jdk8-mips64-public/hotspot: comparison src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp

--1:000000000000
+:f90c822e73f8
+/*
+* Copyright (c) 2001, 2014, 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.
+*
+*/
+#ifndef __clang_major__
+#define ATTRIBUTE_PRINTF(x,y) // FIXME, formats are a mess.
+#endif
+#include "precompiled.hpp"
+#include "gc_implementation/g1/concurrentG1Refine.hpp"
+#include "gc_implementation/g1/concurrentMark.hpp"
+#include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
+#include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
+#include "gc_implementation/g1/g1CollectorPolicy.hpp"
+#include "gc_implementation/g1/g1ErgoVerbose.hpp"
+#include "gc_implementation/g1/g1GCPhaseTimes.hpp"
+#include "gc_implementation/g1/g1Log.hpp"
+#include "gc_implementation/g1/heapRegionRemSet.hpp"
+#include "gc_implementation/shared/gcPolicyCounters.hpp"
+#include "runtime/arguments.hpp"
+#include "runtime/java.hpp"
+#include "runtime/mutexLocker.hpp"
+#include "utilities/debug.hpp"
+// Different defaults for different number of GC threads
+// They were chosen by running GCOld and SPECjbb on debris with different
+//   numbers of GC threads and choosing them based on the results
+// all the same
+static double rs_length_diff_defaults[] = {
+0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0
+};
+static double cost_per_card_ms_defaults[] = {
+0.01, 0.005, 0.005, 0.003, 0.003, 0.002, 0.002, 0.0015
+};
+// all the same
+static double young_cards_per_entry_ratio_defaults[] = {
+1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
+};
+static double cost_per_entry_ms_defaults[] = {
+0.015, 0.01, 0.01, 0.008, 0.008, 0.0055, 0.0055, 0.005
+};
+static double cost_per_byte_ms_defaults[] = {
+0.00006, 0.00003, 0.00003, 0.000015, 0.000015, 0.00001, 0.00001, 0.000009
+};
+// these should be pretty consistent
+static double constant_other_time_ms_defaults[] = {
+5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0
+};
+static double young_other_cost_per_region_ms_defaults[] = {
+0.3, 0.2, 0.2, 0.15, 0.15, 0.12, 0.12, 0.1
+};
+static double non_young_other_cost_per_region_ms_defaults[] = {
+1.0, 0.7, 0.7, 0.5, 0.5, 0.42, 0.42, 0.30
+};
+G1CollectorPolicy::G1CollectorPolicy() :
+_parallel_gc_threads(G1CollectedHeap::use_parallel_gc_threads()
+? ParallelGCThreads : 1),
+_recent_gc_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
+_stop_world_start(0.0),
+_concurrent_mark_remark_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
+_concurrent_mark_cleanup_times_ms(new TruncatedSeq(NumPrevPausesForHeuristics)),
+_alloc_rate_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
+_prev_collection_pause_end_ms(0.0),
+_rs_length_diff_seq(new TruncatedSeq(TruncatedSeqLength)),
+_cost_per_card_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
+_young_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
+_mixed_cards_per_entry_ratio_seq(new TruncatedSeq(TruncatedSeqLength)),
+_cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
+_mixed_cost_per_entry_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
+_cost_per_byte_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
+_cost_per_byte_ms_during_cm_seq(new TruncatedSeq(TruncatedSeqLength)),
+_constant_other_time_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
+_young_other_cost_per_region_ms_seq(new TruncatedSeq(TruncatedSeqLength)),
+_non_young_other_cost_per_region_ms_seq(
+new TruncatedSeq(TruncatedSeqLength)),
+_pending_cards_seq(new TruncatedSeq(TruncatedSeqLength)),
+_rs_lengths_seq(new TruncatedSeq(TruncatedSeqLength)),
+_pause_time_target_ms((double) MaxGCPauseMillis),
+_gcs_are_young(true),
+_during_marking(false),
+_in_marking_window(false),
+_in_marking_window_im(false),
+_recent_prev_end_times_for_all_gcs_sec(
+new TruncatedSeq(NumPrevPausesForHeuristics)),
+_recent_avg_pause_time_ratio(0.0),
+_initiate_conc_mark_if_possible(false),
+_during_initial_mark_pause(false),
+_last_young_gc(false),
+_last_gc_was_young(false),
+_eden_used_bytes_before_gc(0),
+_survivor_used_bytes_before_gc(0),
+_heap_used_bytes_before_gc(0),
+_metaspace_used_bytes_before_gc(0),
+_eden_capacity_bytes_before_gc(0),
+_heap_capacity_bytes_before_gc(0),
+_eden_cset_region_length(0),
+_survivor_cset_region_length(0),
+_old_cset_region_length(0),
+_collection_set(NULL),
+_collection_set_bytes_used_before(0),
+// Incremental CSet attributes
+_inc_cset_build_state(Inactive),
+_inc_cset_head(NULL),
+_inc_cset_tail(NULL),
+_inc_cset_bytes_used_before(0),
+_inc_cset_max_finger(NULL),
+_inc_cset_recorded_rs_lengths(0),
+_inc_cset_recorded_rs_lengths_diffs(0),
+_inc_cset_predicted_elapsed_time_ms(0.0),
+_inc_cset_predicted_elapsed_time_ms_diffs(0.0),
+#ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
+#pragma warning( disable:4355 ) // 'this' : used in base member initializer list
+#endif // _MSC_VER
+_short_lived_surv_rate_group(new SurvRateGroup(this, "Short Lived",
+G1YoungSurvRateNumRegionsSummary)),
+_survivor_surv_rate_group(new SurvRateGroup(this, "Survivor",
+G1YoungSurvRateNumRegionsSummary)),
+// add here any more surv rate groups
+_recorded_survivor_regions(0),
+_recorded_survivor_head(NULL),
+_recorded_survivor_tail(NULL),
+_survivors_age_table(true),
+_gc_overhead_perc(0.0) {
+// Set up the region size and associated fields. Given that the
+// policy is created before the heap, we have to set this up here,
+// so it's done as soon as possible.
+// It would have been natural to pass initial_heap_byte_size() and
+// max_heap_byte_size() to setup_heap_region_size() but those have
+// not been set up at this point since they should be aligned with
+// the region size. So, there is a circular dependency here. We base
+// the region size on the heap size, but the heap size should be
+// aligned with the region size. To get around this we use the
+// unaligned values for the heap.
+HeapRegion::setup_heap_region_size(InitialHeapSize, MaxHeapSize);
+HeapRegionRemSet::setup_remset_size();
+G1ErgoVerbose::initialize();
+if (PrintAdaptiveSizePolicy) {
+// Currently, we only use a single switch for all the heuristics.
+G1ErgoVerbose::set_enabled(true);
+// Given that we don't currently have a verboseness level
+// parameter, we'll hardcode this to high. This can be easily
+// changed in the future.
+G1ErgoVerbose::set_level(ErgoHigh);
+} else {
+G1ErgoVerbose::set_enabled(false);
+}
+// Verify PLAB sizes
+const size_t region_size = HeapRegion::GrainWords;
+if (YoungPLABSize > region_size || OldPLABSize > region_size) {
+char buffer[128];
+jio_snprintf(buffer, sizeof(buffer), "%sPLABSize should be at most "SIZE_FORMAT,
+OldPLABSize > region_size ? "Old" : "Young", region_size);
+vm_exit_during_initialization(buffer);
+}
+_recent_prev_end_times_for_all_gcs_sec->add(os::elapsedTime());
+_prev_collection_pause_end_ms = os::elapsedTime() * 1000.0;
+_phase_times = new G1GCPhaseTimes(_parallel_gc_threads);
+int index = MIN2(_parallel_gc_threads - 1, 7);
+_rs_length_diff_seq->add(rs_length_diff_defaults[index]);
+_cost_per_card_ms_seq->add(cost_per_card_ms_defaults[index]);
+_young_cards_per_entry_ratio_seq->add(
+young_cards_per_entry_ratio_defaults[index]);
+_cost_per_entry_ms_seq->add(cost_per_entry_ms_defaults[index]);
+_cost_per_byte_ms_seq->add(cost_per_byte_ms_defaults[index]);
+_constant_other_time_ms_seq->add(constant_other_time_ms_defaults[index]);
+_young_other_cost_per_region_ms_seq->add(
+young_other_cost_per_region_ms_defaults[index]);
+_non_young_other_cost_per_region_ms_seq->add(
+non_young_other_cost_per_region_ms_defaults[index]);
+// Below, we might need to calculate the pause time target based on
+// the pause interval. When we do so we are going to give G1 maximum
+// flexibility and allow it to do pauses when it needs to. So, we'll
+// arrange that the pause interval to be pause time target + 1 to
+// ensure that a) the pause time target is maximized with respect to
+// the pause interval and b) we maintain the invariant that pause
+// time target < pause interval. If the user does not want this
+// maximum flexibility, they will have to set the pause interval
+// explicitly.
+// First make sure that, if either parameter is set, its value is
+// reasonable.
+if (!FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
+if (MaxGCPauseMillis < 1) {
+vm_exit_during_initialization("MaxGCPauseMillis should be "
+"greater than 0");
+}
+}
+if (!FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
+if (GCPauseIntervalMillis < 1) {
+vm_exit_during_initialization("GCPauseIntervalMillis should be "
+"greater than 0");
+}
+}
+// Then, if the pause time target parameter was not set, set it to
+// the default value.
+if (FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
+if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
+// The default pause time target in G1 is 200ms
+FLAG_SET_DEFAULT(MaxGCPauseMillis, 200);
+} else {
+// We do not allow the pause interval to be set without the
+// pause time target
+vm_exit_during_initialization("GCPauseIntervalMillis cannot be set "
+"without setting MaxGCPauseMillis");
+}
+}
+// Then, if the interval parameter was not set, set it according to
+// the pause time target (this will also deal with the case when the
+// pause time target is the default value).
