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src/hotspot/share/gc/shared/preservedMarks.cpp

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


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












 54 void PreservedMarks::restore_and_increment(volatile size_t* const total_size_addr) {
 55   const size_t stack_size = size();
 56   restore();
 57   // Only do the atomic add if the size is > 0.
 58   if (stack_size > 0) {
 59     Atomic::add(total_size_addr, stack_size);
 60   }
 61 }
 62 
 63 #ifndef PRODUCT
 64 void PreservedMarks::assert_empty() {
 65   assert(_stack.is_empty(), "stack expected to be empty, size = " SIZE_FORMAT,
 66          _stack.size());
 67   assert(_stack.cache_size() == 0,
 68          "stack expected to have no cached segments, cache size = " SIZE_FORMAT,
 69          _stack.cache_size());
 70 }
 71 #endif // ndef PRODUCT
 72 
 73 void RemoveForwardedPointerClosure::do_object(oop obj) {
 74   if (obj->is_forwarded()) {
 75     PreservedMarks::init_forwarded_mark(obj);














 76   }
 77 }
 78 
 79 void PreservedMarksSet::init(uint num) {
 80   assert(_stacks == nullptr && _num == 0, "do not re-initialize");
 81   assert(num > 0, "pre-condition");
 82   if (_in_c_heap) {
 83     _stacks = NEW_C_HEAP_ARRAY(Padded<PreservedMarks>, num, mtGC);
 84   } else {
 85     _stacks = NEW_RESOURCE_ARRAY(Padded<PreservedMarks>, num);
 86   }
 87   for (uint i = 0; i < num; i += 1) {
 88     ::new (_stacks + i) PreservedMarks();
 89   }
 90   _num = num;
 91 
 92   assert_empty();
 93 }
 94 
 95 class RestorePreservedMarksTask : public AbstractGangTask {

  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/slidingForwarding.inline.hpp"
 28 #include "gc/shared/workgroup.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 // TODO: This method is unused, except in the gunit test. Change the test
 44 // to exercise the updated method below instead, and remove this one.
 45 void PreservedMarks::adjust_during_full_gc() {
 46   StackIterator<OopAndMarkWord, mtGC> iter(_stack);
 47   while (!iter.is_empty()) {
 48     OopAndMarkWord* elem = iter.next_addr();
 49 
 50     oop obj = elem->get_oop();
 51     if (obj->is_forwarded()) {
 52       elem->set_oop(obj->forwardee());
 53     }
 54   }
 55 }
 56 
 57 void PreservedMarks::adjust_during_full_gc(const SlidingForwarding* const forwarding) {
 58   StackIterator<OopAndMarkWord, mtGC> iter(_stack);
 59   while (!iter.is_empty()) {
 60     OopAndMarkWord* elem = iter.next_addr();
 61 
 62     oop obj = elem->get_oop();
 63     if (obj->is_forwarded()) {
 64       elem->set_oop(forwarding->forwardee(obj));
 65     }
 66   }
 67 }
 68 
 69 void PreservedMarks::restore_and_increment(volatile size_t* const total_size_addr) {
 70   const size_t stack_size = size();
 71   restore();
 72   // Only do the atomic add if the size is > 0.
 73   if (stack_size > 0) {
 74     Atomic::add(total_size_addr, stack_size);
 75   }
 76 }
 77 
 78 #ifndef PRODUCT
 79 void PreservedMarks::assert_empty() {
 80   assert(_stack.is_empty(), "stack expected to be empty, size = " SIZE_FORMAT,
 81          _stack.size());
 82   assert(_stack.cache_size() == 0,
 83          "stack expected to have no cached segments, cache size = " SIZE_FORMAT,
 84          _stack.cache_size());
 85 }
 86 #endif // ndef PRODUCT
 87 
 88 void RemoveForwardedPointerClosure::do_object(oop obj) {
 89   if (obj->is_forwarded()) {
 90 #ifdef _LP64
 91     if (UseCompactObjectHeaders) {
 92       oop forwardee = obj->forwardee();
 93       markWord header = forwardee->mark();
 94       if (header.has_displaced_mark_helper()) {
 95         header = header.displaced_mark_helper();
 96       }
 97       assert(UseCompressedClassPointers, "assume +UseCompressedClassPointers");
 98       narrowKlass nklass = header.narrow_klass();
 99       obj->set_mark(markWord::prototype().set_narrow_klass(nklass));
100     } else
101 #endif
102     {
103       PreservedMarks::init_forwarded_mark(obj);
104     }
105   }
106 }
107 
108 void PreservedMarksSet::init(uint num) {
109   assert(_stacks == nullptr && _num == 0, "do not re-initialize");
110   assert(num > 0, "pre-condition");
111   if (_in_c_heap) {
112     _stacks = NEW_C_HEAP_ARRAY(Padded<PreservedMarks>, num, mtGC);
113   } else {
114     _stacks = NEW_RESOURCE_ARRAY(Padded<PreservedMarks>, num);
115   }
116   for (uint i = 0; i < num; i += 1) {
117     ::new (_stacks + i) PreservedMarks();
118   }
119   _num = num;
120 
121   assert_empty();
122 }
123 
124 class RestorePreservedMarksTask : public AbstractGangTask {
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