1 /*
2 * Copyright (c) 2001, 2018, 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/g1RemSet.hpp"
29 #include "gc/g1/g1ThreadLocalData.hpp"
30 #include "gc/g1/heapRegionRemSet.hpp"
31 #include "gc/shared/workgroup.hpp"
32 #include "runtime/atomic.hpp"
33 #include "runtime/mutexLocker.hpp"
34 #include "runtime/safepoint.hpp"
35 #include "runtime/thread.inline.hpp"
36 #include "runtime/threadSMR.hpp"
37
38 // Closure used for updating remembered sets and recording references that
39 // point into the collection set while the mutator is running.
40 // Assumed to be only executed concurrently with the mutator. Yields via
41 // SuspendibleThreadSet after every card.
42 class G1RefineCardConcurrentlyClosure: public CardTableEntryClosure {
43 public:
44 bool do_card_ptr(jbyte* card_ptr, uint worker_i) {
45 G1CollectedHeap::heap()->g1_rem_set()->refine_card_concurrently(card_ptr, worker_i);
46
47 if (SuspendibleThreadSet::should_yield()) {
48 // Caller will actually yield.
49 return false;
50 }
51 // Otherwise, we finished successfully; return true.
52 return true;
53 }
54 };
55
56 // Represents a set of free small integer ids.
57 class FreeIdSet : public CHeapObj<mtGC> {
58 enum {
59 end_of_list = UINT_MAX,
60 claimed = UINT_MAX - 1
61 };
62
63 uint _size;
64 Monitor* _mon;
65
66 uint* _ids;
67 uint _hd;
68 uint _waiters;
69 uint _claimed;
70
71 public:
72 FreeIdSet(uint size, Monitor* mon);
73 ~FreeIdSet();
74
75 // Returns an unclaimed parallel id (waiting for one to be released if
76 // necessary).
77 uint claim_par_id();
78
79 void release_par_id(uint id);
80 };
81
82 FreeIdSet::FreeIdSet(uint size, Monitor* mon) :
83 _size(size), _mon(mon), _hd(0), _waiters(0), _claimed(0)
84 {
85 guarantee(size != 0, "must be");
86 _ids = NEW_C_HEAP_ARRAY(uint, size, mtGC);
87 for (uint i = 0; i < size - 1; i++) {
88 _ids[i] = i+1;
89 }
90 _ids[size-1] = end_of_list; // end of list.
91 }
92
93 FreeIdSet::~FreeIdSet() {
94 FREE_C_HEAP_ARRAY(uint, _ids);
95 }
96
97 uint FreeIdSet::claim_par_id() {
98 MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag);
99 while (_hd == end_of_list) {
100 _waiters++;
101 _mon->wait(Mutex::_no_safepoint_check_flag);
102 _waiters--;
103 }
104 uint res = _hd;
105 _hd = _ids[res];
106 _ids[res] = claimed; // For debugging.
107 _claimed++;
108 return res;
109 }
110
111 void FreeIdSet::release_par_id(uint id) {
112 MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag);
113 assert(_ids[id] == claimed, "Precondition.");
114 _ids[id] = _hd;
115 _hd = id;
116 _claimed--;
117 if (_waiters > 0) {
118 _mon->notify_all();
119 }
120 }
121
122 DirtyCardQueue::DirtyCardQueue(DirtyCardQueueSet* qset, bool permanent) :
123 // Dirty card queues are always active, so we create them with their
124 // active field set to true.
125 PtrQueue(qset, permanent, true /* active */)
126 { }
127
128 DirtyCardQueue::~DirtyCardQueue() {
129 if (!is_permanent()) {
130 flush();
131 }
132 }
133
134 DirtyCardQueueSet::DirtyCardQueueSet(bool notify_when_complete) :
135 PtrQueueSet(notify_when_complete),
136 _shared_dirty_card_queue(this, true /* permanent */),
137 _free_ids(NULL),
138 _processed_buffers_mut(0), _processed_buffers_rs_thread(0)
139 {
140 _all_active = true;
141 }
142
143 // Determines how many mutator threads can process the buffers in parallel.