+if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
+FLAG_SET_DEFAULT(GCPauseIntervalMillis, MaxGCPauseMillis + 1);
+}
+// Finally, make sure that the two parameters are consistent.
+if (MaxGCPauseMillis >= GCPauseIntervalMillis) {
+char buffer[256];
+jio_snprintf(buffer, 256,
+"MaxGCPauseMillis (%u) should be less than "
+"GCPauseIntervalMillis (%u)",
+MaxGCPauseMillis, GCPauseIntervalMillis);
+vm_exit_during_initialization(buffer);
+}
+double max_gc_time = (double) MaxGCPauseMillis / 1000.0;
+double time_slice  = (double) GCPauseIntervalMillis / 1000.0;
+_mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time);
+uintx confidence_perc = G1ConfidencePercent;
+// Put an artificial ceiling on this so that it's not set to a silly value.
+if (confidence_perc > 100) {
+confidence_perc = 100;
+warning("G1ConfidencePercent is set to a value that is too large, "
+"it's been updated to %u", confidence_perc);
+}
+_sigma = (double) confidence_perc / 100.0;
+// start conservatively (around 50ms is about right)
+_concurrent_mark_remark_times_ms->add(0.05);
+_concurrent_mark_cleanup_times_ms->add(0.20);
+_tenuring_threshold = MaxTenuringThreshold;
+// _max_survivor_regions will be calculated by
+// update_young_list_target_length() during initialization.
+_max_survivor_regions = 0;
+assert(GCTimeRatio > 0,
+"we should have set it to a default value set_g1_gc_flags() "
+"if a user set it to 0");
+_gc_overhead_perc = 100.0 * (1.0 / (1.0 + GCTimeRatio));
+uintx reserve_perc = G1ReservePercent;
+// Put an artificial ceiling on this so that it's not set to a silly value.
+if (reserve_perc > 50) {
+reserve_perc = 50;
+warning("G1ReservePercent is set to a value that is too large, "
+"it's been updated to %u", reserve_perc);
+}
+_reserve_factor = (double) reserve_perc / 100.0;
+// This will be set when the heap is expanded
+// for the first time during initialization.
+_reserve_regions = 0;
+_collectionSetChooser = new CollectionSetChooser();
+}
+void G1CollectorPolicy::initialize_alignments() {
+_space_alignment = HeapRegion::GrainBytes;
+size_t card_table_alignment = GenRemSet::max_alignment_constraint(GenRemSet::CardTable);
+size_t page_size = UseLargePages ? os::large_page_size() : os::vm_page_size();
+_heap_alignment = MAX3(card_table_alignment, _space_alignment, page_size);
+}
+void G1CollectorPolicy::initialize_flags() {
+if (G1HeapRegionSize != HeapRegion::GrainBytes) {
+FLAG_SET_ERGO(uintx, G1HeapRegionSize, HeapRegion::GrainBytes);
+}
+if (SurvivorRatio < 1) {
+vm_exit_during_initialization("Invalid survivor ratio specified");
+}
+CollectorPolicy::initialize_flags();
+_young_gen_sizer = new G1YoungGenSizer(); // Must be after call to initialize_flags
+}
+void G1CollectorPolicy::post_heap_initialize() {
+uintx max_regions = G1CollectedHeap::heap()->max_regions();
+size_t max_young_size = (size_t)_young_gen_sizer->max_young_length(max_regions) * HeapRegion::GrainBytes;
+if (max_young_size != MaxNewSize) {
+FLAG_SET_ERGO(uintx, MaxNewSize, max_young_size);
+}
+}
+G1YoungGenSizer::G1YoungGenSizer() : _sizer_kind(SizerDefaults), _adaptive_size(true),
+_min_desired_young_length(0), _max_desired_young_length(0) {
+if (FLAG_IS_CMDLINE(NewRatio)) {
+if (FLAG_IS_CMDLINE(NewSize) || FLAG_IS_CMDLINE(MaxNewSize)) {
+warning("-XX:NewSize and -XX:MaxNewSize override -XX:NewRatio");
+} else {
+_sizer_kind = SizerNewRatio;
+_adaptive_size = false;
+return;
+}
+}
+if (NewSize > MaxNewSize) {
+if (FLAG_IS_CMDLINE(MaxNewSize)) {
+warning("NewSize (" SIZE_FORMAT "k) is greater than the MaxNewSize (" SIZE_FORMAT "k). "
+"A new max generation size of " SIZE_FORMAT "k will be used.",
+NewSize/K, MaxNewSize/K, NewSize/K);
+}
+MaxNewSize = NewSize;
+}
+if (FLAG_IS_CMDLINE(NewSize)) {
+_min_desired_young_length = MAX2((uint) (NewSize / HeapRegion::GrainBytes),
+1U);
+if (FLAG_IS_CMDLINE(MaxNewSize)) {
+_max_desired_young_length =
+MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes),
+1U);
+_sizer_kind = SizerMaxAndNewSize;
+_adaptive_size = _min_desired_young_length == _max_desired_young_length;
+} else {
+_sizer_kind = SizerNewSizeOnly;
+}
+} else if (FLAG_IS_CMDLINE(MaxNewSize)) {
+_max_desired_young_length =
+MAX2((uint) (MaxNewSize / HeapRegion::GrainBytes),
+1U);
+_sizer_kind = SizerMaxNewSizeOnly;
+}
+}
+uint G1YoungGenSizer::calculate_default_min_length(uint new_number_of_heap_regions) {
+uint default_value = (new_number_of_heap_regions * G1NewSizePercent) / 100;
+return MAX2(1U, default_value);
+}
+uint G1YoungGenSizer::calculate_default_max_length(uint new_number_of_heap_regions) {
+uint default_value = (new_number_of_heap_regions * G1MaxNewSizePercent) / 100;
+return MAX2(1U, default_value);
+}
+void G1YoungGenSizer::recalculate_min_max_young_length(uint number_of_heap_regions, uint* min_young_length, uint* max_young_length) {
+assert(number_of_heap_regions > 0, "Heap must be initialized");
+switch (_sizer_kind) {
+case SizerDefaults:
+*min_young_length = calculate_default_min_length(number_of_heap_regions);
+*max_young_length = calculate_default_max_length(number_of_heap_regions);
+break;
+case SizerNewSizeOnly:
+*max_young_length = calculate_default_max_length(number_of_heap_regions);
+*max_young_length = MAX2(*min_young_length, *max_young_length);
+break;
+case SizerMaxNewSizeOnly:
+*min_young_length = calculate_default_min_length(number_of_heap_regions);
+*min_young_length = MIN2(*min_young_length, *max_young_length);
+break;
+case SizerMaxAndNewSize:
+// Do nothing. Values set on the command line, don't update them at runtime.
+break;
+case SizerNewRatio:
+*min_young_length = number_of_heap_regions / (NewRatio + 1);
+*max_young_length = *min_young_length;
+break;
+default:
+ShouldNotReachHere();
+}
+assert(*min_young_length <= *max_young_length, "Invalid min/max young gen size values");
+}
+uint G1YoungGenSizer::max_young_length(uint number_of_heap_regions) {
+// We need to pass the desired values because recalculation may not update these
+// values in some cases.
+uint temp = _min_desired_young_length;
+uint result = _max_desired_young_length;
+recalculate_min_max_young_length(number_of_heap_regions, &temp, &result);
+return result;
+}
+void G1YoungGenSizer::heap_size_changed(uint new_number_of_heap_regions) {
+recalculate_min_max_young_length(new_number_of_heap_regions, &_min_desired_young_length,
+&_max_desired_young_length);
+}
+void G1CollectorPolicy::init() {
+// Set aside an initial future to_space.
+_g1 = G1CollectedHeap::heap();
+assert(Heap_lock->owned_by_self(), "Locking discipline.");
+initialize_gc_policy_counters();
+if (adaptive_young_list_length()) {
+_young_list_fixed_length = 0;
+} else {
+_young_list_fixed_length = _young_gen_sizer->min_desired_young_length();
+}
+_free_regions_at_end_of_collection = _g1->free_regions();
+update_young_list_target_length();
+// We may immediately start allocating regions and placing them on the
+// collection set list. Initialize the per-collection set info
+start_incremental_cset_building();
+}
+// Create the jstat counters for the policy.
+void G1CollectorPolicy::initialize_gc_policy_counters() {
+_gc_policy_counters = new GCPolicyCounters("GarbageFirst", 1, 3);
+}
+bool G1CollectorPolicy::predict_will_fit(uint young_length,
+double base_time_ms,
+uint base_free_regions,
+double target_pause_time_ms) {
+if (young_length >= base_free_regions) {
+// end condition 1: not enough space for the young regions
+return false;
+}
+double accum_surv_rate = accum_yg_surv_rate_pred((int) young_length - 1);
+size_t bytes_to_copy =
+(size_t) (accum_surv_rate * (double) HeapRegion::GrainBytes);
+double copy_time_ms = predict_object_copy_time_ms(bytes_to_copy);
+double young_other_time_ms = predict_young_other_time_ms(young_length);
+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;
+}
+size_t free_bytes =
+(base_free_regions - young_length) * HeapRegion::GrainBytes;
+if ((2.0 * sigma()) * (double) bytes_to_copy > (double) free_bytes) {
+// end condition 3: out-of-space (conservatively!)
+return false;
+}
+// success!
+return true;
+}
+void G1CollectorPolicy::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);
+}
+uint G1CollectorPolicy::calculate_young_list_desired_min_length(
+uint base_min_length) {
+uint desired_min_length = 0;
+if (adaptive_young_list_length()) {
+if (_alloc_rate_ms_seq->num() > 3) {
+double now_sec = os::elapsedTime();
+double when_ms = _mmu_tracker->when_max_gc_sec(now_sec) * 1000.0;
+double alloc_rate_ms = 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 G1CollectorPolicy::calculate_young_list_desired_max_length() {
+// 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();
+}
+void G1CollectorPolicy::update_young_list_target_length(size_t rs_lengths) {
+if (rs_lengths == (size_t) -1) {
+// if it's set to the default value (-1), we should predict it;
+// otherwise, use the given value.
