Tue, 28 Sep 2010 15:56:15 -0700
6423256: GC stacks should use a better data structure
6942771: SEGV in ParScanThreadState::take_from_overflow_stack
Reviewed-by: apetrusenko, ysr, pbk
jcoomes@2191 | 1 | /* |
jcoomes@2191 | 2 | * Copyright 2009 Sun Microsystems, Inc. All Rights Reserved. |
jcoomes@2191 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
jcoomes@2191 | 4 | * |
jcoomes@2191 | 5 | * This code is free software; you can redistribute it and/or modify it |
jcoomes@2191 | 6 | * under the terms of the GNU General Public License version 2 only, as |
jcoomes@2191 | 7 | * published by the Free Software Foundation. |
jcoomes@2191 | 8 | * |
jcoomes@2191 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
jcoomes@2191 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
jcoomes@2191 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
jcoomes@2191 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
jcoomes@2191 | 13 | * accompanied this code). |
jcoomes@2191 | 14 | * |
jcoomes@2191 | 15 | * You should have received a copy of the GNU General Public License version |
jcoomes@2191 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
jcoomes@2191 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
jcoomes@2191 | 18 | * |
jcoomes@2191 | 19 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
jcoomes@2191 | 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
jcoomes@2191 | 21 | * have any questions. |
jcoomes@2191 | 22 | * |
jcoomes@2191 | 23 | */ |
jcoomes@2191 | 24 | |
jcoomes@2191 | 25 | StackBase::StackBase(size_t segment_size, size_t max_cache_size, |
jcoomes@2191 | 26 | size_t max_size): |
jcoomes@2191 | 27 | _seg_size(segment_size), |
jcoomes@2191 | 28 | _max_cache_size(max_cache_size), |
jcoomes@2191 | 29 | _max_size(adjust_max_size(max_size, segment_size)) |
jcoomes@2191 | 30 | { |
jcoomes@2191 | 31 | assert(_max_size % _seg_size == 0, "not a multiple"); |
jcoomes@2191 | 32 | } |
jcoomes@2191 | 33 | |
jcoomes@2191 | 34 | size_t StackBase::adjust_max_size(size_t max_size, size_t seg_size) |
jcoomes@2191 | 35 | { |
jcoomes@2191 | 36 | assert(seg_size > 0, "cannot be 0"); |
jcoomes@2191 | 37 | assert(max_size >= seg_size || max_size == 0, "max_size too small"); |
jcoomes@2191 | 38 | const size_t limit = max_uintx - (seg_size - 1); |
jcoomes@2191 | 39 | if (max_size == 0 || max_size > limit) { |
jcoomes@2191 | 40 | max_size = limit; |
jcoomes@2191 | 41 | } |
jcoomes@2191 | 42 | return (max_size + seg_size - 1) / seg_size * seg_size; |
jcoomes@2191 | 43 | } |
jcoomes@2191 | 44 | |
jcoomes@2191 | 45 | template <class E> |
jcoomes@2191 | 46 | Stack<E>::Stack(size_t segment_size, size_t max_cache_size, size_t max_size): |
jcoomes@2191 | 47 | StackBase(adjust_segment_size(segment_size), max_cache_size, max_size) |
jcoomes@2191 | 48 | { |
jcoomes@2191 | 49 | reset(true); |
jcoomes@2191 | 50 | } |
jcoomes@2191 | 51 | |
jcoomes@2191 | 52 | template <class E> |
jcoomes@2191 | 53 | void Stack<E>::push(E item) |
jcoomes@2191 | 54 | { |
jcoomes@2191 | 55 | assert(!is_full(), "pushing onto a full stack"); |
jcoomes@2191 | 56 | if (_cur_seg_size == _seg_size) { |
jcoomes@2191 | 57 | push_segment(); |
jcoomes@2191 | 58 | } |
jcoomes@2191 | 59 | _cur_seg[_cur_seg_size] = item; |
