| /* |
| * 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; |
| } |