--- a/src/hotspot/share/gc/g1/g1DefaultPolicy.cpp Fri Mar 23 18:44:47 2018 +0000
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,1165 +0,0 @@
-/*
- * Copyright (c) 2001, 2017, Oracle and/or its affiliates. All rights reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- *
- */
-
-#include "precompiled.hpp"
-#include "gc/g1/concurrentMarkThread.inline.hpp"
-#include "gc/g1/g1Analytics.hpp"
-#include "gc/g1/g1CollectedHeap.inline.hpp"
-#include "gc/g1/g1CollectionSet.hpp"
-#include "gc/g1/g1ConcurrentMark.hpp"
-#include "gc/g1/g1ConcurrentRefine.hpp"
-#include "gc/g1/g1DefaultPolicy.hpp"
-#include "gc/g1/g1HotCardCache.hpp"
-#include "gc/g1/g1IHOPControl.hpp"
-#include "gc/g1/g1GCPhaseTimes.hpp"
-#include "gc/g1/g1Policy.hpp"
-#include "gc/g1/g1SurvivorRegions.hpp"
-#include "gc/g1/g1YoungGenSizer.hpp"
-#include "gc/g1/heapRegion.inline.hpp"
-#include "gc/g1/heapRegionRemSet.hpp"
-#include "gc/shared/gcPolicyCounters.hpp"
-#include "logging/logStream.hpp"
-#include "runtime/arguments.hpp"
-#include "runtime/java.hpp"
-#include "runtime/mutexLocker.hpp"
-#include "utilities/debug.hpp"
-#include "utilities/growableArray.hpp"
-#include "utilities/pair.hpp"
-
-G1DefaultPolicy::G1DefaultPolicy(STWGCTimer* gc_timer) :
- _predictor(G1ConfidencePercent / 100.0),
- _analytics(new G1Analytics(&_predictor)),
- _mmu_tracker(new G1MMUTrackerQueue(GCPauseIntervalMillis / 1000.0, MaxGCPauseMillis / 1000.0)),
- _ihop_control(create_ihop_control(&_predictor)),
- _policy_counters(new GCPolicyCounters("GarbageFirst", 1, 2)),
- _young_list_fixed_length(0),
- _short_lived_surv_rate_group(new SurvRateGroup()),
- _survivor_surv_rate_group(new SurvRateGroup()),
- _reserve_factor((double) G1ReservePercent / 100.0),
- _reserve_regions(0),
- _rs_lengths_prediction(0),
- _bytes_allocated_in_old_since_last_gc(0),
- _initial_mark_to_mixed(),
- _collection_set(NULL),
- _g1(NULL),
- _phase_times(new G1GCPhaseTimes(gc_timer, ParallelGCThreads)),
- _tenuring_threshold(MaxTenuringThreshold),
- _max_survivor_regions(0),
- _survivors_age_table(true),
- _collection_pause_end_millis(os::javaTimeNanos() / NANOSECS_PER_MILLISEC) { }
-
-G1DefaultPolicy::~G1DefaultPolicy() {
- delete _ihop_control;
-}
-
-G1CollectorState* G1DefaultPolicy::collector_state() const { return _g1->collector_state(); }
-
-void G1DefaultPolicy::init(G1CollectedHeap* g1h, G1CollectionSet* collection_set) {
- _g1 = g1h;
- _collection_set = collection_set;
-
- assert(Heap_lock->owned_by_self(), "Locking discipline.");
-
- if (!adaptive_young_list_length()) {
- _young_list_fixed_length = _young_gen_sizer.min_desired_young_length();
- }
- _young_gen_sizer.adjust_max_new_size(_g1->max_regions());
-
- _free_regions_at_end_of_collection = _g1->num_free_regions();
-
- update_young_list_max_and_target_length();
- // We may immediately start allocating regions and placing them on the
- // collection set list. Initialize the per-collection set info
- _collection_set->start_incremental_building();
-}
-
-void G1DefaultPolicy::note_gc_start() {
- phase_times()->note_gc_start();
-}
-
-class G1YoungLengthPredictor VALUE_OBJ_CLASS_SPEC {
- const bool _during_cm;
- const double _base_time_ms;
- const double _base_free_regions;
- const double _target_pause_time_ms;
- const G1DefaultPolicy* const _policy;
-
- public:
- G1YoungLengthPredictor(bool during_cm,
- double base_time_ms,
- double base_free_regions,
- double target_pause_time_ms,
- const G1DefaultPolicy* policy) :
- _during_cm(during_cm),
- _base_time_ms(base_time_ms),
- _base_free_regions(base_free_regions),
- _target_pause_time_ms(target_pause_time_ms),
- _policy(policy) {}
-
- bool will_fit(uint young_length) const {
- if (young_length >= _base_free_regions) {
- // end condition 1: not enough space for the young regions
- return false;
- }
-
- const double accum_surv_rate = _policy->accum_yg_surv_rate_pred((int) young_length - 1);
- const size_t bytes_to_copy =
- (size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
- const double copy_time_ms =
- _policy->analytics()->predict_object_copy_time_ms(bytes_to_copy, _during_cm);
- const double young_other_time_ms = _policy->analytics()->predict_young_other_time_ms(young_length);
- const double pause_time_ms = _base_time_ms + copy_time_ms + young_other_time_ms;
- if (pause_time_ms > _target_pause_time_ms) {
- // end condition 2: prediction is over the target pause time
- return false;
- }
-
- const size_t free_bytes = (_base_free_regions - young_length) * HeapRegion::GrainBytes;
-
- // When copying, we will likely need more bytes free than is live in the region.
- // Add some safety margin to factor in the confidence of our guess, and the
- // natural expected waste.
- // (100.0 / G1ConfidencePercent) is a scale factor that expresses the uncertainty
- // of the calculation: the lower the confidence, the more headroom.
- // (100 + TargetPLABWastePct) represents the increase in expected bytes during
- // copying due to anticipated waste in the PLABs.
- const double safety_factor = (100.0 / G1ConfidencePercent) * (100 + TargetPLABWastePct) / 100.0;
- const size_t expected_bytes_to_copy = (size_t)(safety_factor * bytes_to_copy);
-
- if (expected_bytes_to_copy > free_bytes) {
- // end condition 3: out-of-space
- return false;
- }
-
- // success!
