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 res = apply_closure_to_buffer(cl, _buf, _index, _sz,
119 consume,
120 worker_i);
121 if (res && consume) {
122 _index = _sz;
123 }
124 }
125 return res;
126 }
127
128 bool DirtyCardQueue::apply_closure_to_buffer(CardTableEntryClosure* cl,
129 void** buf,
130 size_t index, size_t sz,
131 bool consume,
132 uint worker_i) {
133 if (cl == NULL) return true;
134 size_t limit = byte_index_to_index(sz);
135 for (size_t i = byte_index_to_index(index); i < limit; ++i) {
136 jbyte* card_ptr = static_cast<jbyte*>(buf[i]);
137 if (card_ptr != NULL) {
138 // Set the entry to null, so we don't do it again (via the test
139 // above) if we reconsider this buffer.
140 if (consume) {
141 buf[i] = NULL;
142 }
143 if (!cl->do_card_ptr(card_ptr, worker_i)) {
144 return false;
145 }
146 }
147 }
148 return true;
149 }
150
151 DirtyCardQueueSet::DirtyCardQueueSet(bool notify_when_complete) :
152 PtrQueueSet(notify_when_complete),
153 _mut_process_closure(NULL),
154 _shared_dirty_card_queue(this, true /* permanent */),
155 _free_ids(NULL),
156 _processed_buffers_mut(0), _processed_buffers_rs_thread(0)
157 {
158 _all_active = true;
159 }
160
161 // Determines how many mutator threads can process the buffers in parallel.
162 uint DirtyCardQueueSet::num_par_ids() {
163 return (uint)os::processor_count();
164 }
165
166 void DirtyCardQueueSet::initialize(CardTableEntryClosure* cl,
167 Monitor* cbl_mon,
168 Mutex* fl_lock,
169 size_t process_completed_threshold,
170 size_t max_completed_queue,
171 Mutex* lock,
172 DirtyCardQueueSet* fl_owner,
173 bool init_free_ids) {
174 _mut_process_closure = cl;
175 PtrQueueSet::initialize(cbl_mon,
176 fl_lock,
177 process_completed_threshold,
178 max_completed_queue,
179 fl_owner);
180 set_buffer_size(G1UpdateBufferSize);
181 _shared_dirty_card_queue.set_lock(lock);
182 if (init_free_ids) {
183 _free_ids = new FreeIdSet(num_par_ids(), _cbl_mon);
184 }
185 }
186
187 void DirtyCardQueueSet::handle_zero_index_for_thread(JavaThread* t) {
188 t->dirty_card_queue().handle_zero_index();
189 }
190
191 bool DirtyCardQueueSet::mut_process_buffer(void** buf) {
192 guarantee(_free_ids != NULL, "must be");
193
194 // claim a par id
195 uint worker_i = _free_ids->claim_par_id();
196
197 bool b = DirtyCardQueue::apply_closure_to_buffer(_mut_process_closure, buf, 0,
198 _sz, true, worker_i);
199 if (b) {
200 Atomic::inc(&_processed_buffers_mut);
201 }
202
203 // release the id
204 _free_ids->release_par_id(worker_i);
205
206 return b;
207 }
208
209
210 BufferNode* DirtyCardQueueSet::get_completed_buffer(size_t stop_at) {
211 BufferNode* nd = NULL;
212 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
213
214 if (_n_completed_buffers <= stop_at) {
215 _process_completed = false;
216 return NULL;
217 }
218
219 if (_completed_buffers_head != NULL) {
220 nd = _completed_buffers_head;
221 assert(_n_completed_buffers > 0, "Invariant");
222 _completed_buffers_head = nd->next();
223 _n_completed_buffers--;
224 if (_completed_buffers_head == NULL) {
225 assert(_n_completed_buffers == 0, "Invariant");
226 _completed_buffers_tail = NULL;
227 }
228 }
229 DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked());
230 return nd;
231 }
232
233 bool DirtyCardQueueSet::apply_closure_to_completed_buffer(CardTableEntryClosure* cl,
234 uint worker_i,
235 size_t stop_at,
236 bool during_pause) {
237 assert(!during_pause || stop_at == 0, "Should not leave any completed buffers during a pause");
238 BufferNode* nd = get_completed_buffer(stop_at);
239 if (nd == NULL) {
240 return false;
241 } else {
242 void** buf = BufferNode::make_buffer_from_node(nd);
243 size_t index = nd->index();
244 if (DirtyCardQueue::apply_closure_to_buffer(cl,
245 buf, index, _sz,
246 true, worker_i)) {
247 // Done with fully processed buffer.
