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src/hotspot/share/gc/g1/g1CollectionSet.cpp

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rev 52675 : 8213890: Implementation of JEP 344: Abortable Mixed Collections for G1
Reviewed-by:
Contributed-by: erik.helin@oracle.com, stefan.johansson@oracle.com
rev 52676 : imported patch AMGC-impl
rev 52677 : imported patch AMGC-tsch-rev1
rev 52678 : imported patch AMGC-tsch-rev1-optcset
rev 52680 : imported patch AMGC-tsch-rev2
rev 52681 : [mq]: AMGC-kbar-rev1
rev 52682 : [mq]: AMGC-kbar-rev1b


   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.hpp"
  27 #include "gc/g1/g1CollectionSet.hpp"
  28 #include "gc/g1/g1CollectorState.hpp"

  29 #include "gc/g1/g1Policy.hpp"
  30 #include "gc/g1/heapRegion.inline.hpp"
  31 #include "gc/g1/heapRegionRemSet.hpp"
  32 #include "gc/g1/heapRegionSet.hpp"
  33 #include "logging/logStream.hpp"
  34 #include "utilities/debug.hpp"

  35 #include "utilities/quickSort.hpp"
  36 
  37 G1CollectorState* G1CollectionSet::collector_state() {
  38   return _g1h->collector_state();
  39 }
  40 
  41 G1GCPhaseTimes* G1CollectionSet::phase_times() {
  42   return _policy->phase_times();
  43 }
  44 
  45 CollectionSetChooser* G1CollectionSet::cset_chooser() {
  46   return _cset_chooser;
  47 }
  48 
  49 double G1CollectionSet::predict_region_elapsed_time_ms(HeapRegion* hr) {
  50   return _policy->predict_region_elapsed_time_ms(hr, collector_state()->in_young_only_phase());
  51 }
  52 
  53 G1CollectionSet::G1CollectionSet(G1CollectedHeap* g1h, G1Policy* policy) :
  54   _g1h(g1h),
  55   _policy(policy),
  56   _cset_chooser(new CollectionSetChooser()),
  57   _eden_region_length(0),
  58   _survivor_region_length(0),
  59   _old_region_length(0),
  60   _collection_set_regions(NULL),
  61   _collection_set_cur_length(0),
  62   _collection_set_max_length(0),



  63   _bytes_used_before(0),
  64   _recorded_rs_lengths(0),
  65   _inc_build_state(Inactive),
  66   _inc_bytes_used_before(0),
  67   _inc_recorded_rs_lengths(0),
  68   _inc_recorded_rs_lengths_diffs(0),
  69   _inc_predicted_elapsed_time_ms(0.0),
  70   _inc_predicted_elapsed_time_ms_diffs(0.0) {
  71 }
  72 
  73 G1CollectionSet::~G1CollectionSet() {
  74   if (_collection_set_regions != NULL) {
  75     FREE_C_HEAP_ARRAY(uint, _collection_set_regions);
  76   }

  77   delete _cset_chooser;
  78 }
  79 
  80 void G1CollectionSet::init_region_lengths(uint eden_cset_region_length,
  81                                           uint survivor_cset_region_length) {
  82   assert_at_safepoint_on_vm_thread();
  83 
  84   _eden_region_length     = eden_cset_region_length;
  85   _survivor_region_length = survivor_cset_region_length;
  86 
  87   assert((size_t) young_region_length() == _collection_set_cur_length,
  88          "Young region length %u should match collection set length " SIZE_FORMAT, young_region_length(), _collection_set_cur_length);
  89 
  90   _old_region_length      = 0;

  91 }
  92 
  93 void G1CollectionSet::initialize(uint max_region_length) {
  94   guarantee(_collection_set_regions == NULL, "Must only initialize once.");
  95   _collection_set_max_length = max_region_length;
  96   _collection_set_regions = NEW_C_HEAP_ARRAY(uint, max_region_length, mtGC);
  97 }
  98 

















  99 void G1CollectionSet::set_recorded_rs_lengths(size_t rs_lengths) {
 100   _recorded_rs_lengths = rs_lengths;
 101 }
 102 
 103 // Add the heap region at the head of the non-incremental collection set
 104 void G1CollectionSet::add_old_region(HeapRegion* hr) {
 105   assert_at_safepoint_on_vm_thread();
 106 
 107   assert(_inc_build_state == Active, "Precondition");