- return true;
- }
-};
-
-void G1DefaultPolicy::record_new_heap_size(uint new_number_of_regions) {
- // re-calculate the necessary reserve
- double reserve_regions_d = (double) new_number_of_regions * _reserve_factor;
- // We use ceiling so that if reserve_regions_d is > 0.0 (but
- // smaller than 1.0) we'll get 1.
- _reserve_regions = (uint) ceil(reserve_regions_d);
-
- _young_gen_sizer.heap_size_changed(new_number_of_regions);
-
- _ihop_control->update_target_occupancy(new_number_of_regions * HeapRegion::GrainBytes);
-}
-
-uint G1DefaultPolicy::calculate_young_list_desired_min_length(uint base_min_length) const {
- uint desired_min_length = 0;
- if (adaptive_young_list_length()) {
- if (_analytics->num_alloc_rate_ms() > 3) {
- double now_sec = os::elapsedTime();
- double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0;
- double alloc_rate_ms = _analytics->predict_alloc_rate_ms();
- desired_min_length = (uint) ceil(alloc_rate_ms * when_ms);
- } else {
- // otherwise we don't have enough info to make the prediction
- }
- }
- desired_min_length += base_min_length;
- // make sure we don't go below any user-defined minimum bound
- return MAX2(_young_gen_sizer.min_desired_young_length(), desired_min_length);
-}
-
-uint G1DefaultPolicy::calculate_young_list_desired_max_length() const {
- // Here, we might want to also take into account any additional
- // constraints (i.e., user-defined minimum bound). Currently, we
- // effectively don't set this bound.
- return _young_gen_sizer.max_desired_young_length();
-}
-
-uint G1DefaultPolicy::update_young_list_max_and_target_length() {
- return update_young_list_max_and_target_length(_analytics->predict_rs_lengths());
-}
-
-uint G1DefaultPolicy::update_young_list_max_and_target_length(size_t rs_lengths) {
- uint unbounded_target_length = update_young_list_target_length(rs_lengths);
- update_max_gc_locker_expansion();
- return unbounded_target_length;
-}
-
-uint G1DefaultPolicy::update_young_list_target_length(size_t rs_lengths) {
- YoungTargetLengths young_lengths = young_list_target_lengths(rs_lengths);
- _young_list_target_length = young_lengths.first;
- return young_lengths.second;
-}
-
-G1DefaultPolicy::YoungTargetLengths G1DefaultPolicy::young_list_target_lengths(size_t rs_lengths) const {
- YoungTargetLengths result;
-
- // Calculate the absolute and desired min bounds first.
-
- // This is how many young regions we already have (currently: the survivors).
- const uint base_min_length = _g1->survivor_regions_count();
- uint desired_min_length = calculate_young_list_desired_min_length(base_min_length);
- // This is the absolute minimum young length. Ensure that we
- // will at least have one eden region available for allocation.
- uint absolute_min_length = base_min_length + MAX2(_g1->eden_regions_count(), (uint)1);
- // If we shrank the young list target it should not shrink below the current size.
- desired_min_length = MAX2(desired_min_length, absolute_min_length);
- // Calculate the absolute and desired max bounds.
-
- uint desired_max_length = calculate_young_list_desired_max_length();
-
- uint young_list_target_length = 0;
- if (adaptive_young_list_length()) {
- if (collector_state()->gcs_are_young()) {
- young_list_target_length =
- calculate_young_list_target_length(rs_lengths,
- base_min_length,
- desired_min_length,
- desired_max_length);
- } else {
- // Don't calculate anything and let the code below bound it to
- // the desired_min_length, i.e., do the next GC as soon as
- // possible to maximize how many old regions we can add to it.
- }
- } else {
- // The user asked for a fixed young gen so we'll fix the young gen
- // whether the next GC is young or mixed.
- young_list_target_length = _young_list_fixed_length;
- }
-
- result.second = young_list_target_length;
-
- // We will try our best not to "eat" into the reserve.
- uint absolute_max_length = 0;
- if (_free_regions_at_end_of_collection > _reserve_regions) {
- absolute_max_length = _free_regions_at_end_of_collection - _reserve_regions;
- }
- if (desired_max_length > absolute_max_length) {
- desired_max_length = absolute_max_length;
- }
-
- // Make sure we don't go over the desired max length, nor under the
- // desired min length. In case they clash, desired_min_length wins
- // which is why that test is second.
- if (young_list_target_length > desired_max_length) {
- young_list_target_length = desired_max_length;
- }
- if (young_list_target_length < desired_min_length) {
- young_list_target_length = desired_min_length;
- }
-
- assert(young_list_target_length > base_min_length,
- "we should be able to allocate at least one eden region");
- assert(young_list_target_length >= absolute_min_length, "post-condition");
-
- result.first = young_list_target_length;
- return result;
-}
-
-uint
-G1DefaultPolicy::calculate_young_list_target_length(size_t rs_lengths,
- uint base_min_length,
- uint desired_min_length,
- uint desired_max_length) const {
- assert(adaptive_young_list_length(), "pre-condition");
- assert(collector_state()->gcs_are_young(), "only call this for young GCs");
-
- // In case some edge-condition makes the desired max length too small...
- if (desired_max_length <= desired_min_length) {
- return desired_min_length;
- }
-
- // We'll adjust min_young_length and max_young_length not to include
- // the already allocated young regions (i.e., so they reflect the
- // min and max eden regions we'll allocate). The base_min_length
- // will be reflected in the predictions by the
- // survivor_regions_evac_time prediction.
- assert(desired_min_length > base_min_length, "invariant");
- uint min_young_length = desired_min_length - base_min_length;
- assert(desired_max_length > base_min_length, "invariant");
- uint max_young_length = desired_max_length - base_min_length;
-
- const double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
- const double survivor_regions_evac_time = predict_survivor_regions_evac_time();
- const size_t pending_cards = _analytics->predict_pending_cards();
- const size_t adj_rs_lengths = rs_lengths + _analytics->predict_rs_length_diff();
- const size_t scanned_cards = _analytics->predict_card_num(adj_rs_lengths, /* gcs_are_young */ true);
- const double base_time_ms =
- predict_base_elapsed_time_ms(pending_cards, scanned_cards) +
- survivor_regions_evac_time;
- const uint available_free_regions = _free_regions_at_end_of_collection;
- const uint base_free_regions =
- available_free_regions > _reserve_regions ? available_free_regions - _reserve_regions : 0;
-
- // Here, we will make sure that the shortest young length that
- // makes sense fits within the target pause time.
