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src/share/vm/gc/g1/ptrQueue.cpp

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rev 10256 : [mq]: bufnode_cleanup
rev 10257 : [mq]: flexible_array
   1 /*
   2  * Copyright (c) 2001, 2015, 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/ptrQueue.hpp"
  27 #include "memory/allocation.hpp"
  28 #include "memory/allocation.inline.hpp"
  29 #include "runtime/mutex.hpp"
  30 #include "runtime/mutexLocker.hpp"
  31 #include "runtime/thread.inline.hpp"
  32 


  33 PtrQueue::PtrQueue(PtrQueueSet* qset, bool permanent, bool active) :
  34   _qset(qset), _buf(NULL), _index(0), _sz(0), _active(active),
  35   _permanent(permanent), _lock(NULL)
  36 {}
  37 
  38 PtrQueue::~PtrQueue() {
  39   assert(_permanent || (_buf == NULL), "queue must be flushed before delete");
  40 }
  41 
  42 void PtrQueue::flush_impl() {
  43   if (!_permanent && _buf != NULL) {
  44     if (_index == _sz) {
  45       // No work to do.
  46       qset()->deallocate_buffer(_buf);
  47     } else {
  48       // We must NULL out the unused entries, then enqueue.
  49       size_t limit = byte_index_to_index(_index);
  50       for (size_t i = 0; i < limit; ++i) {
  51         _buf[i] = NULL;
  52       }


  70   _index -= sizeof(void*);
  71   _buf[byte_index_to_index(_index)] = ptr;
  72   assert(_index <= _sz, "Invariant.");
  73 }
  74 
  75 void PtrQueue::locking_enqueue_completed_buffer(void** buf) {
  76   assert(_lock->owned_by_self(), "Required.");
  77 
  78   // We have to unlock _lock (which may be Shared_DirtyCardQ_lock) before
  79   // we acquire DirtyCardQ_CBL_mon inside enqueue_complete_buffer as they
  80   // have the same rank and we may get the "possible deadlock" message
  81   _lock->unlock();
  82 
  83   qset()->enqueue_complete_buffer(buf);
  84   // We must relock only because the caller will unlock, for the normal
  85   // case.
  86   _lock->lock_without_safepoint_check();
  87 }
  88 
  89 













  90 PtrQueueSet::PtrQueueSet(bool notify_when_complete) :
  91   _max_completed_queue(0),
  92   _cbl_mon(NULL), _fl_lock(NULL),
  93   _notify_when_complete(notify_when_complete),
  94   _sz(0),
  95   _completed_buffers_head(NULL),
  96   _completed_buffers_tail(NULL),
  97   _n_completed_buffers(0),
  98   _process_completed_threshold(0), _process_completed(false),
  99   _buf_free_list(NULL), _buf_free_list_sz(0)
 100 {
 101   _fl_owner = this;
 102 }
 103 
 104 PtrQueueSet::~PtrQueueSet() {
 105   // There are presently only a couple (derived) instances ever
 106   // created, and they are permanent, so no harm currently done by
 107   // doing nothing here.
 108 }
 109 
 110 void PtrQueueSet::initialize(Monitor* cbl_mon,
 111                              Mutex* fl_lock,
 112                              int process_completed_threshold,
 113                              int max_completed_queue,
 114                              PtrQueueSet *fl_owner) {
 115   _max_completed_queue = max_completed_queue;
 116   _process_completed_threshold = process_completed_threshold;
 117   _completed_queue_padding = 0;
 118   assert(cbl_mon != NULL && fl_lock != NULL, "Init order issue?");
 119   _cbl_mon = cbl_mon;
 120   _fl_lock = fl_lock;
 121   _fl_owner = (fl_owner != NULL) ? fl_owner : this;
 122 }
 123 
 124 void** PtrQueueSet::allocate_buffer() {
 125   assert(_sz > 0, "Didn't set a buffer size.");


 126   MutexLockerEx x(_fl_owner->_fl_lock, Mutex::_no_safepoint_check_flag);
 127   if (_fl_owner->_buf_free_list != NULL) {
 128     void** res = BufferNode::make_buffer_from_node(_fl_owner->_buf_free_list);
 129     _fl_owner->_buf_free_list = _fl_owner->_buf_free_list->next();
 130     _fl_owner->_buf_free_list_sz--;
 131     return res;



