1 /*
  2  * Copyright (c) 2017, 2022, Oracle and/or its affiliates. All rights reserved.
  3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  4  *
  5  * This code is free software; you can redistribute it and/or modify it
  6  * under the terms of the GNU General Public License version 2 only, as
  7  * published by the Free Software Foundation.
  8  *
  9  * This code is distributed in the hope that it will be useful, but WITHOUT
 10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 12  * version 2 for more details (a copy is included in the LICENSE file that
 13  * accompanied this code).
 14  *
 15  * You should have received a copy of the GNU General Public License version
 16  * 2 along with this work; if not, write to the Free Software Foundation,
 17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 18  *
 19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 20  * or visit www.oracle.com if you need additional information or have any
 21  * questions.
 22  *
 23  */
 24 
 25 #include "precompiled.hpp"
 26 #include "gc/g1/g1CollectedHeap.inline.hpp"
 27 #include "gc/g1/g1ConcurrentMarkBitMap.inline.hpp"
 28 #include "gc/g1/g1FullCollector.inline.hpp"
 29 #include "gc/g1/g1FullGCCompactionPoint.hpp"
 30 #include "gc/g1/g1FullGCMarker.hpp"
 31 #include "gc/g1/g1FullGCOopClosures.inline.hpp"
 32 #include "gc/g1/g1FullGCPrepareTask.inline.hpp"
 33 #include "gc/g1/g1HotCardCache.hpp"
 34 #include "gc/g1/heapRegion.inline.hpp"
 35 #include "gc/shared/gcTraceTime.inline.hpp"
 36 #include "gc/shared/referenceProcessor.hpp"
 37 #include "logging/log.hpp"
 38 #include "memory/iterator.inline.hpp"
 39 #include "oops/oop.inline.hpp"
 40 #include "utilities/ticks.hpp"
 41 
 42 G1DetermineCompactionQueueClosure::G1DetermineCompactionQueueClosure(G1FullCollector* collector) :
 43   _g1h(G1CollectedHeap::heap()),
 44   _collector(collector),
 45   _cur_worker(0) { }
 46 
 47 bool G1FullGCPrepareTask::G1CalculatePointersClosure::do_heap_region(HeapRegion* hr) {
 48   uint region_idx = hr->hrm_index();
 49   assert(_collector->is_compaction_target(region_idx), "must be");
 50 
 51   assert(!hr->is_pinned(), "must be");
 52   assert(!hr->is_closed_archive(), "must be");
 53   assert(!hr->is_open_archive(), "must be");
 54 
 55   prepare_for_compaction(hr);
 56 
 57   return false;
 58 }
 59 
 60 G1FullGCPrepareTask::G1FullGCPrepareTask(G1FullCollector* collector) :
 61     G1FullGCTask("G1 Prepare Compact Task", collector),
 62     _has_free_compaction_targets(false),
 63     _hrclaimer(collector->workers()) {
 64 }
 65 
 66 void G1FullGCPrepareTask::set_has_free_compaction_targets() {
 67   if (!_has_free_compaction_targets) {
 68     _has_free_compaction_targets = true;
 69   }
 70 }
 71 
 72 bool G1FullGCPrepareTask::has_free_compaction_targets() {
 73   return _has_free_compaction_targets;
 74 }
 75 
 76 void G1FullGCPrepareTask::work(uint worker_id) {
 77   Ticks start = Ticks::now();
 78   // Calculate the target locations for the objects in the non-free regions of
 79   // the compaction queues provided by the associate compaction point.
 80   {
 81     G1FullGCCompactionPoint* compaction_point = collector()->compaction_point(worker_id);
 82     G1CalculatePointersClosure closure(collector(), compaction_point);
 83 
 84     for (GrowableArrayIterator<HeapRegion*> it = compaction_point->regions()->begin();
 85          it != compaction_point->regions()->end();
 86          ++it) {
 87       closure.do_heap_region(*it);
 88     }
 89     compaction_point->update();
 90     // Determine if there are any unused compaction targets. This is only the case if
 91     // there are
 92     // - any regions in queue, so no free ones either.
 93     // - and the current region is not the last one in the list.
 94     if (compaction_point->has_regions() &&
 95         compaction_point->current_region() != compaction_point->regions()->last()) {
 96       set_has_free_compaction_targets();
 97     }
 98   }
 99 
100   // Clear region metadata that is invalid after GC for all regions.
101   {
102     G1ResetMetadataClosure closure(collector());
103     G1CollectedHeap::heap()->heap_region_par_iterate_from_start(&closure, &_hrclaimer);
104   }
105   log_task("Prepare compaction task", worker_id, start);
106 }
107 
108 G1FullGCPrepareTask::G1CalculatePointersClosure::G1CalculatePointersClosure(G1FullCollector* collector,
109                                                                             G1FullGCCompactionPoint* cp) :
110   _g1h(G1CollectedHeap::heap()),
111   _collector(collector),
112   _bitmap(collector->mark_bitmap()),
113   _cp(cp) { }
114 
115 G1FullGCPrepareTask::G1ResetMetadataClosure::G1ResetMetadataClosure(G1FullCollector* collector) :
116   _g1h(G1CollectedHeap::heap()),
117   _collector(collector) { }
118 
119 void G1FullGCPrepareTask::G1ResetMetadataClosure::reset_region_metadata(HeapRegion* hr) {
120   hr->rem_set()->clear();
121   hr->clear_cardtable();
122 
123   G1HotCardCache* hcc = _g1h->hot_card_cache();
124   if (hcc->use_cache()) {
125     hcc->reset_card_counts(hr);
126   }
127 }
128 
129 bool G1FullGCPrepareTask::G1ResetMetadataClosure::do_heap_region(HeapRegion* hr) {
130   uint const region_idx = hr->hrm_index();
131   if (!_collector->is_compaction_target(region_idx)) {
132     assert(!hr->is_free(), "all free regions should be compaction targets");
133     assert(_collector->is_skip_compacting(region_idx) || hr->is_closed_archive(), "must be");
134     if (hr->is_young()) {
135       // G1 updates the BOT for old region contents incrementally, but young regions
136       // lack BOT information for performance reasons.
137       // Recreate BOT information of high live ratio young regions here to keep expected
138       // performance during scanning their card tables in the collection pauses later.
139       hr->update_bot();
140     }
141   }
142 
143   // Reset data structures not valid after Full GC.
144   reset_region_metadata(hr);
145 
146   return false;
147 }
148 
149 G1FullGCPrepareTask::G1PrepareCompactLiveClosure::G1PrepareCompactLiveClosure(G1FullGCCompactionPoint* cp) :
150     _cp(cp) { }
151 
152 size_t G1FullGCPrepareTask::G1PrepareCompactLiveClosure::apply(oop object) {
153   size_t size = object->size();
154   _cp->forward(object, size);
155   return size;
156 }
157 
158 void G1FullGCPrepareTask::G1CalculatePointersClosure::prepare_for_compaction(HeapRegion* hr) {
159   if (!_collector->is_free(hr->hrm_index())) {
160     G1PrepareCompactLiveClosure prepare_compact(_cp);
161     hr->apply_to_marked_objects(_bitmap, &prepare_compact);
162   }
163 }