1 /*
2 * Copyright (c) 2001, 2016, 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 // Represents a set of free small integer ids.
36 class FreeIdSet : public CHeapObj<mtGC> {
37 enum {
38 end_of_list = UINT_MAX,
39 claimed = UINT_MAX - 1
40 };
41
42 uint _size;
43 Monitor* _mon;
44
45 uint* _ids;
46 uint _hd;
47 uint _waiters;
48 uint _claimed;
49
50 public:
51 FreeIdSet(uint size, Monitor* mon);
52 ~FreeIdSet();
53
54 // Returns an unclaimed parallel id (waiting for one to be released if
55 // necessary).
56 uint claim_par_id();
57
58 void release_par_id(uint id);
59 };
60
61 FreeIdSet::FreeIdSet(uint size, Monitor* mon) :
62 _size(size), _mon(mon), _hd(0), _waiters(0), _claimed(0)
63 {
64 guarantee(size != 0, "must be");
65 _ids = NEW_C_HEAP_ARRAY(uint, size, mtGC);
66 for (uint i = 0; i < size - 1; i++) {
67 _ids[i] = i+1;
68 }
69 _ids[size-1] = end_of_list; // end of list.
70 }
71
72 FreeIdSet::~FreeIdSet() {
73 FREE_C_HEAP_ARRAY(uint, _ids);
74 }
75
76 uint FreeIdSet::claim_par_id() {
77 MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag);
78 while (_hd == end_of_list) {
79 _waiters++;
80 _mon->wait(Mutex::_no_safepoint_check_flag);
81 _waiters--;
82 }
83 uint res = _hd;
84 _hd = _ids[res];
85 _ids[res] = claimed; // For debugging.
86 _claimed++;
87 return res;
88 }
89
90 void FreeIdSet::release_par_id(uint id) {
91 MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag);
92 assert(_ids[id] == claimed, "Precondition.");
93 _ids[id] = _hd;
94 _hd = id;
95 _claimed--;
96 if (_waiters > 0) {
97 _mon->notify_all();
98 }
99 }
100
101 DirtyCardQueue::DirtyCardQueue(DirtyCardQueueSet* qset, bool permanent) :
102 // Dirty card queues are always active, so we create them with their
103 // active field set to true.
104 PtrQueue(qset, permanent, true /* active */)
105 { }
106
107 DirtyCardQueue::~DirtyCardQueue() {
108 if (!is_permanent()) {
109 flush();
110 }
111 }
112
113 bool DirtyCardQueue::apply_closure(CardTableEntryClosure* cl,
114 bool consume,
115 uint worker_i) {
116 bool res = true;
117 if (_buf != NULL) {
118 BufferNode* node = BufferNode::make_node_from_buffer(_buf, _index);
119 res = apply_closure_to_buffer(cl, node, _sz, consume, worker_i);
120 if (res && consume) {
121 _index = _sz;
122 }
123 }
124 return res;
125 }
126
127 bool DirtyCardQueue::apply_closure_to_buffer(CardTableEntryClosure* cl,
128 BufferNode* node, size_t sz,
129 bool consume,
130 uint worker_i) {
131 if (cl == NULL) return true;
132 void** buf = BufferNode::make_buffer_from_node(node);
133 size_t limit = byte_index_to_index(sz);
134 for (size_t i = byte_index_to_index(node->index()); i < limit; ++i) {
135 jbyte* card_ptr = static_cast<jbyte*>(buf[i]);
136 assert(card_ptr != NULL, "invariant");
137 if (!cl->do_card_ptr(card_ptr, worker_i)) {
138 if (consume) {
139 size_t new_index = index_to_byte_index(i + 1);
140 assert(new_index <= sz, "invariant");
141 node->set_index(new_index);
142 }
143 return false;
144 }
145 }
146 if (consume) {
147 node->set_index(sz);
148 }
149 return true;
150 }
151
152 DirtyCardQueueSet::DirtyCardQueueSet(bool notify_when_complete) :
153 PtrQueueSet(notify_when_complete),
154 _mut_process_closure(NULL),
155 _shared_dirty_card_queue(this, true /* permanent */),
156 _free_ids(NULL),
157 _processed_buffers_mut(0), _processed_buffers_rs_thread(0)
158 {
159 _all_active = true;
160 }
161
162 // Determines how many mutator threads can process the buffers in parallel.