 108   assert(hr->is_old(), "the region should be old");
 109 
 110   assert(!hr->in_collection_set(), "should not already be in the CSet");
 111   _g1h->register_old_region_with_cset(hr);
 112 
 113   _collection_set_regions[_collection_set_cur_length++] = hr->hrm_index();
 114   assert(_collection_set_cur_length <= _collection_set_max_length, "Collection set now larger than maximum size.");
 115 
 116   _bytes_used_before += hr->used();
 117   size_t rs_length = hr->rem_set()->occupied();
 118   _recorded_rs_lengths += rs_length;
 119   _old_region_length += 1;
















 120 }
 121 
 122 // Initialize the per-collection-set information
 123 void G1CollectionSet::start_incremental_building() {
 124   assert(_collection_set_cur_length == 0, "Collection set must be empty before starting a new collection set.");
 125   assert(_inc_build_state == Inactive, "Precondition");
 126 
 127   _inc_bytes_used_before = 0;
 128 
 129   _inc_recorded_rs_lengths = 0;
 130   _inc_recorded_rs_lengths_diffs = 0;
 131   _inc_predicted_elapsed_time_ms = 0.0;
 132   _inc_predicted_elapsed_time_ms_diffs = 0.0;
 133   _inc_build_state = Active;
 134 }
 135 
 136 void G1CollectionSet::finalize_incremental_building() {
 137   assert(_inc_build_state == Active, "Precondition");
 138   assert(SafepointSynchronize::is_at_safepoint(), "should be at a safepoint");
 139 


 151     // as RSets can only grow between GCs. However, given that we
 152     // sample their size concurrently with other threads updating them
 153     // it's possible that we might get the wrong size back, which
 154     // could make the calculations somewhat inaccurate.
 155     size_t diffs = (size_t) (-_inc_recorded_rs_lengths_diffs);
 156     if (_inc_recorded_rs_lengths >= diffs) {
 157       _inc_recorded_rs_lengths -= diffs;
 158     } else {
 159       _inc_recorded_rs_lengths = 0;
 160     }
 161   }
 162   _inc_predicted_elapsed_time_ms += _inc_predicted_elapsed_time_ms_diffs;
 163 
 164   _inc_recorded_rs_lengths_diffs = 0;
 165   _inc_predicted_elapsed_time_ms_diffs = 0.0;
 166 }
 167 
 168 void G1CollectionSet::clear() {
 169   assert_at_safepoint_on_vm_thread();
 170   _collection_set_cur_length = 0;

 171 }
 172 
 173 void G1CollectionSet::iterate(HeapRegionClosure* cl) const {
 174   iterate_from(cl, 0, 1);
 175 }
 176 
 177 void G1CollectionSet::iterate_from(HeapRegionClosure* cl, uint worker_id, uint total_workers) const {
 178   size_t len = _collection_set_cur_length;
 179   OrderAccess::loadload();
 180   if (len == 0) {
 181     return;
 182   }
 183   size_t start_pos = (worker_id * len) / total_workers;
 184   size_t cur_pos = start_pos;
 185 
 186   do {
 187     HeapRegion* r = _g1h->region_at(_collection_set_regions[cur_pos]);
 188     bool result = cl->do_heap_region(r);
 189     if (result) {
 190       cl->set_incomplete();


 379 
 380   // Clear the fields that point to the survivor list - they are all young now.
 381   survivors->convert_to_eden();
 382 
 383   _bytes_used_before = _inc_bytes_used_before;
 384   time_remaining_ms = MAX2(time_remaining_ms - _inc_predicted_elapsed_time_ms, 0.0);
 385 
 386   log_trace(gc, ergo, cset)("Add young regions to CSet. eden: %u regions, survivors: %u regions, predicted young region time: %1.2fms, target pause time: %1.2fms",
 387                             eden_region_length, survivor_region_length, _inc_predicted_elapsed_time_ms, target_pause_time_ms);
 388 
 389   // The number of recorded young regions is the incremental
 390   // collection set's current size
 391   set_recorded_rs_lengths(_inc_recorded_rs_lengths);
 392 
 393   double young_end_time_sec = os::elapsedTime();
 394   phase_times()->record_young_cset_choice_time_ms((young_end_time_sec - young_start_time_sec) * 1000.0);
 395 
 396   return time_remaining_ms;
 397 }
 398 
























 399 static int compare_region_idx(const uint a, const uint b) {
 400   if (a > b) {
 401     return 1;
 402   } else if (a == b) {
 403     return 0;
 404   } else {
 405     return -1;
 406   }
 407 }
 408 
 409 void G1CollectionSet::finalize_old_part(double time_remaining_ms) {
 410   double non_young_start_time_sec = os::elapsedTime();
 411   double predicted_old_time_ms = 0.0;