 132   } else {
 133     // Allocate space for the BufferNode in front of the buffer.
 134     char *b =  NEW_C_HEAP_ARRAY(char, _sz + BufferNode::aligned_size(), mtGC);
 135     return BufferNode::make_buffer_from_block(b);
 136   }

 137 }
 138 
 139 void PtrQueueSet::deallocate_buffer(void** buf) {
 140   assert(_sz > 0, "Didn't set a buffer size.");
 141   MutexLockerEx x(_fl_owner->_fl_lock, Mutex::_no_safepoint_check_flag);
 142   BufferNode *node = BufferNode::make_node_from_buffer(buf);
 143   node->set_next(_fl_owner->_buf_free_list);
 144   _fl_owner->_buf_free_list = node;
 145   _fl_owner->_buf_free_list_sz++;
 146 }
 147 
 148 void PtrQueueSet::reduce_free_list() {
 149   assert(_fl_owner == this, "Free list reduction is allowed only for the owner");
 150   // For now we'll adopt the strategy of deleting half.
 151   MutexLockerEx x(_fl_lock, Mutex::_no_safepoint_check_flag);
 152   size_t n = _buf_free_list_sz / 2;
 153   while (n > 0) {
 154     assert(_buf_free_list != NULL, "_buf_free_list_sz must be wrong.");
 155     void* b = BufferNode::make_block_from_node(_buf_free_list);
 156     _buf_free_list = _buf_free_list->next();
 157     FREE_C_HEAP_ARRAY(char, b);
 158     _buf_free_list_sz --;
 159     n--;
 160   }
 161 }
 162 
 163 void PtrQueue::handle_zero_index() {
 164   assert(_index == 0, "Precondition.");
 165 
 166   // This thread records the full buffer and allocates a new one (while
 167   // holding the lock if there is one).
 168   if (_buf != NULL) {
 169     if (!should_enqueue_buffer()) {
 170       assert(_index > 0, "the buffer can only be re-used if it's not full");
 171       return;
 172     }
 173 
 174     if (_lock) {
 175       assert(_lock->owned_by_self(), "Required.");
 176 
 177       // The current PtrQ may be the shared dirty card queue and
 178       // may be being manipulated by more than one worker thread
 179       // during a pause. Since the enqueueing of the completed


 219 
 220 bool PtrQueueSet::process_or_enqueue_complete_buffer(void** buf) {
 221   if (Thread::current()->is_Java_thread()) {
 222     // We don't lock. It is fine to be epsilon-precise here.
 223     if (_max_completed_queue == 0 || _max_completed_queue > 0 &&
 224         _n_completed_buffers >= _max_completed_queue + _completed_queue_padding) {
 225       bool b = mut_process_buffer(buf);
 226       if (b) {
 227         // True here means that the buffer hasn't been deallocated and the caller may reuse it.
 228         return true;
 229       }
 230     }
 231   }
 232   // The buffer will be enqueued. The caller will have to get a new one.
 233   enqueue_complete_buffer(buf);
 234   return false;
 235 }
 236 
 237 void PtrQueueSet::enqueue_complete_buffer(void** buf, size_t index) {
 238   MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
 239   BufferNode* cbn = BufferNode::new_from_buffer(buf);
 240   cbn->set_index(index);

 241   if (_completed_buffers_tail == NULL) {
 242     assert(_completed_buffers_head == NULL, "Well-formedness");
 243     _completed_buffers_head = cbn;
 244     _completed_buffers_tail = cbn;
 245   } else {
 246     _completed_buffers_tail->set_next(cbn);
 247     _completed_buffers_tail = cbn;
 248   }
 249   _n_completed_buffers++;
 250 
 251   if (!_process_completed && _process_completed_threshold >= 0 &&
 252       _n_completed_buffers >= _process_completed_threshold) {
 253     _process_completed = true;
 254     if (_notify_when_complete)
 255       _cbl_mon->notify();
 256   }
 257   DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked());
 258 }
 259 
 260 int PtrQueueSet::completed_buffers_list_length() {


