1/*
2 * Copyright (c) 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 */
23
24#ifndef SHARE_GC_Z_ZMARKTERMINATE_INLINE_HPP
25#define SHARE_GC_Z_ZMARKTERMINATE_INLINE_HPP
26
27#include "runtime/atomic.hpp"
28#include "runtime/orderAccess.hpp"
29
30inline ZMarkTerminate::ZMarkTerminate() :
31 _nworkers(0),
32 _nworking_stage0(0),
33 _nworking_stage1(0) {}
34
35inline bool ZMarkTerminate::enter_stage(volatile uint* nworking_stage) {
36 return Atomic::sub(1u, nworking_stage) == 0;
37}
38
39inline void ZMarkTerminate::exit_stage(volatile uint* nworking_stage) {
40 Atomic::add(1u, nworking_stage);
41}
42
43inline bool ZMarkTerminate::try_exit_stage(volatile uint* nworking_stage) {
44 uint nworking = Atomic::load(nworking_stage);
45
46 for (;;) {
47 if (nworking == 0) {
48 return false;
49 }
50
51 const uint new_nworking = nworking + 1;
52 const uint prev_nworking = Atomic::cmpxchg(new_nworking, nworking_stage, nworking);
53 if (prev_nworking == nworking) {
54 // Success
55 return true;
56 }
57
58 // Retry
59 nworking = prev_nworking;
60 }
61}
62
63inline void ZMarkTerminate::reset(uint nworkers) {
64 _nworkers = _nworking_stage0 = _nworking_stage1 = nworkers;
65}
66
67inline bool ZMarkTerminate::enter_stage0() {
68 return enter_stage(&_nworking_stage0);
69}
70
71inline void ZMarkTerminate::exit_stage0() {
72 exit_stage(&_nworking_stage0);
73}
74
75inline bool ZMarkTerminate::try_exit_stage0() {
76 return try_exit_stage(&_nworking_stage0);
77}
78
79inline bool ZMarkTerminate::enter_stage1() {
80 return enter_stage(&_nworking_stage1);
81}
82
83inline bool ZMarkTerminate::try_exit_stage1() {
84 return try_exit_stage(&_nworking_stage1);
85}
86
87#endif // SHARE_GC_Z_ZMARKTERMINATE_INLINE_HPP
88