144 uint DirtyCardQueueSet::num_par_ids() {
145 return (uint)os::initial_active_processor_count();
146 }
147
148 void DirtyCardQueueSet::initialize(Monitor* cbl_mon,
149 BufferNode::Allocator* allocator,
150 int process_completed_threshold,
151 int max_completed_queue,
152 Mutex* lock,
153 bool init_free_ids) {
154 PtrQueueSet::initialize(cbl_mon,
155 allocator,
156 process_completed_threshold,
157 max_completed_queue);
158 _shared_dirty_card_queue.set_lock(lock);
159 if (init_free_ids) {
160 _free_ids = new FreeIdSet(num_par_ids(), _cbl_mon);
161 }
162 }
163
164 void DirtyCardQueueSet::handle_zero_index_for_thread(JavaThread* t) {
165 G1ThreadLocalData::dirty_card_queue(t).handle_zero_index();
166 }
167
168 bool DirtyCardQueueSet::apply_closure_to_buffer(CardTableEntryClosure* cl,
169 BufferNode* node,
170 bool consume,
171 uint worker_i) {
172 if (cl == NULL) return true;
173 bool result = true;
174 void** buf = BufferNode::make_buffer_from_node(node);
175 size_t i = node->index();
176 size_t limit = buffer_size();
177 for ( ; i < limit; ++i) {
178 jbyte* card_ptr = static_cast<jbyte*>(buf[i]);
179 assert(card_ptr != NULL, "invariant");
180 if (!cl->do_card_ptr(card_ptr, worker_i)) {
181 result = false; // Incomplete processing.
182 break;
183 }
184 }
185 if (consume) {
186 assert(i <= buffer_size(), "invariant");
187 node->set_index(i);
188 }
189 return result;
190 }
191
192 #ifndef ASSERT
193 #define assert_fully_consumed(node, buffer_size)
194 #else
195 #define assert_fully_consumed(node, buffer_size) \
196 do { \
197 size_t _afc_index = (node)->index(); \
198 size_t _afc_size = (buffer_size); \
199 assert(_afc_index == _afc_size, \
200 "Buffer was not fully consumed as claimed: index: " \
201 SIZE_FORMAT ", size: " SIZE_FORMAT, \
202 _afc_index, _afc_size); \
203 } while (0)
204 #endif // ASSERT
205
206 bool DirtyCardQueueSet::mut_process_buffer(BufferNode* node) {
207 guarantee(_free_ids != NULL, "must be");
208
209 uint worker_i = _free_ids->claim_par_id(); // temporarily claim an id
210 G1RefineCardConcurrentlyClosure cl;
211 bool result = apply_closure_to_buffer(&cl, node, true, worker_i);
212 _free_ids->release_par_id(worker_i); // release the id
213
214 if (result) {
215 assert_fully_consumed(node, buffer_size());
216 Atomic::inc(&_processed_buffers_mut);
217 }
218 return result;
219 }
220
221
222 BufferNode* DirtyCardQueueSet::get_completed_buffer(size_t stop_at) {
223 BufferNode* nd = NULL;
224 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
225
226 if (_n_completed_buffers <= stop_at) {
227 _process_completed = false;
228 return NULL;
229 }
230
231 if (_completed_buffers_head != NULL) {
232 nd = _completed_buffers_head;
233 assert(_n_completed_buffers > 0, "Invariant");
234 _completed_buffers_head = nd->next();
235 _n_completed_buffers--;
236 if (_completed_buffers_head == NULL) {
237 assert(_n_completed_buffers == 0, "Invariant");
238 _completed_buffers_tail = NULL;
239 }
240 }
241 DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked());
242 return nd;
243 }
244
245 bool DirtyCardQueueSet::refine_completed_buffer_concurrently(uint worker_i, size_t stop_at) {
246 G1RefineCardConcurrentlyClosure cl;
247 return apply_closure_to_completed_buffer(&cl, worker_i, stop_at, false);
248 }
249
250 bool DirtyCardQueueSet::apply_closure_during_gc(CardTableEntryClosure* cl, uint worker_i) {
251 assert_at_safepoint();
252 return apply_closure_to_completed_buffer(cl, worker_i, 0, true);
253 }
254
255 bool DirtyCardQueueSet::apply_closure_to_completed_buffer(CardTableEntryClosure* cl,
256 uint worker_i,
257 size_t stop_at,
258 bool during_pause) {
259 assert(!during_pause || stop_at == 0, "Should not leave any completed buffers during a pause");
260 BufferNode* nd = get_completed_buffer(stop_at);
261 if (nd == NULL) {
262 return false;
263 } else {
264 if (apply_closure_to_buffer(cl, nd, true, worker_i)) {
265 assert_fully_consumed(nd, buffer_size());
266 // Done with fully processed buffer.