jcoomes@2191 | 60 | ++_cur_seg_size; |
jcoomes@2191 | 61 | } |
jcoomes@2191 | 62 | |
jcoomes@2191 | 63 | template <class E> |
jcoomes@2191 | 64 | E Stack<E>::pop() |
jcoomes@2191 | 65 | { |
jcoomes@2191 | 66 | assert(!is_empty(), "popping from an empty stack"); |
jcoomes@2191 | 67 | if (_cur_seg_size == 1) { |
jcoomes@2191 | 68 | E tmp = _cur_seg[--_cur_seg_size]; |
jcoomes@2191 | 69 | pop_segment(); |
jcoomes@2191 | 70 | return tmp; |
jcoomes@2191 | 71 | } |
jcoomes@2191 | 72 | return _cur_seg[--_cur_seg_size]; |
jcoomes@2191 | 73 | } |
jcoomes@2191 | 74 | |
jcoomes@2191 | 75 | template <class E> |
jcoomes@2191 | 76 | void Stack<E>::clear(bool clear_cache) |
jcoomes@2191 | 77 | { |
jcoomes@2191 | 78 | free_segments(_cur_seg); |
jcoomes@2191 | 79 | if (clear_cache) free_segments(_cache); |
jcoomes@2191 | 80 | reset(clear_cache); |
jcoomes@2191 | 81 | } |
jcoomes@2191 | 82 | |
jcoomes@2191 | 83 | template <class E> |
jcoomes@2191 | 84 | size_t Stack<E>::default_segment_size() |
jcoomes@2191 | 85 | { |
jcoomes@2191 | 86 | // Number of elements that fit in 4K bytes minus the size of two pointers |
jcoomes@2191 | 87 | // (link field and malloc header). |
jcoomes@2191 | 88 | return (4096 - 2 * sizeof(E*)) / sizeof(E); |
jcoomes@2191 | 89 | } |
jcoomes@2191 | 90 | |
jcoomes@2191 | 91 | template <class E> |
jcoomes@2191 | 92 | size_t Stack<E>::adjust_segment_size(size_t seg_size) |
jcoomes@2191 | 93 | { |
jcoomes@2191 | 94 | const size_t elem_sz = sizeof(E); |
jcoomes@2191 | 95 | const size_t ptr_sz = sizeof(E*); |
jcoomes@2191 | 96 | assert(elem_sz % ptr_sz == 0 || ptr_sz % elem_sz == 0, "bad element size"); |
jcoomes@2191 | 97 | if (elem_sz < ptr_sz) { |
jcoomes@2191 | 98 | return align_size_up(seg_size * elem_sz, ptr_sz) / elem_sz; |
jcoomes@2191 | 99 | } |
jcoomes@2191 | 100 | return seg_size; |
jcoomes@2191 | 101 | } |
jcoomes@2191 | 102 | |
jcoomes@2191 | 103 | template <class E> |
jcoomes@2191 | 104 | size_t Stack<E>::link_offset() const |
jcoomes@2191 | 105 | { |
jcoomes@2191 | 106 | return align_size_up(_seg_size * sizeof(E), sizeof(E*)); |
jcoomes@2191 | 107 | } |
jcoomes@2191 | 108 | |
jcoomes@2191 | 109 | template <class E> |
jcoomes@2191 | 110 | size_t Stack<E>::segment_bytes() const |
jcoomes@2191 | 111 | { |
jcoomes@2191 | 112 | return link_offset() + sizeof(E*); |
jcoomes@2191 | 113 | } |
jcoomes@2191 | 114 | |
jcoomes@2191 | 115 | template <class E> |
jcoomes@2191 | 116 | E** Stack<E>::link_addr(E* seg) const |
jcoomes@2191 | 117 | { |
jcoomes@2191 | 118 | return (E**) ((char*)seg + link_offset()); |
jcoomes@2191 | 119 | } |
jcoomes@2191 | 120 | |
jcoomes@2191 | 121 | template <class E> |
jcoomes@2191 | 122 | E* Stack<E>::get_link(E* seg) const |
jcoomes@2191 | 123 | { |
jcoomes@2191 | 124 | return *link_addr(seg); |
jcoomes@2191 | 125 | } |
jcoomes@2191 | 126 | |
jcoomes@2191 | 127 | template <class E> |
jcoomes@2191 | 128 | E* Stack<E>::set_link(E* new_seg, E* old_seg) |
jcoomes@2191 | 129 | { |
jcoomes@2191 | 130 | *link_addr(new_seg) = old_seg; |
jcoomes@2191 | 131 | return new_seg; |
jcoomes@2191 | 132 | } |
jcoomes@2191 | 133 | |
jcoomes@2191 | 134 | template <class E> |
jcoomes@2191 | 135 | E* Stack<E>::alloc(size_t bytes) |