163 uint DirtyCardQueueSet::num_par_ids() {
164 return (uint)os::processor_count();
165 }
166
167 void DirtyCardQueueSet::initialize(CardTableEntryClosure* cl,
168 Monitor* cbl_mon,
169 Mutex* fl_lock,
170 int process_completed_threshold,
171 int max_completed_queue,
172 Mutex* lock,
173 DirtyCardQueueSet* fl_owner,
174 bool init_free_ids) {
175 _mut_process_closure = cl;
176 PtrQueueSet::initialize(cbl_mon,
177 fl_lock,
178 process_completed_threshold,
179 max_completed_queue,
180 fl_owner);
181 set_buffer_size(G1UpdateBufferSize);
182 _shared_dirty_card_queue.set_lock(lock);
183 if (init_free_ids) {
184 _free_ids = new FreeIdSet(num_par_ids(), _cbl_mon);
185 }
186 }
187
188 void DirtyCardQueueSet::handle_zero_index_for_thread(JavaThread* t) {
189 t->dirty_card_queue().handle_zero_index();
190 }
191
192 bool DirtyCardQueueSet::mut_process_buffer(BufferNode* node) {
193 guarantee(_free_ids != NULL, "must be");
194
195 // claim a par id
196 uint worker_i = _free_ids->claim_par_id();
197
198 bool b = DirtyCardQueue::apply_closure_to_buffer(_mut_process_closure,
199 node, _sz,
200 true, worker_i);
201 if (b) {
202 Atomic::inc(&_processed_buffers_mut);
203 }
204
205 // release the id
206 _free_ids->release_par_id(worker_i);
207
208 return b;
209 }
210
211
212 BufferNode* DirtyCardQueueSet::get_completed_buffer(size_t stop_at) {
213 BufferNode* nd = NULL;
214 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
215
216 if (_n_completed_buffers <= stop_at) {
217 _process_completed = false;
218 return NULL;
219 }
220
221 if (_completed_buffers_head != NULL) {
222 nd = _completed_buffers_head;
223 assert(_n_completed_buffers > 0, "Invariant");
224 _completed_buffers_head = nd->next();
225 _n_completed_buffers--;
226 if (_completed_buffers_head == NULL) {
227 assert(_n_completed_buffers == 0, "Invariant");
228 _completed_buffers_tail = NULL;
229 }
230 }
231 DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked());
232 return nd;
233 }
234
235 bool DirtyCardQueueSet::apply_closure_to_completed_buffer(CardTableEntryClosure* cl,
236 uint worker_i,
237 size_t stop_at,
238 bool during_pause) {
239 assert(!during_pause || stop_at == 0, "Should not leave any completed buffers during a pause");
240 BufferNode* nd = get_completed_buffer(stop_at);
241 if (nd == NULL) {
242 return false;
243 } else {
244 if (DirtyCardQueue::apply_closure_to_buffer(cl, nd, _sz, true, worker_i)) {
245 // Done with fully processed buffer.
246 deallocate_buffer(nd);
247 Atomic::inc(&_processed_buffers_rs_thread);
248 return true;
249 } else {
250 // Return partially processed buffer to the queue.
251 enqueue_complete_buffer(nd);
252 return false;
253 }
254 }
255 }
256
257 void DirtyCardQueueSet::par_apply_closure_to_all_completed_buffers(CardTableEntryClosure* cl) {
258 BufferNode* nd = _cur_par_buffer_node;
259 while (nd != NULL) {
260 BufferNode* next = nd->next();
261 void* actual = Atomic::cmpxchg_ptr(next, &_cur_par_buffer_node, nd);
262 if (actual == nd) {
263 bool b = DirtyCardQueue::apply_closure_to_buffer(cl, nd, _sz, false);
264 guarantee(b, "Should not stop early.");
265 nd = next;
266 } else {
267 nd = static_cast<BufferNode*>(actual);
268 }
269 }
270 }
271
272 // Deallocates any completed log buffers
273 void DirtyCardQueueSet::clear() {
274 BufferNode* buffers_to_delete = NULL;
275 {
276 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
277 while (_completed_buffers_head != NULL) {
278 BufferNode* nd = _completed_buffers_head;
279 _completed_buffers_head = nd->next();
280 nd->set_next(buffers_to_delete);
281 buffers_to_delete = nd;
282 }
283 _n_completed_buffers = 0;
284 _completed_buffers_tail = NULL;
285 DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked());
286 }
287 while (buffers_to_delete != NULL) {
288 BufferNode* nd = buffers_to_delete;
289 buffers_to_delete = nd->next();
290 deallocate_buffer(nd);
291 }
292
293 }
294
295 void DirtyCardQueueSet::abandon_logs() {
296 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
297 clear();
298 // Since abandon is done only at safepoints, we can safely manipulate
299 // these queues.
300 for (JavaThread* t = Threads::first(); t; t = t->next()) {
301 t->dirty_card_queue().reset();
302 }
303 shared_dirty_card_queue()->reset();
304 }
305
306 void DirtyCardQueueSet::concatenate_log(DirtyCardQueue& dcq) {
307 if (!dcq.is_empty()) {
308 enqueue_complete_buffer(
309 BufferNode::make_node_from_buffer(dcq.get_buf(), dcq.get_index()));
310 dcq.reinitialize();
311 }
312 }
313
314 void DirtyCardQueueSet::concatenate_logs() {
315 // Iterate over all the threads, if we find a partial log add it to
316 // the global list of logs. Temporarily turn off the limit on the number
317 // of outstanding buffers.
318 int save_max_completed_queue = _max_completed_queue;
319 _max_completed_queue = max_jint;
320 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
321 for (JavaThread* t = Threads::first(); t; t = t->next()) {
322 concatenate_log(t->dirty_card_queue());
323 }
324 concatenate_log(_shared_dirty_card_queue);
325 // Restore the completed buffer queue limit.
326 _max_completed_queue = save_max_completed_queue;
327 }