+rs_lengths = (size_t) get_new_prediction(_rs_lengths_seq);
+}
+// Calculate the absolute and desired min bounds.
+// This is how many young regions we already have (currently: the survivors).
+uint base_min_length = recorded_survivor_regions();
+// This is the absolute minimum young length, which ensures that we
+// can allocate one eden region in the worst-case.
+uint absolute_min_length = base_min_length + 1;
+uint desired_min_length =
+calculate_young_list_desired_min_length(base_min_length);
+if (desired_min_length < absolute_min_length) {
+desired_min_length = absolute_min_length;
+}
+// Calculate the absolute and desired max bounds.
+// 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;
+}
+uint desired_max_length = calculate_young_list_desired_max_length();
+if (desired_max_length > absolute_max_length) {
+desired_max_length = absolute_max_length;
+}
+uint young_list_target_length = 0;
+if (adaptive_young_list_length()) {
+if (gcs_are_young()) {
+young_list_target_length =
+calculate_young_list_target_length(rs_lengths,
+base_min_length,
+desired_min_length,
+desired_max_length);
+_rs_lengths_prediction = rs_lengths;
+} 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;
+}
+// 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 > recorded_survivor_regions(),
+"we should be able to allocate at least one eden region");
+assert(young_list_target_length >= absolute_min_length, "post-condition");
+_young_list_target_length = young_list_target_length;
+update_max_gc_locker_expansion();
+}
+uint
+G1CollectorPolicy::calculate_young_list_target_length(size_t rs_lengths,
+uint base_min_length,
+uint desired_min_length,
+uint desired_max_length) {
+assert(adaptive_young_list_length(), "pre-condition");
+assert(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;
+double target_pause_time_ms = _mmu_tracker->max_gc_time() * 1000.0;
+double survivor_regions_evac_time = predict_survivor_regions_evac_time();
+size_t pending_cards = (size_t) get_new_prediction(_pending_cards_seq);
+size_t adj_rs_lengths = rs_lengths + predict_rs_length_diff();
+size_t scanned_cards = predict_young_card_num(adj_rs_lengths);
+double base_time_ms =
+predict_base_elapsed_time_ms(pending_cards, scanned_cards) +
+survivor_regions_evac_time;
+uint available_free_regions = _free_regions_at_end_of_collection;
+uint base_free_regions = 0;
+if (available_free_regions > _reserve_regions) {
+base_free_regions = available_free_regions - _reserve_regions;
+}
+// Here, we will make sure that the shortest young length that
+// makes sense fits within the target pause time.
+if (predict_will_fit(min_young_length, base_time_ms,
+base_free_regions, target_pause_time_ms)) {
+// 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 (predict_will_fit(max_young_length, base_time_ms,
+base_free_regions, target_pause_time_ms)) {
+// 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 (predict_will_fit(young_length, base_time_ms,
+base_free_regions, target_pause_time_ms)) {
+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(predict_will_fit(min_young_length, base_time_ms,
+base_free_regions, target_pause_time_ms),
+"min_young_length, the result of the binary search, should "
+"fit into the pause target");
+assert(!predict_will_fit(min_young_length + 1, base_time_ms,
+base_free_regions, target_pause_time_ms),
+"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 G1CollectorPolicy::predict_survivor_regions_evac_time() {
+double survivor_regions_evac_time = 0.0;
+for (HeapRegion * r = _recorded_survivor_head;
+r != NULL && r != _recorded_survivor_tail->get_next_young_region();
+r = r->get_next_young_region()) {
+survivor_regions_evac_time += predict_region_elapsed_time_ms(r, gcs_are_young());
+}
+return survivor_regions_evac_time;
+}
+void G1CollectorPolicy::revise_young_list_target_length_if_necessary() {
+guarantee( adaptive_young_list_length(), "should not call this otherwise" );
+size_t rs_lengths = _g1->young_list()->sampled_rs_lengths();
+if (rs_lengths > _rs_lengths_prediction) {
+// add 10% to avoid having to recalculate often
+size_t rs_lengths_prediction = rs_lengths * 1100 / 1000;
+update_young_list_target_length(rs_lengths_prediction);
+}
+}
+HeapWord* G1CollectorPolicy::mem_allocate_work(size_t size,
+bool is_tlab,
+bool* gc_overhead_limit_was_exceeded) {
+guarantee(false, "Not using this policy feature yet.");
+return NULL;
+}
+// This method controls how a collector handles one or more
+// of its generations being fully allocated.
+HeapWord* G1CollectorPolicy::satisfy_failed_allocation(size_t size,
+bool is_tlab) {
+guarantee(false, "Not using this policy feature yet.");
+return NULL;
+}
+#ifndef PRODUCT
+bool G1CollectorPolicy::verify_young_ages() {
+HeapRegion* head = _g1->young_list()->first_region();
+return
+verify_young_ages(head, _short_lived_surv_rate_group);
+// also call verify_young_ages on any additional surv rate groups
+}
+bool
+G1CollectorPolicy::verify_young_ages(HeapRegion* head,
+SurvRateGroup *surv_rate_group) {
+guarantee( surv_rate_group != NULL, "pre-condition" );
+const char* name = surv_rate_group->name();
+bool ret = true;
+int prev_age = -1;
+for (HeapRegion* curr = head;
+curr != NULL;
+curr = curr->get_next_young_region()) {
+SurvRateGroup* group = curr->surv_rate_group();
+if (group == NULL && !curr->is_survivor()) {
+gclog_or_tty->print_cr("## %s: encountered NULL surv_rate_group", name);
+ret = false;
+}
+if (surv_rate_group == group) {
+int age = curr->age_in_surv_rate_group();
+if (age < 0) {
+gclog_or_tty->print_cr("## %s: encountered negative age", name);
+ret = false;
+}
+if (age <= prev_age) {
+gclog_or_tty->print_cr("## %s: region ages are not strictly increasing "
+"(%d, %d)", name, age, prev_age);
+ret = false;
+}
+prev_age = age;
+}
+}
+return ret;
+}
+#endif // PRODUCT
+void G1CollectorPolicy::record_full_collection_start() {
+_full_collection_start_sec = os::elapsedTime();
+record_heap_size_info_at_start(true /* full */);
+// Release the future to-space so that it is available for compaction into.
+_g1->set_full_collection();
+}
+void G1CollectorPolicy::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;
+_trace_gen1_time_data.record_full_collection(full_gc_time_ms);
+update_recent_gc_times(end_sec, full_gc_time_ms);
+_g1->clear_full_collection();
+// "Nuke" the heuristics that control the young/mixed GC
+// transitions and make sure we start with young GCs after the Full GC.
+set_gcs_are_young(true);
+_last_young_gc = false;
+clear_initiate_conc_mark_if_possible();
+clear_during_initial_mark_pause();
+_in_marking_window = false;
+_in_marking_window_im = false;
+_short_lived_surv_rate_group->start_adding_regions();
+// also call this on any additional surv rate groups
+record_survivor_regions(0, NULL, NULL);
+_free_regions_at_end_of_collection = _g1->free_regions();
+// Reset survivors SurvRateGroup.
+_survivor_surv_rate_group->reset();
+update_young_list_target_length();
+_collectionSetChooser->clear();
+}
+void G1CollectorPolicy::record_stop_world_start() {
+_stop_world_start = os::elapsedTime();
+}
+void G1CollectorPolicy::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(),
+err_msg("sanity, used: "SIZE_FORMAT" recalculate_used: "SIZE_FORMAT,
+_g1->used(), _g1->recalculate_used()));
+double s_w_t_ms = (start_time_sec - _stop_world_start) * 1000.0;
+_trace_gen0_time_data.record_start_collection(s_w_t_ms);
+_stop_world_start = 0.0;
+record_heap_size_info_at_start(false /* full */);
+phase_times()->record_cur_collection_start_sec(start_time_sec);
+_pending_cards = _g1->pending_card_num();
+_collection_set_bytes_used_before = 0;
+_bytes_copied_during_gc = 0;
+_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( verify_young_ages(), "region age verification" );
+}
+void G1CollectorPolicy::record_concurrent_mark_init_end(double
+mark_init_elapsed_time_ms) {
+_during_marking = true;
+assert(!initiate_conc_mark_if_possible(), "we should have cleared it by now");
+clear_during_initial_mark_pause();
+_cur_mark_stop_world_time_ms = mark_init_elapsed_time_ms;
+}
+void G1CollectorPolicy::record_concurrent_mark_remark_start() {
+_mark_remark_start_sec = os::elapsedTime();
+_during_marking = false;
+}
+void G1CollectorPolicy::record_concurrent_mark_remark_end() {
+double end_time_sec = os::elapsedTime();
+double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0;
+_concurrent_mark_remark_times_ms->add(elapsed_time_ms);
+_cur_mark_stop_world_time_ms += elapsed_time_ms;
+_prev_collection_pause_end_ms += elapsed_time_ms;
+_mmu_tracker->add_pause(_mark_remark_start_sec, end_time_sec, true);
+}
+void G1CollectorPolicy::record_concurrent_mark_cleanup_start() {
+_mark_cleanup_start_sec = os::elapsedTime();
+}
+void G1CollectorPolicy::record_concurrent_mark_cleanup_completed() {
+_last_young_gc = true;
+_in_marking_window = false;
+}
+void G1CollectorPolicy::record_concurrent_pause() {
+if (_stop_world_start > 0.0) {
+double yield_ms = (os::elapsedTime() - _stop_world_start) * 1000.0;
+_trace_gen0_time_data.record_yield_time(yield_ms);
+}
+}
+bool G1CollectorPolicy::need_to_start_conc_mark(const char* source, size_t alloc_word_size) {
+if (_g1->concurrent_mark()->cmThread()->during_cycle()) {
+return false;
+}
+size_t marking_initiating_used_threshold =
+(_g1->capacity() / 100) * InitiatingHeapOccupancyPercent;
+size_t cur_used_bytes = _g1->non_young_capacity_bytes();
+size_t alloc_byte_size = alloc_word_size * HeapWordSize;
+if ((cur_used_bytes + alloc_byte_size) > marking_initiating_used_threshold) {
+if (gcs_are_young() && !_last_young_gc) {
+ergo_verbose5(ErgoConcCycles,
+"request concurrent cycle initiation",
+ergo_format_reason("occupancy higher than threshold")
+ergo_format_byte("occupancy")
+ergo_format_byte("allocation request")
+ergo_format_byte_perc("threshold")
+ergo_format_str("source"),
+cur_used_bytes,
+alloc_byte_size,
+marking_initiating_used_threshold,
+(double) InitiatingHeapOccupancyPercent,
+source);
+return true;
+} else {
+ergo_verbose5(ErgoConcCycles,
+"do not request concurrent cycle initiation",
+ergo_format_reason("still doing mixed collections")
+ergo_format_byte("occupancy")
+ergo_format_byte("allocation request")
+ergo_format_byte_perc("threshold")
+ergo_format_str("source"),
+cur_used_bytes,
+alloc_byte_size,
+marking_initiating_used_threshold,
+(double) InitiatingHeapOccupancyPercent,
+source);
+}
+}
+return false;
+}
+// Anything below that is considered to be zero
+#define MIN_TIMER_GRANULARITY 0.0000001
+void G1CollectorPolicy::record_collection_pause_end(double pause_time_ms, EvacuationInfo& evacuation_info) {
+double end_time_sec = os::elapsedTime();
+assert(_cur_collection_pause_used_regions_at_start >= cset_region_length(),
+"otherwise, the subtraction below does not make sense");
+size_t rs_size =
+_cur_collection_pause_used_regions_at_start - cset_region_length();
+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();
+#ifndef PRODUCT
+if (G1YoungSurvRateVerbose) {
+gclog_or_tty->cr();
+_short_lived_surv_rate_group->print();
+// do that for any other surv rate groups too
+}
+#endif // PRODUCT
+last_pause_included_initial_mark = during_initial_mark_pause();
+if (last_pause_included_initial_mark) {
+record_concurrent_mark_init_end(0.0);
+} else 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.
