284             "target_pause_time_ms = %1.6lf should be positive", target_pause_time_ms);
 285   guarantee(_head == NULL, "Precondition");
 286 
 287   size_t pending_cards = _policy->pending_cards();
 288   double base_time_ms = _policy->predict_base_elapsed_time_ms(pending_cards);
 289   double time_remaining_ms = MAX2(target_pause_time_ms - base_time_ms, 0.0);
 290 
 291   log_trace(gc, ergo, cset)("Start choosing CSet. pending cards: " SIZE_FORMAT " predicted base time: %1.2fms remaining time: %1.2fms target pause time: %1.2fms",
 292                             pending_cards, base_time_ms, time_remaining_ms, target_pause_time_ms);
 293 
 294   collector_state()->set_last_gc_was_young(collector_state()->gcs_are_young());
 295 
 296   // The young list is laid with the survivor regions from the previous
 297   // pause are appended to the RHS of the young list, i.e.
 298   //   [Newly Young Regions ++ Survivors from last pause].
 299 
 300   uint survivor_region_length = young_list->survivor_length();
 301   uint eden_region_length = young_list->eden_length();
 302   init_region_lengths(eden_region_length, survivor_region_length);
 303 
 304   HeapRegion* hr = young_list->first_survivor_region();
 305   while (hr != NULL) {



 306     assert(hr->is_survivor(), "badly formed young list");
 307     // There is a convention that all the young regions in the CSet
 308     // are tagged as "eden", so we do this for the survivors here. We
 309     // use the special set_eden_pre_gc() as it doesn't check that the
 310     // region is free (which is not the case here).
 311     hr->set_eden_pre_gc();
 312     hr = hr->get_next_young_region();
 313   }
 314 
 315   verify_young_cset_indices();
 316 
 317   // Clear the fields that point to the survivor list - they are all young now.
 318   young_list->clear_survivors();
 319 
 320   _head = _inc_head;
 321   _bytes_used_before = _inc_bytes_used_before;
 322   time_remaining_ms = MAX2(time_remaining_ms - _inc_predicted_elapsed_time_ms, 0.0);
 323 
 324   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",
 325                             eden_region_length, survivor_region_length, _inc_predicted_elapsed_time_ms, target_pause_time_ms);
 326 
 327   // The number of recorded young regions is the incremental
 328   // collection set's current size
 329   set_recorded_rs_lengths(_inc_recorded_rs_lengths);
 330 
 331   double young_end_time_sec = os::elapsedTime();
 332   phase_times()->record_young_cset_choice_time_ms((young_end_time_sec - young_start_time_sec) * 1000.0);

 284             "target_pause_time_ms = %1.6lf should be positive", target_pause_time_ms);
 285   guarantee(_head == NULL, "Precondition");
 286 
 287   size_t pending_cards = _policy->pending_cards();
 288   double base_time_ms = _policy->predict_base_elapsed_time_ms(pending_cards);
 289   double time_remaining_ms = MAX2(target_pause_time_ms - base_time_ms, 0.0);
 290 
 291   log_trace(gc, ergo, cset)("Start choosing CSet. pending cards: " SIZE_FORMAT " predicted base time: %1.2fms remaining time: %1.2fms target pause time: %1.2fms",
 292                             pending_cards, base_time_ms, time_remaining_ms, target_pause_time_ms);
 293 
 294   collector_state()->set_last_gc_was_young(collector_state()->gcs_are_young());
 295 
 296   // The young list is laid with the survivor regions from the previous
 297   // pause are appended to the RHS of the young list, i.e.
 298   //   [Newly Young Regions ++ Survivors from last pause].
 299 
 300   uint survivor_region_length = young_list->survivor_length();
 301   uint eden_region_length = young_list->eden_length();
 302   init_region_lengths(eden_region_length, survivor_region_length);
 303 
 304   const GrowableArray<HeapRegion*>* survivor_regions = _g1->young_list()->survivor_regions();
 305   for (GrowableArrayIterator<HeapRegion*> it = survivor_regions->begin();
 306        it != survivor_regions->end();
 307        ++it) {
 308     HeapRegion* hr = *it;
 309     assert(hr->is_survivor(), "badly formed young list");
 310     // There is a convention that all the young regions in the CSet
 311     // are tagged as "eden", so we do this for the survivors here. We
 312     // use the special set_eden_pre_gc() as it doesn't check that the
 313     // region is free (which is not the case here).
 314     hr->set_eden_pre_gc();

 315   }
 316 
 317   verify_young_cset_indices();
 318 
 319   // Clear the fields that point to the survivor list - they are all young now.
 320   young_list->clear_survivors();
 321 
 322   _head = _inc_head;
 323   _bytes_used_before = _inc_bytes_used_before;
 324   time_remaining_ms = MAX2(time_remaining_ms - _inc_predicted_elapsed_time_ms, 0.0);
 325 
 326   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",
 327                             eden_region_length, survivor_region_length, _inc_predicted_elapsed_time_ms, target_pause_time_ms);
 328 
 329   // The number of recorded young regions is the incremental
 330   // collection set's current size
 331   set_recorded_rs_lengths(_inc_recorded_rs_lengths);
 332 
 333   double young_end_time_sec = os::elapsedTime();
 334   phase_times()->record_young_cset_choice_time_ms((young_end_time_sec - young_start_time_sec) * 1000.0);