1 /*
   2  * Copyright (c) 2001, 2019, 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/g1CollectedHeap.inline.hpp"
  27 #include "gc/g1/g1DirtyCardQueue.hpp"
  28 #include "gc/g1/g1FreeIdSet.hpp"
  29 #include "gc/g1/g1RemSet.hpp"
  30 #include "gc/g1/g1ThreadLocalData.hpp"
  31 #include "gc/g1/heapRegionRemSet.hpp"
  32 #include "gc/shared/suspendibleThreadSet.hpp"
  33 #include "gc/shared/workgroup.hpp"
  34 #include "runtime/atomic.hpp"
  35 #include "runtime/flags/flagSetting.hpp"
  36 #include "runtime/mutexLocker.hpp"
  37 #include "runtime/safepoint.hpp"
  38 #include "runtime/thread.inline.hpp"
  39 #include "runtime/threadSMR.hpp"
  40 
  41 // Closure used for updating remembered sets and recording references that
  42 // point into the collection set while the mutator is running.
  43 // Assumed to be only executed concurrently with the mutator. Yields via
  44 // SuspendibleThreadSet after every card.
  45 class G1RefineCardConcurrentlyClosure: public G1CardTableEntryClosure {
  46 public:
  47   bool do_card_ptr(jbyte* card_ptr, uint worker_i) {
  48     G1CollectedHeap::heap()->g1_rem_set()->refine_card_concurrently(card_ptr, worker_i);
  49 
  50     if (SuspendibleThreadSet::should_yield()) {
  51       // Caller will actually yield.
  52       return false;
  53     }
  54     // Otherwise, we finished successfully; return true.
  55     return true;
  56   }
  57 };
  58 
  59 G1DirtyCardQueue::G1DirtyCardQueue(G1DirtyCardQueueSet* qset, bool permanent) :
  60   // Dirty card queues are always active, so we create them with their
  61   // active field set to true.
  62   PtrQueue(qset, permanent, true /* active */)
  63 { }
  64 
  65 G1DirtyCardQueue::~G1DirtyCardQueue() {
  66   if (!is_permanent()) {
  67     flush();
  68   }
  69 }
  70 
  71 G1DirtyCardQueueSet::G1DirtyCardQueueSet(bool notify_when_complete) :
  72   PtrQueueSet(notify_when_complete),
  73   _shared_dirty_card_queue(this, true /* permanent */),
  74   _free_ids(NULL),
  75   _processed_buffers_mut(0),
  76   _processed_buffers_rs_thread(0),
  77   _cur_par_buffer_node(NULL)
  78 {
  79   _all_active = true;
  80 }
  81 
  82 G1DirtyCardQueueSet::~G1DirtyCardQueueSet() {
  83   delete _free_ids;
  84 }
  85 
  86 // Determines how many mutator threads can process the buffers in parallel.
  87 uint G1DirtyCardQueueSet::num_par_ids() {
  88   return (uint)os::initial_active_processor_count();
  89 }
  90 
  91 void G1DirtyCardQueueSet::initialize(Monitor* cbl_mon,
  92                                      BufferNode::Allocator* allocator,
  93                                      Mutex* lock,
  94                                      bool init_free_ids) {
  95   PtrQueueSet::initialize(cbl_mon, allocator);
  96   _shared_dirty_card_queue.set_lock(lock);
  97   if (init_free_ids) {
  98     _free_ids = new G1FreeIdSet(0, num_par_ids());
  99   }
 100 }
 101 
 102 void G1DirtyCardQueueSet::handle_zero_index_for_thread(JavaThread* t) {
 103   G1ThreadLocalData::dirty_card_queue(t).handle_zero_index();
 104 }
 105 
 106 bool G1DirtyCardQueueSet::apply_closure_to_buffer(G1CardTableEntryClosure* cl,
 107                                                   BufferNode* node,
 108                                                   bool consume,
 109                                                   uint worker_i) {
 110   if (cl == NULL) return true;
 111   bool result = true;
 112   void** buf = BufferNode::make_buffer_from_node(node);
 113   size_t i = node->index();
 114   size_t limit = buffer_size();
 115   for ( ; i < limit; ++i) {
 116     jbyte* card_ptr = static_cast<jbyte*>(buf[i]);
 117     assert(card_ptr != NULL, "invariant");
 118     if (!cl->do_card_ptr(card_ptr, worker_i)) {
 119       result = false;           // Incomplete processing.