 412 
 413   if (collector_state()->in_mixed_phase()) {
 414     cset_chooser()->verify();
 415     const uint min_old_cset_length = _policy->calc_min_old_cset_length();
 416     const uint max_old_cset_length = _policy->calc_max_old_cset_length();
 417 
 418     uint expensive_region_num = 0;
 419     bool check_time_remaining = _policy->adaptive_young_list_length();
 420 





 421     HeapRegion* hr = cset_chooser()->peek();
 422     while (hr != NULL) {
 423       if (old_region_length() >= max_old_cset_length) {
 424         // Added maximum number of old regions to the CSet.
 425         log_debug(gc, ergo, cset)("Finish adding old regions to CSet (old CSet region num reached max). old %u regions, max %u regions",
 426                                   old_region_length(), max_old_cset_length);

 427         break;
 428       }
 429 
 430       // Stop adding regions if the remaining reclaimable space is
 431       // not above G1HeapWastePercent.
 432       size_t reclaimable_bytes = cset_chooser()->remaining_reclaimable_bytes();
 433       double reclaimable_percent = _policy->reclaimable_bytes_percent(reclaimable_bytes);
 434       double threshold = (double) G1HeapWastePercent;
 435       if (reclaimable_percent <= threshold) {
 436         // We've added enough old regions that the amount of uncollected
 437         // reclaimable space is at or below the waste threshold. Stop
 438         // adding old regions to the CSet.
 439         log_debug(gc, ergo, cset)("Finish adding old regions to CSet (reclaimable percentage not over threshold). "
 440                                   "old %u regions, max %u regions, reclaimable: " SIZE_FORMAT "B (%1.2f%%) threshold: " UINTX_FORMAT "%%",
 441                                   old_region_length(), max_old_cset_length, reclaimable_bytes, reclaimable_percent, G1HeapWastePercent);

 442         break;
 443       }
 444 
 445       double predicted_time_ms = predict_region_elapsed_time_ms(hr);
 446       if (check_time_remaining) {
 447         if (predicted_time_ms > time_remaining_ms) {
 448           // Too expensive for the current CSet.
 449 
 450           if (old_region_length() >= min_old_cset_length) {
 451             // We have added the minimum number of old regions to the CSet,
 452             // we are done with this CSet.
 453             log_debug(gc, ergo, cset)("Finish adding old regions to CSet (predicted time is too high). "
 454                                       "predicted time: %1.2fms, remaining time: %1.2fms old %u regions, min %u regions",
 455                                       predicted_time_ms, time_remaining_ms, old_region_length(), min_old_cset_length);
 456             break;
 457           }
 458 
 459           // We'll add it anyway given that we haven't reached the
 460           // minimum number of old regions.
 461           expensive_region_num += 1;
 462         }
 463       } else {
 464         if (old_region_length() >= min_old_cset_length) {
 465           // In the non-auto-tuning case, we'll finish adding regions
 466           // to the CSet if we reach the minimum.
 467 
 468           log_debug(gc, ergo, cset)("Finish adding old regions to CSet (old CSet region num reached min). old %u regions, min %u regions",
 469                                     old_region_length(), min_old_cset_length);
 470           break;
 471         }
 472       }
 473 
 474       // We will add this region to the CSet.
 475       time_remaining_ms = MAX2(time_remaining_ms - predicted_time_ms, 0.0);
 476       predicted_old_time_ms += predicted_time_ms;
 477       cset_chooser()->pop(); // already have region via peek()
 478       _g1h->old_set_remove(hr);
 479       add_old_region(hr);
 480 











 481       hr = cset_chooser()->peek();
 482     }
 483     if (hr == NULL) {
 484       log_debug(gc, ergo, cset)("Finish adding old regions to CSet (candidate old regions not available)");
 485     }
 486 
 487     if (expensive_region_num > 0) {
 488       // We print the information once here at the end, predicated on
 489       // whether we added any apparently expensive regions or not, to
 490       // avoid generating output per region.
 491       log_debug(gc, ergo, cset)("Added expensive regions to CSet (old CSet region num not reached min)."
 492                                 "old: %u regions, expensive: %u regions, min: %u regions, remaining time: %1.2fms",
 493                                 old_region_length(), expensive_region_num, min_old_cset_length, time_remaining_ms);
 494     }
 495 
 496     cset_chooser()->verify();
 497   }
 498 
 499   stop_incremental_building();
 500 
 501   log_debug(gc, ergo, cset)("Finish choosing CSet. old: %u regions, predicted old region time: %1.2fms, time remaining: %1.2f",
 502                             old_region_length(), predicted_old_time_ms, time_remaining_ms);






