1 /*
2 * Copyright (c) 2001, 2017, 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.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 DirtyCardQueueSet::DirtyCardQueueSet(bool notify_when_complete) :
114 PtrQueueSet(notify_when_complete),
115 _mut_process_closure(NULL),
116 _shared_dirty_card_queue(this, true /* permanent */),
117 _free_ids(NULL),
118 _processed_buffers_mut(0), _processed_buffers_rs_thread(0)
119 {
120 _all_active = true;
121 }
122
123 // Determines how many mutator threads can process the buffers in parallel.
124 uint DirtyCardQueueSet::num_par_ids() {
125 return (uint)os::initial_active_processor_count();
126 }
127
128 void DirtyCardQueueSet::initialize(CardTableEntryClosure* cl,
129 Monitor* cbl_mon,
130 Mutex* fl_lock,
131 int process_completed_threshold,
132 int max_completed_queue,
133 Mutex* lock,
134 DirtyCardQueueSet* fl_owner,
135 bool init_free_ids) {
136 _mut_process_closure = cl;
137 PtrQueueSet::initialize(cbl_mon,
138 fl_lock,
139 process_completed_threshold,
140 max_completed_queue,
141 fl_owner);
142 set_buffer_size(G1UpdateBufferSize);
143 _shared_dirty_card_queue.set_lock(lock);
144 if (init_free_ids) {
145 _free_ids = new FreeIdSet(num_par_ids(), _cbl_mon);
146 }
147 }
148
149 void DirtyCardQueueSet::handle_zero_index_for_thread(JavaThread* t) {
150 t->dirty_card_queue().handle_zero_index();
151 }
152
153 bool DirtyCardQueueSet::apply_closure_to_buffer(CardTableEntryClosure* cl,
154 BufferNode* node,
155 bool consume,
156 uint worker_i) {
157 if (cl == NULL) return true;
158 bool result = true;
159 void** buf = BufferNode::make_buffer_from_node(node);
160 size_t i = node->index();
161 size_t limit = buffer_size();
162 for ( ; i < limit; ++i) {
163 jbyte* card_ptr = static_cast<jbyte*>(buf[i]);
164 assert(card_ptr != NULL, "invariant");
165 if (!cl->do_card_ptr(card_ptr, worker_i)) {
166 result = false; // Incomplete processing.
167 break;
168 }
169 }
170 if (consume) {
171 assert(i <= buffer_size(), "invariant");
172 node->set_index(i);
173 }
174 return result;
175 }
176
177 #ifndef ASSERT
178 #define assert_fully_consumed(node, buffer_size)
179 #else
180 #define assert_fully_consumed(node, buffer_size) \
181 do { \
182 size_t _afc_index = (node)->index(); \
183 size_t _afc_size = (buffer_size); \
184 assert(_afc_index == _afc_size, \
185 "Buffer was not fully consumed as claimed: index: " \
186 SIZE_FORMAT ", size: " SIZE_FORMAT, \
187 _afc_index, _afc_size); \
188 } while (0)
189 #endif // ASSERT
190
191 bool DirtyCardQueueSet::mut_process_buffer(BufferNode* node) {
192 guarantee(_free_ids != NULL, "must be");
193
194 uint worker_i = _free_ids->claim_par_id(); // temporarily claim an id
195 bool result = apply_closure_to_buffer(_mut_process_closure, node, true, worker_i);
196 _free_ids->release_par_id(worker_i); // release the id
197
198 if (result) {
199 assert_fully_consumed(node, buffer_size());
200 Atomic::inc(&_processed_buffers_mut);
201 }
202 return result;
203 }
204
205
206 BufferNode* DirtyCardQueueSet::get_completed_buffer(size_t stop_at) {
207 BufferNode* nd = NULL;
208 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
209
210 if (_n_completed_buffers <= stop_at) {
211 _process_completed = false;
212 return NULL;
213 }
214
215 if (_completed_buffers_head != NULL) {
216 nd = _completed_buffers_head;
217 assert(_n_completed_buffers > 0, "Invariant");
218 _completed_buffers_head = nd->next();
219 _n_completed_buffers--;
220 if (_completed_buffers_head == NULL) {
221 assert(_n_completed_buffers == 0, "Invariant");
222 _completed_buffers_tail = NULL;
223 }
224 }
225 DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked());
226 return nd;
227 }
228
229 bool DirtyCardQueueSet::apply_closure_to_completed_buffer(CardTableEntryClosure* cl,
230 uint worker_i,
231 size_t stop_at,
232 bool during_pause) {
233 assert(!during_pause || stop_at == 0, "Should not leave any completed buffers during a pause");
234 BufferNode* nd = get_completed_buffer(stop_at);
235 if (nd == NULL) {
236 return false;
237 } else {
238 if (apply_closure_to_buffer(cl, nd, true, worker_i)) {
239 assert_fully_consumed(nd, buffer_size());
240 // Done with fully processed buffer.