-
- G1YoungLengthPredictor p(collector_state()->during_concurrent_mark(),
- base_time_ms,
- base_free_regions,
- target_pause_time_ms,
- this);
- if (p.will_fit(min_young_length)) {
- // The shortest young length will fit into the target pause time;
- // we'll now check whether the absolute maximum number of young
- // regions will fit in the target pause time. If not, we'll do
- // a binary search between min_young_length and max_young_length.
- if (p.will_fit(max_young_length)) {
- // The maximum young length will fit into the target pause time.
- // We are done so set min young length to the maximum length (as
- // the result is assumed to be returned in min_young_length).
- min_young_length = max_young_length;
- } else {
- // The maximum possible number of young regions will not fit within
- // the target pause time so we'll search for the optimal
- // length. The loop invariants are:
- //
- // min_young_length < max_young_length
- // min_young_length is known to fit into the target pause time
- // max_young_length is known not to fit into the target pause time
- //
- // Going into the loop we know the above hold as we've just
- // checked them. Every time around the loop we check whether
- // the middle value between min_young_length and
- // max_young_length fits into the target pause time. If it
- // does, it becomes the new min. If it doesn't, it becomes
- // the new max. This way we maintain the loop invariants.
-
- assert(min_young_length < max_young_length, "invariant");
- uint diff = (max_young_length - min_young_length) / 2;
- while (diff > 0) {
- uint young_length = min_young_length + diff;
- if (p.will_fit(young_length)) {
- min_young_length = young_length;
- } else {
- max_young_length = young_length;
- }
- assert(min_young_length < max_young_length, "invariant");
- diff = (max_young_length - min_young_length) / 2;
- }
- // The results is min_young_length which, according to the
- // loop invariants, should fit within the target pause time.
-
- // These are the post-conditions of the binary search above:
- assert(min_young_length < max_young_length,
- "otherwise we should have discovered that max_young_length "
- "fits into the pause target and not done the binary search");
- assert(p.will_fit(min_young_length),
- "min_young_length, the result of the binary search, should "
- "fit into the pause target");
- assert(!p.will_fit(min_young_length + 1),
- "min_young_length, the result of the binary search, should be "
- "optimal, so no larger length should fit into the pause target");
- }
- } else {
- // Even the minimum length doesn't fit into the pause time
- // target, return it as the result nevertheless.
- }
- return base_min_length + min_young_length;
-}
-
-double G1DefaultPolicy::predict_survivor_regions_evac_time() const {
- double survivor_regions_evac_time = 0.0;
- const GrowableArray<HeapRegion*>* survivor_regions = _g1->survivor()->regions();
-
- for (GrowableArrayIterator<HeapRegion*> it = survivor_regions->begin();
- it != survivor_regions->end();
- ++it) {
- survivor_regions_evac_time += predict_region_elapsed_time_ms(*it, collector_state()->gcs_are_young());
- }
- return survivor_regions_evac_time;
-}
-
-void G1DefaultPolicy::revise_young_list_target_length_if_necessary(size_t rs_lengths) {
- guarantee( adaptive_young_list_length(), "should not call this otherwise" );
-
- if (rs_lengths > _rs_lengths_prediction) {
- // add 10% to avoid having to recalculate often
- size_t rs_lengths_prediction = rs_lengths * 1100 / 1000;
- update_rs_lengths_prediction(rs_lengths_prediction);
-
- update_young_list_max_and_target_length(rs_lengths_prediction);
- }
-}
-
-void G1DefaultPolicy::update_rs_lengths_prediction() {
- update_rs_lengths_prediction(_analytics->predict_rs_lengths());
-}
-
-void G1DefaultPolicy::update_rs_lengths_prediction(size_t prediction) {
- if (collector_state()->gcs_are_young() && adaptive_young_list_length()) {
- _rs_lengths_prediction = prediction;
- }
-}
-
-void G1DefaultPolicy::record_full_collection_start() {
- _full_collection_start_sec = os::elapsedTime();
- // Release the future to-space so that it is available for compaction into.
- collector_state()->set_full_collection(true);
-}
-
-void G1DefaultPolicy::record_full_collection_end() {
- // Consider this like a collection pause for the purposes of allocation
- // since last pause.
- double end_sec = os::elapsedTime();
- double full_gc_time_sec = end_sec - _full_collection_start_sec;
- double full_gc_time_ms = full_gc_time_sec * 1000.0;
-
- _analytics->update_recent_gc_times(end_sec, full_gc_time_ms);
-
- collector_state()->set_full_collection(false);
-
- // "Nuke" the heuristics that control the young/mixed GC
- // transitions and make sure we start with young GCs after the Full GC.
- collector_state()->set_gcs_are_young(true);
- collector_state()->set_last_young_gc(false);
- collector_state()->set_initiate_conc_mark_if_possible(need_to_start_conc_mark("end of Full GC", 0));
- collector_state()->set_during_initial_mark_pause(false);
- collector_state()->set_in_marking_window(false);
- collector_state()->set_in_marking_window_im(false);
-
- _short_lived_surv_rate_group->start_adding_regions();
- // also call this on any additional surv rate groups
-
- _free_regions_at_end_of_collection = _g1->num_free_regions();
- // Reset survivors SurvRateGroup.
- _survivor_surv_rate_group->reset();
- update_young_list_max_and_target_length();
- update_rs_lengths_prediction();
- cset_chooser()->clear();
-
- _bytes_allocated_in_old_since_last_gc = 0;
-
- record_pause(FullGC, _full_collection_start_sec, end_sec);
-}
-
-void G1DefaultPolicy::record_collection_pause_start(double start_time_sec) {
- // We only need to do this here as the policy will only be applied
- // to the GC we're about to start. so, no point is calculating this
- // every time we calculate / recalculate the target young length.