 503 
 504   double non_young_end_time_sec = os::elapsedTime();
 505   phase_times()->record_non_young_cset_choice_time_ms((non_young_end_time_sec - non_young_start_time_sec) * 1000.0);
 506 
 507   QuickSort::sort(_collection_set_regions, _collection_set_cur_length, compare_region_idx, true);
















































































 508 }
 509 
 510 #ifdef ASSERT
 511 class G1VerifyYoungCSetIndicesClosure : public HeapRegionClosure {
 512 private:
 513   size_t _young_length;
 514   int* _heap_region_indices;
 515 public:
 516   G1VerifyYoungCSetIndicesClosure(size_t young_length) : HeapRegionClosure(), _young_length(young_length) {
 517     _heap_region_indices = NEW_C_HEAP_ARRAY(int, young_length, mtGC);
 518     for (size_t i = 0; i < young_length; i++) {
 519       _heap_region_indices[i] = -1;
 520     }
 521   }
 522   ~G1VerifyYoungCSetIndicesClosure() {
 523     FREE_C_HEAP_ARRAY(int, _heap_region_indices);
 524   }
 525 
 526   virtual bool do_heap_region(HeapRegion* r) {
 527     const int idx = r->young_index_in_cset();




   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/g1CollectionSet.hpp"
  28 #include "gc/g1/g1CollectorState.hpp"
  29 #include "gc/g1/g1ParScanThreadState.hpp"
  30 #include "gc/g1/g1Policy.hpp"
  31 #include "gc/g1/heapRegion.inline.hpp"
  32 #include "gc/g1/heapRegionRemSet.hpp"
  33 #include "gc/g1/heapRegionSet.hpp"
  34 #include "logging/logStream.hpp"
  35 #include "utilities/debug.hpp"
  36 #include "utilities/globalDefinitions.hpp"
  37 #include "utilities/quickSort.hpp"
  38 
  39 G1CollectorState* G1CollectionSet::collector_state() {
  40   return _g1h->collector_state();
  41 }
  42 
  43 G1GCPhaseTimes* G1CollectionSet::phase_times() {
  44   return _policy->phase_times();
  45 }
  46 
  47 CollectionSetChooser* G1CollectionSet::cset_chooser() {
  48   return _cset_chooser;
  49 }
  50 
  51 double G1CollectionSet::predict_region_elapsed_time_ms(HeapRegion* hr) {
  52   return _policy->predict_region_elapsed_time_ms(hr, collector_state()->in_young_only_phase());
  53 }
  54 
  55 G1CollectionSet::G1CollectionSet(G1CollectedHeap* g1h, G1Policy* policy) :
  56   _g1h(g1h),
  57   _policy(policy),
  58   _cset_chooser(new CollectionSetChooser()),
  59   _eden_region_length(0),
  60   _survivor_region_length(0),
  61   _old_region_length(0),
  62   _collection_set_regions(NULL),
  63   _collection_set_cur_length(0),
  64   _collection_set_max_length(0),
  65   _optional_regions(NULL),
  66   _optional_region_length(0),
  67   _optional_region_max_length(0),
  68   _bytes_used_before(0),
  69   _recorded_rs_lengths(0),
  70   _inc_build_state(Inactive),
  71   _inc_bytes_used_before(0),
  72   _inc_recorded_rs_lengths(0),
  73   _inc_recorded_rs_lengths_diffs(0),
  74   _inc_predicted_elapsed_time_ms(0.0),
  75   _inc_predicted_elapsed_time_ms_diffs(0.0) {
  76 }
  77 
  78 G1CollectionSet::~G1CollectionSet() {
  79   if (_collection_set_regions != NULL) {
  80     FREE_C_HEAP_ARRAY(uint, _collection_set_regions);
  81   }
  82   free_optional_regions();
  83   delete _cset_chooser;
  84 }
  85 
  86 void G1CollectionSet::init_region_lengths(uint eden_cset_region_length,
  87                                           uint survivor_cset_region_length) {
  88   assert_at_safepoint_on_vm_thread();
  89 
  90   _eden_region_length     = eden_cset_region_length;
  91   _survivor_region_length = survivor_cset_region_length;
  92 
  93   assert((size_t) young_region_length() == _collection_set_cur_length,
  94          "Young region length %u should match collection set length " SIZE_FORMAT, young_region_length(), _collection_set_cur_length);