+set_initiate_conc_mark_if_possible();
+}
+_mmu_tracker->add_pause(end_time_sec - pause_time_ms/1000.0,
+end_time_sec, false);
+evacuation_info.set_collectionset_used_before(_collection_set_bytes_used_before);
+evacuation_info.set_bytes_copied(_bytes_copied_during_gc);
+if (update_stats) {
+_trace_gen0_time_data.record_end_collection(pause_time_ms, phase_times());
+// this is where we update the allocation rate of the application
+double app_time_ms =
+(phase_times()->cur_collection_start_sec() * 1000.0 - _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;
+}
+// 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 = eden_cset_region_length();
+double alloc_rate_ms = (double) regions_allocated / app_time_ms;
+_alloc_rate_ms_seq->add(alloc_rate_ms);
+double interval_ms =
+(end_time_sec - _recent_prev_end_times_for_all_gcs_sec->oldest()) * 1000.0;
+update_recent_gc_times(end_time_sec, pause_time_ms);
+_recent_avg_pause_time_ratio = _recent_gc_times_ms->sum()/interval_ms;
+if (recent_avg_pause_time_ratio() < 0.0 ||
+(recent_avg_pause_time_ratio() - 1.0 > 0.0)) {
+#ifndef PRODUCT
+// Dump info to allow post-facto debugging
+gclog_or_tty->print_cr("recent_avg_pause_time_ratio() out of bounds");
+gclog_or_tty->print_cr("-------------------------------------------");
+gclog_or_tty->print_cr("Recent GC Times (ms):");
+_recent_gc_times_ms->dump();
+gclog_or_tty->print_cr("(End Time=%3.3f) Recent GC End Times (s):", end_time_sec);
+_recent_prev_end_times_for_all_gcs_sec->dump();
+gclog_or_tty->print_cr("GC = %3.3f, Interval = %3.3f, Ratio = %3.3f",
+_recent_gc_times_ms->sum(), interval_ms, recent_avg_pause_time_ratio());
+// In debug mode, terminate the JVM if the user wants to debug at this point.
+assert(!G1FailOnFPError, "Debugging data for CR 6898948 has been dumped above");
+#endif  // !PRODUCT
+// Clip ratio between 0.0 and 1.0, and continue. This will be fixed in
+// CR 6902692 by redoing the manner in which the ratio is incrementally computed.
+if (_recent_avg_pause_time_ratio < 0.0) {
+_recent_avg_pause_time_ratio = 0.0;
+} else {
+assert(_recent_avg_pause_time_ratio - 1.0 > 0.0, "Ctl-point invariant");
+_recent_avg_pause_time_ratio = 1.0;
+}
+}
+}
+bool new_in_marking_window = _in_marking_window;
+bool new_in_marking_window_im = false;
+if (during_initial_mark_pause()) {
+new_in_marking_window = true;
+new_in_marking_window_im = true;
+}
+if (_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.
+if (!last_pause_included_initial_mark) {
+if (next_gc_should_be_mixed("start mixed GCs",
+"do not start mixed GCs")) {
+set_gcs_are_young(false);
+}
+} else {
+ergo_verbose0(ErgoMixedGCs,
+"do not start mixed GCs",
+ergo_format_reason("concurrent cycle is about to start"));
+}
+_last_young_gc = false;
+}
+if (!_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")) {
+set_gcs_are_young(true);
+}
+}
+_short_lived_surv_rate_group->start_adding_regions();
+// do that for any other surv rate groupsx
+if (update_stats) {
+double cost_per_card_ms = 0.0;
+if (_pending_cards > 0) {
+cost_per_card_ms = phase_times()->average_last_update_rs_time() / (double) _pending_cards;
+_cost_per_card_ms_seq->add(cost_per_card_ms);
+}
+size_t cards_scanned = _g1->cards_scanned();
+double cost_per_entry_ms = 0.0;
+if (cards_scanned > 10) {
+cost_per_entry_ms = phase_times()->average_last_scan_rs_time() / (double) cards_scanned;
+if (_last_gc_was_young) {
+_cost_per_entry_ms_seq->add(cost_per_entry_ms);
+} else {
+_mixed_cost_per_entry_ms_seq->add(cost_per_entry_ms);
+}
+}
+if (_max_rs_lengths > 0) {
+double cards_per_entry_ratio =
+(double) cards_scanned / (double) _max_rs_lengths;
+if (_last_gc_was_young) {
+_young_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
+} else {
+_mixed_cards_per_entry_ratio_seq->add(cards_per_entry_ratio);
+}
+}
+// 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;
+if (_max_rs_lengths > _recorded_rs_lengths) {
+rs_length_diff = _max_rs_lengths - _recorded_rs_lengths;
+}
+_rs_length_diff_seq->add((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 = phase_times()->average_last_obj_copy_time() / (double) copied_bytes;
+if (_in_marking_window) {
+_cost_per_byte_ms_during_cm_seq->add(cost_per_byte_ms);
+} else {
+_cost_per_byte_ms_seq->add(cost_per_byte_ms);
+}
+}
+double all_other_time_ms = pause_time_ms -
+(phase_times()->average_last_update_rs_time() + phase_times()->average_last_scan_rs_time()
++ phase_times()->average_last_obj_copy_time() + phase_times()->average_last_termination_time());
+double young_other_time_ms = 0.0;
+if (young_cset_region_length() > 0) {
+young_other_time_ms =
+phase_times()->young_cset_choice_time_ms() +
+phase_times()->young_free_cset_time_ms();
+_young_other_cost_per_region_ms_seq->add(young_other_time_ms /
+(double) young_cset_region_length());
+}
+double non_young_other_time_ms = 0.0;
+if (old_cset_region_length() > 0) {
+non_young_other_time_ms =
+phase_times()->non_young_cset_choice_time_ms() +
+phase_times()->non_young_free_cset_time_ms();
+_non_young_other_cost_per_region_ms_seq->add(non_young_other_time_ms /
+(double) old_cset_region_length());
+}
+double constant_other_time_ms = all_other_time_ms -
+(young_other_time_ms + non_young_other_time_ms);
+_constant_other_time_ms_seq->add(constant_other_time_ms);
+double survival_ratio = 0.0;
+if (_collection_set_bytes_used_before > 0) {
+survival_ratio = (double) _bytes_copied_during_gc /
+(double) _collection_set_bytes_used_before;
+}
+_pending_cards_seq->add((double) _pending_cards);
+_rs_lengths_seq->add((double) _max_rs_lengths);
+}
+_in_marking_window = new_in_marking_window;
+_in_marking_window_im = new_in_marking_window_im;
+_free_regions_at_end_of_collection = _g1->free_regions();
+update_young_list_target_length();
+// 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;
+adjust_concurrent_refinement(phase_times()->average_last_update_rs_time(),
+phase_times()->sum_last_update_rs_processed_buffers(), update_rs_time_goal_ms);
+_collectionSetChooser->verify();
+}
+#define EXT_SIZE_FORMAT "%.1f%s"
+#define EXT_SIZE_PARAMS(bytes)                                  \
+byte_size_in_proper_unit((double)(bytes)),                    \
+proper_unit_for_byte_size((bytes))
+void G1CollectorPolicy::record_heap_size_info_at_start(bool full) {
+YoungList* young_list = _g1->young_list();
+_eden_used_bytes_before_gc = young_list->eden_used_bytes();
+_survivor_used_bytes_before_gc = young_list->survivor_used_bytes();
+_heap_capacity_bytes_before_gc = _g1->capacity();
+_heap_used_bytes_before_gc = _g1->used();
+_cur_collection_pause_used_regions_at_start = _g1->used_regions();
+_eden_capacity_bytes_before_gc =
+(_young_list_target_length * HeapRegion::GrainBytes) - _survivor_used_bytes_before_gc;
+if (full) {
+_metaspace_used_bytes_before_gc = MetaspaceAux::used_bytes();
+}
+}
+void G1CollectorPolicy::print_heap_transition() {
+_g1->print_size_transition(gclog_or_tty,
+_heap_used_bytes_before_gc,
+_g1->used(),
+_g1->capacity());
+}
+void G1CollectorPolicy::print_detailed_heap_transition(bool full) {
+YoungList* young_list = _g1->young_list();
+size_t eden_used_bytes_after_gc = young_list->eden_used_bytes();
+size_t survivor_used_bytes_after_gc = young_list->survivor_used_bytes();
+size_t heap_used_bytes_after_gc = _g1->used();
+size_t heap_capacity_bytes_after_gc = _g1->capacity();
+size_t eden_capacity_bytes_after_gc =
