1 /*
2 * Copyright (c) 2001, 2015, 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 #include "precompiled.hpp"
26 #include "gc/g1/dirtyCardQueue.hpp"
27 #include "gc/g1/g1CollectedHeap.inline.hpp"
28 #include "gc/g1/heapRegionRemSet.hpp"
29 #include "gc/shared/workgroup.hpp"
30 #include "runtime/atomic.inline.hpp"
31 #include "runtime/mutexLocker.hpp"
32 #include "runtime/safepoint.hpp"
33 #include "runtime/thread.inline.hpp"
34
35 DirtyCardQueue::DirtyCardQueue(DirtyCardQueueSet* qset, bool permanent) :
36 // Dirty card queues are always active, so we create them with their
37 // active field set to true.
38 PtrQueue(qset, permanent, true /* active */)
39 { }
40
41 DirtyCardQueue::~DirtyCardQueue() {
42 if (!is_permanent()) {
43 flush();
44 }
45 }
46
47 bool DirtyCardQueue::apply_closure(CardTableEntryClosure* cl,
48 bool consume,
49 uint worker_i) {
50 bool res = true;
51 if (_buf != NULL) {
52 res = apply_closure_to_buffer(cl, _buf, _index, _sz,
53 consume,
54 worker_i);
55 if (res && consume) {
56 _index = _sz;
57 }
58 }
59 return res;
60 }
61
62 bool DirtyCardQueue::apply_closure_to_buffer(CardTableEntryClosure* cl,
63 void** buf,
64 size_t index, size_t sz,
65 bool consume,
66 uint worker_i) {
67 if (cl == NULL) return true;
68 size_t limit = byte_index_to_index(sz);
69 for (size_t i = byte_index_to_index(index); i < limit; ++i) {
70 jbyte* card_ptr = static_cast<jbyte*>(buf[i]);
71 if (card_ptr != NULL) {
72 // Set the entry to null, so we don't do it again (via the test
73 // above) if we reconsider this buffer.
74 if (consume) {
75 buf[i] = NULL;
76 }
77 if (!cl->do_card_ptr(card_ptr, worker_i)) {
78 return false;
79 }
80 }
81 }
82 return true;
83 }
84
85 DirtyCardQueueSet::DirtyCardQueueSet(bool notify_when_complete) :
86 PtrQueueSet(notify_when_complete),
87 _mut_process_closure(NULL),
88 _shared_dirty_card_queue(this, true /* permanent */),
89 _free_ids(NULL),
90 _processed_buffers_mut(0), _processed_buffers_rs_thread(0)
91 {
92 _all_active = true;
93 }
94
95 // Determines how many mutator threads can process the buffers in parallel.
96 uint DirtyCardQueueSet::num_par_ids() {
97 return (uint)os::processor_count();
98 }
99
100 void DirtyCardQueueSet::initialize(CardTableEntryClosure* cl,
101 Monitor* cbl_mon,
102 Mutex* fl_lock,
103 int process_completed_threshold,
104 int max_completed_queue,
105 Mutex* lock,
106 DirtyCardQueueSet* fl_owner) {
107 _mut_process_closure = cl;
108 PtrQueueSet::initialize(cbl_mon,
109 fl_lock,
110 process_completed_threshold,
111 max_completed_queue,
112 fl_owner);
113 set_buffer_size(G1UpdateBufferSize);
114 _shared_dirty_card_queue.set_lock(lock);
115 _free_ids = new FreeIdSet((int) num_par_ids(), _cbl_mon);
116 }
117
118 void DirtyCardQueueSet::handle_zero_index_for_thread(JavaThread* t) {
119 t->dirty_card_queue().handle_zero_index();
120 }
121
122 bool DirtyCardQueueSet::mut_process_buffer(void** buf) {
123
124 // Used to determine if we had already claimed a par_id
125 // before entering this method.
126 bool already_claimed = false;
127
128 // We grab the current JavaThread.
129 JavaThread* thread = JavaThread::current();
130
131 // We get the the number of any par_id that this thread
132 // might have already claimed.
133 uint worker_i = thread->get_claimed_par_id();
134
135 // If worker_i is not UINT_MAX then the thread has already claimed
136 // a par_id. We make note of it using the already_claimed value
137 if (worker_i != UINT_MAX) {
138 already_claimed = true;
139 } else {
140
141 // Otherwise we need to claim a par id
142 worker_i = _free_ids->claim_par_id();
143
144 // And store the par_id value in the thread
145 thread->set_claimed_par_id(worker_i);
146 }
147
148 bool b = false;
149 if (worker_i != UINT_MAX) {
150 b = DirtyCardQueue::apply_closure_to_buffer(_mut_process_closure, buf, 0,
151 _sz, true, worker_i);
152 if (b) Atomic::inc(&_processed_buffers_mut);
153
154 // If we had not claimed an id before entering the method
155 // then we must release the id.
