1 /* 2 * Copyright (c) 2017, 2023, 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.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/g1FullGCCompactTask.hpp" 31 #include "gc/g1/heapRegion.inline.hpp" 32 #include "gc/shared/gcTraceTime.inline.hpp" 33 #include "gc/shared/slidingForwarding.inline.hpp" 34 #include "logging/log.hpp" 35 #include "oops/oop.inline.hpp" 36 #include "utilities/ticks.hpp" 37 38 void G1FullGCCompactTask::G1CompactRegionClosure::clear_in_bitmap(oop obj) { 39 assert(_bitmap->is_marked(obj), "Should only compact marked objects"); 40 _bitmap->clear(obj); 41 } 42 43 size_t G1FullGCCompactTask::G1CompactRegionClosure::apply(oop obj) { 44 size_t size = obj->size(); 45 if (obj->is_forwarded()) { 46 HeapWord* destination = cast_from_oop<HeapWord*>(_forwarding->forwardee(obj)); 47 48 // copy object and reinit its mark 49 HeapWord* obj_addr = cast_from_oop<HeapWord*>(obj); 50 assert(obj_addr != destination, "everything in this pass should be moving"); 51 Copy::aligned_conjoint_words(obj_addr, destination, size); 52 53 // There is no need to transform stack chunks - marking already did that. 54 cast_to_oop(destination)->init_mark(); 55 assert(cast_to_oop(destination)->klass() != NULL, "should have a class"); 56 } 57 58 // Clear the mark for the compacted object to allow reuse of the 59 // bitmap without an additional clearing step. 60 clear_in_bitmap(obj); 61 return size; 62 } 63 64 void G1FullGCCompactTask::compact_region(HeapRegion* hr) { 65 assert(!hr->is_pinned(), "Should be no pinned region in compaction queue"); 66 assert(!hr->is_humongous(), "Should be no humongous regions in compaction queue"); 67 68 if (!collector()->is_free(hr->hrm_index())) { 69 // The compaction closure not only copies the object to the new 70 // location, but also clears the bitmap for it. This is needed 71 // for bitmap verification and to be able to use the bitmap 72 // for evacuation failures in the next young collection. Testing 73 // showed that it was better overall to clear bit by bit, compared 74 // to clearing the whole region at the end. This difference was 75 // clearly seen for regions with few marks. 76 G1CompactRegionClosure compact(collector()->mark_bitmap()); 77 hr->apply_to_marked_objects(collector()->mark_bitmap(), &compact); 78 } 79 80 hr->reset_compacted_after_full_gc(_collector->compaction_top(hr)); 81 } 82 83 void G1FullGCCompactTask::work(uint worker_id) { 84 Ticks start = Ticks::now(); 85 GrowableArray<HeapRegion*>* compaction_queue = collector()->compaction_point(worker_id)->regions(); 86 for (GrowableArrayIterator<HeapRegion*> it = compaction_queue->begin(); 87 it != compaction_queue->end(); 88 ++it) { 89 compact_region(*it); 90 } 91 } 92 93 void G1FullGCCompactTask::serial_compaction() { 94 GCTraceTime(Debug, gc, phases) tm("Phase 4: Serial Compaction", collector()->scope()->timer()); 95 GrowableArray<HeapRegion*>* compaction_queue = collector()->serial_compaction_point()->regions(); 96 for (GrowableArrayIterator<HeapRegion*> it = compaction_queue->begin(); 97 it != compaction_queue->end(); 98 ++it) { 99 compact_region(*it); 100 } 101 }