- update_survivors_policy();
-
- assert(_g1->used() == _g1->recalculate_used(),
- "sanity, used: " SIZE_FORMAT " recalculate_used: " SIZE_FORMAT,
- _g1->used(), _g1->recalculate_used());
-
- phase_times()->record_cur_collection_start_sec(start_time_sec);
- _pending_cards = _g1->pending_card_num();
-
- _collection_set->reset_bytes_used_before();
- _bytes_copied_during_gc = 0;
-
- collector_state()->set_last_gc_was_young(false);
-
- // do that for any other surv rate groups
- _short_lived_surv_rate_group->stop_adding_regions();
- _survivors_age_table.clear();
-
- assert(_g1->collection_set()->verify_young_ages(), "region age verification failed");
-}
-
-void G1DefaultPolicy::record_concurrent_mark_init_end(double mark_init_elapsed_time_ms) {
- collector_state()->set_during_marking(true);
- assert(!collector_state()->initiate_conc_mark_if_possible(), "we should have cleared it by now");
- collector_state()->set_during_initial_mark_pause(false);
-}
-
-void G1DefaultPolicy::record_concurrent_mark_remark_start() {
- _mark_remark_start_sec = os::elapsedTime();
- collector_state()->set_during_marking(false);
-}
-
-void G1DefaultPolicy::record_concurrent_mark_remark_end() {
- double end_time_sec = os::elapsedTime();
- double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0;
- _analytics->report_concurrent_mark_remark_times_ms(elapsed_time_ms);
- _analytics->append_prev_collection_pause_end_ms(elapsed_time_ms);
-
- record_pause(Remark, _mark_remark_start_sec, end_time_sec);
-}
-
-void G1DefaultPolicy::record_concurrent_mark_cleanup_start() {
- _mark_cleanup_start_sec = os::elapsedTime();
-}
-
-void G1DefaultPolicy::record_concurrent_mark_cleanup_completed() {
- bool should_continue_with_reclaim = next_gc_should_be_mixed("request last young-only gc",
- "skip last young-only gc");
- collector_state()->set_last_young_gc(should_continue_with_reclaim);
- // We skip the marking phase.
- if (!should_continue_with_reclaim) {
- abort_time_to_mixed_tracking();
- }
- collector_state()->set_in_marking_window(false);
-}
-
-double G1DefaultPolicy::average_time_ms(G1GCPhaseTimes::GCParPhases phase) const {
- return phase_times()->average_time_ms(phase);
-}
-
-double G1DefaultPolicy::young_other_time_ms() const {
- return phase_times()->young_cset_choice_time_ms() +
- phase_times()->average_time_ms(G1GCPhaseTimes::YoungFreeCSet);
-}
-
-double G1DefaultPolicy::non_young_other_time_ms() const {
- return phase_times()->non_young_cset_choice_time_ms() +
- phase_times()->average_time_ms(G1GCPhaseTimes::NonYoungFreeCSet);
-}
-
-double G1DefaultPolicy::other_time_ms(double pause_time_ms) const {
- return pause_time_ms - phase_times()->cur_collection_par_time_ms();
-}
-
-double G1DefaultPolicy::constant_other_time_ms(double pause_time_ms) const {
- return other_time_ms(pause_time_ms) - phase_times()->total_free_cset_time_ms();
-}
-
-CollectionSetChooser* G1DefaultPolicy::cset_chooser() const {
- return _collection_set->cset_chooser();
-}
-
-bool G1DefaultPolicy::about_to_start_mixed_phase() const {
- return _g1->concurrent_mark()->cm_thread()->during_cycle() || collector_state()->last_young_gc();
-}
-
-bool G1DefaultPolicy::need_to_start_conc_mark(const char* source, size_t alloc_word_size) {
- if (about_to_start_mixed_phase()) {
- return false;
- }
-
- size_t marking_initiating_used_threshold = _ihop_control->get_conc_mark_start_threshold();
-
- size_t cur_used_bytes = _g1->non_young_capacity_bytes();
- size_t alloc_byte_size = alloc_word_size * HeapWordSize;
- size_t marking_request_bytes = cur_used_bytes + alloc_byte_size;
-
- bool result = false;
- if (marking_request_bytes > marking_initiating_used_threshold) {
- result = collector_state()->gcs_are_young() && !collector_state()->last_young_gc();
- log_debug(gc, ergo, ihop)("%s occupancy: " SIZE_FORMAT "B allocation request: " SIZE_FORMAT "B threshold: " SIZE_FORMAT "B (%1.2f) source: %s",
- result ? "Request concurrent cycle initiation (occupancy higher than threshold)" : "Do not request concurrent cycle initiation (still doing mixed collections)",
- cur_used_bytes, alloc_byte_size, marking_initiating_used_threshold, (double) marking_initiating_used_threshold / _g1->capacity() * 100, source);
- }
-
- return result;
-}
-
-// Anything below that is considered to be zero
-#define MIN_TIMER_GRANULARITY 0.0000001
-
-void G1DefaultPolicy::record_collection_pause_end(double pause_time_ms, size_t cards_scanned, size_t heap_used_bytes_before_gc) {
- double end_time_sec = os::elapsedTime();
-
- size_t cur_used_bytes = _g1->used();
- assert(cur_used_bytes == _g1->recalculate_used(), "It should!");
- bool last_pause_included_initial_mark = false;
- bool update_stats = !_g1->evacuation_failed();
-
- record_pause(young_gc_pause_kind(), end_time_sec - pause_time_ms / 1000.0, end_time_sec);
-
- _collection_pause_end_millis = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
-
- last_pause_included_initial_mark = collector_state()->during_initial_mark_pause();
- if (last_pause_included_initial_mark) {
- record_concurrent_mark_init_end(0.0);
- } else {
- maybe_start_marking();
- }
-
- double app_time_ms = (phase_times()->cur_collection_start_sec() * 1000.0 - _analytics->prev_collection_pause_end_ms());
- if (app_time_ms < MIN_TIMER_GRANULARITY) {
- // This usually happens due to the timer not having the required
- // granularity. Some Linuxes are the usual culprits.
- // We'll just set it to something (arbitrarily) small.
- app_time_ms = 1.0;
- }
-
- if (update_stats) {
- // We maintain the invariant that all objects allocated by mutator
- // threads will be allocated out of eden regions. So, we can use
- // the eden region number allocated since the previous GC to
- // calculate the application's allocate rate. The only exception
- // to that is humongous objects that are allocated separately. But
- // given that humongous object allocations do not really affect
- // either the pause's duration nor when the next pause will take
- // place we can safely ignore them here.