267 deallocate_buffer(nd);
268 Atomic::inc(&_processed_buffers_rs_thread);
269 } else {
270 // Return partially processed buffer to the queue.
271 guarantee(!during_pause, "Should never stop early");
272 enqueue_complete_buffer(nd);
273 }
274 return true;
275 }
276 }
277
278 void DirtyCardQueueSet::par_apply_closure_to_all_completed_buffers(CardTableEntryClosure* cl) {
279 BufferNode* nd = _cur_par_buffer_node;
280 while (nd != NULL) {
281 BufferNode* next = nd->next();
282 BufferNode* actual = Atomic::cmpxchg(next, &_cur_par_buffer_node, nd);
283 if (actual == nd) {
284 bool b = apply_closure_to_buffer(cl, nd, false);
285 guarantee(b, "Should not stop early.");
286 nd = next;
287 } else {
288 nd = actual;
289 }
290 }
291 }
292
293 // Deallocates any completed log buffers
294 void DirtyCardQueueSet::clear() {
295 BufferNode* buffers_to_delete = NULL;
296 {
297 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
298 while (_completed_buffers_head != NULL) {
299 BufferNode* nd = _completed_buffers_head;
300 _completed_buffers_head = nd->next();
301 nd->set_next(buffers_to_delete);
302 buffers_to_delete = nd;
303 }
304 _n_completed_buffers = 0;
305 _completed_buffers_tail = NULL;
306 DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked());
307 }
308 while (buffers_to_delete != NULL) {
309 BufferNode* nd = buffers_to_delete;
310 buffers_to_delete = nd->next();
311 deallocate_buffer(nd);
312 }
313
314 }
315
316 void DirtyCardQueueSet::abandon_logs() {
317 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
318 clear();
319 // Since abandon is done only at safepoints, we can safely manipulate
320 // these queues.
321 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
322 G1ThreadLocalData::dirty_card_queue(t).reset();
323 }
324 shared_dirty_card_queue()->reset();
325 }
326
327 void DirtyCardQueueSet::concatenate_log(DirtyCardQueue& dcq) {
328 if (!dcq.is_empty()) {
329 dcq.flush();
330 }
331 }
332
333 void DirtyCardQueueSet::concatenate_logs() {
334 // Iterate over all the threads, if we find a partial log add it to
335 // the global list of logs. Temporarily turn off the limit on the number
336 // of outstanding buffers.
337 int save_max_completed_queue = _max_completed_queue;
338 _max_completed_queue = max_jint;
339 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
340 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
341 concatenate_log(G1ThreadLocalData::dirty_card_queue(t));
342 }
343 concatenate_log(_shared_dirty_card_queue);
344 // Restore the completed buffer queue limit.
345 _max_completed_queue = save_max_completed_queue;
346 }