1 /*
  2  * Copyright (c) 2016, 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/shared/preservedMarks.inline.hpp"

 27 #include "gc/shared/workerThread.hpp"
 28 #include "gc/shared/workerUtils.hpp"
 29 #include "memory/allocation.inline.hpp"
 30 #include "memory/resourceArea.hpp"
 31 #include "oops/oop.inline.hpp"
 32 #include "runtime/atomic.hpp"
 33 #include "utilities/macros.hpp"
 34 
 35 void PreservedMarks::restore() {
 36   while (!_stack.is_empty()) {
 37     const OopAndMarkWord elem = _stack.pop();
 38     elem.set_mark();
 39   }
 40   assert_empty();
 41 }
 42 
 43 void PreservedMarks::adjust_during_full_gc() {

 44   StackIterator<OopAndMarkWord, mtGC> iter(_stack);
 45   while (!iter.is_empty()) {
 46     OopAndMarkWord* elem = iter.next_addr();
 47 
 48     oop obj = elem->get_oop();
 49     if (obj->is_forwarded()) {
 50       elem->set_oop(obj->forwardee());
 51     }
 52   }
 53 }
 54 








 55 void PreservedMarks::restore_and_increment(volatile size_t* const total_size_addr) {
 56   const size_t stack_size = size();
 57   restore();
 58   // Only do the atomic add if the size is > 0.
 59   if (stack_size > 0) {
 60     Atomic::add(total_size_addr, stack_size);
 61   }
 62 }
 63 
 64 #ifndef PRODUCT
 65 void PreservedMarks::assert_empty() {
 66   assert(_stack.is_empty(), "stack expected to be empty, size = " SIZE_FORMAT,
 67          _stack.size());
 68   assert(_stack.cache_size() == 0,
 69          "stack expected to have no cached segments, cache size = " SIZE_FORMAT,
 70          _stack.cache_size());
 71 }
 72 #endif // ndef PRODUCT
 73 
 74 void PreservedMarksSet::init(uint num) {
 75   assert(_stacks == nullptr && _num == 0, "do not re-initialize");
 76   assert(num > 0, "pre-condition");
 77   if (_in_c_heap) {
 78     _stacks = NEW_C_HEAP_ARRAY(Padded<PreservedMarks>, num, mtGC);
 79   } else {
 80     _stacks = NEW_RESOURCE_ARRAY(Padded<PreservedMarks>, num);
 81   }
 82   for (uint i = 0; i < num; i += 1) {
 83     ::new (_stacks + i) PreservedMarks();
 84   }
 85   _num = num;
 86 
 87   assert_empty();
 88 }
 89 
 90 class RestorePreservedMarksTask : public WorkerTask {
 91   PreservedMarksSet* const _preserved_marks_set;
 92   SequentialSubTasksDone _sub_tasks;
 93   volatile size_t _total_size;
 94 #ifdef ASSERT
 95   size_t _total_size_before;
 96 #endif // ASSERT
 97 
 98 public:
 99   void work(uint worker_id) override {
100     uint task_id = 0;
101     while (_sub_tasks.try_claim_task(task_id)) {
102       _preserved_marks_set->get(task_id)->restore_and_increment(&_total_size);
103     }
104   }
105 
106   RestorePreservedMarksTask(PreservedMarksSet* preserved_marks_set)
107     : WorkerTask("Restore Preserved Marks"),
108       _preserved_marks_set(preserved_marks_set),
109       _sub_tasks(preserved_marks_set->num()),
110       _total_size(0)
111       DEBUG_ONLY(COMMA _total_size_before(0)) {
112 #ifdef ASSERT
113     // This is to make sure the total_size we'll calculate below is correct.
114     for (uint i = 0; i < _preserved_marks_set->num(); ++i) {
115       _total_size_before += _preserved_marks_set->get(i)->size();
116     }
117 #endif // ASSERT
118   }
119 
120   ~RestorePreservedMarksTask() {
121     assert(_total_size == _total_size_before, "total_size = %zu before = %zu", _total_size, _total_size_before);
122     size_t mem_size = _total_size * (sizeof(oop) + sizeof(markWord));
123     log_trace(gc)("Restored %zu marks, occupying %zu %s", _total_size,
124                                                           byte_size_in_proper_unit(mem_size),
125                                                           proper_unit_for_byte_size(mem_size));
126   }
127 };
128 
129 void PreservedMarksSet::restore(WorkerThreads* workers) {
130   {
131     RestorePreservedMarksTask cl(this);
132     if (workers == nullptr) {
133       cl.work(0);
134     } else {
135       workers->run_task(&cl);
136     }
137   }
138 
139   assert_empty();
140 }
141 
142 WorkerTask* PreservedMarksSet::create_task() {
143   return new RestorePreservedMarksTask(this);
144 }
145 
146 void PreservedMarksSet::reclaim() {
147   assert_empty();
148 
149   for (uint i = 0; i < _num; i += 1) {
150     _stacks[i].~Padded<PreservedMarks>();
151   }
152 
153   if (_in_c_heap) {
154     FREE_C_HEAP_ARRAY(Padded<PreservedMarks>, _stacks);
155   } else {
156     // the array was resource-allocated, so nothing to do
157   }
158   _stacks = nullptr;
159   _num = 0;
160 }
161 
162 #ifndef PRODUCT
163 void PreservedMarksSet::assert_empty() {
164   assert(_stacks != nullptr && _num > 0, "should have been initialized");
165   for (uint i = 0; i < _num; i += 1) {
166     get(i)->assert_empty();
167   }
168 }
169 #endif // ndef PRODUCT
--- EOF ---