- uint regions_allocated = _collection_set->eden_region_length();
- double alloc_rate_ms = (double) regions_allocated / app_time_ms;
- _analytics->report_alloc_rate_ms(alloc_rate_ms);
-
- double interval_ms =
- (end_time_sec - _analytics->last_known_gc_end_time_sec()) * 1000.0;
- _analytics->update_recent_gc_times(end_time_sec, pause_time_ms);
- _analytics->compute_pause_time_ratio(interval_ms, pause_time_ms);
- }
-
- bool new_in_marking_window = collector_state()->in_marking_window();
- bool new_in_marking_window_im = false;
- if (last_pause_included_initial_mark) {
- new_in_marking_window = true;
- new_in_marking_window_im = true;
- }
-
- if (collector_state()->last_young_gc()) {
- // This is supposed to to be the "last young GC" before we start
- // doing mixed GCs. Here we decide whether to start mixed GCs or not.
- assert(!last_pause_included_initial_mark, "The last young GC is not allowed to be an initial mark GC");
-
- if (next_gc_should_be_mixed("start mixed GCs",
- "do not start mixed GCs")) {
- collector_state()->set_gcs_are_young(false);
- } else {
- // We aborted the mixed GC phase early.
- abort_time_to_mixed_tracking();
- }
-
- collector_state()->set_last_young_gc(false);
- }
-
- if (!collector_state()->last_gc_was_young()) {
- // This is a mixed GC. Here we decide whether to continue doing
- // mixed GCs or not.
- if (!next_gc_should_be_mixed("continue mixed GCs",
- "do not continue mixed GCs")) {
- collector_state()->set_gcs_are_young(true);
-
- maybe_start_marking();
- }
- }
-
- _short_lived_surv_rate_group->start_adding_regions();
- // Do that for any other surv rate groups
-
- double scan_hcc_time_ms = G1HotCardCache::default_use_cache() ? average_time_ms(G1GCPhaseTimes::ScanHCC) : 0.0;
-
- if (update_stats) {
- double cost_per_card_ms = 0.0;
- if (_pending_cards > 0) {
- cost_per_card_ms = (average_time_ms(G1GCPhaseTimes::UpdateRS) - scan_hcc_time_ms) / (double) _pending_cards;
- _analytics->report_cost_per_card_ms(cost_per_card_ms);
- }
- _analytics->report_cost_scan_hcc(scan_hcc_time_ms);
-
- double cost_per_entry_ms = 0.0;
- if (cards_scanned > 10) {
- cost_per_entry_ms = average_time_ms(G1GCPhaseTimes::ScanRS) / (double) cards_scanned;
- _analytics->report_cost_per_entry_ms(cost_per_entry_ms, collector_state()->last_gc_was_young());
- }
-
- if (_max_rs_lengths > 0) {
- double cards_per_entry_ratio =
- (double) cards_scanned / (double) _max_rs_lengths;
- _analytics->report_cards_per_entry_ratio(cards_per_entry_ratio, collector_state()->last_gc_was_young());
- }
-
- // This is defensive. For a while _max_rs_lengths could get
- // smaller than _recorded_rs_lengths which was causing
- // rs_length_diff to get very large and mess up the RSet length
- // predictions. The reason was unsafe concurrent updates to the
- // _inc_cset_recorded_rs_lengths field which the code below guards
- // against (see CR 7118202). This bug has now been fixed (see CR
- // 7119027). However, I'm still worried that
- // _inc_cset_recorded_rs_lengths might still end up somewhat
- // inaccurate. The concurrent refinement thread calculates an
- // RSet's length concurrently with other CR threads updating it
- // which might cause it to calculate the length incorrectly (if,
- // say, it's in mid-coarsening). So I'll leave in the defensive
- // conditional below just in case.
- size_t rs_length_diff = 0;
- size_t recorded_rs_lengths = _collection_set->recorded_rs_lengths();
- if (_max_rs_lengths > recorded_rs_lengths) {
- rs_length_diff = _max_rs_lengths - recorded_rs_lengths;
- }
- _analytics->report_rs_length_diff((double) rs_length_diff);
-
- size_t freed_bytes = heap_used_bytes_before_gc - cur_used_bytes;
- size_t copied_bytes = _collection_set->bytes_used_before() - freed_bytes;
- double cost_per_byte_ms = 0.0;
-
- if (copied_bytes > 0) {
- cost_per_byte_ms = average_time_ms(G1GCPhaseTimes::ObjCopy) / (double) copied_bytes;
- _analytics->report_cost_per_byte_ms(cost_per_byte_ms, collector_state()->in_marking_window());
- }
-
- if (_collection_set->young_region_length() > 0) {
- _analytics->report_young_other_cost_per_region_ms(young_other_time_ms() /
- _collection_set->young_region_length());
- }
-
- if (_collection_set->old_region_length() > 0) {
- _analytics->report_non_young_other_cost_per_region_ms(non_young_other_time_ms() /
- _collection_set->old_region_length());
- }
-
- _analytics->report_constant_other_time_ms(constant_other_time_ms(pause_time_ms));
-
- _analytics->report_pending_cards((double) _pending_cards);
- _analytics->report_rs_lengths((double) _max_rs_lengths);
- }
-
- collector_state()->set_in_marking_window(new_in_marking_window);
- collector_state()->set_in_marking_window_im(new_in_marking_window_im);
- _free_regions_at_end_of_collection = _g1->num_free_regions();
- // IHOP control wants to know the expected young gen length if it were not
- // restrained by the heap reserve. Using the actual length would make the
- // prediction too small and the limit the young gen every time we get to the
- // predicted target occupancy.
- size_t last_unrestrained_young_length = update_young_list_max_and_target_length();
- update_rs_lengths_prediction();
-
- update_ihop_prediction(app_time_ms / 1000.0,
- _bytes_allocated_in_old_since_last_gc,
- last_unrestrained_young_length * HeapRegion::GrainBytes);
- _bytes_allocated_in_old_since_last_gc = 0;
-
- _ihop_control->send_trace_event(_g1->gc_tracer_stw());
-
- // Note that _mmu_tracker->max_gc_time() returns the time in seconds.
