ysr@777: /*
xdono@905:  * Copyright 2001-2008 Sun Microsystems, Inc.  All Rights Reserved.
ysr@777:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
ysr@777:  *
ysr@777:  * This code is free software; you can redistribute it and/or modify it
ysr@777:  * under the terms of the GNU General Public License version 2 only, as
ysr@777:  * published by the Free Software Foundation.
ysr@777:  *
ysr@777:  * This code is distributed in the hope that it will be useful, but WITHOUT
ysr@777:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
ysr@777:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
ysr@777:  * version 2 for more details (a copy is included in the LICENSE file that
ysr@777:  * accompanied this code).
ysr@777:  *
ysr@777:  * You should have received a copy of the GNU General Public License version
ysr@777:  * 2 along with this work; if not, write to the Free Software Foundation,
ysr@777:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
ysr@777:  *
ysr@777:  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
ysr@777:  * CA 95054 USA or visit www.sun.com if you need additional information or
ysr@777:  * have any questions.
ysr@777:  *
ysr@777:  */
ysr@777: 
ysr@777: # include "incls/_precompiled.incl"
ysr@777: # include "incls/_ptrQueue.cpp.incl"
ysr@777: 
ysr@777: PtrQueue::PtrQueue(PtrQueueSet* qset_, bool perm) :
ysr@777:   _qset(qset_), _buf(NULL), _index(0), _active(false),
ysr@777:   _perm(perm), _lock(NULL)
ysr@777: {}
ysr@777: 
iveresov@876: void PtrQueue::flush() {
ysr@777:   if (!_perm && _buf != NULL) {
ysr@777:     if (_index == _sz) {
ysr@777:       // No work to do.
ysr@777:       qset()->deallocate_buffer(_buf);
ysr@777:     } else {
ysr@777:       // We must NULL out the unused entries, then enqueue.
ysr@777:       for (size_t i = 0; i < _index; i += oopSize) {
ysr@777:         _buf[byte_index_to_index((int)i)] = NULL;
ysr@777:       }
ysr@777:       qset()->enqueue_complete_buffer(_buf);
ysr@777:     }
iveresov@876:     _buf = NULL;
iveresov@876:     _index = 0;
ysr@777:   }
ysr@777: }
ysr@777: 
ysr@777: 
ysr@777: static int byte_index_to_index(int ind) {
ysr@777:   assert((ind % oopSize) == 0, "Invariant.");
ysr@777:   return ind / oopSize;
ysr@777: }
ysr@777: 
ysr@777: static int index_to_byte_index(int byte_ind) {
ysr@777:   return byte_ind * oopSize;
ysr@777: }
ysr@777: 
ysr@777: void PtrQueue::enqueue_known_active(void* ptr) {
ysr@777:   assert(0 <= _index && _index <= _sz, "Invariant.");
ysr@777:   assert(_index == 0 || _buf != NULL, "invariant");
ysr@777: 
ysr@777:   while (_index == 0) {
ysr@777:     handle_zero_index();
ysr@777:   }
ysr@777:   assert(_index > 0, "postcondition");
ysr@777: 
ysr@777:   _index -= oopSize;
ysr@777:   _buf[byte_index_to_index((int)_index)] = ptr;
ysr@777:   assert(0 <= _index && _index <= _sz, "Invariant.");
ysr@777: }
ysr@777: 
ysr@777: void PtrQueue::locking_enqueue_completed_buffer(void** buf) {
ysr@777:   assert(_lock->owned_by_self(), "Required.");
ysr@777:   _lock->unlock();
ysr@777:   qset()->enqueue_complete_buffer(buf);
ysr@777:   // We must relock only because the caller will unlock, for the normal
ysr@777:   // case.
ysr@777:   _lock->lock_without_safepoint_check();
ysr@777: }
ysr@777: 
ysr@777: 
ysr@777: PtrQueueSet::PtrQueueSet(bool notify_when_complete) :
ysr@777:   _max_completed_queue(0),
ysr@777:   _cbl_mon(NULL), _fl_lock(NULL),
ysr@777:   _notify_when_complete(notify_when_complete),
ysr@777:   _sz(0),
ysr@777:   _completed_buffers_head(NULL),
ysr@777:   _completed_buffers_tail(NULL),
ysr@777:   _n_completed_buffers(0),
ysr@777:   _process_completed_threshold(0), _process_completed(false),
ysr@777:   _buf_free_list(NULL), _buf_free_list_sz(0)
iveresov@1051: {
iveresov@1051:   _fl_owner = this;
iveresov@1051: }
ysr@777: 
ysr@777: void** PtrQueueSet::allocate_buffer() {
ysr@777:   assert(_sz > 0, "Didn't set a buffer size.");
iveresov@1051:   MutexLockerEx x(_fl_owner->_fl_lock, Mutex::_no_safepoint_check_flag);
iveresov@1051:   if (_fl_owner->_buf_free_list != NULL) {
iveresov@1051:     void** res = _fl_owner->_buf_free_list;
iveresov@1051:     _fl_owner->_buf_free_list = (void**)_fl_owner->_buf_free_list[0];
iveresov@1051:     _fl_owner->_buf_free_list_sz--;
ysr@777:     // Just override the next pointer with NULL, just in case we scan this part
ysr@777:     // of the buffer.
