1 /* 2 * Copyright (c) 2017, 2020, 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_ARENA_HPP 26 #define SHARE_MEMORY_ARENA_HPP 27 28 #include "memory/allocation.hpp" 29 #include "runtime/globals.hpp" 30 #include "utilities/globalDefinitions.hpp" 31 #include "utilities/powerOfTwo.hpp" 32 33 #include <new> 34 35 // The byte alignment to be used by Arena::Amalloc. See bugid 4169348. 36 // Note: this value must be a power of 2 37 38 #define ARENA_AMALLOC_ALIGNMENT (2*BytesPerWord) 39 40 #define ARENA_ALIGN_M1 (((size_t)(ARENA_AMALLOC_ALIGNMENT)) - 1) 41 #define ARENA_ALIGN_MASK (~((size_t)ARENA_ALIGN_M1)) 42 #define ARENA_ALIGN(x) ((((size_t)(x)) + ARENA_ALIGN_M1) & ARENA_ALIGN_MASK) 43 44 //------------------------------Chunk------------------------------------------ 45 // Linked list of raw memory chunks 46 class Chunk: CHeapObj<mtChunk> { 47 48 private: 49 Chunk* _next; // Next Chunk in list 50 const size_t _len; // Size of this Chunk 51 public: 52 void* operator new(size_t size, AllocFailType alloc_failmode, size_t length) throw(); 53 void operator delete(void* p); 54 Chunk(size_t length); 55 56 enum { 57 // default sizes; make them slightly smaller than 2**k to guard against 58 // buddy-system style malloc implementations 59 #ifdef _LP64 60 slack = 40, // [RGV] Not sure if this is right, but make it 61 // a multiple of 8. 62 #else 63 slack = 20, // suspected sizeof(Chunk) + internal malloc headers 64 #endif 65 66 tiny_size = 256 - slack, // Size of first chunk (tiny) 67 init_size = 1*K - slack, // Size of first chunk (normal aka small) 68 medium_size= 10*K - slack, // Size of medium-sized chunk 69 size = 32*K - slack, // Default size of an Arena chunk (following the first) 70 non_pool_size = init_size + 32 // An initial size which is not one of above 71 }; 72 73 void chop(); // Chop this chunk 74 void next_chop(); // Chop next chunk 75 static size_t aligned_overhead_size(void) { return ARENA_ALIGN(sizeof(Chunk)); } 76 static size_t aligned_overhead_size(size_t byte_size) { return ARENA_ALIGN(byte_size); } 77 78 size_t length() const { return _len; } 79 Chunk* next() const { return _next; } 80 void set_next(Chunk* n) { _next = n; } 81 // Boundaries of data area (possibly unused) 82 char* bottom() const { return ((char*) this) + aligned_overhead_size(); } 83 char* top() const { return bottom() + _len; } 84 bool contains(char* p) const { return bottom() <= p && p <= top(); } 85 86 // Start the chunk_pool cleaner task 87 static void start_chunk_pool_cleaner_task(); 88 89 static void clean_chunk_pool(); 90 }; 91 92 //------------------------------Arena------------------------------------------ 93 // Fast allocation of memory 94 class Arena : public CHeapObj<mtNone> { 95 protected: 96 friend class ResourceMark; 97 friend class HandleMark; 98 friend class NoHandleMark; 99 friend class VMStructs; 100 101 MEMFLAGS _flags; // Memory tracking flags 102 103 Chunk *_first; // First chunk 104 Chunk *_chunk; // current chunk 105 char *_hwm, *_max; // High water mark and max in current chunk 106 // Get a new Chunk of at least size x 107 void* grow(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM); 108 size_t _size_in_bytes; // Size of arena (used for native memory tracking) 109 110 debug_only(void* malloc(size_t size);) 111 debug_only(void* internal_malloc_4(size_t x);) 112 113 void signal_out_of_memory(size_t request, const char* whence) const; 114 115 bool check_for_overflow(size_t request, const char* whence, 116 AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) const { 117 if (UINTPTR_MAX - request < (uintptr_t)_hwm) { 118 if (alloc_failmode == AllocFailStrategy::RETURN_NULL) { 119 return false; 120 } 121 signal_out_of_memory(request, whence); 122 } 123 return true; 124 } 125 126 public: 127 Arena(MEMFLAGS memflag); 128 Arena(MEMFLAGS memflag, size_t init_size); 129 ~Arena(); 130 void destruct_contents(); 131 char* hwm() const { return _hwm; } 132 133 // new operators 134 void* operator new (size_t size) throw(); 135 void* operator new (size_t size, const std::nothrow_t& nothrow_constant) throw(); 136 137 // dynamic memory type tagging 138 void* operator new(size_t size, MEMFLAGS flags) throw(); 139 void* operator new(size_t size, const std::nothrow_t& nothrow_constant, MEMFLAGS flags) throw(); 140 void operator delete(void* p); 141 142 // Fast allocate in the arena. Common case is: pointer test + increment. 