1 /*
  2  * Copyright (c) 2017, 2021, 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.hpp"
 29 #include "gc/g1/g1FullCollector.inline.hpp"
 30 #include "gc/g1/g1FullGCCompactionPoint.hpp"
 31 #include "gc/g1/g1FullGCCompactTask.hpp"
 32 #include "gc/g1/heapRegion.inline.hpp"
 33 #include "gc/shared/gcTraceTime.inline.hpp"
 34 #include "gc/shared/slidingForwarding.inline.hpp"
 35 #include "logging/log.hpp"
 36 #include "oops/oop.inline.hpp"
 37 #include "utilities/ticks.hpp"
 38 
 39 // Do work for all skip-compacting regions.
 40 class G1ResetSkipCompactingClosure : public HeapRegionClosure {
 41   G1FullCollector* _collector;
 42 
 43 public:
 44   G1ResetSkipCompactingClosure(G1FullCollector* collector) : _collector(collector) { }
 45 
 46   bool do_heap_region(HeapRegion* r) {
 47     uint region_index = r->hrm_index();
 48     // Only for skip-compaction regions; early return otherwise.
 49     if (!_collector->is_skip_compacting(region_index)) {
 50 
 51       return false;
 52     }
 53     assert(_collector->live_words(region_index) > _collector->scope()->region_compaction_threshold() ||
 54          !r->is_starts_humongous() ||
 55          _collector->mark_bitmap()->is_marked(cast_to_oop(r->bottom())),
 56          "must be, otherwise reclaimed earlier");
 57     r->reset_skip_compacting_after_full_gc();
 58     return false;
 59   }
 60 };
 61 
 62 size_t G1FullGCCompactTask::G1CompactRegionClosure::apply(oop obj) {
 63   size_t size = obj->size();
 64   if (!obj->is_forwarded()) {
 65     // Object not moving
 66     return size;
 67   }
 68 
 69   HeapWord* destination = cast_from_oop<HeapWord*>(_forwarding->forwardee(obj));
 70 
 71   // copy object and reinit its mark
 72   HeapWord* obj_addr = cast_from_oop<HeapWord*>(obj);
 73   assert(obj_addr != destination, "everything in this pass should be moving");
 74   Copy::aligned_conjoint_words(obj_addr, destination, size);
 75   cast_to_oop(destination)->init_mark();
 76   assert(cast_to_oop(destination)->klass() != NULL, "should have a class");
 77 
 78   return size;
 79 }
 80 
 81 void G1FullGCCompactTask::compact_region(HeapRegion* hr) {
 82   assert(!hr->is_pinned(), "Should be no pinned region in compaction queue");
 83   assert(!hr->is_humongous(), "Should be no humongous regions in compaction queue");
 84   G1CompactRegionClosure compact(collector()->mark_bitmap());
 85   hr->apply_to_marked_objects(collector()->mark_bitmap(), &compact);
 86   // Clear the liveness information for this region if necessary i.e. if we actually look at it
 87   // for bitmap verification. Otherwise it is sufficient that we move the TAMS to bottom().
 88   if (G1VerifyBitmaps) {
 89     collector()->mark_bitmap()->clear_region(hr);
 90   }
 91   hr->reset_compacted_after_full_gc();
 92 }
 93 
 94 void G1FullGCCompactTask::work(uint worker_id) {
 95   Ticks start = Ticks::now();
 96   GrowableArray<HeapRegion*>* compaction_queue = collector()->compaction_point(worker_id)->regions();
 97   for (GrowableArrayIterator<HeapRegion*> it = compaction_queue->begin();
 98        it != compaction_queue->end();
 99        ++it) {
100     compact_region(*it);
101   }
102 
103   G1ResetSkipCompactingClosure hc(collector());
104   G1CollectedHeap::heap()->heap_region_par_iterate_from_worker_offset(&hc, &_claimer, worker_id);
105   log_task("Compaction task", worker_id, start);
106 }
107 
108 void G1FullGCCompactTask::serial_compaction() {
109   GCTraceTime(Debug, gc, phases) tm("Phase 4: Serial Compaction", collector()->scope()->timer());
110   GrowableArray<HeapRegion*>* compaction_queue = collector()->serial_compaction_point()->regions();
111   for (GrowableArrayIterator<HeapRegion*> it = compaction_queue->begin();
112        it != compaction_queue->end();
113        ++it) {
114     compact_region(*it);
115   }
116 }