1 /*
2 * Copyright (c) 2009, 2014, 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_VM_UTILITIES_STACK_INLINE_HPP
26 #define SHARE_VM_UTILITIES_STACK_INLINE_HPP
27
28 #include "utilities/stack.hpp"
29
30 template <MEMFLAGS F> StackBase<F>::StackBase(size_t segment_size, size_t max_cache_size,
31 size_t max_size):
32 _seg_size(segment_size),
33 _max_cache_size(max_cache_size),
34 _max_size(adjust_max_size(max_size, segment_size))
35 {
36 assert(_max_size % _seg_size == 0, "not a multiple");
37 }
38
39 template <MEMFLAGS F> size_t StackBase<F>::adjust_max_size(size_t max_size, size_t seg_size)
40 {
41 assert(seg_size > 0, "cannot be 0");
42 assert(max_size >= seg_size || max_size == 0, "max_size too small");
43 const size_t limit = max_uintx - (seg_size - 1);
44 if (max_size == 0 || max_size > limit) {
45 max_size = limit;
46 }
47 return (max_size + seg_size - 1) / seg_size * seg_size;
48 }
49
50 template <class E, MEMFLAGS F>
51 Stack<E, F>::Stack(size_t segment_size, size_t max_cache_size, size_t max_size):
52 StackBase<F>(adjust_segment_size(segment_size), max_cache_size, max_size)
53 {
54 reset(true);
55 }
56
57 template <class E, MEMFLAGS F>
58 void Stack<E, F>::push(E item)
59 {
60 assert(!is_full(), "pushing onto a full stack");
61 if (this->_cur_seg_size == this->_seg_size) {
62 push_segment();
63 }
64 this->_cur_seg[this->_cur_seg_size] = item;
65 ++this->_cur_seg_size;
66 }
67
68 template <class E, MEMFLAGS F>
69 E Stack<E, F>::pop()
70 {
71 assert(!is_empty(), "popping from an empty stack");
72 if (this->_cur_seg_size == 1) {
73 E tmp = _cur_seg[--this->_cur_seg_size];
74 pop_segment();
75 return tmp;
76 }
77 return this->_cur_seg[--this->_cur_seg_size];
78 }
79
80 template <class E, MEMFLAGS F>
81 void Stack<E, F>::clear(bool clear_cache)
82 {
83 free_segments(_cur_seg);
84 if (clear_cache) free_segments(_cache);
85 reset(clear_cache);
86 }
87
88 template <class E, MEMFLAGS F>
89 size_t Stack<E, F>::default_segment_size()
90 {
91 // Number of elements that fit in 4K bytes minus the size of two pointers
92 // (link field and malloc header).
93 return (4096 - 2 * sizeof(E*)) / sizeof(E);
94 }
95
96 template <class E, MEMFLAGS F>
97 size_t Stack<E, F>::adjust_segment_size(size_t seg_size)
98 {
99 const size_t elem_sz = sizeof(E);
100 const size_t ptr_sz = sizeof(E*);
101 assert(elem_sz % ptr_sz == 0 || ptr_sz % elem_sz == 0, "bad element size");
102 if (elem_sz < ptr_sz) {
103 return align_size_up(seg_size * elem_sz, ptr_sz) / elem_sz;
104 }
105 return seg_size;
106 }
107
108 template <class E, MEMFLAGS F>
109 size_t Stack<E, F>::link_offset() const
110 {
111 return align_size_up(this->_seg_size * sizeof(E), sizeof(E*));
112 }
113
114 template <class E, MEMFLAGS F>
115 size_t Stack<E, F>::segment_bytes() const
116 {
117 return link_offset() + sizeof(E*);
118 }
119
120 template <class E, MEMFLAGS F>
121 E** Stack<E, F>::link_addr(E* seg) const
122 {
123 return (E**) ((char*)seg + link_offset());
124 }
125
126 template <class E, MEMFLAGS F>
127 E* Stack<E, F>::get_link(E* seg) const
128 {
129 return *link_addr(seg);
130 }
131
132 template <class E, MEMFLAGS F>
133 E* Stack<E, F>::set_link(E* new_seg, E* old_seg)
134 {
135 *link_addr(new_seg) = old_seg;
136 return new_seg;
137 }
138
139 template <class E, MEMFLAGS F>
140 E* Stack<E, F>::alloc(size_t bytes)
141 {
142 return (E*) NEW_C_HEAP_ARRAY(char, bytes, F);
143 }
144
145 template <class E, MEMFLAGS F>
146 void Stack<E, F>::free(E* addr, size_t bytes)
147 {
148 FREE_C_HEAP_ARRAY(char, (char*) addr);
149 }
150
151 template <class E, MEMFLAGS F>
152 void Stack<E, F>::push_segment()
153 {
154 assert(this->_cur_seg_size == this->_seg_size, "current segment is not full");
155 E* next;
156 if (this->_cache_size > 0) {
157 // Use a cached segment.