+(_young_list_target_length * HeapRegion::GrainBytes) - survivor_used_bytes_after_gc;
+gclog_or_tty->print(
+"   [Eden: "EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")->"EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT") "
+"Survivors: "EXT_SIZE_FORMAT"->"EXT_SIZE_FORMAT" "
+"Heap: "EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")->"
+EXT_SIZE_FORMAT"("EXT_SIZE_FORMAT")]",
+EXT_SIZE_PARAMS(_eden_used_bytes_before_gc),
+EXT_SIZE_PARAMS(_eden_capacity_bytes_before_gc),
+EXT_SIZE_PARAMS(eden_used_bytes_after_gc),
+EXT_SIZE_PARAMS(eden_capacity_bytes_after_gc),
+EXT_SIZE_PARAMS(_survivor_used_bytes_before_gc),
+EXT_SIZE_PARAMS(survivor_used_bytes_after_gc),
+EXT_SIZE_PARAMS(_heap_used_bytes_before_gc),
+EXT_SIZE_PARAMS(_heap_capacity_bytes_before_gc),
+EXT_SIZE_PARAMS(heap_used_bytes_after_gc),
+EXT_SIZE_PARAMS(heap_capacity_bytes_after_gc));
+if (full) {
+MetaspaceAux::print_metaspace_change(_metaspace_used_bytes_before_gc);
+}
+gclog_or_tty->cr();
+}
+void G1CollectorPolicy::adjust_concurrent_refinement(double update_rs_time,
+double update_rs_processed_buffers,
+double goal_ms) {
+DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
+ConcurrentG1Refine *cg1r = G1CollectedHeap::heap()->concurrent_g1_refine();
+if (G1UseAdaptiveConcRefinement) {
+const int k_gy = 3, k_gr = 6;
+const double inc_k = 1.1, dec_k = 0.9;
+int g = cg1r->green_zone();
+if (update_rs_time > goal_ms) {
+g = (int)(g * dec_k);  // Can become 0, that's OK. That would mean a mutator-only processing.
+} else {
+if (update_rs_time < goal_ms && update_rs_processed_buffers > g) {
+g = (int)MAX2(g * inc_k, g + 1.0);
+}
+}
+// Change the refinement threads params
+cg1r->set_green_zone(g);
+cg1r->set_yellow_zone(g * k_gy);
+cg1r->set_red_zone(g * k_gr);
+cg1r->reinitialize_threads();
+int processing_threshold_delta = MAX2((int)(cg1r->green_zone() * sigma()), 1);
+int processing_threshold = MIN2(cg1r->green_zone() + processing_threshold_delta,
+cg1r->yellow_zone());
+// Change the barrier params
+dcqs.set_process_completed_threshold(processing_threshold);
+dcqs.set_max_completed_queue(cg1r->red_zone());
+}
+int curr_queue_size = dcqs.completed_buffers_num();
+if (curr_queue_size >= cg1r->yellow_zone()) {
+dcqs.set_completed_queue_padding(curr_queue_size);
+} else {
+dcqs.set_completed_queue_padding(0);
+}
+dcqs.notify_if_necessary();
+}
+double
+G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards,
+size_t scanned_cards) {
+return
+predict_rs_update_time_ms(pending_cards) +
+predict_rs_scan_time_ms(scanned_cards) +
+predict_constant_other_time_ms();
+}
+double
+G1CollectorPolicy::predict_base_elapsed_time_ms(size_t pending_cards) {
+size_t rs_length = predict_rs_length_diff();
+size_t card_num;
+if (gcs_are_young()) {
+card_num = predict_young_card_num(rs_length);
+} else {
+card_num = predict_non_young_card_num(rs_length);
+}
+return predict_base_elapsed_time_ms(pending_cards, card_num);
+}
+size_t G1CollectorPolicy::predict_bytes_to_copy(HeapRegion* hr) {
+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) ((double) hr->used() * yg_surv_rate);
+}
+return bytes_to_copy;
+}
+double
+G1CollectorPolicy::predict_region_elapsed_time_ms(HeapRegion* hr,
+bool for_young_gc) {
+size_t rs_length = hr->rem_set()->occupied();
+size_t card_num;
+// Predicting the number of cards is based on which type of GC
+// we're predicting for.
+if (for_young_gc) {
+card_num = predict_young_card_num(rs_length);
+} else {
+card_num = predict_non_young_card_num(rs_length);
+}
+size_t bytes_to_copy = predict_bytes_to_copy(hr);
+double region_elapsed_time_ms =
+predict_rs_scan_time_ms(card_num) +
+predict_object_copy_time_ms(bytes_to_copy);
+// 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 += predict_young_other_time_ms(1);
+} else {
+region_elapsed_time_ms += predict_non_young_other_time_ms(1);
+}
+return region_elapsed_time_ms;
+}
+void
+G1CollectorPolicy::init_cset_region_lengths(uint eden_cset_region_length,
+uint survivor_cset_region_length) {
+_eden_cset_region_length     = eden_cset_region_length;
+_survivor_cset_region_length = survivor_cset_region_length;
+_old_cset_region_length      = 0;
+}
+void G1CollectorPolicy::set_recorded_rs_lengths(size_t rs_lengths) {
+_recorded_rs_lengths = rs_lengths;
+}
+void G1CollectorPolicy::update_recent_gc_times(double end_time_sec,
+double elapsed_ms) {
+_recent_gc_times_ms->add(elapsed_ms);
+_recent_prev_end_times_for_all_gcs_sec->add(end_time_sec);
+_prev_collection_pause_end_ms = end_time_sec * 1000.0;
+}
+size_t G1CollectorPolicy::expansion_amount() {
+double recent_gc_overhead = recent_avg_pause_time_ratio() * 100.0;
+double threshold = _gc_overhead_perc;
+if (recent_gc_overhead > threshold) {
+// We will double the existing space, or take
+// G1ExpandByPercentOfAvailable % of the available expansion
+// space, whichever is smaller, bounded below by a minimum
+// expansion (unless that's all that's left.)
+const size_t min_expand_bytes = 1*M;
+size_t reserved_bytes = _g1->max_capacity();
+size_t committed_bytes = _g1->capacity();
+size_t uncommitted_bytes = reserved_bytes - committed_bytes;
+size_t expand_bytes;
+size_t expand_bytes_via_pct =
+uncommitted_bytes * G1ExpandByPercentOfAvailable / 100;
+expand_bytes = MIN2(expand_bytes_via_pct, committed_bytes);
+expand_bytes = MAX2(expand_bytes, min_expand_bytes);
+expand_bytes = MIN2(expand_bytes, uncommitted_bytes);
+ergo_verbose5(ErgoHeapSizing,
+"attempt heap expansion",
+ergo_format_reason("recent GC overhead higher than "
+"threshold after GC")
+ergo_format_perc("recent GC overhead")
+ergo_format_perc("threshold")
+ergo_format_byte("uncommitted")
+ergo_format_byte_perc("calculated expansion amount"),
+recent_gc_overhead, threshold,
+uncommitted_bytes,
+expand_bytes_via_pct, (double) G1ExpandByPercentOfAvailable);
+return expand_bytes;
+} else {
+return 0;
+}
+}
+void G1CollectorPolicy::print_tracing_info() const {
+_trace_gen0_time_data.print();
+_trace_gen1_time_data.print();
+}
+void G1CollectorPolicy::print_yg_surv_rate_info() const {
+#ifndef PRODUCT
+_short_lived_surv_rate_group->print_surv_rate_summary();
+// add this call for any other surv rate groups
+#endif // PRODUCT
+}
+uint G1CollectorPolicy::max_regions(int purpose) {
+switch (purpose) {
+case GCAllocForSurvived:
+return _max_survivor_regions;
+case GCAllocForTenured:
+return REGIONS_UNLIMITED;
+default:
+ShouldNotReachHere();
+return REGIONS_UNLIMITED;
+};
+}
+void G1CollectorPolicy::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 G1CollectorPolicy::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(
+HeapRegion::GrainWords * _max_survivor_regions);
+}
+bool G1CollectorPolicy::force_initial_mark_if_outside_cycle(
+GCCause::Cause gc_cause) {
+bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
+if (!during_cycle) {
+ergo_verbose1(ErgoConcCycles,
+"request concurrent cycle initiation",
+ergo_format_reason("requested by GC cause")
+ergo_format_str("GC cause"),
+GCCause::to_string(gc_cause));
+set_initiate_conc_mark_if_possible();
+return true;
+} else {
+ergo_verbose1(ErgoConcCycles,
+"do not request concurrent cycle initiation",
+ergo_format_reason("concurrent cycle already in progress")
+ergo_format_str("GC cause"),
+GCCause::to_string(gc_cause));
+return false;
+}
+}
+void
+G1CollectorPolicy::decide_on_conc_mark_initiation() {
+// We are about to decide on whether this pause will be an
+// initial-mark pause.