241 deallocate_buffer(nd);
242 Atomic::inc(&_processed_buffers_rs_thread);
243 } else {
244 // Return partially processed buffer to the queue.
245 guarantee(!during_pause, "Should never stop early");
246 enqueue_complete_buffer(nd);
247 }
248 return true;
249 }
250 }
251
252 void DirtyCardQueueSet::par_apply_closure_to_all_completed_buffers(CardTableEntryClosure* cl) {
253 BufferNode* nd = _cur_par_buffer_node;
254 while (nd != NULL) {
255 BufferNode* next = nd->next();
256 void* actual = Atomic::cmpxchg_ptr(next, &_cur_par_buffer_node, nd);
257 if (actual == nd) {
258 bool b = apply_closure_to_buffer(cl, nd, false);
259 guarantee(b, "Should not stop early.");
260 nd = next;
261 } else {
262 nd = static_cast<BufferNode*>(actual);
263 }
264 }
265 }
266
267 // Deallocates any completed log buffers
268 void DirtyCardQueueSet::clear() {
269 BufferNode* buffers_to_delete = NULL;
270 {
271 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
272 while (_completed_buffers_head != NULL) {
273 BufferNode* nd = _completed_buffers_head;
274 _completed_buffers_head = nd->next();
275 nd->set_next(buffers_to_delete);
276 buffers_to_delete = nd;
277 }
278 _n_completed_buffers = 0;
279 _completed_buffers_tail = NULL;
280 DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked());
281 }
282 while (buffers_to_delete != NULL) {
283 BufferNode* nd = buffers_to_delete;
284 buffers_to_delete = nd->next();
285 deallocate_buffer(nd);
286 }
287
288 }
289
290 void DirtyCardQueueSet::abandon_logs() {
291 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
292 clear();
293 // Since abandon is done only at safepoints, we can safely manipulate
294 // these queues.
295 for (JavaThread* t = Threads::first(); t; t = t->next()) {
296 t->dirty_card_queue().reset();
297 }
298 shared_dirty_card_queue()->reset();
299 }
300
301 void DirtyCardQueueSet::concatenate_log(DirtyCardQueue& dcq) {
302 if (!dcq.is_empty()) {
303 dcq.flush();
304 }
305 }
306
307 void DirtyCardQueueSet::concatenate_logs() {
308 // Iterate over all the threads, if we find a partial log add it to
309 // the global list of logs. Temporarily turn off the limit on the number
310 // of outstanding buffers.
311 int save_max_completed_queue = _max_completed_queue;
312 _max_completed_queue = max_jint;
313 assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
314 for (JavaThread* t = Threads::first(); t; t = t->next()) {
315 concatenate_log(t->dirty_card_queue());
316 }
317 concatenate_log(_shared_dirty_card_queue);
318 // Restore the completed buffer queue limit.
319 _max_completed_queue = save_max_completed_queue;
320 }