  95 
  96   _old_region_length      = 0;
  97   _optional_region_length = 0;
  98 }
  99 
 100 void G1CollectionSet::initialize(uint max_region_length) {
 101   guarantee(_collection_set_regions == NULL, "Must only initialize once.");
 102   _collection_set_max_length = max_region_length;
 103   _collection_set_regions = NEW_C_HEAP_ARRAY(uint, max_region_length, mtGC);
 104 }
 105 
 106 void G1CollectionSet::initialize_optional(uint max_length) {
 107   assert(_optional_regions == NULL, "Already initialized");
 108   assert(_optional_region_length == 0, "Already initialized");
 109   assert(_optional_region_max_length == 0, "Already initialized");
 110   _optional_region_max_length = max_length;
 111   _optional_regions = NEW_C_HEAP_ARRAY(HeapRegion*, _optional_region_max_length, mtGC);
 112 }
 113 
 114 void G1CollectionSet::free_optional_regions() {
 115   _optional_region_length = 0;
 116   _optional_region_max_length = 0;
 117   if (_optional_regions != NULL) {
 118     FREE_C_HEAP_ARRAY(HeapRegion*, _optional_regions);
 119     _optional_regions = NULL;
 120   }
 121 }
 122 
 123 void G1CollectionSet::set_recorded_rs_lengths(size_t rs_lengths) {
 124   _recorded_rs_lengths = rs_lengths;
 125 }
 126 
 127 // Add the heap region at the head of the non-incremental collection set
 128 void G1CollectionSet::add_old_region(HeapRegion* hr) {
 129   assert_at_safepoint_on_vm_thread();
 130 
 131   assert(_inc_build_state == Active || hr->index_in_opt_cset() != G1OptionalCSet::InvalidCSetIndex,
 132          "Precondition, actively building cset or adding optional later on");
 133   assert(hr->is_old(), "the region should be old");
 134 
 135   assert(!hr->in_collection_set(), "should not already be in the CSet");
 136   _g1h->register_old_region_with_cset(hr);
 137 
 138   _collection_set_regions[_collection_set_cur_length++] = hr->hrm_index();
 139   assert(_collection_set_cur_length <= _collection_set_max_length, "Collection set now larger than maximum size.");
 140 
 141   _bytes_used_before += hr->used();
 142   size_t rs_length = hr->rem_set()->occupied();
 143   _recorded_rs_lengths += rs_length;
 144   _old_region_length += 1;
 145 
 146   log_trace(gc, cset)("Added old region %d to collection set", hr->hrm_index());
 147 }
 148 
 149 void G1CollectionSet::add_optional_region(HeapRegion* hr) {
 150   assert(!optional_is_full(), "Precondition, must have room left for this region");
 151   assert(hr->is_old(), "the region should be old");
 152   assert(!hr->in_collection_set(), "should not already be in the CSet");
 153 
 154   _g1h->register_optional_region_with_cset(hr);
 155 
 156   _optional_regions[_optional_region_length] = hr;
 157   uint index = _optional_region_length++;
 158   hr->set_index_in_opt_cset(index);
 159 
 160   log_trace(gc, cset)("Added region %d to optional collection set (%u)", hr->hrm_index(), _optional_region_length);
 161 }
 162 
 163 // Initialize the per-collection-set information
 164 void G1CollectionSet::start_incremental_building() {
 165   assert(_collection_set_cur_length == 0, "Collection set must be empty before starting a new collection set.");
 166   assert(_inc_build_state == Inactive, "Precondition");
 167 
 168   _inc_bytes_used_before = 0;
 169 
 170   _inc_recorded_rs_lengths = 0;
 171   _inc_recorded_rs_lengths_diffs = 0;
 172   _inc_predicted_elapsed_time_ms = 0.0;
 173   _inc_predicted_elapsed_time_ms_diffs = 0.0;
 174   _inc_build_state = Active;
 175 }
 176 
 177 void G1CollectionSet::finalize_incremental_building() {
 178   assert(_inc_build_state == Active, "Precondition");
 179   assert(SafepointSynchronize::is_at_safepoint(), "should be at a safepoint");
 180 


