1 /*
2 * Copyright (c) 2017, 2019, 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/atomic.hpp"
30 #include "runtime/globals.hpp"
31 #include "utilities/globalDefinitions.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 #ifndef PRODUCT
111 static julong _bytes_allocated; // total #bytes allocated since start
112 // Inlinable increment function (not atomic on MP, but avoids word-tearing on 32 bit)
113 void inc_bytes_allocated(size_t x) {
114 // Only do it if needed. Otherwise avoid contention.
115 if (PrintMallocStatistics) {
116 #ifdef _LP64
117 _bytes_allocated += x;
118 #else
119 julong value = Atomic::load(&_bytes_allocated);
120 Atomic::store(value + x, &_bytes_allocated);
121 #endif
122 }
123 }
124 #endif
125
126 friend class AllocStats;
127 debug_only(void* malloc(size_t size);)
128 debug_only(void* internal_malloc_4(size_t x);)
129
130 void signal_out_of_memory(size_t request, const char* whence) const;
131
132 bool check_for_overflow(size_t request, const char* whence,
133 AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) const {
134 if (UINTPTR_MAX - request < (uintptr_t)_hwm) {
135 if (alloc_failmode == AllocFailStrategy::RETURN_NULL) {
136 return false;
137 }
138 signal_out_of_memory(request, whence);
139 }
140 return true;
141 }
142
143 public:
144 Arena(MEMFLAGS memflag);
145 Arena(MEMFLAGS memflag, size_t init_size);
146 ~Arena();
147 void destruct_contents();
148 char* hwm() const { return _hwm; }
149
150 // new operators
151 void* operator new (size_t size) throw();
152 void* operator new (size_t size, const std::nothrow_t& nothrow_constant) throw();
153
154 // dynamic memory type tagging
155 void* operator new(size_t size, MEMFLAGS flags) throw();
156 void* operator new(size_t size, const std::nothrow_t& nothrow_constant, MEMFLAGS flags) throw();
157 void operator delete(void* p);
158
159 // Fast allocate in the arena. Common case is: pointer test + increment.
160 void* Amalloc(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) {
161 assert(is_power_of_2(ARENA_AMALLOC_ALIGNMENT) , "should be a power of 2");
162 x = ARENA_ALIGN(x);
163 debug_only(if (UseMallocOnly) return malloc(x);)
164 if (!check_for_overflow(x, "Arena::Amalloc", alloc_failmode))
165 return NULL;
166 NOT_PRODUCT(inc_bytes_allocated(x);)
167 if (_hwm + x > _max) {
168 return grow(x, alloc_failmode);
169 } else {
170 char *old = _hwm;
171 _hwm += x;
172 return old;
173 }
174 }
175 // Further assume size is padded out to words
176 void *Amalloc_4(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) {
177 assert( (x&(sizeof(char*)-1)) == 0, "misaligned size" );
178 debug_only(if (UseMallocOnly) return malloc(x);)
179 if (!check_for_overflow(x, "Arena::Amalloc_4", alloc_failmode))
180 return NULL;
181 NOT_PRODUCT(inc_bytes_allocated(x);)
182 if (_hwm + x > _max) {
183 return grow(x, alloc_failmode);
184 } else {
185 char *old = _hwm;
186 _hwm += x;
187 return old;
188 }
189 }
190
191 // Allocate with 'double' alignment. It is 8 bytes on sparc.
192 // In other cases Amalloc_D() should be the same as Amalloc_4().
193 void* Amalloc_D(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) {
194 assert( (x&(sizeof(char*)-1)) == 0, "misaligned size" );
195 debug_only(if (UseMallocOnly) return malloc(x);)
196 #if defined(SPARC) && !defined(_LP64)
197 #define DALIGN_M1 7
198 size_t delta = (((size_t)_hwm + DALIGN_M1) & ~DALIGN_M1) - (size_t)_hwm;
199 x += delta;
200 #endif
201 if (!check_for_overflow(x, "Arena::Amalloc_D", alloc_failmode))
202 return NULL;
203 NOT_PRODUCT(inc_bytes_allocated(x);)
204 if (_hwm + x > _max) {
205 return grow(x, alloc_failmode); // grow() returns a result aligned >= 8 bytes.
206 } else {
207 char *old = _hwm;
208 _hwm += x;
209 #if defined(SPARC) && !defined(_LP64)
210 old += delta; // align to 8-bytes
211 #endif
212 return old;
213 }
214 }
215
216 // Fast delete in area. Common case is: NOP (except for storage reclaimed)
217 bool Afree(void *ptr, size_t size) {
218 #ifdef ASSERT
219 if (ZapResourceArea) memset(ptr, badResourceValue, size); // zap freed memory
220 if (UseMallocOnly) return true;
221 #endif
222 if (((char*)ptr) + size == _hwm) {
223 _hwm = (char*)ptr;
224 return true;
225 } else {
226 // Unable to fast free, so we just drop it.
227 return false;
228 }
229 }
230
231 void *Arealloc( void *old_ptr, size_t old_size, size_t new_size,
232 AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
233
234 // Move contents of this arena into an empty arena
235 Arena *move_contents(Arena *empty_arena);
236
237 // Determine if pointer belongs to this Arena or not.
238 bool contains( const void *ptr ) const;
239
240 // Total of all chunks in use (not thread-safe)
241 size_t used() const;
242
243 // Total # of bytes used
244 size_t size_in_bytes() const { return _size_in_bytes; };
245 void set_size_in_bytes(size_t size);
246
247 static void free_malloced_objects(Chunk* chunk, char* hwm, char* max, char* hwm2) PRODUCT_RETURN;
248 static void free_all(char** start, char** end) PRODUCT_RETURN;
249
250 private:
251 // Reset this Arena to empty, access will trigger grow if necessary
252 void reset(void) {
253 _first = _chunk = NULL;
254 _hwm = _max = NULL;
255 set_size_in_bytes(0);
256 }
257 };
258
259 // One of the following macros must be used when allocating
260 // an array or object from an arena
261 #define NEW_ARENA_ARRAY(arena, type, size) \
262 (type*) (arena)->Amalloc((size) * sizeof(type))
263
264 #define REALLOC_ARENA_ARRAY(arena, type, old, old_size, new_size) \
265 (type*) (arena)->Arealloc((char*)(old), (old_size) * sizeof(type), \
266 (new_size) * sizeof(type) )
267
268 #define FREE_ARENA_ARRAY(arena, type, old, size) \
269 (arena)->Afree((char*)(old), (size) * sizeof(type))
270
271 #define NEW_ARENA_OBJ(arena, type) \
272 NEW_ARENA_ARRAY(arena, type, 1)
273
274 #endif // SHARE_MEMORY_ARENA_HPP