceObj& r); // default copy assignment ~ResourceObj(); #endif // ASSERT public: void* operator new(size_t size, allocation_type type, MEMFLAGS flags) throw(); void* operator new [](size_t size, allocation_type type, MEMFLAGS flags) throw(); void* operator new(size_t size, const std::nothrow_t& nothrow_constant, allocation_type type, MEMFLAGS flags) throw(); void* operator new [](size_t size, const std::nothrow_t& nothrow_constant, allocation_type type, MEMFLAGS flags) throw(); void* operator new(size_t size, Arena *arena) throw() { address res = (address)arena->Amalloc(size); DEBUG_ONLY(set_allocation_type(res, ARENA);) return res; } void* operator new [](size_t size, Arena *arena) throw() { address res = (address)arena->Amalloc(size); DEBUG_ONLY(set_allocation_type(res, ARENA);) return res; } void* operator new(size_t size) throw() { address res = (address)resource_allocate_bytes(size); DEBUG_ONLY(set_allocation_type(res, RESOURCE_AREA);) return res; } void* operator new(size_t size, const std::nothrow_t& nothrow_constant) throw() { address res = (address)resource_allocate_bytes(size, AllocFailStrategy::RETURN_NULL); DEBUG_ONLY(if (res != NULL) set_allocation_type(res, RESOURCE_AREA);) return res; } void* operator new [](size_t size) throw() { address res = (address)resource_allocate_bytes(size); DEBUG_ONLY(set_allocation_type(res, RESOURCE_AREA);) return res; } void* operator new [](size_t size, const std::nothrow_t& nothrow_constant) throw() { address res = (address)resource_allocate_bytes(size, AllocFailStrategy::RETURN_NULL); DEBUG_ONLY(if (res != NULL) set_allocation_type(res, RESOURCE_AREA);) return res; } void operator delete(void* p); void operator delete [](void* p); }; // One of the following macros must be used when allocating an array // or object to determine whether it should reside in the C heap on in // the resource area. #define NEW_RESOURCE_ARRAY(type, size)\ (type*) resource_allocate_bytes((size) * sizeof(type)) #define NEW_RESOURCE_ARRAY_RETURN_NULL(type, size)\ (type*) resource_allocate_bytes((size) * sizeof(type), AllocFailStrategy::RETURN_NULL) #define NEW_RESOURCE_ARRAY_IN_THREAD(thread, type, size)\ (type*) resource_allocate_bytes(thread, (size) * sizeof(type)) #define NEW_RESOURCE_ARRAY_IN_THREAD_RETURN_NULL(thread, type, size)\ (type*) resource_allocate_bytes(thread, (size) * sizeof(type), AllocFailStrategy::RETURN_NULL) #define REALLOC_RESOURCE_ARRAY(type, old, old_size, new_size)\ (type*) resource_reallocate_bytes((char*)(old), (old_size) * sizeof(type), (new_size) * sizeof(type)) #define REALLOC_RESOURCE_ARRAY_RETURN_NULL(type, old, old_size, new_size)\ (type*) resource_reallocate_bytes((char*)(old), (old_size) * sizeof(type),\ (new_size) * sizeof(type), AllocFailStrategy::RETURN_NULL) #define FREE_RESOURCE_ARRAY(type, old, size)\ resource_free_bytes((char*)(old), (size) * sizeof(type)) #define FREE_FAST(old)\ /* nop */ #define NEW_RESOURCE_OBJ(type)\ NEW_RESOURCE_ARRAY(type, 1) #define NEW_RESOURCE_OBJ_RETURN_NULL(type)\ NEW_RESOURCE_ARRAY_RETURN_NULL(type, 1) #define NEW_C_HEAP_ARRAY3(type, size, memflags, pc, allocfail)\ (type*) AllocateHeap((size) * sizeof(type), memflags, pc, allocfail) #define NEW_C_HEAP_ARRAY2(type, size, memflags, pc)\ (type*) (AllocateHeap((size) * sizeof(type), memflags, pc)) #define NEW_C_HEAP_ARRAY(type, size, memflags)\ (type*) (AllocateHeap((size) * sizeof(type), memflags)) #define NEW_C_HEAP_ARRAY2_RETURN_NULL(type, size, memflags, pc)\ NEW_C_HEAP_ARRAY3(type, (size), memflags, pc, AllocFailStrategy::RETURN_NULL) #define NEW_C_HEAP_ARRAY_RETURN_NULL(type, size, memflags)\ NEW_C_HEAP_ARRAY3(type, (size), memflags, CURRENT_PC, AllocFailStrategy::RETURN_NULL) #define REALLOC_C_HEAP_ARRAY(type, old, size, memflags)\ (type*) (ReallocateHeap((char*)(old), (size) * sizeof(type), memflags)) #define REALLOC_C_HEAP_ARRAY_RETURN_NULL(type, old, size, memflags)\ (type*) (ReallocateHeap((char*)(old), (size) * sizeof(type), memflags, AllocFailStrategy::RETURN_NULL)) #define FREE_C_HEAP_ARRAY(type, old) \ FreeHeap((char*)(old)) // allocate type in heap without calling ctor #define NEW_C_HEAP_OBJ(type, memflags)\ NEW_C_HEAP_ARRAY(type, 1, memflags) #define NEW_C_HEAP_OBJ_RETURN_NULL(type, memflags)\ NEW_C_HEAP_ARRAY_RETURN_NULL(type, 1, memflags) // deallocate obj of type in heap without calling dtor #define FREE_C_HEAP_OBJ(objname)\ FreeHeap((char*)objname); // for statistics #ifndef PRODUCT class AllocStats : StackObj { julong start_mallocs, start_frees; julong start_malloc_bytes, start_mfree_bytes, start_res_bytes; public: AllocStats(); julong num_mallocs(); // since creation of receiver julong alloc_bytes(); julong num_frees(); julong free_bytes(); julong resource_bytes(); void print(); }; #endif //------------------------------ReallocMark--------------------------------- // Code which uses REALLOC_RESOURCE_ARRAY should check an associated // ReallocMark, which is declared in the same scope as the reallocated // pointer. Any operation that could __potentially__ cause a reallocation // should check the ReallocMark. class ReallocMark: public StackObj { protected: NOT_PRODUCT(int _nesting;) public: ReallocMark() PRODUCT_RETURN; void check() PRODUCT_RETURN; }; // Helper class to allocate arrays that may become large. // Uses the OS malloc for allocations smaller than ArrayAllocatorMallocLimit // and uses mapped memory for larger allocations. // Most OS mallocs do something similar but Solaris malloc does not revert // to mapped memory for large allocations. By default ArrayAllocatorMallocLimit // is set so that we always use malloc except for Solaris where we set the // limit to get mapped memory. template class ArrayAllocator : public AllStatic { private: static bool should_use_malloc(size_t length); static E* allocate_malloc(size_t length); static E* allocate_mmap(size_t length); static void free_malloc(E* addr, size_t length); static void free_mmap(E* addr, size_t length); public: static E* allocate(size_t length); static E* reallocate(E* old_addr, size_t old_length, size_t new_length); static void free(E* addr, size_t length); }; // Uses mmaped memory for all allocations. All allocations are initially // zero-filled. No pre-touching. template class MmapArrayAllocator : public AllStatic { private: static size_t size_for(size_t length); public: static E* allocate_or_null(size_t length); static E* allocate(size_t length); static void free(E* addr, size_t length); }; // Uses malloc:ed memory for all allocations. template class MallocArrayAllocator : public AllStatic { public: static size_t size_for(size_t length); static E* allocate(size_t length); static void free(E* addr, size_t length); }; #endif // SHARE_VM_MEMORY_ALLOCATION_HPP