- double update_rs_time_goal_ms = _mmu_tracker->max_gc_time() * MILLIUNITS * G1RSetUpdatingPauseTimePercent / 100.0;
-
- if (update_rs_time_goal_ms < scan_hcc_time_ms) {
- log_debug(gc, ergo, refine)("Adjust concurrent refinement thresholds (scanning the HCC expected to take longer than Update RS time goal)."
- "Update RS time goal: %1.2fms Scan HCC time: %1.2fms",
- update_rs_time_goal_ms, scan_hcc_time_ms);
-
- update_rs_time_goal_ms = 0;
- } else {
- update_rs_time_goal_ms -= scan_hcc_time_ms;
- }
- _g1->concurrent_refine()->adjust(average_time_ms(G1GCPhaseTimes::UpdateRS) - scan_hcc_time_ms,
- phase_times()->sum_thread_work_items(G1GCPhaseTimes::UpdateRS),
- update_rs_time_goal_ms);
-
- cset_chooser()->verify();
-}
-
-G1IHOPControl* G1DefaultPolicy::create_ihop_control(const G1Predictions* predictor){
- if (G1UseAdaptiveIHOP) {
- return new G1AdaptiveIHOPControl(InitiatingHeapOccupancyPercent,
- predictor,
- G1ReservePercent,
- G1HeapWastePercent);
- } else {
- return new G1StaticIHOPControl(InitiatingHeapOccupancyPercent);
- }
-}
-
-void G1DefaultPolicy::update_ihop_prediction(double mutator_time_s,
- size_t mutator_alloc_bytes,
- size_t young_gen_size) {
- // Always try to update IHOP prediction. Even evacuation failures give information
- // about e.g. whether to start IHOP earlier next time.
-
- // Avoid using really small application times that might create samples with
- // very high or very low values. They may be caused by e.g. back-to-back gcs.
- double const min_valid_time = 1e-6;
-
- bool report = false;
-
- double marking_to_mixed_time = -1.0;
- if (!collector_state()->last_gc_was_young() && _initial_mark_to_mixed.has_result()) {
- marking_to_mixed_time = _initial_mark_to_mixed.last_marking_time();
- assert(marking_to_mixed_time > 0.0,
- "Initial mark to mixed time must be larger than zero but is %.3f",
- marking_to_mixed_time);
- if (marking_to_mixed_time > min_valid_time) {
- _ihop_control->update_marking_length(marking_to_mixed_time);
- report = true;
- }
- }
-
- // As an approximation for the young gc promotion rates during marking we use
- // all of them. In many applications there are only a few if any young gcs during
- // marking, which makes any prediction useless. This increases the accuracy of the
- // prediction.
- if (collector_state()->last_gc_was_young() && mutator_time_s > min_valid_time) {
- _ihop_control->update_allocation_info(mutator_time_s, mutator_alloc_bytes, young_gen_size);
- report = true;
- }
-
- if (report) {
- report_ihop_statistics();
- }
-}
-
-void G1DefaultPolicy::report_ihop_statistics() {
- _ihop_control->print();
-}
-
-void G1DefaultPolicy::print_phases() {
- phase_times()->print();
-}
-
-double G1DefaultPolicy::predict_yg_surv_rate(int age, SurvRateGroup* surv_rate_group) const {
- TruncatedSeq* seq = surv_rate_group->get_seq(age);
- guarantee(seq->num() > 0, "There should be some young gen survivor samples available. Tried to access with age %d", age);
- double pred = _predictor.get_new_prediction(seq);
- if (pred > 1.0) {
- pred = 1.0;
- }
- return pred;
-}
-
-double G1DefaultPolicy::accum_yg_surv_rate_pred(int age) const {
- return _short_lived_surv_rate_group->accum_surv_rate_pred(age);
-}
-
-double G1DefaultPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
- size_t scanned_cards) const {
- return
- _analytics->predict_rs_update_time_ms(pending_cards) +
- _analytics->predict_rs_scan_time_ms(scanned_cards, collector_state()->gcs_are_young()) +
- _analytics->predict_constant_other_time_ms();
-}
-
-double G1DefaultPolicy::predict_base_elapsed_time_ms(size_t pending_cards) const {
- size_t rs_length = _analytics->predict_rs_lengths() + _analytics->predict_rs_length_diff();
- size_t card_num = _analytics->predict_card_num(rs_length, collector_state()->gcs_are_young());
- return predict_base_elapsed_time_ms(pending_cards, card_num);
-}
-
-size_t G1DefaultPolicy::predict_bytes_to_copy(HeapRegion* hr) const {
- size_t bytes_to_copy;
- if (hr->is_marked())
- bytes_to_copy = hr->max_live_bytes();
- else {
- assert(hr->is_young() && hr->age_in_surv_rate_group() != -1, "invariant");
- int age = hr->age_in_surv_rate_group();
- double yg_surv_rate = predict_yg_surv_rate(age, hr->surv_rate_group());
- bytes_to_copy = (size_t) (hr->used() * yg_surv_rate);
- }
- return bytes_to_copy;
-}
-
-double G1DefaultPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
- bool for_young_gc) const {
- size_t rs_length = hr->rem_set()->occupied();
- // Predicting the number of cards is based on which type of GC
- // we're predicting for.
- size_t card_num = _analytics->predict_card_num(rs_length, for_young_gc);
- size_t bytes_to_copy = predict_bytes_to_copy(hr);
-
- double region_elapsed_time_ms =
- _analytics->predict_rs_scan_time_ms(card_num, collector_state()->gcs_are_young()) +
- _analytics->predict_object_copy_time_ms(bytes_to_copy, collector_state()->during_concurrent_mark());
-
- // The prediction of the "other" time for this region is based
- // upon the region type and NOT the GC type.
