Tue, 05 May 2009 22:15:35 -0700
6833576: G1: assert illegal index, growableArray.hpp:186
Summary: The code that calculates the heap region index for an object address incorrectly used signed arithmetic.
Reviewed-by: jcoomes, ysr
1 /*
2 * Copyright 2001-2008 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
25 # include "incls/_precompiled.incl"
26 # include "incls/_ptrQueue.cpp.incl"
28 PtrQueue::PtrQueue(PtrQueueSet* qset_, bool perm) :
29 _qset(qset_), _buf(NULL), _index(0), _active(false),
30 _perm(perm), _lock(NULL)
31 {}
33 void PtrQueue::flush() {
34 if (!_perm && _buf != NULL) {
35 if (_index == _sz) {
36 // No work to do.
37 qset()->deallocate_buffer(_buf);
38 } else {
39 // We must NULL out the unused entries, then enqueue.
40 for (size_t i = 0; i < _index; i += oopSize) {
41 _buf[byte_index_to_index((int)i)] = NULL;
42 }
43 qset()->enqueue_complete_buffer(_buf);
44 }
45 _buf = NULL;
46 _index = 0;
47 }
48 }
51 static int byte_index_to_index(int ind) {
52 assert((ind % oopSize) == 0, "Invariant.");
53 return ind / oopSize;
54 }
56 static int index_to_byte_index(int byte_ind) {
57 return byte_ind * oopSize;
58 }
60 void PtrQueue::enqueue_known_active(void* ptr) {
61 assert(0 <= _index && _index <= _sz, "Invariant.");
62 assert(_index == 0 || _buf != NULL, "invariant");
64 while (_index == 0) {
65 handle_zero_index();
66 }
67 assert(_index > 0, "postcondition");
69 _index -= oopSize;
70 _buf[byte_index_to_index((int)_index)] = ptr;
71 assert(0 <= _index && _index <= _sz, "Invariant.");
72 }
74 void PtrQueue::locking_enqueue_completed_buffer(void** buf) {
75 assert(_lock->owned_by_self(), "Required.");
76 _lock->unlock();
77 qset()->enqueue_complete_buffer(buf);
78 // We must relock only because the caller will unlock, for the normal
79 // case.
80 _lock->lock_without_safepoint_check();
81 }
84 PtrQueueSet::PtrQueueSet(bool notify_when_complete) :
85 _max_completed_queue(0),
86 _cbl_mon(NULL), _fl_lock(NULL),
87 _notify_when_complete(notify_when_complete),
88 _sz(0),
89 _completed_buffers_head(NULL),
90 _completed_buffers_tail(NULL),
91 _n_completed_buffers(0),
92 _process_completed_threshold(0), _process_completed(false),
93 _buf_free_list(NULL), _buf_free_list_sz(0)
94 {
95 _fl_owner = this;
96 }
98 void** PtrQueueSet::allocate_buffer() {
99 assert(_sz > 0, "Didn't set a buffer size.");
100 MutexLockerEx x(_fl_owner->_fl_lock, Mutex::_no_safepoint_check_flag);
101 if (_fl_owner->_buf_free_list != NULL) {
102 void** res = _fl_owner->_buf_free_list;
103 _fl_owner->_buf_free_list = (void**)_fl_owner->_buf_free_list[0];
104 _fl_owner->_buf_free_list_sz--;
105 // Just override the next pointer with NULL, just in case we scan this part
106 // of the buffer.
107 res[0] = NULL;
108 return res;
109 } else {
110 return NEW_C_HEAP_ARRAY(void*, _sz);
111 }
112 }
114 void PtrQueueSet::deallocate_buffer(void** buf) {
115 assert(_sz > 0, "Didn't set a buffer size.");
116 MutexLockerEx x(_fl_owner->_fl_lock, Mutex::_no_safepoint_check_flag);
117 buf[0] = (void*)_fl_owner->_buf_free_list;
118 _fl_owner->_buf_free_list = buf;
119 _fl_owner->_buf_free_list_sz++;
120 }
122 void PtrQueueSet::reduce_free_list() {
123 // For now we'll adopt the strategy of deleting half.
124 MutexLockerEx x(_fl_lock, Mutex::_no_safepoint_check_flag);
125 size_t n = _buf_free_list_sz / 2;
126 while (n > 0) {
127 assert(_buf_free_list != NULL, "_buf_free_list_sz must be wrong.");
128 void** head = _buf_free_list;
129 _buf_free_list = (void**)_buf_free_list[0];
130 FREE_C_HEAP_ARRAY(void*,head);
131 n--;
132 }
133 }
135 void PtrQueueSet::enqueue_complete_buffer(void** buf, size_t index, bool ignore_max_completed) {
136 // I use explicit locking here because there's a bailout in the middle.