ysr@777:     res[0] = NULL;
ysr@777:     return res;
ysr@777:   } else {
ysr@777:     return NEW_C_HEAP_ARRAY(void*, _sz);
ysr@777:   }
ysr@777: }
ysr@777: 
ysr@777: void PtrQueueSet::deallocate_buffer(void** buf) {
ysr@777:   assert(_sz > 0, "Didn't set a buffer size.");
iveresov@1051:   MutexLockerEx x(_fl_owner->_fl_lock, Mutex::_no_safepoint_check_flag);
iveresov@1051:   buf[0] = (void*)_fl_owner->_buf_free_list;
iveresov@1051:   _fl_owner->_buf_free_list = buf;
iveresov@1051:   _fl_owner->_buf_free_list_sz++;
ysr@777: }
ysr@777: 
ysr@777: void PtrQueueSet::reduce_free_list() {
ysr@777:   // For now we'll adopt the strategy of deleting half.
ysr@777:   MutexLockerEx x(_fl_lock, Mutex::_no_safepoint_check_flag);
ysr@777:   size_t n = _buf_free_list_sz / 2;
ysr@777:   while (n > 0) {
ysr@777:     assert(_buf_free_list != NULL, "_buf_free_list_sz must be wrong.");
ysr@777:     void** head = _buf_free_list;
ysr@777:     _buf_free_list = (void**)_buf_free_list[0];
ysr@777:     FREE_C_HEAP_ARRAY(void*,head);
ysr@777:     n--;
ysr@777:   }
ysr@777: }
ysr@777: 
ysr@777: void PtrQueueSet::enqueue_complete_buffer(void** buf, size_t index, bool ignore_max_completed) {
ysr@777:   // I use explicit locking here because there's a bailout in the middle.
ysr@777:   _cbl_mon->lock_without_safepoint_check();
ysr@777: 
ysr@777:   Thread* thread = Thread::current();
ysr@777:   assert( ignore_max_completed ||
ysr@777:           thread->is_Java_thread() ||
ysr@777:           SafepointSynchronize::is_at_safepoint(),
ysr@777:           "invariant" );
ysr@777:   ignore_max_completed = ignore_max_completed || !thread->is_Java_thread();
ysr@777: 
ysr@777:   if (!ignore_max_completed && _max_completed_queue > 0 &&
ysr@777:       _n_completed_buffers >= (size_t) _max_completed_queue) {
ysr@777:     _cbl_mon->unlock();
ysr@777:     bool b = mut_process_buffer(buf);
ysr@777:     if (b) {
ysr@777:       deallocate_buffer(buf);
ysr@777:       return;
ysr@777:     }
ysr@777: 
ysr@777:     // Otherwise, go ahead and enqueue the buffer.  Must reaquire the lock.
ysr@777:     _cbl_mon->lock_without_safepoint_check();
ysr@777:   }
ysr@777: 
ysr@777:   // Here we still hold the _cbl_mon.
ysr@777:   CompletedBufferNode* cbn = new CompletedBufferNode;
ysr@777:   cbn->buf = buf;
ysr@777:   cbn->next = NULL;
ysr@777:   cbn->index = index;
ysr@777:   if (_completed_buffers_tail == NULL) {
ysr@777:     assert(_completed_buffers_head == NULL, "Well-formedness");
ysr@777:     _completed_buffers_head = cbn;
ysr@777:     _completed_buffers_tail = cbn;
ysr@777:   } else {
ysr@777:     _completed_buffers_tail->next = cbn;
ysr@777:     _completed_buffers_tail = cbn;
ysr@777:   }
ysr@777:   _n_completed_buffers++;
ysr@777: 
ysr@777:   if (!_process_completed &&
iveresov@1229:       _n_completed_buffers >= _process_completed_threshold) {
ysr@777:     _process_completed = true;
ysr@777:     if (_notify_when_complete)
ysr@777:       _cbl_mon->notify_all();
ysr@777:   }
ysr@777:   debug_only(assert_completed_buffer_list_len_correct_locked());
ysr@777:   _cbl_mon->unlock();
ysr@777: }
ysr@777: 
ysr@777: int PtrQueueSet::completed_buffers_list_length() {
ysr@777:   int n = 0;
ysr@777:   CompletedBufferNode* cbn = _completed_buffers_head;
ysr@777:   while (cbn != NULL) {
ysr@777:     n++;
ysr@777:     cbn = cbn->next;
ysr@777:   }
ysr@777:   return n;
ysr@777: }
ysr@777: 
ysr@777: void PtrQueueSet::assert_completed_buffer_list_len_correct() {
ysr@777:   MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
ysr@777:   assert_completed_buffer_list_len_correct_locked();
ysr@777: }
ysr@777: 
ysr@777: void PtrQueueSet::assert_completed_buffer_list_len_correct_locked() {
ysr@777:   guarantee((size_t)completed_buffers_list_length() ==  _n_completed_buffers,
ysr@777:             "Completed buffer length is wrong.");
ysr@777: }
ysr@777: 
ysr@777: void PtrQueueSet::set_buffer_size(size_t sz) {
ysr@777:   assert(_sz == 0 && sz > 0, "Should be called only once.");
ysr@777:   _sz = sz * oopSize;
ysr@777: }
ysr@777: 
ysr@777: void PtrQueueSet::set_process_completed_threshold(size_t sz) {
ysr@777:   _process_completed_threshold = sz;
ysr@777: }
iveresov@1051: 
iveresov@1051: // Merge lists of buffers. Notify waiting threads if the length of the list
iveresov@1051: // exceeds threshold. The source queue is emptied as a result. The queues
iveresov@1051: // must share the monitor.
iveresov@1051: void PtrQueueSet::merge_bufferlists(PtrQueueSet *src) {
iveresov@1051:   assert(_cbl_mon == src->_cbl_mon, "Should share the same lock");
iveresov@1051:   MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
iveresov@1051:   if (_completed_buffers_tail == NULL) {
iveresov@1051:     assert(_completed_buffers_head == NULL, "Well-formedness");
iveresov@1051:     _completed_buffers_head = src->_completed_buffers_head;
iveresov@1051:     _completed_buffers_tail = src->_completed_buffers_tail;
iveresov@1051:   } else {
iveresov@1051:     assert(_completed_buffers_head != NULL, "Well formedness");
iveresov@1051:     if (src->_completed_buffers_head != NULL) {
iveresov@1051:       _completed_buffers_tail->next = src->_completed_buffers_head;
iveresov@1051:       _completed_buffers_tail = src->_completed_buffers_tail;
iveresov@1051:     }
iveresov@1051:   }
iveresov@1051:   _n_completed_buffers += src->_n_completed_buffers;
iveresov@1051: 
iveresov@1051:   src->_n_completed_buffers = 0;
iveresov@1051:   src->_completed_buffers_head = NULL;
iveresov@1051:   src->_completed_buffers_tail = NULL;
iveresov@1051: 
iveresov@1051:   assert(_completed_buffers_head == NULL && _completed_buffers_tail == NULL ||
iveresov@1051:          _completed_buffers_head != NULL && _completed_buffers_tail != NULL,
iveresov@1051:          "Sanity");
iveresov@1051: 
iveresov@1051:   if (!_process_completed &&
iveresov@1051:       _n_completed_buffers >= _process_completed_threshold) {
iveresov@1051:     _process_completed = true;
iveresov@1051:     if (_notify_when_complete)
iveresov@1051:       _cbl_mon->notify_all();
iveresov@1051:   }
iveresov@1051: }
iveresov@1051: 
iveresov@1051: // Merge free lists of the two queues. The free list of the source
iveresov@1051: // queue is emptied as a result. The queues must share the same
iveresov@1051: // mutex that guards free lists.
iveresov@1051: void PtrQueueSet::merge_freelists(PtrQueueSet* src) {
iveresov@1051:   assert(_fl_lock == src->_fl_lock, "Should share the same lock");
iveresov@1051:   MutexLockerEx x(_fl_lock, Mutex::_no_safepoint_check_flag);
iveresov@1051:   if (_buf_free_list != NULL) {
iveresov@1051:     void **p = _buf_free_list;
iveresov@1051:     while (*p != NULL) {
iveresov@1051:       p = (void**)*p;
iveresov@1051:     }
iveresov@1051:     *p = src->_buf_free_list;
iveresov@1051:   } else {
iveresov@1051:     _buf_free_list = src->_buf_free_list;
iveresov@1051:   }
iveresov@1051:   _buf_free_list_sz += src->_buf_free_list_sz;
iveresov@1051:   src->_buf_free_list = NULL;
iveresov@1051:   src->_buf_free_list_sz = 0;
iveresov@1051: }