+// First, 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(!during_initial_mark_pause(), "pre-condition");
+if (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.
+bool during_cycle = _g1->concurrent_mark()->cmThread()->during_cycle();
+if (!during_cycle) {
+// The concurrent marking thread is not "during a cycle", i.e.,
+// it has completed the last one. So we can go ahead and
+// initiate a new cycle.
+set_during_initial_mark_pause();
+// We do not allow mixed GCs during marking.
+if (!gcs_are_young()) {
+set_gcs_are_young(true);
+ergo_verbose0(ErgoMixedGCs,
+"end mixed GCs",
+ergo_format_reason("concurrent cycle is about to start"));
+}
+// And we can now clear initiate_conc_mark_if_possible() as
+// we've already acted on it.
+clear_initiate_conc_mark_if_possible();
+ergo_verbose0(ErgoConcCycles,
+"initiate concurrent cycle",
+ergo_format_reason("concurrent cycle initiation requested"));
+} 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.
+ergo_verbose0(ErgoConcCycles,
+"do not initiate concurrent cycle",
+ergo_format_reason("concurrent cycle already in progress"));
+}
+}
+}
+class KnownGarbageClosure: public HeapRegionClosure {
+G1CollectedHeap* _g1h;
+CollectionSetChooser* _hrSorted;
+public:
+KnownGarbageClosure(CollectionSetChooser* hrSorted) :
+_g1h(G1CollectedHeap::heap()), _hrSorted(hrSorted) { }
+bool doHeapRegion(HeapRegion* r) {
+// We only include humongous regions in collection
+// sets when concurrent mark shows that their contained object is
+// unreachable.
+// Do we have any marking information for this region?
+if (r->is_marked()) {
+// We will skip any region that's currently used as an old GC
+// alloc region (we should not consider those for collection
+// before we fill them up).
+if (_hrSorted->should_add(r) && !_g1h->is_old_gc_alloc_region(r)) {
+_hrSorted->add_region(r);
+}
+}
+return false;
+}
+};
+class ParKnownGarbageHRClosure: public HeapRegionClosure {
+G1CollectedHeap* _g1h;
+CSetChooserParUpdater _cset_updater;
+public:
+ParKnownGarbageHRClosure(CollectionSetChooser* hrSorted,
+uint chunk_size) :
+_g1h(G1CollectedHeap::heap()),
+_cset_updater(hrSorted, true /* parallel */, chunk_size) { }
+bool doHeapRegion(HeapRegion* r) {
+// Do we have any marking information for this region?
+if (r->is_marked()) {
+// We will skip any region that's currently used as an old GC
+// alloc region (we should not consider those for collection
+// before we fill them up).
+if (_cset_updater.should_add(r) && !_g1h->is_old_gc_alloc_region(r)) {
+_cset_updater.add_region(r);
+}
+}
+return false;
+}
+};
+class ParKnownGarbageTask: public AbstractGangTask {
+CollectionSetChooser* _hrSorted;
+uint _chunk_size;
+G1CollectedHeap* _g1;
+public:
+ParKnownGarbageTask(CollectionSetChooser* hrSorted, uint chunk_size) :
+AbstractGangTask("ParKnownGarbageTask"),
+_hrSorted(hrSorted), _chunk_size(chunk_size),
+_g1(G1CollectedHeap::heap()) { }
+void work(uint worker_id) {
+ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size);
+// Back to zero for the claim value.
+_g1->heap_region_par_iterate_chunked(&parKnownGarbageCl, worker_id,
+_g1->workers()->active_workers(),
+HeapRegion::InitialClaimValue);
+}
+};
+void
+G1CollectorPolicy::record_concurrent_mark_cleanup_end(int no_of_gc_threads) {
+_collectionSetChooser->clear();
+uint region_num = _g1->n_regions();
+if (G1CollectedHeap::use_parallel_gc_threads()) {
+const uint OverpartitionFactor = 4;
+uint WorkUnit;
+// The use of MinChunkSize = 8 in the original code
+// causes some assertion failures when the total number of
+// region is less than 8.  The code here tries to fix that.
+// Should the original code also be fixed?
+if (no_of_gc_threads > 0) {
+const uint MinWorkUnit = MAX2(region_num / no_of_gc_threads, 1U);
+WorkUnit = MAX2(region_num / (no_of_gc_threads * OverpartitionFactor),
+MinWorkUnit);
+} else {
+assert(no_of_gc_threads > 0,
+"The active gc workers should be greater than 0");
+// In a product build do something reasonable to avoid a crash.
+const uint MinWorkUnit = MAX2(region_num / (uint) ParallelGCThreads, 1U);
+WorkUnit =
+MAX2(region_num / (uint) (ParallelGCThreads * OverpartitionFactor),
+MinWorkUnit);
+}
+_collectionSetChooser->prepare_for_par_region_addition(_g1->n_regions(),
+WorkUnit);
+ParKnownGarbageTask parKnownGarbageTask(_collectionSetChooser,
+(int) WorkUnit);
+_g1->workers()->run_task(&parKnownGarbageTask);
+assert(_g1->check_heap_region_claim_values(HeapRegion::InitialClaimValue),
+"sanity check");
+} else {
+KnownGarbageClosure knownGarbagecl(_collectionSetChooser);
+_g1->heap_region_iterate(&knownGarbagecl);
+}
+_collectionSetChooser->sort_regions();
+double end_sec = os::elapsedTime();
+double elapsed_time_ms = (end_sec - _mark_cleanup_start_sec) * 1000.0;
+_concurrent_mark_cleanup_times_ms->add(elapsed_time_ms);
+_cur_mark_stop_world_time_ms += elapsed_time_ms;
+_prev_collection_pause_end_ms += elapsed_time_ms;
+_mmu_tracker->add_pause(_mark_cleanup_start_sec, end_sec, true);
+}
+// Add the heap region at the head of the non-incremental collection set
+void G1CollectorPolicy::add_old_region_to_cset(HeapRegion* hr) {
+assert(_inc_cset_build_state == Active, "Precondition");
+assert(!hr->is_young(), "non-incremental add of young region");
+assert(!hr->in_collection_set(), "should not already be in the CSet");
+hr->set_in_collection_set(true);
+hr->set_next_in_collection_set(_collection_set);
+_collection_set = hr;
+_collection_set_bytes_used_before += hr->used();
+_g1->register_region_with_in_cset_fast_test(hr);
+size_t rs_length = hr->rem_set()->occupied();
+_recorded_rs_lengths += rs_length;
+_old_cset_region_length += 1;
+}
+// Initialize the per-collection-set information
+void G1CollectorPolicy::start_incremental_cset_building() {
+assert(_inc_cset_build_state == Inactive, "Precondition");
+_inc_cset_head = NULL;
+_inc_cset_tail = NULL;
+_inc_cset_bytes_used_before = 0;
+_inc_cset_max_finger = 0;
+_inc_cset_recorded_rs_lengths = 0;
+_inc_cset_recorded_rs_lengths_diffs = 0;
+_inc_cset_predicted_elapsed_time_ms = 0.0;
+_inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
+_inc_cset_build_state = Active;
+}
+void G1CollectorPolicy::finalize_incremental_cset_building() {
+assert(_inc_cset_build_state == Active, "Precondition");
+assert(SafepointSynchronize::is_at_safepoint(), "should be at a safepoint");
+// The two "main" fields, _inc_cset_recorded_rs_lengths and
+// _inc_cset_predicted_elapsed_time_ms, are updated by the thread
+// that adds a new region to the CSet. Further updates by the
+// concurrent refinement thread that samples the young RSet lengths
+// are accumulated in the *_diffs fields. Here we add the diffs to
+// the "main" fields.
+if (_inc_cset_recorded_rs_lengths_diffs >= 0) {
+_inc_cset_recorded_rs_lengths += _inc_cset_recorded_rs_lengths_diffs;
+} else {
+// This is defensive. The diff should in theory be always positive
+// as RSets can only grow between GCs. However, given that we
+// sample their size concurrently with other threads updating them
+// it's possible that we might get the wrong size back, which
+// could make the calculations somewhat inaccurate.
+size_t diffs = (size_t) (-_inc_cset_recorded_rs_lengths_diffs);
+if (_inc_cset_recorded_rs_lengths >= diffs) {
+_inc_cset_recorded_rs_lengths -= diffs;
+} else {
+_inc_cset_recorded_rs_lengths = 0;
+}
+}
+_inc_cset_predicted_elapsed_time_ms +=
+_inc_cset_predicted_elapsed_time_ms_diffs;
+_inc_cset_recorded_rs_lengths_diffs = 0;
+_inc_cset_predicted_elapsed_time_ms_diffs = 0.0;
+}
+void G1CollectorPolicy::add_to_incremental_cset_info(HeapRegion* hr, size_t rs_length) {
+// This routine is used when:
+// * adding survivor regions to the incremental cset at the end of an
+//   evacuation pause,
+// * adding the current allocation region to the incremental cset
+//   when it is retired, and
+// * updating existing policy information for a region in the
+//   incremental cset via young list RSet sampling.
+// Therefore this routine may be called at a safepoint by the
+// VM thread, or in-between safepoints by mutator threads (when
+// retiring the current allocation region) or a concurrent
+// refine thread (RSet sampling).