   1 /*
   2  * Copyright (c) 2001, 2016, 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/ptrQueue.hpp"
  27 #include "memory/allocation.hpp"
  28 #include "memory/allocation.inline.hpp"
  29 #include "runtime/mutex.hpp"
  30 #include "runtime/mutexLocker.hpp"
  31 #include "runtime/thread.inline.hpp"
  32 
  33 #include <new>
  34 
  35 PtrQueue::PtrQueue(PtrQueueSet* qset, bool permanent, bool active) :
  36   _qset(qset), _buf(NULL), _index(0), _sz(0), _active(active),
  37   _permanent(permanent), _lock(NULL)
  38 {}
  39 
  40 PtrQueue::~PtrQueue() {
  41   assert(_permanent || (_buf == NULL), "queue must be flushed before delete");
  42 }
  43 
  44 void PtrQueue::flush_impl() {
  45   if (!_permanent && _buf != NULL) {
  46     if (_index == _sz) {
  47       // No work to do.
  48       qset()->deallocate_buffer(_buf);
  49     } else {
  50       // We must NULL out the unused entries, then enqueue.
  51       size_t limit = byte_index_to_index(_index);
  52       for (size_t i = 0; i < limit; ++i) {
  53         _buf[i] = NULL;
  54       }


  72   _index -= sizeof(void*);
  73   _buf[byte_index_to_index(_index)] = ptr;
  74   assert(_index <= _sz, "Invariant.");
  75 }
  76 
  77 void PtrQueue::locking_enqueue_completed_buffer(void** buf) {
  78   assert(_lock->owned_by_self(), "Required.");
  79 
  80   // We have to unlock _lock (which may be Shared_DirtyCardQ_lock) before
  81   // we acquire DirtyCardQ_CBL_mon inside enqueue_complete_buffer as they
  82   // have the same rank and we may get the "possible deadlock" message
  83   _lock->unlock();
  84 
  85   qset()->enqueue_complete_buffer(buf);
  86   // We must relock only because the caller will unlock, for the normal
  87   // case.
  88   _lock->lock_without_safepoint_check();
  89 }
  90 
  91 
  92 BufferNode* BufferNode::allocate(size_t byte_size) {
  93   assert(byte_size > 0, "precondition");
  94   assert(is_size_aligned(byte_size, sizeof(void**)),
  95          "Invalid buffer size " SIZE_FORMAT, byte_size);
  96   void* data = NEW_C_HEAP_ARRAY(char, buffer_offset() + byte_size, mtGC);
  97   return new (data) BufferNode;
  98 }
  99 
 100 void BufferNode::deallocate(BufferNode* node) {
 101   node->~BufferNode();
 102   FREE_C_HEAP_ARRAY(char, node);
 103 }
 104 
 105 PtrQueueSet::PtrQueueSet(bool notify_when_complete) :
 106   _max_completed_queue(0),
 107   _cbl_mon(NULL), _fl_lock(NULL),
 108   _notify_when_complete(notify_when_complete),
 109   _sz(0),
 110   _completed_buffers_head(NULL),
 111   _completed_buffers_tail(NULL),
 112   _n_completed_buffers(0),
 113   _process_completed_threshold(0), _process_completed(false),
 114   _buf_free_list(NULL), _buf_free_list_sz(0)
 115 {
 116   _fl_owner = this;
 117 }
 118 
 119 PtrQueueSet::~PtrQueueSet() {
 120   // There are presently only a couple (derived) instances ever
 121   // created, and they are permanent, so no harm currently done by
 122   // doing nothing here.
 123 }
 124 
 125 void PtrQueueSet::initialize(Monitor* cbl_mon,
 126                              Mutex* fl_lock,
 127                              int process_completed_threshold,
 128                              int max_completed_queue,
 129                              PtrQueueSet *fl_owner) {
 130   _max_completed_queue = max_completed_queue;
 131   _process_completed_threshold = process_completed_threshold;
 132   _completed_queue_padding = 0;
 133   assert(cbl_mon != NULL && fl_lock != NULL, "Init order issue?");
 134   _cbl_mon = cbl_mon;
 135   _fl_lock = fl_lock;
 136   _fl_owner = (fl_owner != NULL) ? fl_owner : this;
 137 }
 138 
 139 void** PtrQueueSet::allocate_buffer() {
 140   assert(_sz > 0, "Didn't set a buffer size.");
 141   BufferNode* node = NULL;
 142   {
 143     MutexLockerEx x(_fl_owner->_fl_lock, Mutex::_no_safepoint_check_flag);
 144     node = _fl_owner->_buf_free_list;
 145     if (node != NULL) {
 146       _fl_owner->_buf_free_list = node->next();
 147       _fl_owner->_buf_free_list_sz--;
 148     }
 149   }
 150   if (node == NULL) {
 151     node = BufferNode::allocate(_sz);
 152   } else {
 153     // Reinitialize buffer obtained from free list.
 154     node->set_index(0);
 155     node->set_next(NULL);
 156   }
 157   return BufferNode::make_buffer_from_node(node);
 158 }
 159 
 160 void PtrQueueSet::deallocate_buffer(void** buf) {
 161   assert(_sz > 0, "Didn't set a buffer size.");
 162   MutexLockerEx x(_fl_owner->_fl_lock, Mutex::_no_safepoint_check_flag);
 163   BufferNode *node = BufferNode::make_node_from_buffer(buf);
 164   node->set_next(_fl_owner->_buf_free_list);
 165   _fl_owner->_buf_free_list = node;
 166   _fl_owner->_buf_free_list_sz++;
 167 }
 168 
 169 void PtrQueueSet::reduce_free_list() {
 170   assert(_fl_owner == this, "Free list reduction is allowed only for the owner");
 171   // For now we'll adopt the strategy of deleting half.
 172   MutexLockerEx x(_fl_lock, Mutex::_no_safepoint_check_flag);
 173   size_t n = _buf_free_list_sz / 2;
 174   for (size_t i = 0; i < n; ++i) {
 175     assert(_buf_free_list != NULL,
 176            "_buf_free_list_sz is wrong: " SIZE_FORMAT, _buf_free_list_sz);
 177     BufferNode* node = _buf_free_list;
 178     _buf_free_list = node->next();
 179     _buf_free_list_sz--;
 180     BufferNode::deallocate(node);
 181   }
 182 }
 183 
 184 void PtrQueue::handle_zero_index() {
 185   assert(_index == 0, "Precondition.");
 186 
 187   // This thread records the full buffer and allocates a new one (while
 188   // holding the lock if there is one).
 189   if (_buf != NULL) {
 190     if (!should_enqueue_buffer()) {
 191       assert(_index > 0, "the buffer can only be re-used if it's not full");
 192       return;
 193     }
 194 
 195     if (_lock) {
 196       assert(_lock->owned_by_self(), "Required.");
 197 
 198       // The current PtrQ may be the shared dirty card queue and
 199       // may be being manipulated by more than one worker thread
 200       // during a pause. Since the enqueueing of the completed


