jdk8-mips64-public/hotspot: src/share/vm/memory/allocation.hpp@f258c5828eb8 (annotated)

src/share/vm/memory/allocation.hpp@f258c5828eb8 (annotated)

src/share/vm/memory/allocation.hpp

Mon, 29 Apr 2013 16:13:57 -0400

author: hseigel
date: Mon, 29 Apr 2013 16:13:57 -0400
changeset 4987: f258c5828eb8
parent 4968: cc12becb22e7
child 5103: f9be75d21404
child 5247: 7ee0d5c53c78
permissions: -rw-r--r--

8011773: Some tests on Interned String crashed JVM with OOM
Summary: Instead of terminating the VM, throw OutOfMemoryError exceptions.
Reviewed-by: coleenp, dholmes

 /*
  * Copyright (c) 1997, 2012, 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 <new>
 #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)
 // noinline attribute
 #ifdef _WINDOWS
   #define _NOINLINE_  __declspec(noinline)
 #else
   #if __GNUC__ < 3    // gcc 2.x does not support noinline attribute
     #define _NOINLINE_
   #else
     #define _NOINLINE_ __attribute__ ((noinline))
   #endif
 #endif
 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:
 //
 //   NEW_RESOURCE_ARRAY(type,size)
 //   NEW_RESOURCE_OBJ(type)
 //   NEW_C_HEAP_ARRAY(type,size)
 //   NEW_C_HEAP_OBJ(type)
 //   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
 /*
  * MemoryType bitmap layout:
  * | 16 15 14 13 12 11 10 09 | 08 07 06 05 | 04 03 02 01 |
  * |      memory type        |   object    | reserved    |
  * |                         |     type    |             |
  */
 enum MemoryType {
   // Memory type by sub systems. It occupies lower byte.
   mtNone              = 0x0000,  // undefined
   mtClass             = 0x0100,  // memory class for Java classes
   mtThread            = 0x0200,  // memory for thread objects
   mtThreadStack       = 0x0300,
   mtCode              = 0x0400,  // memory for generated code
   mtGC                = 0x0500,  // memory for GC
   mtCompiler          = 0x0600,  // memory for compiler
   mtInternal          = 0x0700,  // memory used by VM, but does not belong to
                                  // any of above categories, and not used for
                                  // native memory tracking
   mtOther             = 0x0800,  // memory not used by VM
   mtSymbol            = 0x0900,  // symbol
   mtNMT               = 0x0A00,  // memory used by native memory tracking
   mtChunk             = 0x0B00,  // chunk that holds content of arenas
   mtJavaHeap          = 0x0C00,  // Java heap
   mtClassShared       = 0x0D00,  // class data sharing
   mtTest              = 0x0E00,  // Test type for verifying NMT
   mt_number_of_types  = 0x000E,  // number of memory types (mtDontTrack
                                  // is not included as validate type)
   mtDontTrack         = 0x0F00,  // memory we do not or cannot track
   mt_masks            = 0x7F00,
   // object type mask
   otArena             = 0x0010, // an arena object
   otNMTRecorder       = 0x0020, // memory recorder object
   ot_masks            = 0x00F0
 };
 #define IS_MEMORY_TYPE(flags, type) ((flags & mt_masks) == type)
 #define HAS_VALID_MEMORY_TYPE(flags)((flags & mt_masks) != mtNone)
 #define FLAGS_TO_MEMORY_TYPE(flags) (flags & mt_masks)
 #define IS_ARENA_OBJ(flags)         ((flags & ot_masks) == otArena)
 #define IS_NMT_RECORDER(flags)      ((flags & ot_masks) == otNMTRecorder)
 #define NMT_CAN_TRACK(flags)        (!IS_NMT_RECORDER(flags) && !(IS_MEMORY_TYPE(flags, mtDontTrack)))
 typedef unsigned short MEMFLAGS;
 #if INCLUDE_NMT
 extern bool NMT_track_callsite;
 #else
 const bool NMT_track_callsite = false;
 #endif // INCLUDE_NMT
 // debug build does not inline
 #if defined(_NMT_NOINLINE_)
   #define CURRENT_PC       (NMT_track_callsite ? os::get_caller_pc(1) : 0)
   #define CALLER_PC        (NMT_track_callsite ? os::get_caller_pc(2) : 0)
   #define CALLER_CALLER_PC (NMT_track_callsite ? os::get_caller_pc(3) : 0)
 #else
   #define CURRENT_PC      (NMT_track_callsite? os::get_caller_pc(0) : 0)
   #define CALLER_PC       (NMT_track_callsite ? os::get_caller_pc(1) : 0)
   #define CALLER_CALLER_PC (NMT_track_callsite ? os::get_caller_pc(2) : 0)
 #endif
 template <MEMFLAGS F> class CHeapObj ALLOCATION_SUPER_CLASS_SPEC {
  public:
   _NOINLINE_ void* operator new(size_t size, address caller_pc = 0);
   _NOINLINE_ void* operator new (size_t size, const std::nothrow_t&  nothrow_constant,
                                address caller_pc = 0);
   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);