 192     // as RSets can only grow between GCs. However, given that we
 193     // sample their size concurrently with other threads updating them
 194     // it's possible that we might get the wrong size back, which
 195     // could make the calculations somewhat inaccurate.
 196     size_t diffs = (size_t) (-_inc_recorded_rs_lengths_diffs);
 197     if (_inc_recorded_rs_lengths >= diffs) {
 198       _inc_recorded_rs_lengths -= diffs;
 199     } else {
 200       _inc_recorded_rs_lengths = 0;
 201     }
 202   }
 203   _inc_predicted_elapsed_time_ms += _inc_predicted_elapsed_time_ms_diffs;
 204 
 205   _inc_recorded_rs_lengths_diffs = 0;
 206   _inc_predicted_elapsed_time_ms_diffs = 0.0;
 207 }
 208 
 209 void G1CollectionSet::clear() {
 210   assert_at_safepoint_on_vm_thread();
 211   _collection_set_cur_length = 0;
 212   _optional_region_length = 0;
 213 }
 214 
 215 void G1CollectionSet::iterate(HeapRegionClosure* cl) const {
 216   iterate_from(cl, 0, 1);
 217 }
 218 
 219 void G1CollectionSet::iterate_from(HeapRegionClosure* cl, uint worker_id, uint total_workers) const {
 220   size_t len = _collection_set_cur_length;
 221   OrderAccess::loadload();
 222   if (len == 0) {
 223     return;
 224   }
 225   size_t start_pos = (worker_id * len) / total_workers;
 226   size_t cur_pos = start_pos;
 227 
 228   do {
 229     HeapRegion* r = _g1h->region_at(_collection_set_regions[cur_pos]);
 230     bool result = cl->do_heap_region(r);
 231     if (result) {
 232       cl->set_incomplete();


 421 
 422   // Clear the fields that point to the survivor list - they are all young now.
 423   survivors->convert_to_eden();
 424 
 425   _bytes_used_before = _inc_bytes_used_before;
 426   time_remaining_ms = MAX2(time_remaining_ms - _inc_predicted_elapsed_time_ms, 0.0);
 427 
 428   log_trace(gc, ergo, cset)("Add young regions to CSet. eden: %u regions, survivors: %u regions, predicted young region time: %1.2fms, target pause time: %1.2fms",
 429                             eden_region_length, survivor_region_length, _inc_predicted_elapsed_time_ms, target_pause_time_ms);
 430 
 431   // The number of recorded young regions is the incremental
 432   // collection set's current size
 433   set_recorded_rs_lengths(_inc_recorded_rs_lengths);
 434 
 435   double young_end_time_sec = os::elapsedTime();
 436   phase_times()->record_young_cset_choice_time_ms((young_end_time_sec - young_start_time_sec) * 1000.0);
 437 
 438   return time_remaining_ms;
 439 }
 440 
 441 void G1CollectionSet::add_as_old(HeapRegion* hr) {
 442   cset_chooser()->pop(); // already have region via peek()
 443   _g1h->old_set_remove(hr);
 444   add_old_region(hr);
 445 }
 446 
 447 void G1CollectionSet::add_as_optional(HeapRegion* hr) {
 448   assert(_optional_regions != NULL, "Must not be called before array is allocated");
 449   cset_chooser()->pop(); // already have region via peek()
 450   _g1h->old_set_remove(hr);
 451   add_optional_region(hr);
 452 }
 453 
 454 bool G1CollectionSet::optional_is_full() {
 455   assert(_optional_region_length <= _optional_region_max_length, "Invariant");
 456   return _optional_region_length == _optional_region_max_length;
 457 }
 458 
 459 void G1CollectionSet::clear_optional_region(const HeapRegion* hr) {
 460   assert(_optional_regions != NULL, "Must not be called before array is allocated");
 461   uint index = hr->index_in_opt_cset();
 462   _optional_regions[index] = NULL;
 463 }
 464 
 465 static int compare_region_idx(const uint a, const uint b) {
 466   if (a > b) {
 467     return 1;
 468   } else if (a == b) {
 469     return 0;
 470   } else {
 471     return -1;
 472   }
 473 }
 474 
 475 void G1CollectionSet::finalize_old_part(double time_remaining_ms) {
 476   double non_young_start_time_sec = os::elapsedTime();
 477   double predicted_old_time_ms = 0.0;
 478   double predicted_optional_time_ms = 0.0;
 479   double optional_threshold_ms = time_remaining_ms * _policy->optional_prediction_fraction();
 480   uint expensive_region_num = 0;
 481 
 482   if (collector_state()->in_mixed_phase()) {
 483     cset_chooser()->verify();
 484     const uint min_old_cset_length = _policy->calc_min_old_cset_length();
 485     const uint max_old_cset_length = MAX2(min_old_cset_length, _policy->calc_max_old_cset_length());


