1/*
2 * Copyright (C) 2010-2018 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 *
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of Apple Inc. ("Apple") nor the names of
14 * its contributors may be used to endorse or promote products derived
15 * from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#include "config.h"
30#include "GCActivityCallback.h"
31
32#include "HeapInlines.h"
33#include "JSLock.h"
34#include "JSObject.h"
35#include "VM.h"
36
37namespace JSC {
38
39bool GCActivityCallback::s_shouldCreateGCTimer = true;
40
41const double timerSlop = 2.0; // Fudge factor to avoid performance cost of resetting timer.
42
43GCActivityCallback::GCActivityCallback(Heap* heap)
44 : GCActivityCallback(heap->vm())
45{
46}
47
48void GCActivityCallback::doWork(VM& vm)
49{
50 if (!isEnabled())
51 return;
52
53 ASSERT(vm.currentThreadIsHoldingAPILock());
54 Heap& heap = vm.heap;
55 if (heap.isDeferred()) {
56 scheduleTimer(0_s);
57 return;
58 }
59
60 doCollection(vm);
61}
62
63void GCActivityCallback::scheduleTimer(Seconds newDelay)
64{
65 if (newDelay * timerSlop > m_delay)
66 return;
67 Seconds delta = m_delay - newDelay;
68 m_delay = newDelay;
69 if (auto timeUntilFire = this->timeUntilFire())
70 setTimeUntilFire(*timeUntilFire - delta);
71 else
72 setTimeUntilFire(newDelay);
73}
74
75void GCActivityCallback::didAllocate(Heap& heap, size_t bytes)
76{
77 // The first byte allocated in an allocation cycle will report 0 bytes to didAllocate.
78 // We pretend it's one byte so that we don't ignore this allocation entirely.
79 if (!bytes)
80 bytes = 1;
81 double bytesExpectedToReclaim = static_cast<double>(bytes) * deathRate(heap);
82 Seconds newDelay = lastGCLength(heap) / gcTimeSlice(bytesExpectedToReclaim);
83 scheduleTimer(newDelay);
84}
85
86void GCActivityCallback::willCollect()
87{
88 cancel();
89}
90
91void GCActivityCallback::cancel()
92{
93 m_delay = s_decade;
94 cancelTimer();
95}
96
97}
98
99