1 /*
   2  * Copyright (c) 2001, 2015, 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 bool DirtyCardQueue::apply_closure(CardTableEntryClosure* cl,
  36                                    bool consume,
  37                                    uint worker_i) {
  38   bool res = true;
  39   if (_buf != NULL) {
  40     res = apply_closure_to_buffer(cl, _buf, _index, _sz,
  41                                   consume,
  42                                   worker_i);
  43     if (res && consume) _index = _sz;
  44   }
  45   return res;
  46 }
  47 
  48 bool DirtyCardQueue::apply_closure_to_buffer(CardTableEntryClosure* cl,
  49                                              void** buf,
  50                                              size_t index, size_t sz,
  51                                              bool consume,
  52                                              uint worker_i) {
  53   if (cl == NULL) return true;
  54   for (size_t i = index; i < sz; i += oopSize) {
  55     int ind = byte_index_to_index((int)i);
  56     jbyte* card_ptr = (jbyte*)buf[ind];
  57     if (card_ptr != NULL) {
  58       // Set the entry to null, so we don't do it again (via the test
  59       // above) if we reconsider this buffer.
  60       if (consume) buf[ind] = NULL;
  61       if (!cl->do_card_ptr(card_ptr, worker_i)) return false;
  62     }
  63   }
  64   return true;
  65 }
  66 
  67 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
  68 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
  69 #endif // _MSC_VER
  70 
  71 DirtyCardQueueSet::DirtyCardQueueSet(bool notify_when_complete) :
  72   PtrQueueSet(notify_when_complete),
  73   _mut_process_closure(NULL),
  74   _shared_dirty_card_queue(this, true /*perm*/),
  75   _free_ids(NULL),
  76   _processed_buffers_mut(0), _processed_buffers_rs_thread(0)
  77 {
  78   _all_active = true;
  79 }
  80 
  81 // Determines how many mutator threads can process the buffers in parallel.
  82 uint DirtyCardQueueSet::num_par_ids() {
  83   return (uint)os::processor_count();
  84 }
  85 
  86 void DirtyCardQueueSet::initialize(CardTableEntryClosure* cl, Monitor* cbl_mon, Mutex* fl_lock,
  87                                    int process_completed_threshold,
  88                                    int max_completed_queue,
  89                                    Mutex* lock, PtrQueueSet* fl_owner) {
  90   _mut_process_closure = cl;
  91   PtrQueueSet::initialize(cbl_mon, fl_lock, process_completed_threshold,
  92                           max_completed_queue, fl_owner);
  93   set_buffer_size(G1UpdateBufferSize);
  94   _shared_dirty_card_queue.set_lock(lock);
  95   _free_ids = new FreeIdSet((int) num_par_ids(), _cbl_mon);
  96 }
  97 
  98 void DirtyCardQueueSet::handle_zero_index_for_thread(JavaThread* t) {
  99   t->dirty_card_queue().handle_zero_index();
 100 }
 101 
 102 void DirtyCardQueueSet::iterate_closure_all_threads(CardTableEntryClosure* cl,
 103                                                     bool consume,
 104                                                     uint worker_i) {
 105   assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
 106   for(JavaThread* t = Threads::first(); t; t = t->next()) {
 107     bool b = t->dirty_card_queue().apply_closure(cl, consume);
 108     guarantee(b, "Should not be interrupted.");
 109   }
 110   bool b = shared_dirty_card_queue()->apply_closure(cl,
 111                                                     consume,
 112                                                     worker_i);
 113   guarantee(b, "Should not be interrupted.");
 114 }
 115 
 116 bool DirtyCardQueueSet::mut_process_buffer(void** buf) {
 117 
 118   // Used to determine if we had already claimed a par_id
 119   // before entering this method.
 120   bool already_claimed = false;
 121 
 122   // We grab the current JavaThread.
 123   JavaThread* thread = JavaThread::current();
 124 
 125   // We get the the number of any par_id that this thread
 126   // might have already claimed.
 127   uint worker_i = thread->get_claimed_par_id();
 128 
 129   // If worker_i is not UINT_MAX then the thread has already claimed
 130   // a par_id. We make note of it using the already_claimed value
 131   if (worker_i != UINT_MAX) {
 132     already_claimed = true;
 133   } else {
 134 
 135     // Otherwise we need to claim a par id
 136     worker_i = _free_ids->claim_par_id();
 137 
 138     // And store the par_id value in the thread
 139     thread->set_claimed_par_id(worker_i);
 140   }
 141 
 142   bool b = false;
 143   if (worker_i != UINT_MAX) {
 144     b = DirtyCardQueue::apply_closure_to_buffer(_mut_process_closure, buf, 0,
 145                                                 _sz, true, worker_i);
 146     if (b) Atomic::inc(&_processed_buffers_mut);
 147 
 148     // If we had not claimed an id before entering the method
 149     // then we must release the id.