 486     bool check_time_remaining = _policy->adaptive_young_list_length();
 487 
 488     initialize_optional(max_old_cset_length - min_old_cset_length);
 489     log_debug(gc, ergo, cset)("Start adding old regions for mixed gc. min %u regions, max %u regions, "
 490                               "time remaining %1.2fms, optional threshold %1.2fms",
 491                               min_old_cset_length, max_old_cset_length, time_remaining_ms, optional_threshold_ms);
 492 
 493     HeapRegion* hr = cset_chooser()->peek();
 494     while (hr != NULL) {
 495       if (old_region_length() + optional_region_length() >= max_old_cset_length) {
 496         // Added maximum number of old regions to the CSet.
 497         log_debug(gc, ergo, cset)("Finish adding old regions to CSet (old CSet region num reached max). "
 498                                   "old %u regions, optional %u regions",
 499                                   old_region_length(), optional_region_length());
 500         break;
 501       }
 502 
 503       // Stop adding regions if the remaining reclaimable space is
 504       // not above G1HeapWastePercent.
 505       size_t reclaimable_bytes = cset_chooser()->remaining_reclaimable_bytes();
 506       double reclaimable_percent = _policy->reclaimable_bytes_percent(reclaimable_bytes);
 507       double threshold = (double) G1HeapWastePercent;
 508       if (reclaimable_percent <= threshold) {
 509         // We've added enough old regions that the amount of uncollected
 510         // reclaimable space is at or below the waste threshold. Stop
 511         // adding old regions to the CSet.
 512         log_debug(gc, ergo, cset)("Finish adding old regions to CSet (reclaimable percentage not over threshold). "
 513                                   "reclaimable: " SIZE_FORMAT "%s (%1.2f%%) threshold: " UINTX_FORMAT "%%",
 514                                   byte_size_in_proper_unit(reclaimable_bytes), proper_unit_for_byte_size(reclaimable_bytes),
 515                                   reclaimable_percent, G1HeapWastePercent);
 516         break;
 517       }
 518 
 519       double predicted_time_ms = predict_region_elapsed_time_ms(hr);
 520       time_remaining_ms = MAX2(time_remaining_ms - predicted_time_ms, 0.0);
 521       // Add regions to old set until we reach minimum amount
 522       if (old_region_length() < min_old_cset_length) {
 523         predicted_old_time_ms += predicted_time_ms;
 524         add_as_old(hr);
 525         // Record the number of regions added when no time remaining
 526         if (time_remaining_ms == 0.0) {
 527           expensive_region_num++;








 528         }
 529       } else {

 530         // In the non-auto-tuning case, we'll finish adding regions
 531         // to the CSet if we reach the minimum.
 532         if (!check_time_remaining) {
 533           log_debug(gc, ergo, cset)("Finish adding old regions to CSet (old CSet region num reached min).");

 534           break;
 535         }
 536         // Keep adding regions to old set until we reach optional threshold
 537         if (time_remaining_ms > optional_threshold_ms) {


 538           predicted_old_time_ms += predicted_time_ms;
 539           add_as_old(hr);
 540         } else if (time_remaining_ms > 0) {
 541           // Keep adding optional regions until time is up
 542           if (!optional_is_full()) {
 543             predicted_optional_time_ms += predicted_time_ms;
 544             add_as_optional(hr);
 545           } else {
 546             log_debug(gc, ergo, cset)("Finish adding old regions to CSet (optional set full).");
 547             break;
 548           }
 549         } else {
 550           log_debug(gc, ergo, cset)("Finish adding old regions to CSet (predicted time is too high).");
 551           break;
 552         }
 553       }
 554       hr = cset_chooser()->peek();
 555     }
 556     if (hr == NULL) {
 557       log_debug(gc, ergo, cset)("Finish adding old regions to CSet (candidate old regions not available)");
 558     }
 559 