   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);
   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_metadata() const;
   bool is_metaspace_object() const;  // more specific test but slower
   bool is_shared() const;
   void print_address_on(outputStream* st) const;  // nonvirtual address printing
   void* operator new(size_t size, ClassLoaderData* loader_data,
                      size_t word_size, bool read_only, Thread* thread);
                      // 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<mtChunk> {
   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, size_t length);
   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
     init_size  =  1*K  - slack, // Size of first chunk
     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<mtNone|otArena> {
 protected:
   friend class ResourceMark;
   friend class HandleMark;
   friend class NoHandleMark;
   friend class VMStructs;
   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;
   void check_for_overflow(size_t request, const char* whence) const {
     if (UINTPTR_MAX - request < (uintptr_t)_hwm) {
       signal_out_of_memory(request, whence);
     }
  }
  public:
   Arena();
   Arena(size_t init_size);
   ~Arena();
   void  destruct_contents();
   char* hwm() const             { return _hwm; }
   // new operators
   void* operator new (size_t size);
   void* operator new (size_t size, const std::nothrow_t& nothrow_constant);
   // dynamic memory type tagging
   void* operator new(size_t size, MEMFLAGS flags);
   void* operator new(size_t size, const std::nothrow_t& nothrow_constant, MEMFLAGS flags);
   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);)
     check_for_overflow(x, "Arena::Amalloc");
     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);)
     check_for_overflow(x, "Arena::Amalloc_4");
     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
     check_for_overflow(x, "Arena::Amalloc_D");
     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;
   // how many arena instances
   NOT_PRODUCT(static volatile jint _instance_count;)
 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 construtor
   ResourceObj(const ResourceObj& r); // default copy construtor
   ResourceObj& operator=(const ResourceObj& r); // default copy assignment
   ~ResourceObj();
 #endif // ASSERT
  public:
   void* operator new(size_t size, allocation_type type, MEMFLAGS flags);
   void* operator new(size_t size, const std::nothrow_t&  nothrow_constant,
       allocation_type type, MEMFLAGS flags);
   void* operator new(size_t size, Arena *arena) {
       address res = (address)arena->Amalloc(size);
       DEBUG_ONLY(set_allocation_type(res, ARENA);)
       return res;
   }
   void* operator new(size_t size) {
       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) {
       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);
 };
 // 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 REALLOC_RESOURCE_ARRAY(type, old, old_size, new_size)\
   (type*) resource_reallocate_bytes((char*)(old), (old_size) * sizeof(type), (new_size) * sizeof(type) )
 #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_C_HEAP_ARRAY(type, size, memflags)\
   (type*) (AllocateHeap((size) * sizeof(type), memflags))
 #define REALLOC_C_HEAP_ARRAY(type, old, size, memflags)\
   (type*) (ReallocateHeap((char*)old, (size) * sizeof(type), memflags))
 #define FREE_C_HEAP_ARRAY(type,old,memflags) \
   FreeHeap((char*)(old), memflags)
 #define NEW_C_HEAP_OBJ(type, memflags)\
   NEW_C_HEAP_ARRAY(type, 1, memflags)
 #define NEW_C_HEAP_ARRAY2(type, size, memflags, pc)\
   (type*) (AllocateHeap((size) * sizeof(type), memflags, pc))
 #define REALLOC_C_HEAP_ARRAY2(type, old, size, memflags, pc)\
   (type*) (ReallocateHeap((char*)old, (size) * sizeof(type), memflags, pc))
 #define NEW_C_HEAP_OBJ2(type, memflags, pc)\
   NEW_C_HEAP_ARRAY2(type, 1, memflags, pc)
 extern bool warn_new_operator;
 // 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 E, MEMFLAGS F>
 class ArrayAllocator : StackObj {
   char* _addr;
   bool _use_malloc;
   size_t _size;
  public:
   ArrayAllocator() : _addr(NULL), _use_malloc(false), _size(0) { }
   ~ArrayAllocator() { free(); }
   E* allocate(size_t length);
   void free();
 };
 #endif // SHARE_VM_MEMORY_ALLOCATION_HPP

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/memory/allocation.hpp@f258c5828eb8 (annotated)

src/share/vm/memory/allocation.hpp