1 /*
2 * Copyright (c) 1998, 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 *
1656
1657 if (policy == 0) { // prepend to EntryList
1658 if (list == NULL) {
1659 iterator->_next = iterator->_prev = NULL;
1660 _EntryList = iterator;
1661 } else {
1662 list->_prev = iterator;
1663 iterator->_next = list;
1664 iterator->_prev = NULL;
1665 _EntryList = iterator;
1666 }
1667 } else if (policy == 1) { // append to EntryList
1668 if (list == NULL) {
1669 iterator->_next = iterator->_prev = NULL;
1670 _EntryList = iterator;
1671 } else {
1672 // CONSIDER: finding the tail currently requires a linear-time walk of
1673 // the EntryList. We can make tail access constant-time by converting to
1674 // a CDLL instead of using our current DLL.
1675 ObjectWaiter * tail;
1676 for (tail = list; tail->_next != NULL; tail = tail->_next) /* empty */;
1677 assert(tail != NULL && tail->_next == NULL, "invariant");
1678 tail->_next = iterator;
1679 iterator->_prev = tail;
1680 iterator->_next = NULL;
1681 }
1682 } else if (policy == 2) { // prepend to cxq
1683 if (list == NULL) {
1684 iterator->_next = iterator->_prev = NULL;
1685 _EntryList = iterator;
1686 } else {
1687 iterator->TState = ObjectWaiter::TS_CXQ;
1688 for (;;) {
1689 ObjectWaiter * front = _cxq;
1690 iterator->_next = front;
1691 if (Atomic::cmpxchg_ptr(iterator, &_cxq, front) == front) {
1692 break;
1693 }
1694 }
1695 }
1696 } else if (policy == 3) { // append to cxq
|
1 /*
2 * Copyright (c) 1998, 2017, 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 *
1656
1657 if (policy == 0) { // prepend to EntryList
1658 if (list == NULL) {
1659 iterator->_next = iterator->_prev = NULL;
1660 _EntryList = iterator;
1661 } else {
1662 list->_prev = iterator;
1663 iterator->_next = list;
1664 iterator->_prev = NULL;
1665 _EntryList = iterator;
1666 }
1667 } else if (policy == 1) { // append to EntryList
1668 if (list == NULL) {
1669 iterator->_next = iterator->_prev = NULL;
1670 _EntryList = iterator;
1671 } else {
1672 // CONSIDER: finding the tail currently requires a linear-time walk of
1673 // the EntryList. We can make tail access constant-time by converting to
1674 // a CDLL instead of using our current DLL.
1675 ObjectWaiter * tail;
1676 for (tail = list; tail->_next != NULL; tail = tail->_next) {}
1677 assert(tail != NULL && tail->_next == NULL, "invariant");
1678 tail->_next = iterator;
1679 iterator->_prev = tail;
1680 iterator->_next = NULL;
1681 }
1682 } else if (policy == 2) { // prepend to cxq
1683 if (list == NULL) {
1684 iterator->_next = iterator->_prev = NULL;
1685 _EntryList = iterator;
1686 } else {
1687 iterator->TState = ObjectWaiter::TS_CXQ;
1688 for (;;) {
1689 ObjectWaiter * front = _cxq;
1690 iterator->_next = front;
1691 if (Atomic::cmpxchg_ptr(iterator, &_cxq, front) == front) {
1692 break;
1693 }
1694 }
1695 }
1696 } else if (policy == 3) { // append to cxq
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