 150     if (!already_claimed) {
 151 
 152       // we release the id
 153       _free_ids->release_par_id(worker_i);
 154 
 155       // and set the claimed_id in the thread to UINT_MAX
 156       thread->set_claimed_par_id(UINT_MAX);
 157     }
 158   }
 159   return b;
 160 }
 161 
 162 
 163 BufferNode*
 164 DirtyCardQueueSet::get_completed_buffer(int stop_at) {
 165   BufferNode* nd = NULL;
 166   MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
 167 
 168   if ((int)_n_completed_buffers <= stop_at) {
 169     _process_completed = false;
 170     return NULL;
 171   }
 172 
 173   if (_completed_buffers_head != NULL) {
 174     nd = _completed_buffers_head;
 175     _completed_buffers_head = nd->next();
 176     if (_completed_buffers_head == NULL)
 177       _completed_buffers_tail = NULL;
 178     _n_completed_buffers--;
 179     assert(_n_completed_buffers >= 0, "Invariant");
 180   }
 181   debug_only(assert_completed_buffer_list_len_correct_locked());
 182   return nd;
 183 }
 184 
 185 bool DirtyCardQueueSet::
 186 apply_closure_to_completed_buffer_helper(CardTableEntryClosure* cl,
 187                                          uint worker_i,
 188                                          BufferNode* nd) {
 189   if (nd != NULL) {
 190     void **buf = BufferNode::make_buffer_from_node(nd);
 191     size_t index = nd->index();
 192     bool b =
 193       DirtyCardQueue::apply_closure_to_buffer(cl, buf,
 194                                               index, _sz,
 195                                               true, worker_i);
 196     if (b) {
 197       deallocate_buffer(buf);
 198       return true;  // In normal case, go on to next buffer.
 199     } else {
 200       enqueue_complete_buffer(buf, index);
 201       return false;
 202     }
 203   } else {
 204     return false;
 205   }
 206 }
 207 
 208 bool DirtyCardQueueSet::apply_closure_to_completed_buffer(CardTableEntryClosure* cl,
 209                                                           uint worker_i,
 210                                                           int stop_at,
 211                                                           bool during_pause) {
 212   assert(!during_pause || stop_at == 0, "Should not leave any completed buffers during a pause");
 213   BufferNode* nd = get_completed_buffer(stop_at);
 214   bool res = apply_closure_to_completed_buffer_helper(cl, worker_i, nd);
 215   if (res) Atomic::inc(&_processed_buffers_rs_thread);
 216   return res;
 217 }
 218 
 219 void DirtyCardQueueSet::apply_closure_to_all_completed_buffers(CardTableEntryClosure* cl) {
 220   BufferNode* nd = _completed_buffers_head;
 221   while (nd != NULL) {
 222     bool b =
 223       DirtyCardQueue::apply_closure_to_buffer(cl,
 224                                               BufferNode::make_buffer_from_node(nd),
 225                                               0, _sz, false);
 226     guarantee(b, "Should not stop early.");
 227     nd = nd->next();
 228   }
 229 }
 230 
 231 void DirtyCardQueueSet::par_apply_closure_to_all_completed_buffers(CardTableEntryClosure* cl) {
 232   BufferNode* nd = _cur_par_buffer_node;
 233   while (nd != NULL) {
 234     BufferNode* next = (BufferNode*)nd->next();
 235     BufferNode* actual = (BufferNode*)Atomic::cmpxchg_ptr((void*)next, (volatile void*)&_cur_par_buffer_node, (void*)nd);
 236     if (actual == nd) {
 237       bool b =
 238         DirtyCardQueue::apply_closure_to_buffer(cl,
 239                                                 BufferNode::make_buffer_from_node(actual),
 240                                                 0, _sz, false);
 241       guarantee(b, "Should not stop early.");
 242       nd = next;
 243     } else {
 244       nd = actual;
 245     }
 246   }
 247 }
 248 
 249 // Deallocates any completed log buffers
 250 void DirtyCardQueueSet::clear() {
 251   BufferNode* buffers_to_delete = NULL;
 252   {
 253     MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
 254     while (_completed_buffers_head != NULL) {
 255       BufferNode* nd = _completed_buffers_head;
 256       _completed_buffers_head = nd->next();
 257       nd->set_next(buffers_to_delete);
 258       buffers_to_delete = nd;
 259     }
 260     _n_completed_buffers = 0;
 261     _completed_buffers_tail = NULL;
 262     debug_only(assert_completed_buffer_list_len_correct_locked());
 263   }
 264   while (buffers_to_delete != NULL) {
 265     BufferNode* nd = buffers_to_delete;
 266     buffers_to_delete = nd->next();
 267     deallocate_buffer(BufferNode::make_buffer_from_node(nd));
 268   }
 269 
 270 }
 271 
 272 void DirtyCardQueueSet::abandon_logs() {
 273   assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
 274   clear();
 275   // Since abandon is done only at safepoints, we can safely manipulate
 276   // these queues.
 277   for (JavaThread* t = Threads::first(); t; t = t->next()) {
 278     t->dirty_card_queue().reset();
 279   }
 280   shared_dirty_card_queue()->reset();
 281 }
 282 
 283 
 284 void DirtyCardQueueSet::concatenate_logs() {
 285   // Iterate over all the threads, if we find a partial log add it to
 286   // the global list of logs.  Temporarily turn off the limit on the number
 287   // of outstanding buffers.
 288   int save_max_completed_queue = _max_completed_queue;
 289   _max_completed_queue = max_jint;
 290   assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
 291   for (JavaThread* t = Threads::first(); t; t = t->next()) {
 292     DirtyCardQueue& dcq = t->dirty_card_queue();
 293     if (dcq.size() != 0) {
 294       void **buf = t->dirty_card_queue().get_buf();
 295       // We must NULL out the unused entries, then enqueue.
 296       for (size_t i = 0; i < t->dirty_card_queue().get_index(); i += oopSize) {
 297         buf[PtrQueue::byte_index_to_index((int)i)] = NULL;
 298       }
 299       enqueue_complete_buffer(dcq.get_buf(), dcq.get_index());
 300       dcq.reinitialize();
 301     }
 302   }
 303   if (_shared_dirty_card_queue.size() != 0) {
 304     enqueue_complete_buffer(_shared_dirty_card_queue.get_buf(),
 305                             _shared_dirty_card_queue.get_index());
 306     _shared_dirty_card_queue.reinitialize();
 307   }
 308   // Restore the completed buffer queue limit.
 309   _max_completed_queue = save_max_completed_queue;
 310 }