156 if (!already_claimed) {
157
158 // we release the id
159 _free_ids->release_par_id(worker_i);
160
161 // and set the claimed_id in the thread to UINT_MAX
162 thread->set_claimed_par_id(UINT_MAX);
163 }
164 }
165 return b;
166 }
167
168
169 BufferNode* DirtyCardQueueSet::get_completed_buffer(int stop_at) {
170 BufferNode* nd = NULL;
171 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
172
173 if ((int)_n_completed_buffers <= stop_at) {
174 _process_completed = false;
175 return NULL;
176 }
177
178 if (_completed_buffers_head != NULL) {
179 nd = _completed_buffers_head;
180 _completed_buffers_head = nd->next();
181 if (_completed_buffers_head == NULL)
182 _completed_buffers_tail = NULL;
183 _n_completed_buffers--;
184 assert(_n_completed_buffers >= 0, "Invariant");
185 }
186 DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked());
187 return nd;
188 }
189
190 bool DirtyCardQueueSet::apply_closure_to_completed_buffer_helper(CardTableEntryClosure* cl,
191 uint worker_i,
192 BufferNode* nd) {
193 if (nd != NULL) {
194 void **buf = BufferNode::make_buffer_from_node(nd);
195 size_t index = nd->index();
196 bool b =
197 DirtyCardQueue::apply_closure_to_buffer(cl, buf,
198 index, _sz,
199 true, worker_i);
200 if (b) {
201 deallocate_buffer(buf);
202 return true; // In normal case, go on to next buffer.
203 } else {
204 enqueue_complete_buffer(buf, index);
205 return false;
206 }
207 } else {
208 return false;
209 }
210 }
211
212 bool DirtyCardQueueSet::apply_closure_to_completed_buffer(CardTableEntryClosure* cl,
213 uint worker_i,
214 int stop_at,
215 bool during_pause) {
216 assert(!during_pause || stop_at == 0, "Should not leave any completed buffers during a pause");
217 BufferNode* nd = get_completed_buffer(stop_at);
218 bool res = apply_closure_to_completed_buffer_helper(cl, worker_i, nd);
219 if (res) Atomic::inc(&_processed_buffers_rs_thread);
220 return res;
221 }
222
223 void DirtyCardQueueSet::apply_closure_to_all_completed_buffers(CardTableEntryClosure* cl) {
224 BufferNode* nd = _completed_buffers_head;
225 while (nd != NULL) {
226 bool b =
227 DirtyCardQueue::apply_closure_to_buffer(cl,
228 BufferNode::make_buffer_from_node(nd),
229 0, _sz, false);
230 guarantee(b, "Should not stop early.");
231 nd = nd->next();
232 }
233 }
234
235 void DirtyCardQueueSet::par_apply_closure_to_all_completed_buffers(CardTableEntryClosure* cl) {
236 BufferNode* nd = _cur_par_buffer_node;
237 while (nd != NULL) {
238 BufferNode* next = (BufferNode*)nd->next();
239 BufferNode* actual = (BufferNode*)Atomic::cmpxchg_ptr((void*)next, (volatile void*)&_cur_par_buffer_node, (void*)nd);
240 if (actual == nd) {
241 bool b =
242 DirtyCardQueue::apply_closure_to_buffer(cl,
243 BufferNode::make_buffer_from_node(actual),
244 0, _sz, false);
245 guarantee(b, "Should not stop early.");
246 nd = next;
247 } else {
248 nd = actual;
249 }
250 }
251 }
252
253 // Deallocates any completed log buffers
254 void DirtyCardQueueSet::clear() {
255 BufferNode* buffers_to_delete = NULL;
256 {
257 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
258 while (_completed_buffers_head != NULL) {
259 BufferNode* nd = _completed_buffers_head;
260 _completed_buffers_head = nd->next();
261 nd->set_next(buffers_to_delete);
262 buffers_to_delete = nd;
263 }
264 _n_completed_buffers = 0;
265 _completed_buffers_tail = NULL;
266 DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked());
267 }
268 while (buffers_to_delete != NULL) {
269 BufferNode* nd = buffers_to_delete;
270 buffers_to_delete = nd->next();
271 deallocate_buffer(BufferNode::make_buffer_from_node(nd));
272 }
273
274 }
275
276 void DirtyCardQueueSet::abandon_logs() {
277 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
278 clear();
279 // Since abandon is done only at safepoints, we can safely manipulate
280 // these queues.
281 for (JavaThread* t = Threads::first(); t; t = t->next()) {
282 t->dirty_card_queue().reset();
283 }
284 shared_dirty_card_queue()->reset();
285 }
286
287
288 void DirtyCardQueueSet::concatenate_logs() {
289 // Iterate over all the threads, if we find a partial log add it to
290 // the global list of logs. Temporarily turn off the limit on the number
291 // of outstanding buffers.
292 int save_max_completed_queue = _max_completed_queue;
293 _max_completed_queue = max_jint;
294 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
295 for (JavaThread* t = Threads::first(); t; t = t->next()) {
296 DirtyCardQueue& dcq = t->dirty_card_queue();
297 if (dcq.size() != 0) {
298 void** buf = dcq.get_buf();
299 // We must NULL out the unused entries, then enqueue.
300 size_t limit = dcq.byte_index_to_index(dcq.get_index());
301 for (size_t i = 0; i < limit; ++i) {
302 buf[i] = NULL;
303 }
304 enqueue_complete_buffer(dcq.get_buf(), dcq.get_index());
305 dcq.reinitialize();
306 }
307 }
308 if (_shared_dirty_card_queue.size() != 0) {
309 enqueue_complete_buffer(_shared_dirty_card_queue.get_buf(),
310 _shared_dirty_card_queue.get_index());
311 _shared_dirty_card_queue.reinitialize();
312 }
313 // Restore the completed buffer queue limit.
314 _max_completed_queue = save_max_completed_queue;
315 }