Tue, 24 Nov 2009 15:19:30 -0800
6899058: G1: Internal error in ptrQueue.cpp:201 in nightly tests
Summary: Fixes a race on the dirty card queue completed buffer list between worker thread(s) performing a flush of a deferred store barrier (enqueueing a newly completed buffer) and worker thread(s) in the RSet updating code claiming completed buffers. Removed the routine that removes elements from the completed update buffer queue using a CAS.
Reviewed-by: ysr, tonyp
1 /*
2 * Copyright 2001-2009 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.
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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.
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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
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23 */
25 # include "incls/_precompiled.incl"
26 # include "incls/_dirtyCardQueue.cpp.incl"
28 bool DirtyCardQueue::apply_closure(CardTableEntryClosure* cl,
29 bool consume,
30 size_t worker_i) {
31 bool res = true;
32 if (_buf != NULL) {
33 res = apply_closure_to_buffer(cl, _buf, _index, _sz,
34 consume,
35 (int) worker_i);
36 if (res && consume) _index = _sz;
37 }
38 return res;
39 }
41 bool DirtyCardQueue::apply_closure_to_buffer(CardTableEntryClosure* cl,
42 void** buf,
43 size_t index, size_t sz,
44 bool consume,
45 int worker_i) {
46 if (cl == NULL) return true;
47 for (size_t i = index; i < sz; i += oopSize) {
48 int ind = byte_index_to_index((int)i);
49 jbyte* card_ptr = (jbyte*)buf[ind];
50 if (card_ptr != NULL) {
51 // Set the entry to null, so we don't do it again (via the test
52 // above) if we reconsider this buffer.
53 if (consume) buf[ind] = NULL;
54 if (!cl->do_card_ptr(card_ptr, worker_i)) return false;
55 }
56 }
57 return true;
58 }
60 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
61 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
62 #endif // _MSC_VER
64 DirtyCardQueueSet::DirtyCardQueueSet() :
65 PtrQueueSet(true /*notify_when_complete*/),
66 _closure(NULL),
67 _shared_dirty_card_queue(this, true /*perm*/),
68 _free_ids(NULL),
69 _processed_buffers_mut(0), _processed_buffers_rs_thread(0)
70 {
71 _all_active = true;
72 }
74 // Determines how many mutator threads can process the buffers in parallel.
75 size_t DirtyCardQueueSet::num_par_ids() {
76 return os::processor_count();
77 }
79 void DirtyCardQueueSet::initialize(Monitor* cbl_mon, Mutex* fl_lock,
80 int max_completed_queue,
81 Mutex* lock, PtrQueueSet* fl_owner) {
82 PtrQueueSet::initialize(cbl_mon, fl_lock, max_completed_queue, fl_owner);
83 set_buffer_size(G1UpdateBufferSize);
84 set_process_completed_threshold(G1UpdateBufferQueueProcessingThreshold);
86 _shared_dirty_card_queue.set_lock(lock);
87 _free_ids = new FreeIdSet((int) num_par_ids(), _cbl_mon);
88 }
90 void DirtyCardQueueSet::handle_zero_index_for_thread(JavaThread* t) {
91 t->dirty_card_queue().handle_zero_index();
92 }
94 void DirtyCardQueueSet::set_closure(CardTableEntryClosure* closure) {
95 _closure = closure;
96 }
98 void DirtyCardQueueSet::iterate_closure_all_threads(bool consume,
99 size_t worker_i) {
100 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
101 for(JavaThread* t = Threads::first(); t; t = t->next()) {
102 bool b = t->dirty_card_queue().apply_closure(_closure, consume);
103 guarantee(b, "Should not be interrupted.");
104 }
105 bool b = shared_dirty_card_queue()->apply_closure(_closure,
106 consume,
107 worker_i);
108 guarantee(b, "Should not be interrupted.");
109 }
111 bool DirtyCardQueueSet::mut_process_buffer(void** buf) {
113 // Used to determine if we had already claimed a par_id
114 // before entering this method.
115 bool already_claimed = false;
117 // We grab the current JavaThread.
118 JavaThread* thread = JavaThread::current();
120 // We get the the number of any par_id that this thread
121 // might have already claimed.
122 int worker_i = thread->get_claimed_par_id();
124 // If worker_i is not -1 then the thread has already claimed
125 // a par_id. We make note of it using the already_claimed value
126 if (worker_i != -1) {
127 already_claimed = true;
128 } else {
130 // Otherwise we need to claim a par id
131 worker_i = _free_ids->claim_par_id();
133 // And store the par_id value in the thread
134 thread->set_claimed_par_id(worker_i);
135 }
137 bool b = false;
138 if (worker_i != -1) {
139 b = DirtyCardQueue::apply_closure_to_buffer(_closure, buf, 0,
140 _sz, true, worker_i);
141 if (b) Atomic::inc(&_processed_buffers_mut);
143 // If we had not claimed an id before entering the method
144 // then we must release the id.
