1/*
2 * Copyright (C) 2012-2018 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#include "config.h"
27#include "IncrementalSweeper.h"
28
29#include "Heap.h"
30#include "JSObject.h"
31#include "JSString.h"
32#include "MarkedBlock.h"
33#include "JSCInlines.h"
34
35namespace JSC {
36
37static const Seconds sweepTimeSlice = 10_ms;
38static const double sweepTimeTotal = .10;
39static const double sweepTimeMultiplier = 1.0 / sweepTimeTotal;
40
41void IncrementalSweeper::scheduleTimer()
42{
43 setTimeUntilFire(sweepTimeSlice * sweepTimeMultiplier);
44}
45
46IncrementalSweeper::IncrementalSweeper(Heap* heap)
47 : Base(heap->vm())
48 , m_currentDirectory(nullptr)
49{
50}
51
52void IncrementalSweeper::doWork(VM& vm)
53{
54 doSweep(vm, MonotonicTime::now());
55}
56
57void IncrementalSweeper::doSweep(VM& vm, MonotonicTime sweepBeginTime)
58{
59 while (sweepNextBlock(vm)) {
60 Seconds elapsedTime = MonotonicTime::now() - sweepBeginTime;
61 if (elapsedTime < sweepTimeSlice)
62 continue;
63
64 scheduleTimer();
65 return;
66 }
67
68 if (m_shouldFreeFastMallocMemoryAfterSweeping) {
69 WTF::releaseFastMallocFreeMemory();
70 m_shouldFreeFastMallocMemoryAfterSweeping = false;
71 }
72 cancelTimer();
73}
74
75bool IncrementalSweeper::sweepNextBlock(VM& vm)
76{
77 vm.heap.stopIfNecessary();
78
79 MarkedBlock::Handle* block = nullptr;
80
81 for (; m_currentDirectory; m_currentDirectory = m_currentDirectory->nextDirectory()) {
82 block = m_currentDirectory->findBlockToSweep();
83 if (block)
84 break;
85 }
86
87 if (block) {
88 DeferGCForAWhile deferGC(vm.heap);
89 block->sweep(nullptr);
90 vm.heap.objectSpace().freeOrShrinkBlock(block);
91 return true;
92 }
93
94 return vm.heap.sweepNextLogicallyEmptyWeakBlock();
95}
96
97void IncrementalSweeper::startSweeping(Heap& heap)
98{
99 scheduleTimer();
100 m_currentDirectory = heap.objectSpace().firstDirectory();
101}
102
103void IncrementalSweeper::stopSweeping()
104{
105 m_currentDirectory = nullptr;
106 cancelTimer();
107}
108
109} // namespace JSC
110