137 _cbl_mon->lock_without_safepoint_check();
139 Thread* thread = Thread::current();
140 assert( ignore_max_completed ||
141 thread->is_Java_thread() ||
142 SafepointSynchronize::is_at_safepoint(),
143 "invariant" );
144 ignore_max_completed = ignore_max_completed || !thread->is_Java_thread();
146 if (!ignore_max_completed && _max_completed_queue > 0 &&
147 _n_completed_buffers >= (size_t) _max_completed_queue) {
148 _cbl_mon->unlock();
149 bool b = mut_process_buffer(buf);
150 if (b) {
151 deallocate_buffer(buf);
152 return;
153 }
155 // Otherwise, go ahead and enqueue the buffer. Must reaquire the lock.
156 _cbl_mon->lock_without_safepoint_check();
157 }
159 // Here we still hold the _cbl_mon.
160 CompletedBufferNode* cbn = new CompletedBufferNode;
161 cbn->buf = buf;
162 cbn->next = NULL;
163 cbn->index = index;
164 if (_completed_buffers_tail == NULL) {
165 assert(_completed_buffers_head == NULL, "Well-formedness");
166 _completed_buffers_head = cbn;
167 _completed_buffers_tail = cbn;
168 } else {
169 _completed_buffers_tail->next = cbn;
170 _completed_buffers_tail = cbn;
171 }
172 _n_completed_buffers++;
174 if (!_process_completed &&
175 _n_completed_buffers == _process_completed_threshold) {
176 _process_completed = true;
177 if (_notify_when_complete)
178 _cbl_mon->notify_all();
179 }
180 debug_only(assert_completed_buffer_list_len_correct_locked());
181 _cbl_mon->unlock();
182 }
184 int PtrQueueSet::completed_buffers_list_length() {
185 int n = 0;
186 CompletedBufferNode* cbn = _completed_buffers_head;
187 while (cbn != NULL) {
188 n++;
189 cbn = cbn->next;
190 }
191 return n;
192 }
194 void PtrQueueSet::assert_completed_buffer_list_len_correct() {
195 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
196 assert_completed_buffer_list_len_correct_locked();
197 }
199 void PtrQueueSet::assert_completed_buffer_list_len_correct_locked() {
200 guarantee((size_t)completed_buffers_list_length() == _n_completed_buffers,
201 "Completed buffer length is wrong.");
202 }
204 void PtrQueueSet::set_buffer_size(size_t sz) {
205 assert(_sz == 0 && sz > 0, "Should be called only once.");
206 _sz = sz * oopSize;
207 }
209 void PtrQueueSet::set_process_completed_threshold(size_t sz) {
210 _process_completed_threshold = sz;
211 }
213 // Merge lists of buffers. Notify waiting threads if the length of the list
214 // exceeds threshold. The source queue is emptied as a result. The queues
215 // must share the monitor.
216 void PtrQueueSet::merge_bufferlists(PtrQueueSet *src) {
217 assert(_cbl_mon == src->_cbl_mon, "Should share the same lock");
218 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
219 if (_completed_buffers_tail == NULL) {
220 assert(_completed_buffers_head == NULL, "Well-formedness");
221 _completed_buffers_head = src->_completed_buffers_head;
222 _completed_buffers_tail = src->_completed_buffers_tail;
223 } else {
224 assert(_completed_buffers_head != NULL, "Well formedness");
225 if (src->_completed_buffers_head != NULL) {
226 _completed_buffers_tail->next = src->_completed_buffers_head;
227 _completed_buffers_tail = src->_completed_buffers_tail;
228 }
229 }
230 _n_completed_buffers += src->_n_completed_buffers;
232 src->_n_completed_buffers = 0;
233 src->_completed_buffers_head = NULL;
234 src->_completed_buffers_tail = NULL;
236 assert(_completed_buffers_head == NULL && _completed_buffers_tail == NULL ||
237 _completed_buffers_head != NULL && _completed_buffers_tail != NULL,
238 "Sanity");
240 if (!_process_completed &&
241 _n_completed_buffers >= _process_completed_threshold) {
242 _process_completed = true;
243 if (_notify_when_complete)
244 _cbl_mon->notify_all();
245 }
246 }
248 // Merge free lists of the two queues. The free list of the source
249 // queue is emptied as a result. The queues must share the same
250 // mutex that guards free lists.
251 void PtrQueueSet::merge_freelists(PtrQueueSet* src) {
252 assert(_fl_lock == src->_fl_lock, "Should share the same lock");
253 MutexLockerEx x(_fl_lock, Mutex::_no_safepoint_check_flag);
254 if (_buf_free_list != NULL) {
255 void **p = _buf_free_list;
256 while (*p != NULL) {
257 p = (void**)*p;
258 }
259 *p = src->_buf_free_list;
260 } else {
261 _buf_free_list = src->_buf_free_list;
262 }
263 _buf_free_list_sz += src->_buf_free_list_sz;
264 src->_buf_free_list = NULL;
265 src->_buf_free_list_sz = 0;
266 }