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
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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
32#include <new>
33
34// The byte alignment to be used by Arena::Amalloc. See bugid 4169348.
35// Note: this value must be a power of 2
36
37#define ARENA_AMALLOC_ALIGNMENT (2*BytesPerWord)
38
39#define ARENA_ALIGN_M1 (((size_t)(ARENA_AMALLOC_ALIGNMENT)) - 1)
40#define ARENA_ALIGN_MASK (~((size_t)ARENA_ALIGN_M1))
41#define ARENA_ALIGN(x) ((((size_t)(x)) + ARENA_ALIGN_M1) & ARENA_ALIGN_MASK)
42
43//------------------------------Chunk------------------------------------------
44// Linked list of raw memory chunks
45class Chunk: CHeapObj<mtChunk> {
46
47 private:
48 Chunk* _next; // Next Chunk in list
49 const size_t _len; // Size of this Chunk
50 public:
51 void* operator new(size_t size, AllocFailType alloc_failmode, size_t length) throw();
52 void operator delete(void* p);
53 Chunk(size_t length);
54
55 enum {
56 // default sizes; make them slightly smaller than 2**k to guard against
57 // buddy-system style malloc implementations
58#ifdef _LP64
59 slack = 40, // [RGV] Not sure if this is right, but make it
60 // a multiple of 8.
61#else
62 slack = 20, // suspected sizeof(Chunk) + internal malloc headers
63#endif
64
65 tiny_size = 256 - slack, // Size of first chunk (tiny)
66 init_size = 1*K - slack, // Size of first chunk (normal aka small)
67 medium_size= 10*K - slack, // Size of medium-sized chunk
68 size = 32*K - slack, // Default size of an Arena chunk (following the first)
69 non_pool_size = init_size + 32 // An initial size which is not one of above
70 };
71
72 void chop(); // Chop this chunk
73 void next_chop(); // Chop next chunk
74 static size_t aligned_overhead_size(void) { return ARENA_ALIGN(sizeof(Chunk)); }
75 static size_t aligned_overhead_size(size_t byte_size) { return ARENA_ALIGN(byte_size); }
76
77 size_t length() const { return _len; }
78 Chunk* next() const { return _next; }
79 void set_next(Chunk* n) { _next = n; }
80 // Boundaries of data area (possibly unused)
81 char* bottom() const { return ((char*) this) + aligned_overhead_size(); }
82 char* top() const { return bottom() + _len; }
83 bool contains(char* p) const { return bottom() <= p && p <= top(); }
84
85 // Start the chunk_pool cleaner task
86 static void start_chunk_pool_cleaner_task();
87
88 static void clean_chunk_pool();
89};
90
91//------------------------------Arena------------------------------------------
92// Fast allocation of memory
93class Arena : public CHeapObj<mtNone> {
94protected:
95 friend class ResourceMark;
96 friend class HandleMark;
97 friend class NoHandleMark;
98 friend class VMStructs;
99
100 MEMFLAGS _flags; // Memory tracking flags
101
102 Chunk *_first; // First chunk
103 Chunk *_chunk; // current chunk
104 char *_hwm, *_max; // High water mark and max in current chunk
105 // Get a new Chunk of at least size x
106 void* grow(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
107 size_t _size_in_bytes; // Size of arena (used for native memory tracking)
108
109 NOT_PRODUCT(static julong _bytes_allocated;) // total #bytes allocated since start
110 friend class AllocStats;
111 debug_only(void* malloc(size_t size);)
112 debug_only(void* internal_malloc_4(size_t x);)
113 NOT_PRODUCT(void inc_bytes_allocated(size_t x);)
114
115 void signal_out_of_memory(size_t request, const char* whence) const;
116
117 bool check_for_overflow(size_t request, const char* whence,
118 AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) const {
119 if (UINTPTR_MAX - request < (uintptr_t)_hwm) {
120 if (alloc_failmode == AllocFailStrategy::RETURN_NULL) {
121 return false;
122 }
123 signal_out_of_memory(request, whence);
124 }
125 return true;
126 }
127
128 public:
129 Arena(MEMFLAGS memflag);
130 Arena(MEMFLAGS memflag, size_t init_size);
131 ~Arena();
132 void destruct_contents();
133 char* hwm() const { return _hwm; }
134
135 // new operators
136 void* operator new (size_t size) throw();
137 void* operator new (size_t size, const std::nothrow_t& nothrow_constant) throw();
138
139 // dynamic memory type tagging
140 void* operator new(size_t size, MEMFLAGS flags) throw();
141 void* operator new(size_t size, const std::nothrow_t& nothrow_constant, MEMFLAGS flags) throw();
142 void operator delete(void* p);
143
144 // Fast allocate in the arena. Common case is: pointer test + increment.