jcoomes@2191 | 136 | { |
jcoomes@2191 | 137 | return (E*) NEW_C_HEAP_ARRAY(char, bytes); |
jcoomes@2191 | 138 | } |
jcoomes@2191 | 139 | |
jcoomes@2191 | 140 | template <class E> |
jcoomes@2191 | 141 | void Stack<E>::free(E* addr, size_t bytes) |
jcoomes@2191 | 142 | { |
jcoomes@2191 | 143 | FREE_C_HEAP_ARRAY(char, (char*) addr); |
jcoomes@2191 | 144 | } |
jcoomes@2191 | 145 | |
jcoomes@2191 | 146 | template <class E> |
jcoomes@2191 | 147 | void Stack<E>::push_segment() |
jcoomes@2191 | 148 | { |
jcoomes@2191 | 149 | assert(_cur_seg_size == _seg_size, "current segment is not full"); |
jcoomes@2191 | 150 | E* next; |
jcoomes@2191 | 151 | if (_cache_size > 0) { |
jcoomes@2191 | 152 | // Use a cached segment. |
jcoomes@2191 | 153 | next = _cache; |
jcoomes@2191 | 154 | _cache = get_link(_cache); |
jcoomes@2191 | 155 | --_cache_size; |
jcoomes@2191 | 156 | } else { |
jcoomes@2191 | 157 | next = alloc(segment_bytes()); |
jcoomes@2191 | 158 | DEBUG_ONLY(zap_segment(next, true);) |
jcoomes@2191 | 159 | } |
jcoomes@2191 | 160 | const bool at_empty_transition = is_empty(); |
jcoomes@2191 | 161 | _cur_seg = set_link(next, _cur_seg); |
jcoomes@2191 | 162 | _cur_seg_size = 0; |
jcoomes@2191 | 163 | _full_seg_size += at_empty_transition ? 0 : _seg_size; |
jcoomes@2191 | 164 | DEBUG_ONLY(verify(at_empty_transition);) |
jcoomes@2191 | 165 | } |
jcoomes@2191 | 166 | |
jcoomes@2191 | 167 | template <class E> |
jcoomes@2191 | 168 | void Stack<E>::pop_segment() |
jcoomes@2191 | 169 | { |
jcoomes@2191 | 170 | assert(_cur_seg_size == 0, "current segment is not empty"); |
jcoomes@2191 | 171 | E* const prev = get_link(_cur_seg); |
jcoomes@2191 | 172 | if (_cache_size < _max_cache_size) { |
jcoomes@2191 | 173 | // Add the current segment to the cache. |
jcoomes@2191 | 174 | DEBUG_ONLY(zap_segment(_cur_seg, false);) |
jcoomes@2191 | 175 | _cache = set_link(_cur_seg, _cache); |
jcoomes@2191 | 176 | ++_cache_size; |
jcoomes@2191 | 177 | } else { |
jcoomes@2191 | 178 | DEBUG_ONLY(zap_segment(_cur_seg, true);) |
jcoomes@2191 | 179 | free(_cur_seg, segment_bytes()); |
jcoomes@2191 | 180 | } |
jcoomes@2191 | 181 | const bool at_empty_transition = prev == NULL; |
jcoomes@2191 | 182 | _cur_seg = prev; |
jcoomes@2191 | 183 | _cur_seg_size = _seg_size; |
jcoomes@2191 | 184 | _full_seg_size -= at_empty_transition ? 0 : _seg_size; |
jcoomes@2191 | 185 | DEBUG_ONLY(verify(at_empty_transition);) |
jcoomes@2191 | 186 | } |
jcoomes@2191 | 187 | |
jcoomes@2191 | 188 | template <class E> |
jcoomes@2191 | 189 | void Stack<E>::free_segments(E* seg) |
jcoomes@2191 | 190 | { |
jcoomes@2191 | 191 | const size_t bytes = segment_bytes(); |
jcoomes@2191 | 192 | while (seg != NULL) { |
jcoomes@2191 | 193 | E* const prev = get_link(seg); |
jcoomes@2191 | 194 | free(seg, bytes); |
jcoomes@2191 | 195 | seg = prev; |
jcoomes@2191 | 196 | } |
jcoomes@2191 | 197 | } |
jcoomes@2191 | 198 | |
jcoomes@2191 | 199 | template <class E> |
jcoomes@2191 | 200 | void Stack<E>::reset(bool reset_cache) |
jcoomes@2191 | 201 | { |
jcoomes@2191 | 202 | _cur_seg_size = _seg_size; // So push() will alloc a new segment. |
jcoomes@2191 | 203 | _full_seg_size = 0; |
jcoomes@2191 | 204 | _cur_seg = NULL; |