 240 
 241 bool PtrQueueSet::process_or_enqueue_complete_buffer(void** buf) {
 242   if (Thread::current()->is_Java_thread()) {
 243     // We don't lock. It is fine to be epsilon-precise here.
 244     if (_max_completed_queue == 0 || _max_completed_queue > 0 &&
 245         _n_completed_buffers >= _max_completed_queue + _completed_queue_padding) {
 246       bool b = mut_process_buffer(buf);
 247       if (b) {
 248         // True here means that the buffer hasn't been deallocated and the caller may reuse it.
 249         return true;
 250       }
 251     }
 252   }
 253   // The buffer will be enqueued. The caller will have to get a new one.
 254   enqueue_complete_buffer(buf);
 255   return false;
 256 }
 257 
 258 void PtrQueueSet::enqueue_complete_buffer(void** buf, size_t index) {
 259   MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
 260   BufferNode* cbn = BufferNode::make_node_from_buffer(buf);
 261   cbn->set_index(index);
 262   cbn->set_next(NULL);
 263   if (_completed_buffers_tail == NULL) {
 264     assert(_completed_buffers_head == NULL, "Well-formedness");
 265     _completed_buffers_head = cbn;
 266     _completed_buffers_tail = cbn;
 267   } else {
 268     _completed_buffers_tail->set_next(cbn);
 269     _completed_buffers_tail = cbn;
 270   }
 271   _n_completed_buffers++;
 272 
 273   if (!_process_completed && _process_completed_threshold >= 0 &&
 274       _n_completed_buffers >= _process_completed_threshold) {
 275     _process_completed = true;
 276     if (_notify_when_complete)
 277       _cbl_mon->notify();
 278   }
 279   DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked());
 280 }
 281 
 282 int PtrQueueSet::completed_buffers_list_length() {


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