--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/g1/g1Policy.cpp Tue Mar 20 04:36:44 2018 +0100
@@ -0,0 +1,1164 @@
+/*
+ * Copyright (c) 2001, 2018, 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/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"
+
+G1Policy::G1Policy(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) { }
+
+G1Policy::~G1Policy() {
+ delete _ihop_control;
+}
+
+G1CollectorState* G1Policy::collector_state() const { return _g1->collector_state(); }
+
+void G1Policy::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 G1Policy::note_gc_start() {
+ phase_times()->note_gc_start();
+}
+
+class G1YoungLengthPredictor {
+ const bool _during_cm;
+ const double _base_time_ms;
+ const double _base_free_regions;
+ const double _target_pause_time_ms;
+ const G1Policy* const _policy;
+
+ public:
+ G1YoungLengthPredictor(bool during_cm,
+ double base_time_ms,
+ double base_free_regions,
+ double target_pause_time_ms,
+ const G1Policy* 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 G1Policy::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 G1Policy::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 G1Policy::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 G1Policy::update_young_list_max_and_target_length() {
+ return update_young_list_max_and_target_length(_analytics->predict_rs_lengths());
+}
+
+uint G1Policy::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 G1Policy::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;
+}
+
+G1Policy::YoungTargetLengths G1Policy::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
+G1Policy::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 G1Policy::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 G1Policy::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 G1Policy::update_rs_lengths_prediction() {
+ update_rs_lengths_prediction(_analytics->predict_rs_lengths());
+}
+
+void G1Policy::update_rs_lengths_prediction(size_t prediction) {
+ if (collector_state()->gcs_are_young() && adaptive_young_list_length()) {
+ _rs_lengths_prediction = prediction;
+ }
+}
+
+void G1Policy::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 G1Policy::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 G1Policy::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 G1Policy::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 G1Policy::record_concurrent_mark_remark_start() {
+ _mark_remark_start_sec = os::elapsedTime();
+ collector_state()->set_during_marking(false);
+}
+
+void G1Policy::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 G1Policy::record_concurrent_mark_cleanup_start() {
+ _mark_cleanup_start_sec = os::elapsedTime();
+}
+
+void G1Policy::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 G1Policy::average_time_ms(G1GCPhaseTimes::GCParPhases phase) const {
+ return phase_times()->average_time_ms(phase);
+}
+
+double G1Policy::young_other_time_ms() const {
+ return phase_times()->young_cset_choice_time_ms() +
+ phase_times()->average_time_ms(G1GCPhaseTimes::YoungFreeCSet);
+}
+
+double G1Policy::non_young_other_time_ms() const {
+ return phase_times()->non_young_cset_choice_time_ms() +
+ phase_times()->average_time_ms(G1GCPhaseTimes::NonYoungFreeCSet);
+}
+
+double G1Policy::other_time_ms(double pause_time_ms) const {
+ return pause_time_ms - phase_times()->cur_collection_par_time_ms();
+}
+
+double G1Policy::constant_other_time_ms(double pause_time_ms) const {
+ return other_time_ms(pause_time_ms) - phase_times()->total_free_cset_time_ms();
+}
+
+CollectionSetChooser* G1Policy::cset_chooser() const {
+ return _collection_set->cset_chooser();
+}
+
+bool G1Policy::about_to_start_mixed_phase() const {
+ return _g1->concurrent_mark()->cm_thread()->during_cycle() || collector_state()->last_young_gc();
+}
+
+bool G1Policy::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 G1Policy::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* G1Policy::create_ihop_control(const G1Predictions* predictor){
+ if (G1UseAdaptiveIHOP) {
+ return new G1AdaptiveIHOPControl(InitiatingHeapOccupancyPercent,
+ predictor,
+ G1ReservePercent,
+ G1HeapWastePercent);
+ } else {
+ return new G1StaticIHOPControl(InitiatingHeapOccupancyPercent);
+ }
+}
+
+void G1Policy::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 G1Policy::report_ihop_statistics() {
+ _ihop_control->print();
+}
+
+void G1Policy::print_phases() {
+ phase_times()->print();
+}
+
+double G1Policy::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 G1Policy::accum_yg_surv_rate_pred(int age) const {
+ return _short_lived_surv_rate_group->accum_surv_rate_pred(age);
+}
+
+double G1Policy::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 G1Policy::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 G1Policy::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 G1Policy::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 G1Policy::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 G1Policy::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 G1Policy::adaptive_young_list_length() const {
+ return _young_gen_sizer.adaptive_young_list_length();
+}
+
+size_t G1Policy::desired_survivor_size() const {
+ size_t const survivor_capacity = HeapRegion::GrainWords * _max_survivor_regions;
+ return (size_t)((((double)survivor_capacity) * TargetSurvivorRatio) / 100);
+}
+
+void G1Policy::print_age_table() {
+ _survivors_age_table.print_age_table(_tenuring_threshold);
+}
+
+void G1Policy::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 G1Policy::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 G1Policy::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 G1Policy::initiate_conc_mark() {
+ collector_state()->set_during_initial_mark_pause(true);
+ collector_state()->set_initiate_conc_mark_if_possible(false);
+}
+
+void G1Policy::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 G1Policy::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 G1Policy::reclaimable_bytes_percent(size_t reclaimable_bytes) const {
+ return percent_of(reclaimable_bytes, _g1->capacity());
+}
+
+void G1Policy::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);
+ }
+}
+
+G1Policy::PauseKind G1Policy::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 G1Policy::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 G1Policy::abort_time_to_mixed_tracking() {
+ _initial_mark_to_mixed.reset();
+}
+
+bool G1Policy::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 G1Policy::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 G1Policy::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 G1Policy::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 G1Policy::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 */);
+}