jcoomes@2191 | 205 | if (reset_cache) { |
jcoomes@2191 | 206 | _cache_size = 0; |
jcoomes@2191 | 207 | _cache = NULL; |
jcoomes@2191 | 208 | } |
jcoomes@2191 | 209 | } |
jcoomes@2191 | 210 | |
jcoomes@2191 | 211 | #ifdef ASSERT |
jcoomes@2191 | 212 | template <class E> |
jcoomes@2191 | 213 | void Stack<E>::verify(bool at_empty_transition) const |
jcoomes@2191 | 214 | { |
jcoomes@2191 | 215 | assert(size() <= max_size(), "stack exceeded bounds"); |
jcoomes@2191 | 216 | assert(cache_size() <= max_cache_size(), "cache exceeded bounds"); |
jcoomes@2191 | 217 | assert(_cur_seg_size <= segment_size(), "segment index exceeded bounds"); |
jcoomes@2191 | 218 | |
jcoomes@2191 | 219 | assert(_full_seg_size % _seg_size == 0, "not a multiple"); |
jcoomes@2191 | 220 | assert(at_empty_transition || is_empty() == (size() == 0), "mismatch"); |
jcoomes@2191 | 221 | assert((_cache == NULL) == (cache_size() == 0), "mismatch"); |
jcoomes@2191 | 222 | |
jcoomes@2191 | 223 | if (is_empty()) { |
jcoomes@2191 | 224 | assert(_cur_seg_size == segment_size(), "sanity"); |
jcoomes@2191 | 225 | } |
jcoomes@2191 | 226 | } |
jcoomes@2191 | 227 | |
jcoomes@2191 | 228 | template <class E> |
jcoomes@2191 | 229 | void Stack<E>::zap_segment(E* seg, bool zap_link_field) const |
jcoomes@2191 | 230 | { |
jcoomes@2191 | 231 | if (!ZapStackSegments) return; |
jcoomes@2191 | 232 | const size_t zap_bytes = segment_bytes() - (zap_link_field ? 0 : sizeof(E*)); |
jcoomes@2191 | 233 | uint32_t* cur = (uint32_t*)seg; |
jcoomes@2191 | 234 | const uint32_t* end = cur + zap_bytes / sizeof(uint32_t); |
jcoomes@2191 | 235 | while (cur < end) { |
jcoomes@2191 | 236 | *cur++ = 0xfadfaded; |
jcoomes@2191 | 237 | } |
jcoomes@2191 | 238 | } |
jcoomes@2191 | 239 | #endif |
jcoomes@2191 | 240 | |
jcoomes@2191 | 241 | template <class E> |
jcoomes@2191 | 242 | E* ResourceStack<E>::alloc(size_t bytes) |
jcoomes@2191 | 243 | { |
jcoomes@2191 | 244 | return (E*) resource_allocate_bytes(bytes); |
jcoomes@2191 | 245 | } |
jcoomes@2191 | 246 | |
jcoomes@2191 | 247 | template <class E> |
jcoomes@2191 | 248 | void ResourceStack<E>::free(E* addr, size_t bytes) |
jcoomes@2191 | 249 | { |
jcoomes@2191 | 250 | resource_free_bytes((char*) addr, bytes); |
jcoomes@2191 | 251 | } |
jcoomes@2191 | 252 | |
jcoomes@2191 | 253 | template <class E> |
jcoomes@2191 | 254 | void StackIterator<E>::sync() |
jcoomes@2191 | 255 | { |
jcoomes@2191 | 256 | _full_seg_size = _stack._full_seg_size; |
jcoomes@2191 | 257 | _cur_seg_size = _stack._cur_seg_size; |
jcoomes@2191 | 258 | _cur_seg = _stack._cur_seg; |
jcoomes@2191 | 259 | } |
jcoomes@2191 | 260 | |
jcoomes@2191 | 261 | template <class E> |
jcoomes@2191 | 262 | E* StackIterator<E>::next_addr() |
jcoomes@2191 | 263 | { |
jcoomes@2191 | 264 | assert(!is_empty(), "no items left"); |
jcoomes@2191 | 265 | if (_cur_seg_size == 1) { |
jcoomes@2191 | 266 | E* addr = _cur_seg; |
jcoomes@2191 | 267 | _cur_seg = _stack.get_link(_cur_seg); |
jcoomes@2191 | 268 | _cur_seg_size = _stack.segment_size(); |
jcoomes@2191 | 269 | _full_seg_size -= _stack.segment_size(); |
jcoomes@2191 | 270 | return addr; |
jcoomes@2191 | 271 | } |
jcoomes@2191 | 272 | return _cur_seg + --_cur_seg_size; |
jcoomes@2191 | 273 | } |