+double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young());
+size_t used_bytes = hr->used();
+_inc_cset_recorded_rs_lengths += rs_length;
+_inc_cset_predicted_elapsed_time_ms += region_elapsed_time_ms;
+_inc_cset_bytes_used_before += used_bytes;
+// Cache the values we have added to the aggregated informtion
+// in the heap region in case we have to remove this region from
+// the incremental collection set, or it is updated by the
+// rset sampling code
+hr->set_recorded_rs_length(rs_length);
+hr->set_predicted_elapsed_time_ms(region_elapsed_time_ms);
+}
+void G1CollectorPolicy::update_incremental_cset_info(HeapRegion* hr,
+size_t new_rs_length) {
+// Update the CSet information that is dependent on the new RS length
+assert(hr->is_young(), "Precondition");
+assert(!SafepointSynchronize::is_at_safepoint(),
+"should not be at a safepoint");
+// We could have updated _inc_cset_recorded_rs_lengths and
+// _inc_cset_predicted_elapsed_time_ms directly but we'd need to do
+// that atomically, as this code is executed by a concurrent
+// refinement thread, potentially concurrently with a mutator thread
+// allocating a new region and also updating the same fields. To
+// avoid the atomic operations we accumulate these updates on two
+// separate fields (*_diffs) and we'll just add them to the "main"
+// fields at the start of a GC.
+ssize_t old_rs_length = (ssize_t) hr->recorded_rs_length();
+ssize_t rs_lengths_diff = (ssize_t) new_rs_length - old_rs_length;
+_inc_cset_recorded_rs_lengths_diffs += rs_lengths_diff;
+double old_elapsed_time_ms = hr->predicted_elapsed_time_ms();
+double new_region_elapsed_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young());
+double elapsed_ms_diff = new_region_elapsed_time_ms - old_elapsed_time_ms;
+_inc_cset_predicted_elapsed_time_ms_diffs += elapsed_ms_diff;
+hr->set_recorded_rs_length(new_rs_length);
+hr->set_predicted_elapsed_time_ms(new_region_elapsed_time_ms);
+}
+void G1CollectorPolicy::add_region_to_incremental_cset_common(HeapRegion* hr) {
+assert(hr->is_young(), "invariant");
+assert(hr->young_index_in_cset() > -1, "should have already been set");
+assert(_inc_cset_build_state == Active, "Precondition");
+// We need to clear and set the cached recorded/cached collection set
+// information in the heap region here (before the region gets added
+// to the collection set). An individual heap region's cached values
+// are calculated, aggregated with the policy collection set info,
+// and cached in the heap region here (initially) and (subsequently)
+// by the Young List sampling code.
+size_t rs_length = hr->rem_set()->occupied();
+add_to_incremental_cset_info(hr, rs_length);
+HeapWord* hr_end = hr->end();
+_inc_cset_max_finger = MAX2(_inc_cset_max_finger, hr_end);
+assert(!hr->in_collection_set(), "invariant");
+hr->set_in_collection_set(true);
+assert( hr->next_in_collection_set() == NULL, "invariant");
+_g1->register_region_with_in_cset_fast_test(hr);
+}
+// Add the region at the RHS of the incremental cset
+void G1CollectorPolicy::add_region_to_incremental_cset_rhs(HeapRegion* hr) {
+// We should only ever be appending survivors at the end of a pause
+assert( hr->is_survivor(), "Logic");
+// Do the 'common' stuff
+add_region_to_incremental_cset_common(hr);
+// Now add the region at the right hand side
+if (_inc_cset_tail == NULL) {
+assert(_inc_cset_head == NULL, "invariant");
+_inc_cset_head = hr;
+} else {
+_inc_cset_tail->set_next_in_collection_set(hr);
+}
+_inc_cset_tail = hr;
+}
+// Add the region to the LHS of the incremental cset
+void G1CollectorPolicy::add_region_to_incremental_cset_lhs(HeapRegion* hr) {
+// Survivors should be added to the RHS at the end of a pause
+assert(!hr->is_survivor(), "Logic");
+// Do the 'common' stuff
+add_region_to_incremental_cset_common(hr);
+// Add the region at the left hand side
+hr->set_next_in_collection_set(_inc_cset_head);
+if (_inc_cset_head == NULL) {
+assert(_inc_cset_tail == NULL, "Invariant");
+_inc_cset_tail = hr;
+}
+_inc_cset_head = hr;
+}
+#ifndef PRODUCT
+void G1CollectorPolicy::print_collection_set(HeapRegion* list_head, outputStream* st) {
+assert(list_head == inc_cset_head() || list_head == collection_set(), "must be");
+st->print_cr("\nCollection_set:");
+HeapRegion* csr = list_head;
+while (csr != NULL) {
+HeapRegion* next = csr->next_in_collection_set();
+assert(csr->in_collection_set(), "bad CS");
+st->print_cr("  "HR_FORMAT", P: "PTR_FORMAT "N: "PTR_FORMAT", age: %4d",
+HR_FORMAT_PARAMS(csr),
+csr->prev_top_at_mark_start(), csr->next_top_at_mark_start(),
+csr->age_in_surv_rate_group_cond());
+csr = next;
+}
+}
+#endif // !PRODUCT
+double G1CollectorPolicy::reclaimable_bytes_perc(size_t reclaimable_bytes) {
+// Returns the given amount of reclaimable bytes (that represents
+// the amount of reclaimable space still to be collected) as a
+// percentage of the current heap capacity.
+size_t capacity_bytes = _g1->capacity();
+return (double) reclaimable_bytes * 100.0 / (double) capacity_bytes;
+}
+bool G1CollectorPolicy::next_gc_should_be_mixed(const char* true_action_str,
+const char* false_action_str) {
+CollectionSetChooser* cset_chooser = _collectionSetChooser;
+if (cset_chooser->is_empty()) {
+ergo_verbose0(ErgoMixedGCs,
+false_action_str,
+ergo_format_reason("candidate old regions not available"));
+return false;
+}
+// Is the amount of uncollected reclaimable space above G1HeapWastePercent?
+size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes();
+double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes);
+double threshold = (double) G1HeapWastePercent;
+if (reclaimable_perc <= threshold) {
+ergo_verbose4(ErgoMixedGCs,
+false_action_str,
+ergo_format_reason("reclaimable percentage not over threshold")
+ergo_format_region("candidate old regions")
+ergo_format_byte_perc("reclaimable")
+ergo_format_perc("threshold"),
+cset_chooser->remaining_regions(),
+reclaimable_bytes,
+reclaimable_perc, threshold);
+return false;
+}
+ergo_verbose4(ErgoMixedGCs,
+true_action_str,
+ergo_format_reason("candidate old regions available")
+ergo_format_region("candidate old regions")
+ergo_format_byte_perc("reclaimable")
+ergo_format_perc("threshold"),
+cset_chooser->remaining_regions(),
+reclaimable_bytes,
+reclaimable_perc, threshold);
+return true;
+}
+uint G1CollectorPolicy::calc_min_old_cset_length() {
+// 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) _collectionSetChooser->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 G1CollectorPolicy::calc_max_old_cset_length() {
+// 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.
+G1CollectedHeap* g1h = G1CollectedHeap::heap();
+const size_t region_num = g1h->n_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 G1CollectorPolicy::finalize_cset(double target_pause_time_ms, EvacuationInfo& evacuation_info) {
+double young_start_time_sec = os::elapsedTime();
+YoungList* young_list = _g1->young_list();
+finalize_incremental_cset_building();
+guarantee(target_pause_time_ms > 0.0,
+err_msg("target_pause_time_ms = %1.6lf should be positive",
+target_pause_time_ms));
+guarantee(_collection_set == NULL, "Precondition");
+double base_time_ms = predict_base_elapsed_time_ms(_pending_cards);
+double predicted_pause_time_ms = base_time_ms;
+double time_remaining_ms = MAX2(target_pause_time_ms - base_time_ms, 0.0);
+ergo_verbose4(ErgoCSetConstruction | ErgoHigh,
+"start choosing CSet",
+ergo_format_size("_pending_cards")
+ergo_format_ms("predicted base time")
+ergo_format_ms("remaining time")
+ergo_format_ms("target pause time"),
+_pending_cards, base_time_ms, time_remaining_ms, target_pause_time_ms);
+_last_gc_was_young = gcs_are_young() ? true : false;
+if (_last_gc_was_young) {
+_trace_gen0_time_data.increment_young_collection_count();
+} else {
+_trace_gen0_time_data.increment_mixed_collection_count();
+}
+// The young list is laid with the survivor regions from the previous
+// pause are appended to the RHS of the young list, i.e.
+//   [Newly Young Regions ++ Survivors from last pause].
+uint survivor_region_length = young_list->survivor_length();
+uint eden_region_length = young_list->length() - survivor_region_length;
+init_cset_region_lengths(eden_region_length, survivor_region_length);
+HeapRegion* hr = young_list->first_survivor_region();
+while (hr != NULL) {
+assert(hr->is_survivor(), "badly formed young list");
+hr->set_young();
+hr = hr->get_next_young_region();
+}
+// Clear the fields that point to the survivor list - they are all young now.
+young_list->clear_survivors();
+_collection_set = _inc_cset_head;
+_collection_set_bytes_used_before = _inc_cset_bytes_used_before;
+time_remaining_ms = MAX2(time_remaining_ms - _inc_cset_predicted_elapsed_time_ms, 0.0);
+predicted_pause_time_ms += _inc_cset_predicted_elapsed_time_ms;
+ergo_verbose3(ErgoCSetConstruction | ErgoHigh,
+"add young regions to CSet",
+ergo_format_region("eden")
+ergo_format_region("survivors")
+ergo_format_ms("predicted young region time"),
+eden_region_length, survivor_region_length,
+_inc_cset_predicted_elapsed_time_ms);
+// The number of recorded young regions is the incremental
+// collection set's current size
+set_recorded_rs_lengths(_inc_cset_recorded_rs_lengths);
+double young_end_time_sec = os::elapsedTime();
+phase_times()->record_young_cset_choice_time_ms((young_end_time_sec - young_start_time_sec) * 1000.0);
+// Set the start of the non-young choice time.
+double non_young_start_time_sec = young_end_time_sec;
+if (!gcs_are_young()) {
+CollectionSetChooser* cset_chooser = _collectionSetChooser;
+cset_chooser->verify();
+const uint min_old_cset_length = calc_min_old_cset_length();
+const uint max_old_cset_length = calc_max_old_cset_length();
+uint expensive_region_num = 0;
+bool check_time_remaining = adaptive_young_list_length();
+HeapRegion* hr = cset_chooser->peek();
+while (hr != NULL) {
+if (old_cset_region_length() >= max_old_cset_length) {
+// Added maximum number of old regions to the CSet.
