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. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23 * THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28namespace JSC {
29
30// We track collector phase in order to allow either the collector thread or the mutator thread to
31// jump in and do work. The collector and mutator trade the conn
32// (https://en.wikipedia.org/wiki/Conn_(nautical)) with each other based on who is available to do work,
33// and they use the phase to help each other know what to do once they take the conn.
34//
35// The collector relinquishes the conn whenever it stopTheMutator's and the mutator is running. Then the
36// collector thread goes to sleep.
37//
38// The mutator relinquishes the conn whenever it releaseAccess's. That wakes up the collector thread.
39enum class CollectorPhase : uint8_t {
40 // We use this phase when the collector is not running at all. After this state is Begin.
41 NotRunning,
42
43 // This is everything from when the collector begins to when it first yields to the mutator for
44 // marking. After this is Fixpoint.
45 Begin,
46
47 // This means that we should try to do some progress with the world stopped. This usually means
48 // doing an iteration of MarkingConstraintSet::executeConvergence, but it could also mean marking
49 // with the world stopped. After this is either Concurrent or End.
50 Fixpoint,
51
52 // In this state the collector is relying on the parallel helpers and incremental mutator work to
53 // make progress. After this is Reloop, once marking stalls.
54 Concurrent,
55
56 // We did some concurrent marking and now we ran out of work. This phase prepares the GC for another
57 // Fixpoint. After this is Fixpoint.
58 Reloop,
59
60 // The collector is trying to finish up. After this state is NotRunning.
61 End
62};
63
64bool worldShouldBeSuspended(CollectorPhase phase);
65
66} // namespace JSC
67
68namespace WTF {
69
70class PrintStream;
71
72void printInternal(PrintStream&, JSC::CollectorPhase);
73
74} // namespace WTF
75
76