145 if (!already_claimed) {
147 // we release the id
148 _free_ids->release_par_id(worker_i);
150 // and set the claimed_id in the thread to -1
151 thread->set_claimed_par_id(-1);
152 }
153 }
154 return b;
155 }
157 DirtyCardQueueSet::CompletedBufferNode*
158 DirtyCardQueueSet::get_completed_buffer(int stop_at) {
159 CompletedBufferNode* nd = NULL;
160 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
162 if ((int)_n_completed_buffers <= stop_at) {
163 _process_completed = false;
164 return NULL;
165 }
167 if (_completed_buffers_head != NULL) {
168 nd = _completed_buffers_head;
169 _completed_buffers_head = nd->next;
170 if (_completed_buffers_head == NULL)
171 _completed_buffers_tail = NULL;
172 _n_completed_buffers--;
173 }
174 debug_only(assert_completed_buffer_list_len_correct_locked());
175 return nd;
176 }
178 bool DirtyCardQueueSet::
179 apply_closure_to_completed_buffer_helper(int worker_i,
180 CompletedBufferNode* nd) {
181 if (nd != NULL) {
182 bool b =
183 DirtyCardQueue::apply_closure_to_buffer(_closure, nd->buf,
184 nd->index, _sz,
185 true, worker_i);
186 void** buf = nd->buf;
187 size_t index = nd->index;
188 delete nd;
189 if (b) {
190 deallocate_buffer(buf);
191 return true; // In normal case, go on to next buffer.
192 } else {
193 enqueue_complete_buffer(buf, index, true);
194 return false;
195 }
196 } else {
197 return false;
198 }
199 }
201 bool DirtyCardQueueSet::apply_closure_to_completed_buffer(int worker_i,
202 int stop_at,
203 bool during_pause)
204 {
205 assert(!during_pause || stop_at == 0, "Should not leave any completed buffers during a pause");
206 CompletedBufferNode* nd = get_completed_buffer(stop_at);
207 bool res = apply_closure_to_completed_buffer_helper(worker_i, nd);
208 if (res) Atomic::inc(&_processed_buffers_rs_thread);
209 return res;
210 }
212 void DirtyCardQueueSet::apply_closure_to_all_completed_buffers() {
213 CompletedBufferNode* nd = _completed_buffers_head;
214 while (nd != NULL) {
215 bool b =
216 DirtyCardQueue::apply_closure_to_buffer(_closure, nd->buf, 0, _sz,
217 false);
218 guarantee(b, "Should not stop early.");
219 nd = nd->next;
220 }
221 }
223 void DirtyCardQueueSet::abandon_logs() {
224 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
225 CompletedBufferNode* buffers_to_delete = NULL;
226 {
227 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
228 while (_completed_buffers_head != NULL) {
229 CompletedBufferNode* nd = _completed_buffers_head;
230 _completed_buffers_head = nd->next;
231 nd->next = buffers_to_delete;
232 buffers_to_delete = nd;
233 }
234 _n_completed_buffers = 0;
235 _completed_buffers_tail = NULL;
236 debug_only(assert_completed_buffer_list_len_correct_locked());
237 }
238 while (buffers_to_delete != NULL) {
239 CompletedBufferNode* nd = buffers_to_delete;
240 buffers_to_delete = nd->next;
241 deallocate_buffer(nd->buf);
242 delete nd;
243 }
244 // Since abandon is done only at safepoints, we can safely manipulate
245 // these queues.
246 for (JavaThread* t = Threads::first(); t; t = t->next()) {
247 t->dirty_card_queue().reset();
248 }
249 shared_dirty_card_queue()->reset();
250 }
253 void DirtyCardQueueSet::concatenate_logs() {
254 // Iterate over all the threads, if we find a partial log add it to
255 // the global list of logs. Temporarily turn off the limit on the number
256 // of outstanding buffers.
257 int save_max_completed_queue = _max_completed_queue;
258 _max_completed_queue = max_jint;
259 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
260 for (JavaThread* t = Threads::first(); t; t = t->next()) {
261 DirtyCardQueue& dcq = t->dirty_card_queue();
262 if (dcq.size() != 0) {
263 void **buf = t->dirty_card_queue().get_buf();
264 // We must NULL out the unused entries, then enqueue.
265 for (size_t i = 0; i < t->dirty_card_queue().get_index(); i += oopSize) {
266 buf[PtrQueue::byte_index_to_index((int)i)] = NULL;
267 }
268 enqueue_complete_buffer(dcq.get_buf(), dcq.get_index());
269 dcq.reinitialize();
270 }
271 }
272 if (_shared_dirty_card_queue.size() != 0) {
273 enqueue_complete_buffer(_shared_dirty_card_queue.get_buf(),
274 _shared_dirty_card_queue.get_index());
275 _shared_dirty_card_queue.reinitialize();
276 }
277 // Restore the completed buffer queue limit.
278 _max_completed_queue = save_max_completed_queue;
279 }