- if (hr->is_young()) {
- region_elapsed_time_ms += _analytics->predict_young_other_time_ms(1);
- } else {
- region_elapsed_time_ms += _analytics->predict_non_young_other_time_ms(1);
- }
- return region_elapsed_time_ms;
-}
-
-bool G1DefaultPolicy::should_allocate_mutator_region() const {
- uint young_list_length = _g1->young_regions_count();
- uint young_list_target_length = _young_list_target_length;
- return young_list_length < young_list_target_length;
-}
-
-bool G1DefaultPolicy::can_expand_young_list() const {
- uint young_list_length = _g1->young_regions_count();
- uint young_list_max_length = _young_list_max_length;
- return young_list_length < young_list_max_length;
-}
-
-bool G1DefaultPolicy::adaptive_young_list_length() const {
- return _young_gen_sizer.adaptive_young_list_length();
-}
-
-size_t G1DefaultPolicy::desired_survivor_size() const {
- size_t const survivor_capacity = HeapRegion::GrainWords * _max_survivor_regions;
- return (size_t)((((double)survivor_capacity) * TargetSurvivorRatio) / 100);
-}
-
-void G1DefaultPolicy::print_age_table() {
- _survivors_age_table.print_age_table(_tenuring_threshold);
-}
-
-void G1DefaultPolicy::update_max_gc_locker_expansion() {
- uint expansion_region_num = 0;
- if (GCLockerEdenExpansionPercent > 0) {
- double perc = (double) GCLockerEdenExpansionPercent / 100.0;
- double expansion_region_num_d = perc * (double) _young_list_target_length;
- // We use ceiling so that if expansion_region_num_d is > 0.0 (but
- // less than 1.0) we'll get 1.
- expansion_region_num = (uint) ceil(expansion_region_num_d);
- } else {
- assert(expansion_region_num == 0, "sanity");
- }
- _young_list_max_length = _young_list_target_length + expansion_region_num;
- assert(_young_list_target_length <= _young_list_max_length, "post-condition");
-}
-
-// Calculates survivor space parameters.
-void G1DefaultPolicy::update_survivors_policy() {
- double max_survivor_regions_d =
- (double) _young_list_target_length / (double) SurvivorRatio;
- // We use ceiling so that if max_survivor_regions_d is > 0.0 (but
- // smaller than 1.0) we'll get 1.
- _max_survivor_regions = (uint) ceil(max_survivor_regions_d);
-
- _tenuring_threshold = _survivors_age_table.compute_tenuring_threshold(desired_survivor_size());
- if (UsePerfData) {
- _policy_counters->tenuring_threshold()->set_value(_tenuring_threshold);
- _policy_counters->desired_survivor_size()->set_value(desired_survivor_size() * oopSize);
- }
-}
-
-bool G1DefaultPolicy::force_initial_mark_if_outside_cycle(GCCause::Cause gc_cause) {
- // We actually check whether we are marking here and not if we are in a
- // reclamation phase. This means that we will schedule a concurrent mark
- // even while we are still in the process of reclaiming memory.
- bool during_cycle = _g1->concurrent_mark()->cm_thread()->during_cycle();
- if (!during_cycle) {
- log_debug(gc, ergo)("Request concurrent cycle initiation (requested by GC cause). GC cause: %s", GCCause::to_string(gc_cause));
- collector_state()->set_initiate_conc_mark_if_possible(true);
- return true;
- } else {
- log_debug(gc, ergo)("Do not request concurrent cycle initiation (concurrent cycle already in progress). GC cause: %s", GCCause::to_string(gc_cause));
- return false;
- }
-}
-
-void G1DefaultPolicy::initiate_conc_mark() {
- collector_state()->set_during_initial_mark_pause(true);
- collector_state()->set_initiate_conc_mark_if_possible(false);
-}
-
-void G1DefaultPolicy::decide_on_conc_mark_initiation() {
- // We are about to decide on whether this pause will be an
- // initial-mark pause.
-
- // First, collector_state()->during_initial_mark_pause() should not be already set. We
- // will set it here if we have to. However, it should be cleared by
- // the end of the pause (it's only set for the duration of an
- // initial-mark pause).
- assert(!collector_state()->during_initial_mark_pause(), "pre-condition");
-
- if (collector_state()->initiate_conc_mark_if_possible()) {
- // We had noticed on a previous pause that the heap occupancy has
- // gone over the initiating threshold and we should start a
- // concurrent marking cycle. So we might initiate one.
-
- if (!about_to_start_mixed_phase() && collector_state()->gcs_are_young()) {
- // Initiate a new initial mark if there is no marking or reclamation going on.
- initiate_conc_mark();
- log_debug(gc, ergo)("Initiate concurrent cycle (concurrent cycle initiation requested)");
- } else if (_g1->is_user_requested_concurrent_full_gc(_g1->gc_cause())) {
- // Initiate a user requested initial mark. An initial mark must be young only
- // GC, so the collector state must be updated to reflect this.
- collector_state()->set_gcs_are_young(true);
- collector_state()->set_last_young_gc(false);
-
- abort_time_to_mixed_tracking();
- initiate_conc_mark();
- log_debug(gc, ergo)("Initiate concurrent cycle (user requested concurrent cycle)");
- } else {
- // The concurrent marking thread is still finishing up the
- // previous cycle. If we start one right now the two cycles
- // overlap. In particular, the concurrent marking thread might
- // be in the process of clearing the next marking bitmap (which
- // we will use for the next cycle if we start one). Starting a
- // cycle now will be bad given that parts of the marking
- // information might get cleared by the marking thread. And we
- // cannot wait for the marking thread to finish the cycle as it
- // periodically yields while clearing the next marking bitmap
- // and, if it's in a yield point, it's waiting for us to
- // finish. So, at this point we will not start a cycle and we'll
- // let the concurrent marking thread complete the last one.
- log_debug(gc, ergo)("Do not initiate concurrent cycle (concurrent cycle already in progress)");
- }
- }
-}
-
-void G1DefaultPolicy::record_concurrent_mark_cleanup_end() {
- cset_chooser()->rebuild(_g1->workers(), _g1->num_regions());
-
- double end_sec = os::elapsedTime();
- double elapsed_time_ms = (end_sec - _mark_cleanup_start_sec) * 1000.0;
- _analytics->report_concurrent_mark_cleanup_times_ms(elapsed_time_ms);
- _analytics->append_prev_collection_pause_end_ms(elapsed_time_ms);
-
- record_pause(Cleanup, _mark_cleanup_start_sec, end_sec);
-}
-
-double G1DefaultPolicy::reclaimable_bytes_percent(size_t reclaimable_bytes) const {
- return percent_of(reclaimable_bytes, _g1->capacity());
-}
-
-void G1DefaultPolicy::maybe_start_marking() {
- if (need_to_start_conc_mark("end of GC")) {
- // Note: this might have already been set, if during the last
- // pause we decided to start a cycle but at the beginning of
- // this pause we decided to postpone it. That's OK.
