1 /*
   2  * Copyright (c) 2017, 2018 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/g1FullGCCompactionPoint.hpp"
  30 #include "gc/g1/g1FullGCCompactTask.hpp"
  31 #include "gc/g1/heapRegion.inline.hpp"
  32 #include "gc/shared/gcTraceTime.inline.hpp"
  33 #include "logging/log.hpp"
  34 #include "oops/oop.inline.hpp"
  35 #include "utilities/ticks.inline.hpp"
  36 
  37 class G1ResetHumongousClosure : public HeapRegionClosure {
  38   G1CMBitMap* _bitmap;
  39 
  40 public:
  41   G1ResetHumongousClosure(G1CMBitMap* bitmap) :
  42       _bitmap(bitmap) { }
  43 
  44   bool do_heap_region(HeapRegion* current) {
  45     if (current->is_humongous()) {
  46       if (current->is_starts_humongous()) {
  47         oop obj = oop(current->bottom());
  48         if (_bitmap->is_marked(obj)) {
  49           // Clear bitmap and fix mark word.
  50           _bitmap->clear(obj);
  51           obj->init_mark_raw();
  52         } else {
  53           assert(current->is_empty(), "Should have been cleared in phase 2.");
  54         }
  55       }
  56       current->reset_during_compaction();
  57     }
  58     return false;
  59   }
  60 };
  61 
  62 size_t G1FullGCCompactTask::G1CompactRegionClosure::apply(oop obj) {
  63   size_t size = obj->size();
  64   HeapWord* destination = (HeapWord*)obj->forwardee();
  65   if (destination == NULL) {
  66     // Object not moving
  67     return size;
  68   }
  69 
  70   // copy object and reinit its mark
  71   HeapWord* obj_addr = (HeapWord*) obj;
  72   assert(obj_addr != destination, "everything in this pass should be moving");
  73   Copy::aligned_conjoint_words(obj_addr, destination, size);
  74   oop(destination)->init_mark_raw();
  75   assert(oop(destination)->klass() != NULL, "should have a class");
  76 
  77   return size;
  78 }
  79 
  80 void G1FullGCCompactTask::compact_region(HeapRegion* hr) {
  81   assert(!hr->is_humongous(), "Should be no humongous regions in compaction queue");
  82   G1CompactRegionClosure compact(collector()->mark_bitmap());
  83   hr->apply_to_marked_objects(collector()->mark_bitmap(), &compact);
  84   // Once all objects have been moved the liveness information
  85   // needs be cleared.
  86   collector()->mark_bitmap()->clear_region(hr);
  87   hr->complete_compaction();
  88 }
  89 
  90 void G1FullGCCompactTask::work(uint worker_id) {
  91   Ticks start = Ticks::now();
  92   GrowableArray<HeapRegion*>* compaction_queue = collector()->compaction_point(worker_id)->regions();
  93   for (GrowableArrayIterator<HeapRegion*> it = compaction_queue->begin();
  94        it != compaction_queue->end();
  95        ++it) {
  96     compact_region(*it);
  97   }
  98 
  99   G1ResetHumongousClosure hc(collector()->mark_bitmap());
 100   G1CollectedHeap::heap()->heap_region_par_iterate_from_worker_offset(&hc, &_claimer, worker_id);
 101   log_task("Compaction task", worker_id, start);
 102 }
 103 
 104 void G1FullGCCompactTask::serial_compaction() {
 105   GCTraceTime(Debug, gc, phases) tm("Phase 4: Serial Compaction", collector()->scope()->timer());
 106   GrowableArray<HeapRegion*>* compaction_queue = collector()->serial_compaction_point()->regions();
 107   for (GrowableArrayIterator<HeapRegion*> it = compaction_queue->begin();
 108        it != compaction_queue->end();
 109        ++it) {
 110     compact_region(*it);
 111   }
 112 }