+ergo_verbose2(ErgoCSetConstruction,
+"finish adding old regions to CSet",
+ergo_format_reason("old CSet region num reached max")
+ergo_format_region("old")
+ergo_format_region("max"),
+old_cset_region_length(), max_old_cset_length);
+break;
+}
+// Stop adding regions if the remaining reclaimable space is
+// not above G1HeapWastePercent.
+size_t reclaimable_bytes = cset_chooser->remaining_reclaimable_bytes();
+double reclaimable_perc = reclaimable_bytes_perc(reclaimable_bytes);
+double threshold = (double) G1HeapWastePercent;
+if (reclaimable_perc <= threshold) {
+// We've added enough old regions that the amount of uncollected
+// reclaimable space is at or below the waste threshold. Stop
+// adding old regions to the CSet.
+ergo_verbose5(ErgoCSetConstruction,
+"finish adding old regions to CSet",
+ergo_format_reason("reclaimable percentage not over threshold")
+ergo_format_region("old")
+ergo_format_region("max")
+ergo_format_byte_perc("reclaimable")
+ergo_format_perc("threshold"),
+old_cset_region_length(),
+max_old_cset_length,
+reclaimable_bytes,
+reclaimable_perc, threshold);
+break;
+}
+double predicted_time_ms = predict_region_elapsed_time_ms(hr, gcs_are_young());
+if (check_time_remaining) {
+if (predicted_time_ms > time_remaining_ms) {
+// Too expensive for the current CSet.
+if (old_cset_region_length() >= min_old_cset_length) {
+// We have added the minimum number of old regions to the CSet,
+// we are done with this CSet.
+ergo_verbose4(ErgoCSetConstruction,
+"finish adding old regions to CSet",
+ergo_format_reason("predicted time is too high")
+ergo_format_ms("predicted time")
+ergo_format_ms("remaining time")
+ergo_format_region("old")
+ergo_format_region("min"),
+predicted_time_ms, time_remaining_ms,
+old_cset_region_length(), min_old_cset_length);
+break;
+}
+// We'll add it anyway given that we haven't reached the
+// minimum number of old regions.
+expensive_region_num += 1;
+}
+} else {
+if (old_cset_region_length() >= min_old_cset_length) {
+// In the non-auto-tuning case, we'll finish adding regions
+// to the CSet if we reach the minimum.
+ergo_verbose2(ErgoCSetConstruction,
+"finish adding old regions to CSet",
+ergo_format_reason("old CSet region num reached min")
+ergo_format_region("old")
+ergo_format_region("min"),
+old_cset_region_length(), min_old_cset_length);
+break;
+}
+}
+// We will add this region to the CSet.
+time_remaining_ms = MAX2(time_remaining_ms - predicted_time_ms, 0.0);
+predicted_pause_time_ms += predicted_time_ms;
+cset_chooser->remove_and_move_to_next(hr);
+_g1->old_set_remove(hr);
+add_old_region_to_cset(hr);
+hr = cset_chooser->peek();
+}
+if (hr == NULL) {
+ergo_verbose0(ErgoCSetConstruction,
+"finish adding old regions to CSet",
+ergo_format_reason("candidate old regions not available"));
+}
+if (expensive_region_num > 0) {
+// We print the information once here at the end, predicated on
+// whether we added any apparently expensive regions or not, to
+// avoid generating output per region.
+ergo_verbose4(ErgoCSetConstruction,
+"added expensive regions to CSet",
+ergo_format_reason("old CSet region num not reached min")
+ergo_format_region("old")
+ergo_format_region("expensive")
+ergo_format_region("min")
+ergo_format_ms("remaining time"),
+old_cset_region_length(),
+expensive_region_num,
+min_old_cset_length,
+time_remaining_ms);
+}
+cset_chooser->verify();
+}
+stop_incremental_cset_building();
+ergo_verbose5(ErgoCSetConstruction,
+"finish choosing CSet",
+ergo_format_region("eden")
+ergo_format_region("survivors")
+ergo_format_region("old")
+ergo_format_ms("predicted pause time")
+ergo_format_ms("target pause time"),
+eden_region_length, survivor_region_length,
+old_cset_region_length(),
+predicted_pause_time_ms, target_pause_time_ms);
+double non_young_end_time_sec = os::elapsedTime();
+phase_times()->record_non_young_cset_choice_time_ms((non_young_end_time_sec - non_young_start_time_sec) * 1000.0);
+evacuation_info.set_collectionset_regions(cset_region_length());
+}
+void TraceGen0TimeData::record_start_collection(double time_to_stop_the_world_ms) {
+if(TraceGen0Time) {
+_all_stop_world_times_ms.add(time_to_stop_the_world_ms);
+}
+}
+void TraceGen0TimeData::record_yield_time(double yield_time_ms) {
+if(TraceGen0Time) {
+_all_yield_times_ms.add(yield_time_ms);
+}
+}
+void TraceGen0TimeData::record_end_collection(double pause_time_ms, G1GCPhaseTimes* phase_times) {
+if(TraceGen0Time) {
+_total.add(pause_time_ms);
+_other.add(pause_time_ms - phase_times->accounted_time_ms());
+_root_region_scan_wait.add(phase_times->root_region_scan_wait_time_ms());
+_parallel.add(phase_times->cur_collection_par_time_ms());
+_ext_root_scan.add(phase_times->average_last_ext_root_scan_time());
+_satb_filtering.add(phase_times->average_last_satb_filtering_times_ms());
+_update_rs.add(phase_times->average_last_update_rs_time());
+_scan_rs.add(phase_times->average_last_scan_rs_time());
+_obj_copy.add(phase_times->average_last_obj_copy_time());
+_termination.add(phase_times->average_last_termination_time());
+double parallel_known_time = phase_times->average_last_ext_root_scan_time() +
+phase_times->average_last_satb_filtering_times_ms() +
+phase_times->average_last_update_rs_time() +
+phase_times->average_last_scan_rs_time() +
+phase_times->average_last_obj_copy_time() +
++ phase_times->average_last_termination_time();
+double parallel_other_time = phase_times->cur_collection_par_time_ms() - parallel_known_time;
+_parallel_other.add(parallel_other_time);
+_clear_ct.add(phase_times->cur_clear_ct_time_ms());
+}
+}
+void TraceGen0TimeData::increment_young_collection_count() {
+if(TraceGen0Time) {
+++_young_pause_num;
+}
+}
+void TraceGen0TimeData::increment_mixed_collection_count() {
+if(TraceGen0Time) {
+++_mixed_pause_num;
+}
+}
+void TraceGen0TimeData::print_summary(const char* str,
+const NumberSeq* seq) const {
+double sum = seq->sum();
+gclog_or_tty->print_cr("%-27s = %8.2lf s (avg = %8.2lf ms)",
+str, sum / 1000.0, seq->avg());
+}
+void TraceGen0TimeData::print_summary_sd(const char* str,
+const NumberSeq* seq) const {
+print_summary(str, seq);
+gclog_or_tty->print_cr("%+45s = %5d, std dev = %8.2lf ms, max = %8.2lf ms)",
+"(num", seq->num(), seq->sd(), seq->maximum());
+}
+void TraceGen0TimeData::print() const {
+if (!TraceGen0Time) {
+return;
+}
+gclog_or_tty->print_cr("ALL PAUSES");
+print_summary_sd("   Total", &_total);
+gclog_or_tty->cr();
+gclog_or_tty->cr();
+gclog_or_tty->print_cr("   Young GC Pauses: %8d", _young_pause_num);
+gclog_or_tty->print_cr("   Mixed GC Pauses: %8d", _mixed_pause_num);
+gclog_or_tty->cr();
+gclog_or_tty->print_cr("EVACUATION PAUSES");
+if (_young_pause_num == 0 && _mixed_pause_num == 0) {
+gclog_or_tty->print_cr("none");
+} else {
+print_summary_sd("   Evacuation Pauses", &_total);
+print_summary("      Root Region Scan Wait", &_root_region_scan_wait);
+print_summary("      Parallel Time", &_parallel);
+print_summary("         Ext Root Scanning", &_ext_root_scan);
+print_summary("         SATB Filtering", &_satb_filtering);
+print_summary("         Update RS", &_update_rs);
+print_summary("         Scan RS", &_scan_rs);
+print_summary("         Object Copy", &_obj_copy);
+print_summary("         Termination", &_termination);
+print_summary("         Parallel Other", &_parallel_other);
+print_summary("      Clear CT", &_clear_ct);
+print_summary("      Other", &_other);
+}
+gclog_or_tty->cr();
+gclog_or_tty->print_cr("MISC");
+print_summary_sd("   Stop World", &_all_stop_world_times_ms);
+print_summary_sd("   Yields", &_all_yield_times_ms);
+}
+void TraceGen1TimeData::record_full_collection(double full_gc_time_ms) {
+if (TraceGen1Time) {
+_all_full_gc_times.add(full_gc_time_ms);
+}
+}
+void TraceGen1TimeData::print() const {
+if (!TraceGen1Time) {
+return;
+}
+if (_all_full_gc_times.num() > 0) {
+gclog_or_tty->print("\n%4d full_gcs: total time = %8.2f s",
+_all_full_gc_times.num(),
+_all_full_gc_times.sum() / 1000.0);
+gclog_or_tty->print_cr(" (avg = %8.2fms).", _all_full_gc_times.avg());
+gclog_or_tty->print_cr("                     [std. dev = %8.2f ms, max = %8.2f ms]",
+_all_full_gc_times.sd(),
+_all_full_gc_times.maximum());
+}
+}

Mercurial > jdk8-mips64-public > hotspot / file comparison

comparison: src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp

src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp