Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright 2001-2008 Sun Microsystems, Inc.  All Rights Reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

  * CA 95054 USA or visit www.sun.com if you need additional information or

  * have any questions.

  *

  */

 # include "incls/_precompiled.incl"

 # include "incls/_ptrQueue.cpp.incl"

 PtrQueue::PtrQueue(PtrQueueSet* qset_, bool perm) :

   _qset(qset_), _buf(NULL), _index(0), _active(false),

   _perm(perm), _lock(NULL)

 {}

 void PtrQueue::flush() {

   if (!_perm && _buf != NULL) {

     if (_index == _sz) {

       // No work to do.

       qset()->deallocate_buffer(_buf);

     } else {

       // We must NULL out the unused entries, then enqueue.

       for (size_t i = 0; i < _index; i += oopSize) {

         _buf[byte_index_to_index((int)i)] = NULL;

       }

       qset()->enqueue_complete_buffer(_buf);

     }

     _buf = NULL;

     _index = 0;

   }

 }

 static int byte_index_to_index(int ind) {

   assert((ind % oopSize) == 0, "Invariant.");

   return ind / oopSize;

 }

 static int index_to_byte_index(int byte_ind) {

   return byte_ind * oopSize;

 }

 void PtrQueue::enqueue_known_active(void* ptr) {

   assert(0 <= _index && _index <= _sz, "Invariant.");

   assert(_index == 0 || _buf != NULL, "invariant");

   while (_index == 0) {

     handle_zero_index();

   }

   assert(_index > 0, "postcondition");

   _index -= oopSize;

   _buf[byte_index_to_index((int)_index)] = ptr;

   assert(0 <= _index && _index <= _sz, "Invariant.");

 }

 void PtrQueue::locking_enqueue_completed_buffer(void** buf) {

   assert(_lock->owned_by_self(), "Required.");

   _lock->unlock();

   qset()->enqueue_complete_buffer(buf);

   // We must relock only because the caller will unlock, for the normal

   // case.

   _lock->lock_without_safepoint_check();

 }

 PtrQueueSet::PtrQueueSet(bool notify_when_complete) :

   _max_completed_queue(0),

   _cbl_mon(NULL), _fl_lock(NULL),

   _notify_when_complete(notify_when_complete),

   _sz(0),

   _completed_buffers_head(NULL),

   _completed_buffers_tail(NULL),

   _n_completed_buffers(0),

   _process_completed_threshold(0), _process_completed(false),

   _buf_free_list(NULL), _buf_free_list_sz(0)

 {

   _fl_owner = this;

 }

 void** PtrQueueSet::allocate_buffer() {

   assert(_sz > 0, "Didn't set a buffer size.");

   MutexLockerEx x(_fl_owner->_fl_lock, Mutex::_no_safepoint_check_flag);

   if (_fl_owner->_buf_free_list != NULL) {

     void** res = _fl_owner->_buf_free_list;

     _fl_owner->_buf_free_list = (void**)_fl_owner->_buf_free_list[0];

     _fl_owner->_buf_free_list_sz--;

     // Just override the next pointer with NULL, just in case we scan this part

     // of the buffer.

     res[0] = NULL;

     return res;

   } else {

     return NEW_C_HEAP_ARRAY(void*, _sz);

   }

 }

 void PtrQueueSet::deallocate_buffer(void** buf) {

   assert(_sz > 0, "Didn't set a buffer size.");

   MutexLockerEx x(_fl_owner->_fl_lock, Mutex::_no_safepoint_check_flag);

   buf[0] = (void*)_fl_owner->_buf_free_list;

   _fl_owner->_buf_free_list = buf;

   _fl_owner->_buf_free_list_sz++;

 }

 void PtrQueueSet::reduce_free_list() {

   // For now we'll adopt the strategy of deleting half.

   MutexLockerEx x(_fl_lock, Mutex::_no_safepoint_check_flag);

   size_t n = _buf_free_list_sz / 2;

   while (n > 0) {

     assert(_buf_free_list != NULL, "_buf_free_list_sz must be wrong.");

     void** head = _buf_free_list;

     _buf_free_list = (void**)_buf_free_list[0];

     FREE_C_HEAP_ARRAY(void*,head);

     n--;

   }

 }

 void PtrQueueSet::enqueue_complete_buffer(void** buf, size_t index, bool ignore_max_completed) {

   // I use explicit locking here because there's a bailout in the middle.