248 deallocate_buffer(buf);
249 Atomic::inc(&_processed_buffers_rs_thread);
250 return true;
251 } else {
252 // Return partially processed buffer to the queue.
253 enqueue_complete_buffer(buf, index);
254 return false;
255 }
256 }
257 }
258
259 void DirtyCardQueueSet::apply_closure_to_all_completed_buffers(CardTableEntryClosure* cl) {
260 BufferNode* nd = _completed_buffers_head;
261 while (nd != NULL) {
262 bool b =
263 DirtyCardQueue::apply_closure_to_buffer(cl,
264 BufferNode::make_buffer_from_node(nd),
265 0, _sz, false);
266 guarantee(b, "Should not stop early.");
267 nd = nd->next();
268 }
269 }
270
271 void DirtyCardQueueSet::par_apply_closure_to_all_completed_buffers(CardTableEntryClosure* cl) {
272 BufferNode* nd = _cur_par_buffer_node;
273 while (nd != NULL) {
274 BufferNode* next = (BufferNode*)nd->next();
275 BufferNode* actual = (BufferNode*)Atomic::cmpxchg_ptr((void*)next, (volatile void*)&_cur_par_buffer_node, (void*)nd);
276 if (actual == nd) {
277 bool b =
278 DirtyCardQueue::apply_closure_to_buffer(cl,
279 BufferNode::make_buffer_from_node(actual),
280 0, _sz, false);
281 guarantee(b, "Should not stop early.");
282 nd = next;
283 } else {
284 nd = actual;
285 }
286 }
287 }
288
289 // Deallocates any completed log buffers
290 void DirtyCardQueueSet::clear() {
291 BufferNode* buffers_to_delete = NULL;
292 {
293 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
294 while (_completed_buffers_head != NULL) {
295 BufferNode* nd = _completed_buffers_head;
296 _completed_buffers_head = nd->next();
297 nd->set_next(buffers_to_delete);
298 buffers_to_delete = nd;
299 }
300 _n_completed_buffers = 0;
301 _completed_buffers_tail = NULL;
302 DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked());
303 }
304 while (buffers_to_delete != NULL) {
305 BufferNode* nd = buffers_to_delete;
306 buffers_to_delete = nd->next();
307 deallocate_buffer(BufferNode::make_buffer_from_node(nd));
308 }
309
310 }
311
312 void DirtyCardQueueSet::abandon_logs() {
313 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
314 clear();
315 // Since abandon is done only at safepoints, we can safely manipulate
316 // these queues.
317 for (JavaThread* t = Threads::first(); t; t = t->next()) {
318 t->dirty_card_queue().reset();
319 }
320 shared_dirty_card_queue()->reset();
321 }
322
323
324 void DirtyCardQueueSet::concatenate_logs() {
325 // Iterate over all the threads, if we find a partial log add it to
326 // the global list of logs. Temporarily turn off the limit on the number
327 // of outstanding buffers.
328 size_t save_max_completed_queue = _max_completed_queue;
329 _max_completed_queue = SIZE_MAX;
330 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
331 for (JavaThread* t = Threads::first(); t; t = t->next()) {
332 DirtyCardQueue& dcq = t->dirty_card_queue();
333 if (dcq.size() != 0) {
334 void** buf = dcq.get_buf();
335 // We must NULL out the unused entries, then enqueue.
336 size_t limit = dcq.byte_index_to_index(dcq.get_index());
337 for (size_t i = 0; i < limit; ++i) {
338 buf[i] = NULL;
339 }
340 enqueue_complete_buffer(dcq.get_buf(), dcq.get_index());
341 dcq.reinitialize();
342 }
343 }
344 if (_shared_dirty_card_queue.size() != 0) {
345 enqueue_complete_buffer(_shared_dirty_card_queue.get_buf(),
346 _shared_dirty_card_queue.get_index());
347 _shared_dirty_card_queue.reinitialize();
348 }
349 // Restore the completed buffer queue limit.
350 _max_completed_queue = save_max_completed_queue;
351 }