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 "classfile/classLoaderDataGraph.hpp"
 27 #include "gc/g1/g1CollectedHeap.hpp"
 28 #include "gc/g1/g1ConcurrentMarkBitMap.inline.hpp"
 29 #include "gc/g1/g1FullCollector.inline.hpp"
 30 #include "gc/g1/g1FullGCAdjustTask.hpp"
 31 #include "gc/g1/g1FullGCCompactionPoint.hpp"
 32 #include "gc/g1/g1FullGCMarker.hpp"
 33 #include "gc/g1/g1FullGCOopClosures.inline.hpp"
 34 #include "gc/g1/heapRegion.inline.hpp"
 35 #include "gc/shared/gcTraceTime.inline.hpp"
 36 #include "gc/shared/referenceProcessor.hpp"
 37 #include "gc/shared/weakProcessor.inline.hpp"
 38 #include "logging/log.hpp"
 39 #include "memory/iterator.inline.hpp"
 40 #include "runtime/atomic.hpp"
 41 
 42 class G1AdjustLiveClosure : public StackObj {
 43   G1AdjustClosure* _adjust_closure;
 44 public:
 45   G1AdjustLiveClosure(G1AdjustClosure* cl) :
 46     _adjust_closure(cl) { }
 47 
 48   size_t apply(oop object) {
 49     return object->oop_iterate_size(_adjust_closure);
 50   }
 51 };
 52 
 53 class G1AdjustRegionClosure : public HeapRegionClosure {
 54   G1FullCollector* _collector;
 55   G1CMBitMap* _bitmap;
 56   uint _worker_id;
 57  public:
 58   G1AdjustRegionClosure(G1FullCollector* collector, uint worker_id) :
 59     _collector(collector),
 60     _bitmap(collector->mark_bitmap()),
 61     _worker_id(worker_id) { }
 62 
 63   bool do_heap_region(HeapRegion* r) {
 64     G1AdjustClosure cl(_collector);
 65     if (r->is_humongous()) {
 66       // Special handling for humongous regions to get somewhat better
 67       // work distribution.
 68       oop obj = cast_to_oop(r->humongous_start_region()->bottom());
 69       obj->oop_iterate(&cl, MemRegion(r->bottom(), r->top()));
 70     } else if (!r->is_closed_archive() && !r->is_free()) {
 71       // Closed archive regions never change references and only contain
 72       // references into other closed regions and are always live. Free
 73       // regions do not contain objects to iterate. So skip both.
 74       G1AdjustLiveClosure adjust(&cl);
 75       r->apply_to_marked_objects(_bitmap, &adjust);
 76     }
 77     return false;
 78   }
 79 };
 80 
 81 G1FullGCAdjustTask::G1FullGCAdjustTask(G1FullCollector* collector) :
 82     G1FullGCTask("G1 Adjust", collector),
 83     _root_processor(G1CollectedHeap::heap(), collector->workers()),
 84     _weak_proc_task(collector->workers()),
 85     _hrclaimer(collector->workers()),
 86     _adjust(collector) {
 87   // Need cleared claim bits for the roots processing
 88   ClassLoaderDataGraph::clear_claimed_marks();
 89 }
 90 
 91 void G1FullGCAdjustTask::work(uint worker_id) {
 92   Ticks start = Ticks::now();
 93   ResourceMark rm;
 94 
 95   // Adjust preserved marks first since they are not balanced.
 96   G1FullGCMarker* marker = collector()->marker(worker_id);
 97   marker->preserved_stack()->adjust_during_full_gc();
 98 
 99   {
100     // Adjust the weak roots.
101     AlwaysTrueClosure always_alive;
102     _weak_proc_task.work(worker_id, &always_alive, &_adjust);
103   }
104 
105   CLDToOopClosure adjust_cld(&_adjust, ClassLoaderData::_claim_strong);
106   CodeBlobToOopClosure adjust_code(&_adjust, CodeBlobToOopClosure::FixRelocations);
107   _root_processor.process_all_roots(&_adjust, &adjust_cld, &adjust_code);
108 
109   // Now adjust pointers region by region
110   G1AdjustRegionClosure blk(collector(), worker_id);
111   G1CollectedHeap::heap()->heap_region_par_iterate_from_worker_offset(&blk, &_hrclaimer, worker_id);
112   log_task("Adjust task", worker_id, start);
113 }