 560     cset_chooser()->verify();
 561   }
 562 
 563   stop_incremental_building();
 564 
 565   log_debug(gc, ergo, cset)("Finish choosing CSet regions old: %u, optional: %u, "
 566                             "predicted old time: %1.2fms, predicted optional time: %1.2fms, time remaining: %1.2f",
 567                             old_region_length(), optional_region_length(),
 568                             predicted_old_time_ms, predicted_optional_time_ms, time_remaining_ms);
 569   if (expensive_region_num > 0) {
 570     log_debug(gc, ergo, cset)("CSet contains %u old regions that were added although the predicted time was too high.",
 571                               expensive_region_num);
 572   }
 573 
 574   double non_young_end_time_sec = os::elapsedTime();
 575   phase_times()->record_non_young_cset_choice_time_ms((non_young_end_time_sec - non_young_start_time_sec) * 1000.0);
 576 
 577   QuickSort::sort(_collection_set_regions, _collection_set_cur_length, compare_region_idx, true);
 578 }
 579 
 580 HeapRegion* G1OptionalCSet::region_at(uint index) {
 581   return _cset->optional_region_at(index);
 582 }
 583 
 584 void G1OptionalCSet::prepare_evacuation(double time_limit) {
 585   assert(_current_index == _current_limit, "Before prepare no regions should be ready for evac");
 586 
 587   uint prepared_regions = 0;
 588   double prediction_ms = 0;
 589 
 590   _prepare_failed = true;
 591   for (uint i = _current_index; i < _cset->optional_region_length(); i++) {
 592     HeapRegion* hr = region_at(i);
 593     prediction_ms += _cset->predict_region_elapsed_time_ms(hr);
 594     if (prediction_ms > time_limit) {
 595       log_debug(gc, cset)("Prepared %u regions for optional evacuation. Predicted time: %.3fms", prepared_regions, prediction_ms);
 596       return;
 597     }
 598 
 599     // This region will be included in the next optional evacuation.
 600     prepare_to_evacuate_optional_region(hr);
 601     prepared_regions++;
 602     _current_limit++;
 603     _prepare_failed = false;
 604   }
 605 
 606   log_debug(gc, cset)("Prepared all %u regions for optional evacuation. Predicted time: %.3fms",
 607                       prepared_regions, prediction_ms);
 608 }
 609 
 610 bool G1OptionalCSet::prepare_failed() {
 611   return _prepare_failed;
 612 }
 613 
 614 void G1OptionalCSet::complete_evacuation() {
 615   _evacuation_failed = false;
 616   for (uint i = _current_index; i < _current_limit; i++) {
 617     HeapRegion* hr = region_at(i);
 618     _cset->clear_optional_region(hr);
 619     if (hr->evacuation_failed()){
 620       _evacuation_failed = true;
 621     }
 622   }
 623   _current_index = _current_limit;
 624 }
 625 
 626 bool G1OptionalCSet::evacuation_failed() {
 627   return _evacuation_failed;
 628 }
 629 
 630 G1OptionalCSet::~G1OptionalCSet() {
 631   G1CollectedHeap* g1h = G1CollectedHeap::heap();
 632   while (!is_empty()) {
 633     // We want to return regions not evacuated to the
 634     // chooser in reverse order to maintain the old order.
 635     HeapRegion* hr = _cset->remove_last_optional_region();
 636     assert(hr != NULL, "Should be valid region left");
 637     _pset->record_unused_optional_region(hr);
 638     g1h->old_set_add(hr);
 639     g1h->clear_in_cset(hr);
 640     hr->set_index_in_opt_cset(InvalidCSetIndex);
 641     _cset->cset_chooser()->push(hr);
 642   }
 643   _cset->free_optional_regions();
 644 }
 645 
 646 uint G1OptionalCSet::size() {
 647   return _cset->optional_region_length() - _current_index;
 648 }
 649 
 650 bool G1OptionalCSet::is_empty() {
 651   return size() == 0;
 652 }
 653 
 654 void G1OptionalCSet::prepare_to_evacuate_optional_region(HeapRegion* hr) {
 655   log_trace(gc, cset)("Adding region %u for optional evacuation", hr->hrm_index());
 656   G1CollectedHeap::heap()->clear_in_cset(hr);
 657   _cset->add_old_region(hr);
 658 }
 659 
 660 #ifdef ASSERT
 661 class G1VerifyYoungCSetIndicesClosure : public HeapRegionClosure {
 662 private:
 663   size_t _young_length;
 664   int* _heap_region_indices;
 665 public:
 666   G1VerifyYoungCSetIndicesClosure(size_t young_length) : HeapRegionClosure(), _young_length(young_length) {
 667     _heap_region_indices = NEW_C_HEAP_ARRAY(int, young_length, mtGC);
 668     for (size_t i = 0; i < young_length; i++) {
 669       _heap_region_indices[i] = -1;
 670     }
 671   }
 672   ~G1VerifyYoungCSetIndicesClosure() {
 673     FREE_C_HEAP_ARRAY(int, _heap_region_indices);
 674   }
 675 
 676   virtual bool do_heap_region(HeapRegion* r) {
 677     const int idx = r->young_index_in_cset();


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