- collector_state()->set_initiate_conc_mark_if_possible(true);
- }
-}
-
-G1DefaultPolicy::PauseKind G1DefaultPolicy::young_gc_pause_kind() const {
- assert(!collector_state()->full_collection(), "must be");
- if (collector_state()->during_initial_mark_pause()) {
- assert(collector_state()->last_gc_was_young(), "must be");
- assert(!collector_state()->last_young_gc(), "must be");
- return InitialMarkGC;
- } else if (collector_state()->last_young_gc()) {
- assert(!collector_state()->during_initial_mark_pause(), "must be");
- assert(collector_state()->last_gc_was_young(), "must be");
- return LastYoungGC;
- } else if (!collector_state()->last_gc_was_young()) {
- assert(!collector_state()->during_initial_mark_pause(), "must be");
- assert(!collector_state()->last_young_gc(), "must be");
- return MixedGC;
- } else {
- assert(collector_state()->last_gc_was_young(), "must be");
- assert(!collector_state()->during_initial_mark_pause(), "must be");
- assert(!collector_state()->last_young_gc(), "must be");
- return YoungOnlyGC;
- }
-}
-
-void G1DefaultPolicy::record_pause(PauseKind kind, double start, double end) {
- // Manage the MMU tracker. For some reason it ignores Full GCs.
- if (kind != FullGC) {
- _mmu_tracker->add_pause(start, end);
- }
- // Manage the mutator time tracking from initial mark to first mixed gc.
- switch (kind) {
- case FullGC:
- abort_time_to_mixed_tracking();
- break;
- case Cleanup:
- case Remark:
- case YoungOnlyGC:
- case LastYoungGC:
- _initial_mark_to_mixed.add_pause(end - start);
- break;
- case InitialMarkGC:
- _initial_mark_to_mixed.record_initial_mark_end(end);
- break;
- case MixedGC:
- _initial_mark_to_mixed.record_mixed_gc_start(start);
- break;
- default:
- ShouldNotReachHere();
- }
-}
-
-void G1DefaultPolicy::abort_time_to_mixed_tracking() {
- _initial_mark_to_mixed.reset();
-}
-
-bool G1DefaultPolicy::next_gc_should_be_mixed(const char* true_action_str,
- const char* false_action_str) const {
- if (cset_chooser()->is_empty()) {
- log_debug(gc, ergo)("%s (candidate old regions not available)", false_action_str);
- return false;
- }
-
- // Is the amount of uncollected reclaimable space above G1HeapWastePercent?
- size_t reclaimable_bytes = cset_chooser()->remaining_reclaimable_bytes();
- double reclaimable_percent = reclaimable_bytes_percent(reclaimable_bytes);
- double threshold = (double) G1HeapWastePercent;
- if (reclaimable_percent <= threshold) {
- log_debug(gc, ergo)("%s (reclaimable percentage not over threshold). candidate old regions: %u reclaimable: " SIZE_FORMAT " (%1.2f) threshold: " UINTX_FORMAT,
- false_action_str, cset_chooser()->remaining_regions(), reclaimable_bytes, reclaimable_percent, G1HeapWastePercent);
- return false;
- }
- log_debug(gc, ergo)("%s (candidate old regions available). candidate old regions: %u reclaimable: " SIZE_FORMAT " (%1.2f) threshold: " UINTX_FORMAT,
- true_action_str, cset_chooser()->remaining_regions(), reclaimable_bytes, reclaimable_percent, G1HeapWastePercent);
- return true;
-}
-
-uint G1DefaultPolicy::calc_min_old_cset_length() const {
- // The min old CSet region bound is based on the maximum desired
- // number of mixed GCs after a cycle. I.e., even if some old regions
- // look expensive, we should add them to the CSet anyway to make
- // sure we go through the available old regions in no more than the
- // maximum desired number of mixed GCs.
- //
- // The calculation is based on the number of marked regions we added
- // to the CSet chooser in the first place, not how many remain, so
- // that the result is the same during all mixed GCs that follow a cycle.
-
- const size_t region_num = (size_t) cset_chooser()->length();
- const size_t gc_num = (size_t) MAX2(G1MixedGCCountTarget, (uintx) 1);
- size_t result = region_num / gc_num;
- // emulate ceiling
- if (result * gc_num < region_num) {
- result += 1;
- }
- return (uint) result;
-}
-
-uint G1DefaultPolicy::calc_max_old_cset_length() const {
- // The max old CSet region bound is based on the threshold expressed
- // as a percentage of the heap size. I.e., it should bound the
- // number of old regions added to the CSet irrespective of how many
- // of them are available.
-
- const G1CollectedHeap* g1h = G1CollectedHeap::heap();
- const size_t region_num = g1h->num_regions();
- const size_t perc = (size_t) G1OldCSetRegionThresholdPercent;
- size_t result = region_num * perc / 100;
- // emulate ceiling
- if (100 * result < region_num * perc) {
- result += 1;
- }
- return (uint) result;
-}
-
-void G1DefaultPolicy::finalize_collection_set(double target_pause_time_ms, G1SurvivorRegions* survivor) {
- double time_remaining_ms = _collection_set->finalize_young_part(target_pause_time_ms, survivor);
- _collection_set->finalize_old_part(time_remaining_ms);
-}
-
-void G1DefaultPolicy::transfer_survivors_to_cset(const G1SurvivorRegions* survivors) {
-
- // Add survivor regions to SurvRateGroup.
- note_start_adding_survivor_regions();
- finished_recalculating_age_indexes(true /* is_survivors */);
-
- HeapRegion* last = NULL;
- for (GrowableArrayIterator<HeapRegion*> it = survivors->regions()->begin();
- it != survivors->regions()->end();
- ++it) {
- HeapRegion* curr = *it;
- set_region_survivor(curr);
-
- // The region is a non-empty survivor so let's add it to
- // the incremental collection set for the next evacuation
- // pause.
- _collection_set->add_survivor_regions(curr);
-
- last = curr;
- }
- note_stop_adding_survivor_regions();
-
- // Don't clear the survivor list handles until the start of
- // the next evacuation pause - we need it in order to re-tag
- // the survivor regions from this evacuation pause as 'young'
- // at the start of the next.
-
- finished_recalculating_age_indexes(false /* is_survivors */);
-}