1/*
2 * Copyright (C) 2017 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#include "MutatorScheduler.h"
29
30namespace JSC {
31
32// The JSC concurrent GC relies on stopping the world to stay ahead of the retreating wavefront.
33// It so happens that the same API can be reused to implement a non-concurrent GC mode, which we
34// use on platforms that don't support the GC's atomicity protocols. That means anything other
35// than X86-64 and ARM64. This scheduler is a drop-in replacement for the concurrent GC's
36// SpaceTimeMutatorScheduler. It tells the GC to never resume the world once the GC cycle begins.
37
38class SynchronousStopTheWorldMutatorScheduler : public MutatorScheduler {
39public:
40 SynchronousStopTheWorldMutatorScheduler();
41 ~SynchronousStopTheWorldMutatorScheduler();
42
43 State state() const override;
44
45 void beginCollection() override;
46
47 MonotonicTime timeToStop() override;
48 MonotonicTime timeToResume() override;
49
50 void endCollection() override;
51
52private:
53 State m_state { Normal };
54};
55
56} // namespace JSC
57
58