158 next = _cache;
159 _cache = get_link(_cache);
160 --this->_cache_size;
161 } else {
162 next = alloc(segment_bytes());
163 DEBUG_ONLY(zap_segment(next, true);)
164 }
165 const bool at_empty_transition = is_empty();
166 this->_cur_seg = set_link(next, _cur_seg);
167 this->_cur_seg_size = 0;
168 this->_full_seg_size += at_empty_transition ? 0 : this->_seg_size;
169 DEBUG_ONLY(verify(at_empty_transition);)
170 }
171
172 template <class E, MEMFLAGS F>
173 void Stack<E, F>::pop_segment()
174 {
175 assert(this->_cur_seg_size == 0, "current segment is not empty");
176 E* const prev = get_link(_cur_seg);
177 if (this->_cache_size < this->_max_cache_size) {
178 // Add the current segment to the cache.
179 DEBUG_ONLY(zap_segment(_cur_seg, false);)
180 _cache = set_link(_cur_seg, _cache);
181 ++this->_cache_size;
182 } else {
183 DEBUG_ONLY(zap_segment(_cur_seg, true);)
184 free(_cur_seg, segment_bytes());
185 }
186 const bool at_empty_transition = prev == NULL;
187 this->_cur_seg = prev;
188 this->_cur_seg_size = this->_seg_size;
189 this->_full_seg_size -= at_empty_transition ? 0 : this->_seg_size;
190 DEBUG_ONLY(verify(at_empty_transition);)
191 }
192
193 template <class E, MEMFLAGS F>
194 void Stack<E, F>::free_segments(E* seg)
195 {
196 const size_t bytes = segment_bytes();
197 while (seg != NULL) {
198 E* const prev = get_link(seg);
199 free(seg, bytes);
200 seg = prev;
201 }
202 }
203
204 template <class E, MEMFLAGS F>
205 void Stack<E, F>::reset(bool reset_cache)
206 {
207 this->_cur_seg_size = this->_seg_size; // So push() will alloc a new segment.
208 this->_full_seg_size = 0;
209 _cur_seg = NULL;
210 if (reset_cache) {
211 this->_cache_size = 0;
212 _cache = NULL;
213 }
214 }
215
216 #ifdef ASSERT
217 template <class E, MEMFLAGS F>
218 void Stack<E, F>::verify(bool at_empty_transition) const
219 {
220 assert(size() <= this->max_size(), "stack exceeded bounds");
221 assert(this->cache_size() <= this->max_cache_size(), "cache exceeded bounds");
222 assert(this->_cur_seg_size <= this->segment_size(), "segment index exceeded bounds");
223
224 assert(this->_full_seg_size % this->_seg_size == 0, "not a multiple");
225 assert(at_empty_transition || is_empty() == (size() == 0), "mismatch");
226 assert((_cache == NULL) == (this->cache_size() == 0), "mismatch");
227
228 if (is_empty()) {
229 assert(this->_cur_seg_size == this->segment_size(), "sanity");
230 }
231 }
232
233 template <class E, MEMFLAGS F>
234 void Stack<E, F>::zap_segment(E* seg, bool zap_link_field) const
235 {
236 if (!ZapStackSegments) return;
237 const size_t zap_bytes = segment_bytes() - (zap_link_field ? 0 : sizeof(E*));
238 uint32_t* cur = (uint32_t*)seg;
239 const uint32_t* end = cur + zap_bytes / sizeof(uint32_t);
240 while (cur < end) {
241 *cur++ = 0xfadfaded;
242 }
243 }
244 #endif
245
246 template <class E, MEMFLAGS F>
247 E* ResourceStack<E, F>::alloc(size_t bytes)
248 {
249 return (E*) resource_allocate_bytes(bytes);
250 }
251
252 template <class E, MEMFLAGS F>
253 void ResourceStack<E, F>::free(E* addr, size_t bytes)
254 {
255 resource_free_bytes((char*) addr, bytes);
256 }
257
258 template <class E, MEMFLAGS F>
259 void StackIterator<E, F>::sync()
260 {
261 _full_seg_size = _stack._full_seg_size;
262 _cur_seg_size = _stack._cur_seg_size;
263 _cur_seg = _stack._cur_seg;
264 }
265
266 template <class E, MEMFLAGS F>
267 E* StackIterator<E, F>::next_addr()
268 {
269 assert(!is_empty(), "no items left");
270 if (_cur_seg_size == 1) {
271 E* addr = _cur_seg;
272 _cur_seg = _stack.get_link(_cur_seg);
273 _cur_seg_size = _stack.segment_size();
274 _full_seg_size -= _stack.segment_size();
275 return addr;
276 }
277 return _cur_seg + --_cur_seg_size;
278 }
279
280 #endif // SHARE_VM_UTILITIES_STACK_INLINE_HPP