145 void* Amalloc(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) {
146 assert(is_power_of_2(ARENA_AMALLOC_ALIGNMENT) , "should be a power of 2");
147 x = ARENA_ALIGN(x);
148 debug_only(if (UseMallocOnly) return malloc(x);)
149 if (!check_for_overflow(x, "Arena::Amalloc", alloc_failmode))
150 return NULL;
151 NOT_PRODUCT(inc_bytes_allocated(x);)
152 if (_hwm + x > _max) {
153 return grow(x, alloc_failmode);
154 } else {
155 char *old = _hwm;
156 _hwm += x;
157 return old;
158 }
159 }
160 // Further assume size is padded out to words
161 void *Amalloc_4(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) {
162 assert( (x&(sizeof(char*)-1)) == 0, "misaligned size" );
163 debug_only(if (UseMallocOnly) return malloc(x);)
164 if (!check_for_overflow(x, "Arena::Amalloc_4", 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
176 // Allocate with 'double' alignment. It is 8 bytes on sparc.
177 // In other cases Amalloc_D() should be the same as Amalloc_4().
178 void* Amalloc_D(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) {
179 assert( (x&(sizeof(char*)-1)) == 0, "misaligned size" );
180 debug_only(if (UseMallocOnly) return malloc(x);)
181#if defined(SPARC) && !defined(_LP64)
182#define DALIGN_M1 7
183 size_t delta = (((size_t)_hwm + DALIGN_M1) & ~DALIGN_M1) - (size_t)_hwm;
184 x += delta;
185#endif
186 if (!check_for_overflow(x, "Arena::Amalloc_D", alloc_failmode))
187 return NULL;
188 NOT_PRODUCT(inc_bytes_allocated(x);)
189 if (_hwm + x > _max) {
190 return grow(x, alloc_failmode); // grow() returns a result aligned >= 8 bytes.
191 } else {
192 char *old = _hwm;
193 _hwm += x;
194#if defined(SPARC) && !defined(_LP64)
195 old += delta; // align to 8-bytes
196#endif
197 return old;
198 }
199 }
200
201 // Fast delete in area. Common case is: NOP (except for storage reclaimed)
202 bool Afree(void *ptr, size_t size) {
203#ifdef ASSERT
204 if (ZapResourceArea) memset(ptr, badResourceValue, size); // zap freed memory
205 if (UseMallocOnly) return true;
206#endif
207 if (((char*)ptr) + size == _hwm) {
208 _hwm = (char*)ptr;
209 return true;
210 } else {
211 // Unable to fast free, so we just drop it.
212 return false;
213 }
214 }
215
216 void *Arealloc( void *old_ptr, size_t old_size, size_t new_size,
217 AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
218
219 // Move contents of this arena into an empty arena
220 Arena *move_contents(Arena *empty_arena);
221
222 // Determine if pointer belongs to this Arena or not.
223 bool contains( const void *ptr ) const;
224
225 // Total of all chunks in use (not thread-safe)
226 size_t used() const;
227
228 // Total # of bytes used
229 size_t size_in_bytes() const { return _size_in_bytes; };
230 void set_size_in_bytes(size_t size);
231
232 static void free_malloced_objects(Chunk* chunk, char* hwm, char* max, char* hwm2) PRODUCT_RETURN;
233 static void free_all(char** start, char** end) PRODUCT_RETURN;
234
235private:
236 // Reset this Arena to empty, access will trigger grow if necessary
237 void reset(void) {
238 _first = _chunk = NULL;
239 _hwm = _max = NULL;
240 set_size_in_bytes(0);
241 }
242};
243
244// One of the following macros must be used when allocating
245// an array or object from an arena
246#define NEW_ARENA_ARRAY(arena, type, size) \
247 (type*) (arena)->Amalloc((size) * sizeof(type))
248
249#define REALLOC_ARENA_ARRAY(arena, type, old, old_size, new_size) \
250 (type*) (arena)->Arealloc((char*)(old), (old_size) * sizeof(type), \
251 (new_size) * sizeof(type) )
252
253#define FREE_ARENA_ARRAY(arena, type, old, size) \
254 (arena)->Afree((char*)(old), (size) * sizeof(type))
255
256#define NEW_ARENA_OBJ(arena, type) \
257 NEW_ARENA_ARRAY(arena, type, 1)
258
259#endif // SHARE_MEMORY_ARENA_HPP
260