dirtyCardQueue.cpp revision 11857:d0fbf661cc16 
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.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.
36class 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
50public:
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
61FreeIdSet::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
72FreeIdSet::~FreeIdSet() {
73  FREE_C_HEAP_ARRAY(uint, _ids);
74}
75
76uint 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
90void 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
101DirtyCardQueue::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
107DirtyCardQueue::~DirtyCardQueue() {
108  if (!is_permanent()) {
109    flush();
110  }
111}
112
113DirtyCardQueueSet::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.
124uint DirtyCardQueueSet::num_par_ids() {
125  return (uint)os::initial_active_processor_count();
126}
127
128void 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
149void DirtyCardQueueSet::handle_zero_index_for_thread(JavaThread* t) {
150  t->dirty_card_queue().handle_zero_index();
151}
152
153bool 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 limit = DirtyCardQueue::byte_index_to_index(buffer_size());
161  size_t i = DirtyCardQueue::byte_index_to_index(node->index());
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    size_t new_index = DirtyCardQueue::index_to_byte_index(i);
172    assert(new_index <= buffer_size(), "invariant");
173    node->set_index(new_index);
174  }
175  return result;
176}
177
178#ifndef ASSERT
179#define assert_fully_consumed(node, buffer_size)
180#else
181#define assert_fully_consumed(node, buffer_size)                \
182  do {                                                          \
183    size_t _afc_index = (node)->index();                        \
184    size_t _afc_size = (buffer_size);                           \
185    assert(_afc_index == _afc_size,                             \
186           "Buffer was not fully consumed as claimed: index: "  \
187           SIZE_FORMAT ", size: " SIZE_FORMAT,                  \
188            _afc_index, _afc_size);                             \
189  } while (0)
190#endif // ASSERT
191
192bool DirtyCardQueueSet::mut_process_buffer(BufferNode* node) {
193  guarantee(_free_ids != NULL, "must be");
194
195  uint worker_i = _free_ids->claim_par_id(); // temporarily claim an id
196  bool result = apply_closure_to_buffer(_mut_process_closure, node, true, worker_i);
197  _free_ids->release_par_id(worker_i); // release the id
198
199  if (result) {
200    assert_fully_consumed(node, buffer_size());
201    Atomic::inc(&_processed_buffers_mut);
202  }
203  return result;
204}
205
206
207BufferNode* DirtyCardQueueSet::get_completed_buffer(size_t stop_at) {
208  BufferNode* nd = NULL;
209  MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
210
211  if (_n_completed_buffers <= stop_at) {
212    _process_completed = false;
213    return NULL;
214  }
215
216  if (_completed_buffers_head != NULL) {
217    nd = _completed_buffers_head;
218    assert(_n_completed_buffers > 0, "Invariant");
219    _completed_buffers_head = nd->next();
220    _n_completed_buffers--;
221    if (_completed_buffers_head == NULL) {
222      assert(_n_completed_buffers == 0, "Invariant");
223      _completed_buffers_tail = NULL;
224    }
225  }
226  DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked());
227  return nd;
228}
229
230bool DirtyCardQueueSet::apply_closure_to_completed_buffer(CardTableEntryClosure* cl,
231                                                          uint worker_i,
232                                                          size_t stop_at,
233                                                          bool during_pause) {
234  assert(!during_pause || stop_at == 0, "Should not leave any completed buffers during a pause");
235  BufferNode* nd = get_completed_buffer(stop_at);
236  if (nd == NULL) {
237    return false;
238  } else {
239    if (apply_closure_to_buffer(cl, nd, true, worker_i)) {
240      assert_fully_consumed(nd, buffer_size());
241      // Done with fully processed buffer.
242      deallocate_buffer(nd);
243      Atomic::inc(&_processed_buffers_rs_thread);
244    } else {
245      // Return partially processed buffer to the queue.
246      guarantee(!during_pause, "Should never stop early");
247      enqueue_complete_buffer(nd);
248    }
249    return true;
250  }
251}
252
253void DirtyCardQueueSet::par_apply_closure_to_all_completed_buffers(CardTableEntryClosure* cl) {
254  BufferNode* nd = _cur_par_buffer_node;
255  while (nd != NULL) {
256    BufferNode* next = nd->next();
257    void* actual = Atomic::cmpxchg_ptr(next, &_cur_par_buffer_node, nd);
258    if (actual == nd) {
259      bool b = apply_closure_to_buffer(cl, nd, false);
260      guarantee(b, "Should not stop early.");
261      nd = next;
262    } else {
263      nd = static_cast<BufferNode*>(actual);
264    }
265  }
266}
267
268// Deallocates any completed log buffers
269void DirtyCardQueueSet::clear() {
270  BufferNode* buffers_to_delete = NULL;
271  {
272    MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
273    while (_completed_buffers_head != NULL) {
274      BufferNode* nd = _completed_buffers_head;
275      _completed_buffers_head = nd->next();
276      nd->set_next(buffers_to_delete);
277      buffers_to_delete = nd;
278    }
279    _n_completed_buffers = 0;
280    _completed_buffers_tail = NULL;
281    DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked());
282  }
283  while (buffers_to_delete != NULL) {
284    BufferNode* nd = buffers_to_delete;
285    buffers_to_delete = nd->next();
286    deallocate_buffer(nd);
287  }
288
289}
290
291void DirtyCardQueueSet::abandon_logs() {
292  assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
293  clear();
294  // Since abandon is done only at safepoints, we can safely manipulate
295  // these queues.
296  for (JavaThread* t = Threads::first(); t; t = t->next()) {
297    t->dirty_card_queue().reset();
298  }
299  shared_dirty_card_queue()->reset();
300}
301
302void DirtyCardQueueSet::concatenate_log(DirtyCardQueue& dcq) {
303  if (!dcq.is_empty()) {
304    enqueue_complete_buffer(
305      BufferNode::make_node_from_buffer(dcq.get_buf(), dcq.get_index()));
306    dcq.reinitialize();
307  }
308}
309
310void DirtyCardQueueSet::concatenate_logs() {
311  // Iterate over all the threads, if we find a partial log add it to
312  // the global list of logs.  Temporarily turn off the limit on the number
313  // of outstanding buffers.
314  int save_max_completed_queue = _max_completed_queue;
315  _max_completed_queue = max_jint;
316  assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
317  for (JavaThread* t = Threads::first(); t; t = t->next()) {
318    concatenate_log(t->dirty_card_queue());
319  }
320  concatenate_log(_shared_dirty_card_queue);
321  // Restore the completed buffer queue limit.
322  _max_completed_queue = save_max_completed_queue;
323}
324