   _cbl_mon->lock_without_safepoint_check();

   Thread* thread = Thread::current();

   assert( ignore_max_completed ||

           thread->is_Java_thread() ||

           SafepointSynchronize::is_at_safepoint(),

           "invariant" );

   ignore_max_completed = ignore_max_completed || !thread->is_Java_thread();

   if (!ignore_max_completed && _max_completed_queue > 0 &&

       _n_completed_buffers >= (size_t) _max_completed_queue) {

     _cbl_mon->unlock();

     bool b = mut_process_buffer(buf);

     if (b) {

       deallocate_buffer(buf);

       return;

     }

     // Otherwise, go ahead and enqueue the buffer.  Must reaquire the lock.

     _cbl_mon->lock_without_safepoint_check();

   }

   // Here we still hold the _cbl_mon.

   CompletedBufferNode* cbn = new CompletedBufferNode;

   cbn->buf = buf;

   cbn->next = NULL;

   cbn->index = index;

   if (_completed_buffers_tail == NULL) {

     assert(_completed_buffers_head == NULL, "Well-formedness");

     _completed_buffers_head = cbn;

     _completed_buffers_tail = cbn;

   } else {

     _completed_buffers_tail->next = cbn;

     _completed_buffers_tail = cbn;

   }

   _n_completed_buffers++;

   if (!_process_completed &&

       _n_completed_buffers >= _process_completed_threshold) {

     _process_completed = true;

     if (_notify_when_complete)

       _cbl_mon->notify_all();

   }

   debug_only(assert_completed_buffer_list_len_correct_locked());

   _cbl_mon->unlock();

 }

 int PtrQueueSet::completed_buffers_list_length() {

   int n = 0;

   CompletedBufferNode* cbn = _completed_buffers_head;

   while (cbn != NULL) {

     n++;

     cbn = cbn->next;

   }

   return n;

 }

 void PtrQueueSet::assert_completed_buffer_list_len_correct() {

   MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);

   assert_completed_buffer_list_len_correct_locked();

 }

 void PtrQueueSet::assert_completed_buffer_list_len_correct_locked() {

   guarantee((size_t)completed_buffers_list_length() ==  _n_completed_buffers,

             "Completed buffer length is wrong.");

 }

 void PtrQueueSet::set_buffer_size(size_t sz) {

   assert(_sz == 0 && sz > 0, "Should be called only once.");

   _sz = sz * oopSize;

 }

 void PtrQueueSet::set_process_completed_threshold(size_t sz) {

   _process_completed_threshold = sz;

 }

 // Merge lists of buffers. Notify waiting threads if the length of the list

 // exceeds threshold. The source queue is emptied as a result. The queues

 // must share the monitor.

 void PtrQueueSet::merge_bufferlists(PtrQueueSet *src) {

   assert(_cbl_mon == src->_cbl_mon, "Should share the same lock");

   MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);

   if (_completed_buffers_tail == NULL) {

     assert(_completed_buffers_head == NULL, "Well-formedness");

     _completed_buffers_head = src->_completed_buffers_head;

     _completed_buffers_tail = src->_completed_buffers_tail;

   } else {

     assert(_completed_buffers_head != NULL, "Well formedness");

     if (src->_completed_buffers_head != NULL) {

       _completed_buffers_tail->next = src->_completed_buffers_head;

       _completed_buffers_tail = src->_completed_buffers_tail;

     }

   }

   _n_completed_buffers += src->_n_completed_buffers;

   src->_n_completed_buffers = 0;

   src->_completed_buffers_head = NULL;

   src->_completed_buffers_tail = NULL;

   assert(_completed_buffers_head == NULL && _completed_buffers_tail == NULL ||

          _completed_buffers_head != NULL && _completed_buffers_tail != NULL,

          "Sanity");

   if (!_process_completed &&

       _n_completed_buffers >= _process_completed_threshold) {

     _process_completed = true;

     if (_notify_when_complete)

       _cbl_mon->notify_all();

   }

 }

 // Merge free lists of the two queues. The free list of the source

 // queue is emptied as a result. The queues must share the same

 // mutex that guards free lists.

 void PtrQueueSet::merge_freelists(PtrQueueSet* src) {

   assert(_fl_lock == src->_fl_lock, "Should share the same lock");

   MutexLockerEx x(_fl_lock, Mutex::_no_safepoint_check_flag);

   if (_buf_free_list != NULL) {

     void **p = _buf_free_list;

     while (*p != NULL) {

       p = (void**)*p;

     }

     *p = src->_buf_free_list;

   } else {

     _buf_free_list = src->_buf_free_list;

   }

   _buf_free_list_sz += src->_buf_free_list_sz;

   src->_buf_free_list = NULL;

   src->_buf_free_list_sz = 0;

 }