 120       break;
 121     }
 122   }
 123   if (consume) {
 124     assert(i <= buffer_size(), "invariant");
 125     node->set_index(i);
 126   }
 127   return result;
 128 }
 129 
 130 #ifndef ASSERT
 131 #define assert_fully_consumed(node, buffer_size)
 132 #else
 133 #define assert_fully_consumed(node, buffer_size)                \
 134   do {                                                          \
 135     size_t _afc_index = (node)->index();                        \
 136     size_t _afc_size = (buffer_size);                           \
 137     assert(_afc_index == _afc_size,                             \
 138            "Buffer was not fully consumed as claimed: index: "  \
 139            SIZE_FORMAT ", size: " SIZE_FORMAT,                  \
 140             _afc_index, _afc_size);                             \
 141   } while (0)
 142 #endif // ASSERT
 143 
 144 bool G1DirtyCardQueueSet::mut_process_buffer(BufferNode* node) {
 145   guarantee(_free_ids != NULL, "must be");
 146 
 147   uint worker_i = _free_ids->claim_par_id(); // temporarily claim an id
 148   G1RefineCardConcurrentlyClosure cl;
 149   bool result = apply_closure_to_buffer(&cl, node, true, worker_i);
 150   _free_ids->release_par_id(worker_i); // release the id
 151 
 152   if (result) {
 153     assert_fully_consumed(node, buffer_size());
 154     Atomic::inc(&_processed_buffers_mut);
 155   }
 156   return result;
 157 }
 158 
 159 bool G1DirtyCardQueueSet::refine_completed_buffer_concurrently(uint worker_i, size_t stop_at) {
 160   G1RefineCardConcurrentlyClosure cl;
 161   return apply_closure_to_completed_buffer(&cl, worker_i, stop_at, false);
 162 }
 163 
 164 bool G1DirtyCardQueueSet::apply_closure_during_gc(G1CardTableEntryClosure* cl, uint worker_i) {
 165   assert_at_safepoint();
 166   return apply_closure_to_completed_buffer(cl, worker_i, 0, true);
 167 }
 168 
 169 bool G1DirtyCardQueueSet::apply_closure_to_completed_buffer(G1CardTableEntryClosure* cl,
 170                                                             uint worker_i,
 171                                                             size_t stop_at,
 172                                                             bool during_pause) {
 173   assert(!during_pause || stop_at == 0, "Should not leave any completed buffers during a pause");
 174   BufferNode* nd = get_completed_buffer(stop_at);
 175   if (nd == NULL) {
 176     return false;
 177   } else {
 178     if (apply_closure_to_buffer(cl, nd, true, worker_i)) {
 179       assert_fully_consumed(nd, buffer_size());
 180       // Done with fully processed buffer.
 181       deallocate_buffer(nd);
 182       Atomic::inc(&_processed_buffers_rs_thread);
 183     } else {
 184       // Return partially processed buffer to the queue.
 185       guarantee(!during_pause, "Should never stop early");
 186       enqueue_completed_buffer(nd);
 187     }
 188     return true;
 189   }
 190 }
 191 
 192 void G1DirtyCardQueueSet::par_apply_closure_to_all_completed_buffers(G1CardTableEntryClosure* cl) {
 193   BufferNode* nd = _cur_par_buffer_node;
 194   while (nd != NULL) {
 195     BufferNode* next = nd->next();
 196     BufferNode* actual = Atomic::cmpxchg(next, &_cur_par_buffer_node, nd);
 197     if (actual == nd) {
 198       bool b = apply_closure_to_buffer(cl, nd, false);
 199       guarantee(b, "Should not stop early.");
 200       nd = next;
 201     } else {
 202       nd = actual;
 203     }
 204   }
 205 }
 206 
 207 void G1DirtyCardQueueSet::abandon_logs() {
 208   assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
 209   abandon_completed_buffers();
 210   // Since abandon is done only at safepoints, we can safely manipulate
 211   // these queues.
 212   for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
 213     G1ThreadLocalData::dirty_card_queue(t).reset();
 214   }
 215   shared_dirty_card_queue()->reset();
 216 }
 217 
 218 void G1DirtyCardQueueSet::concatenate_log(G1DirtyCardQueue& dcq) {
 219   if (!dcq.is_empty()) {
 220     dcq.flush();
 221   }
 222 }
 223 
 224 void G1DirtyCardQueueSet::concatenate_logs() {
 225   // Iterate over all the threads, if we find a partial log add it to
 226   // the global list of logs.  Temporarily turn off the limit on the number
 227   // of outstanding buffers.
 228   assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
 229   size_t old_limit = max_completed_buffers();
 230   set_max_completed_buffers(MaxCompletedBuffersUnlimited);
 231   for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
 232     concatenate_log(G1ThreadLocalData::dirty_card_queue(t));
 233   }
 234   concatenate_log(_shared_dirty_card_queue);
 235   set_max_completed_buffers(old_limit);
 236 }