143 void* Amalloc(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) { 144 assert(is_power_of_2(ARENA_AMALLOC_ALIGNMENT) , "should be a power of 2"); 145 x = ARENA_ALIGN(x); 146 debug_only(if (UseMallocOnly) return malloc(x);) 147 if (!check_for_overflow(x, "Arena::Amalloc", alloc_failmode)) 148 return NULL; 149 if (_hwm + x > _max) { 150 return grow(x, alloc_failmode); 151 } else { 152 char *old = _hwm; 153 _hwm += x; 154 return old; 155 } 156 } 157 // Further assume size is padded out to words 158 void *Amalloc_4(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) { 159 assert( (x&(sizeof(char*)-1)) == 0, "misaligned size" ); 160 debug_only(if (UseMallocOnly) return malloc(x);) 161 if (!check_for_overflow(x, "Arena::Amalloc_4", alloc_failmode)) 162 return NULL; 163 if (_hwm + x > _max) { 164 return grow(x, alloc_failmode); 165 } else { 166 char *old = _hwm; 167 _hwm += x; 168 return old; 169 } 170 } 171 172 // Allocate with 'double' alignment. It is 8 bytes on sparc. 173 // In other cases Amalloc_D() should be the same as Amalloc_4(). 174 void* Amalloc_D(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) { 175 assert( (x&(sizeof(char*)-1)) == 0, "misaligned size" ); 176 debug_only(if (UseMallocOnly) return malloc(x);) 177 if (!check_for_overflow(x, "Arena::Amalloc_D", alloc_failmode)) 178 return NULL; 179 if (_hwm + x > _max) { 180 return grow(x, alloc_failmode); // grow() returns a result aligned >= 8 bytes. 181 } else { 182 char *old = _hwm; 183 _hwm += x; 184 return old; 185 } 186 } 187 188 // Fast delete in area. Common case is: NOP (except for storage reclaimed) 189 bool Afree(void *ptr, size_t size) { 190 #ifdef ASSERT 191 if (ZapResourceArea) memset(ptr, badResourceValue, size); // zap freed memory 192 if (UseMallocOnly) return true; 193 #endif 194 if (((char*)ptr) + size == _hwm) { 195 _hwm = (char*)ptr; 196 return true; 197 } else { 198 // Unable to fast free, so we just drop it. 199 return false; 200 } 201 } 202 203 void *Arealloc( void *old_ptr, size_t old_size, size_t new_size, 204 AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM); 205 206 // Move contents of this arena into an empty arena 207 Arena *move_contents(Arena *empty_arena); 208 209 // Determine if pointer belongs to this Arena or not. 210 bool contains( const void *ptr ) const; 211 212 // Total of all chunks in use (not thread-safe) 213 size_t used() const; 214 215 // Total # of bytes used 216 size_t size_in_bytes() const { return _size_in_bytes; }; 217 void set_size_in_bytes(size_t size); 218 219 static void free_malloced_objects(Chunk* chunk, char* hwm, char* max, char* hwm2) PRODUCT_RETURN; 220 static void free_all(char** start, char** end) PRODUCT_RETURN; 221 222 private: 223 // Reset this Arena to empty, access will trigger grow if necessary 224 void reset(void) { 225 _first = _chunk = NULL; 226 _hwm = _max = NULL; 227 set_size_in_bytes(0); 228 } 229 }; 230 231 // One of the following macros must be used when allocating 232 // an array or object from an arena 233 #define NEW_ARENA_ARRAY(arena, type, size) \ 234 (type*) (arena)->Amalloc((size) * sizeof(type)) 235 236 #define REALLOC_ARENA_ARRAY(arena, type, old, old_size, new_size) \ 237 (type*) (arena)->Arealloc((char*)(old), (old_size) * sizeof(type), \ 238 (new_size) * sizeof(type) ) 239 240 #define FREE_ARENA_ARRAY(arena, type, old, size) \ 241 (arena)->Afree((char*)(old), (size) * sizeof(type)) 242 243 #define NEW_ARENA_OBJ(arena, type) \ 244 NEW_ARENA_ARRAY(arena, type, 1) 245 246 #endif // SHARE_MEMORY_ARENA_HPP